The vibration of pumping units is mainly low- and medium-frequency of hydroaerodynamic origin. The vibration level, according to the survey data of some PSs, exceeds the sanitary standards by 1-5.9 times (Table 29).
When vibration propagates through the structural elements of the units, when the natural vibration frequencies of individual parts turn out to be close and equal to the frequencies of the main current or its harmonics, resonant oscillations occur r threatening the integrity of some components and parts, in particular, the angular contact rolling bearing and oil pipelines of thrust bearings. One of the means of reducing vibration is to increase the losses due to inelastic resistance, i.e., applying to the pump and motor casing
Unit brand
24ND-14X1 NM7000-210
| 1,9-3,1 1,8-5,9 1,6-2,7 |
ATD-2500/AZP-2000
AZP-2500/6000
Note. Rotation speed 3000 rpm.
Anti-vibration coating, for example ShVIM-18 mastic. The source of low-frequency mechanical vibration of units on the foundation is the unbalance force and the misalignment of the pump and motor shafts, the frequency of which is a multiple of the shaft rotational speed divided by 60. Vibration caused by misalignment of the shafts leads to increased loads on the shafts and plain bearings, their heating and destruction, loosening of machines on the foundation, cutting off anchor bolts, and in some cases, to a violation of the explosion resistance of the electric motor. To reduce the vibration amplitudes of the shafts and increase the standard overhaul period of babbitt plain bearings up to 7000 motor-hours, the PS uses calibrated steel gasket sheets installed in the bearing cap slots to select the wear gap.
The reduction of mechanical vibration is achieved by careful balancing and alignment of the shafts, timely replacement of worn parts and elimination of limiting clearances in bearings.
The cooling system must ensure that the temperature of the bearings does not exceed 60 °C. If the stuffing box becomes too hot, the pump should be stopped several times and immediately started to allow oil to seep through the packing. The absence of oil indicates that the stuffing box is packed too tightly and should be loosened. When a knock occurs, the pump is stopped to find out the cause of this phenomenon: they check the lubrication, oil filters. If the pressure loss in the system exceeds 0.1 MPa, the filter is cleaned.
Heating of the bearings, loss of lubrication, excessive vibration or abnormal noise indicate a problem with the pump unit. It must be stopped immediately to correct the detected problems. To stop one of the pumping units, close the valve on the discharge line and the valve on the hydraulic discharge line, then turn on the engine. After the pump has cooled, close all the valves of the pipelines supplying oil and water, and the valves at the pressure gauges. When the pump is stopped for a long time, to prevent corrosion, the impeller, sealing rings, shaft protection sleeves, bushings and all parts that come into contact with the pumped liquid should be lubricated, and the gland packing should be removed.
During the operation of pumping units, various malfunctions are possible, which can be caused by various reasons. Let's consider malfunctions of pumps and ways to eliminate them.
1. The pump cannot be started:
the pump shaft, connected by a gear coupling to the motor shaft, does not rotate - manually check the rotation! of the pump hall and the motor separately, the correct assembly of the gear coupling; if the shafts rotate separately, ta.216
check the centering of the unit; check the operation of the pump and wires when they are connected through a turbo transmission or gearbox;
the pump shaft, disconnected from the motor shaft, does not turn or rotates tightly due to the ingress of foreign objects into the pump, breakage of its moving parts and seals, jamming in the sealing rings - inspect, sequentially eliminating the detected mechanical damage.
2. The pump is started, but does not deliver liquid or after starting
submission is terminated:
the suction capacity of the pump is insufficient, since there is air in the intake pipeline due to incomplete filling of the pump with liquid or due to leaks in the suction pipeline, stuffing boxes - repeat filling, eliminate leaks;
incorrect rotation of the pump shaft - ensure the correct rotation of the rotor;
the actual suction height is greater than the permissible one, due to the mismatch of the viscosity, temperature or partial vapor pressure of the pumped liquid with the design parameters of the installation - provide the necessary backwater.
3. The pump consumes more power during start-up: ■
the valve on the discharge pipeline is open - close
gate valve during start-up;
impellers installed incorrectly - eliminate incorrect assembly;
seizing occurs in the sealing rings due to large clearances in the bearings or as a result of the displacement of the rotor - check the rotation of the rotor by hand; if the rotor turns hard, remove the jam;
the tube of the loading device is clogged - inspect and: clean the pipeline of the unloading device;
A fuse blows in one of the phases of the electric motor - replace the fuse.
4. The pump does not generate the calculated head:
reduced pump shaft speed - change the speed, check the engine and troubleshoot;
damaged or worn sealing rings of the impeller, leading edges of the impeller blades - replace the impeller and damaged parts;
the hydraulic resistance of the discharge pipeline is less than the calculated one due to a rupture of the pipeline, excessive opening of the valve on the discharge or bypass line - check the supply; if it has increased, then close the valve on the bypass line or cover it on the discharge line; eliminate various leaks in the discharge pipeline;
The density of the pumped liquid is less than the calculated one, the content of air or gases in the liquid is increased - check the density of the liquid and the tightness of the suction pipeline, stuffing boxes;
cavitation is observed in the suction pipeline or pump working elements - check the actual cavitation reserve of specific energy; at an underestimated value, eliminate the possibility of the appearance of a cavitation regime.
5. Pump flow less than calculated:
rotation speed is less than nominal - change the rotation speed, check the engine and eliminate faults;
the suction lift is greater than the permissible one, as a result of which the pump operates in cavitation mode - perform the work specified in paragraph 2;
the formation of funnels on the suction pipeline, which is not deep enough immersed in the liquid, as a result of which air enters with the liquid - install a cut-off valve to eliminate the funnel, increase the liquid level above the inlet of the suction pipeline;
increase in resistance in the pressure pipeline, as a result of which the pump discharge pressure exceeds the calculated one - fully open the valve on the discharge line, check all the valves of the manifold system, linear valves, clean the clogs;
damaged or clogged impeller; increased gaps in the sealing rings of the labyrinth seal due to their wear - clean the impeller, replace worn and damaged parts;
Air enters through leaks in the suction pipeline or stuffing box - check the tightness of the pipeline, stretch or change the packing of the stuffing box.
6. Increased power consumption:
the pump flow is higher than the calculated one, the pressure is less due to the opening of the valve on the bypass line, the rupture of the pipeline or the excessive opening of the valve on the discharge pipeline - close the valve on the bypass line, check the tightness of the pipeline system or close the valve on the pressure pipeline;
damaged pump (worn impellers, O-rings, labyrinth seals) or motor - check pump and motor, repair damage.
7. Increased vibration and pump noise:
bearings are displaced due to the weakening of their fastening; worn bearings - check the shaft laying and the clearances in the bearings; in case of deviation, bring the size of the gaps to the permissible value;
the fastenings of the suction and discharge pipelines, foundation bolts and valves are loosened - check the fastening of the nodes and eliminate the shortcomings; 218
ingress of foreign objects into the flow part - clean the flow part;
the balance of the pump or the motor is disturbed due to the curvature of the shafts, their incorrect alignment or the eccentric installation of the coupling - check the alignment of the shafts and the coupling, eliminate damage;
increased wear and play in check valves and gate valves on the discharge pipeline - eliminate play;
the rotor balance is broken as a result of impeller clogging - clean the impeller and balance the rotor;
the pump operates in cavitation mode - reduce the flow by closing the valve on the discharge line, seal the connections in the suction pipeline, increase the back pressure, reduce the resistance in the suction pipeline.
8. Increased temperature of oil seals and bearings:
heating of the glands due to excessive and uneven tightening, small radial clearance between the pressure sleeve and the shaft, installation of the sleeve with a warp, jamming or distortion of the gland lantern, insufficient supply of sealing fluid - loosen the glands; if this does not give an effect, then disassemble and eliminate installation defects, replace the packing; increase the supply of sealing fluid;
heating of bearings due to poor oil circulation in the forced lubrication system of bearings, lack of rotation of the rings in bearings with ring lubrication, oil leakage and contamination - check the pressure in the lubrication system, the operation of the oil pump and eliminate the defect; ensure the tightness of the oil bath and pipeline, change the oil;
heating of the bearings due to improper installation (small clearances between the bushing and the shaft), wear of the bearings, increased tightening of the support rings, small gaps between the washer and the rings in the thrust bearings, scuffing of the thrust or thrust bearing or melting of the babbit - check and eliminate defects; clean the burrs or replace the bearing.
Piston compressors. Parts where the most dangerous defects are possible include shafts, connecting rods, crossheads, rods, cylinder heads, crank pins, bolts and studs. The zones in which the maximum concentration of stresses is observed are threads, fillets, mating surfaces, pressings, necks and cheeks of columnar shafts, keyways.
During operation of the frame (bed) and guides, the deformation of their elements is checked. Vertical movements greater than 0.2 mm are a sign that the compressor is not working. Cracks are detected on the surface of the frame and their development is controlled.
The fit to the foundation of the frame, as well as any of the guides fixed on the foundation, must be at least G) 0% of the perimeter of their common joint. At least once a year, the horizontal position of the frame is checked (the deviation of the frame plane in any direction over a length of 1 m should not exceed 2 mm). On the sliding surfaces of the guides there should be no scratches, dents, nicks with a depth of more than 0.3 mm. For the crankshaft during operation, the temperature of its sections operating in the friction mode is controlled. It must not exceed the values specified in the operating instructions.
For connecting rod bolts, their tightening, the state of the locking device and the surface of the bolt are controlled. The signs of bolt inoperability are as follows: the presence of cracks on the surface, in the body or thread of the bolt, corrosion in the fitting part of the bolt, stripping or crushing of the threads. The total contact area should be at least 50 ° / about the area of the support belt. have breaks exceeding 25% of the circumference If the residual elongation of the bolt exceeds 0.2% of its original length, the bolt is rejected.
For the crosshead, the condition of the elements of its connection with the rod, as well as the pin, is checked, the gaps between the upper guide and the crosshead shoe are checked. During operation, pay attention to the condition of the outer surface of the cylinder, the sealing of the oil lines of the indicator plugs, and the flange connections of the water cooling system. Fistulas and omissions of gas, water, oil in the body or flange connections are unacceptable. The water temperature at the outlet of the water jackets and cylinder heads must not exceed the values given in the operating instructions.
For pistons, the condition of the surface is subject to control (including the condition and thickness of the bearing surface of the sliding type piston), as well as the fixation of the piston on the rod and plugs (for cast pistons) of the pressure stage. Signs of piston rejection are as follows: scoring in the form of grooves on an area constituting more than 10% of the casting surface, the presence of areas with lagged, melted or crumbled babbit, as well as cracks with a closed contour. The radial crack in the pour layer should not decrease to 60% of the original. Violations of the fixation of the piston nut for the plugs of cast pistons, piston play on the rod, leakage of the surface of the welds, separation of the piston bottom from the stiffeners are not allowed.
For rods, before taking the compressor out for repair, they control the beating of the rod within the stage piston, the state of the rod surface; scoring or traces of enveloping of the metal of the sealing elements on the surface of the rod are detected. No cracks on surface, threads or 220
stem fillets, deformation, thread breakage or collapse. During operation, the tightness of the stem seal, which is not equipped and equipped with a leak removal system, is checked. The indicator of tightness of the seals of the rods is the gas content in the controlled places of the compressor and the room, which should not exceed the values allowed by the current standards.
Check the condition of the stem seal annually during repairs. Cracks on the element or its breakage are unacceptable. The wear of the sealing element should be no more than 30% of its nominal radial thickness, and the gap between the stem and the protective ring of the stem seal with non-metallic sealing elements should not exceed 0.1 mm.
During operation, performance monitoring piston rings carried out according to the regulated pressure and temperature of the compressible medium. There should be no increase in noise or knocking in the cylinders in the cylinders. Seizure of the sliding surface of the rings must be less than 10% of the circumference. If the radial wear of the ring in any of its sections exceeds 30% of the original thickness, the ring is discarded.
The signs of valve inoperability are as follows: abnormal knocking in the valve cavities, deviations in pressure and temperature of the compressible medium from the regulated ones. When monitoring the condition of the valves, the integrity of the plates, springs and the presence of cracks in the valve elements are checked. The area of the valve flow section as a result of contamination should not decrease by more than 30% of the original, and the density should not be below the established norms.
Piston pumps. Cylinders and their liners may have the following defects: wear of the working surface as a result of friction, corrosion and erosion wear, cracks, scoring. The amount of cylinder wear is determined after the piston (plunger) is removed by measuring the diameter of the bore in the vertical and horizontal planes in three sections (middle and two extreme) using a micrometric pin.
On the working surface of the piston, scuffing, nicks, burrs and torn edges are unacceptable. The maximum allowable wear of the piston is (0.008-0.011) G> n, where About l- minimum piston diameter. If cracks are found on the surface of the piston rings, significant and uneven wear, ellipse, loss of elasticity of the rings, they must be replaced with new ones.
The rejection gaps of the piston rings of the pump are determined as follows: the smallest gap in the ring lock in the free state D "(0.06 ^ -0.08) B; the largest gap in the lock of the ring in working condition L \u003d k (0.015-^0.03) D where ABOUT is the minimum diameter of the cylinder.
Permissible radial warping for rings with a diameter of up to 150, 150-400, over 400 mm is, respectively, no more than 0.06-0.07; 0.08-0.09; 0.1-0.11 mm.
The rejection gap between the rings and the walls of the piston grooves is calculated according to the following ratios: L t y = = 0.003 /g; A t ah \u003d (0.008-4-9.01) To, Where To- nominal height of the rings.
Upon detection of scratches with a depth of 0.5 mm, ellipsoidality of 0.15-0.2 mm, the rods and plungers are machined. The stem can be machined to a depth of no more than 2 mm.
The misalignment of the cylinder and the rod guide is allowed within 0.01 mm. If the runout of the rod exceeds 0.1 mm, then the rod is machined for 7 g of the runout value or corrected.
The diploma project contains 109 pages, 24 figures, 16 tables, 9 references, 6 applications.
AUTOMATION OF THE MAIN PUMPING UNIT HM1250-260, SENSOR, SIGNAL, ACS OF THE SERIES "MODICON TSX QUANTUM", VIBRATION CONTROL, VIBRATION CONTROL SYSTEMS
The object of the study is the main pumping unit NM 1250-260, which is used in the Cherkasy LPDS.
In the course of the study, an analysis was made of the existing level of automation of the unit, the need to modernize its control system was substantiated.
The purpose of the work is to develop a control program for the Modicon TSX Quantum PLC by Schneider Electric.
As a result of the study, an automation system for the main pumping unit was developed based on modern software and hardware. The ST language of the ISaGRAF program was used as the project software.
Experimental design and technical and economic indicators indicate an increase in the efficiency of the modernized control system of the main pumping unit.
The degree of implementation the results obtained applied in the vibration control system "Cascade".
The effectiveness of the implementation is based on increasing the reliability of the automation system of the MND, which is confirmed by the calculation of the economic effect for the billing period.
Definitions, symbols and abbreviations………………………………………… 6
Introduction…………………………………………………………………………….. 7
1 Linear production dispatching station "Cherkasy"…. 9 1.1 a brief description of linear production dispatching station "Cherkasy"……………………………………………………………….. 9
1.2 Characteristics of technological equipment…………………………. 9
1.3 Characteristics of technological premises……………………………… 12 1.4 Operating modes of LPDS “Cherkassy”……………………………………. 13 1.5 Main pump unit…………………………………………. 16 1.6 Piping of pumps LPDS Cherkasy………………………………………. 18
1.7 Analysis of the existing automation scheme for LPDS "Cherkasy"……... 19
2 Patent elaboration…………………………………………………………... 22
3.1 Automation of the main pump unit…………………….. 27
3.2 Emergency protection system……………………………………… 33
3.3 APCS based on Modicon TSX Quantum controllers………………….. 35
3.4 Structural diagram of APCS based on the Quantum system………………… 39
3.5 Devices included in the system………………………………….. 42
3.6 Sensors and technical means automation…………………………. 48
4 Selection of MHA vibration control system…………………………………………... 54 4.1 Vibromonitoring control equipment (AKV)……………………………. 54
4.2 Vibration control equipment "Cascade"….…………………………….. 56
4.3 Development of a pump unit control program………….…….. 64
4.4 Tool system for programming industrial controllers………………………………………………………………………. 65
4.5 ST language description…………………………………………………………. 67
4.6 Creating a project and programs in the ISaGRAF system………………………. 71
4.7 Controller programming……………………………………………... 73
4.8 Algorithm for signaling and controlling the pumping unit…………....... 74
4.9 Results of the program…….…………………..…………………... 77
5 Occupational health and safety of the main pumping station “Ufa-Zapadnoye Direction”…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….
5.1 Analysis of potential hazards and occupational hazards… 80
5.2 Safety measures during the operation of the objects of the Cherkasy LPDS ..........................................................................................................................
5.3 Measures for industrial sanitation……………………………… 86
5.4 Fire safety measures………………………………… 89
5.5 Calculation of the installation of foam extinguishing and fire water supply……… 91
6 Evaluation of the economic efficiency of automation of the linear production dispatching station "Cherkassy"……………………. 96
6.1 Main sources of efficiency improvement………………… 97 6.2 Methodology for calculating economic efficiency……………………… 97
6.3 Calculation of economic effect…………………………………………. 99
Conclusion…………………………………………………………………… 107
List of used sources………………………………………... 109
Appendix A. List of demonstration sheets ……………………… 110
Appendix B. Specifications and connection diagrams of power sources ..............................................................................................................................
Appendix B. CPU Specification... 114
Appendix D. I/O Module Specifications…………………….. 117
Appendix E. Advantech Module Specifications…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… 122
Appendix E. Listing of the control program………………………… 125
DEFINITIONS, SYMBOLS AND ABBREVIATIONS
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Linear production and dispatching station |
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Workplaces |
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Manual control unit |
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Ufa-Western direction |
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Automatic switch on of the reserve |
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local control room |
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Main pump unit |
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Main oil product pipeline |
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Microprocessor automation system |
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Fire safety standards |
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Oil pumping station |
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Program logic controller |
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electric motor |
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District control center |
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Supervisory control and data collection |
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Cleaner and diagnostic tool |
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Programming language |
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Pressure Wave Smoothing System |
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high voltage circuit breaker |
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Object communication device |
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Dirt filters |
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CPU |
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Rules for the installation of electrical installations |
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Building regulations |
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Occupational safety standards system |
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Information processing system |
INTRODUCTION
Automation of technological processes is one of the decisive factors in increasing productivity and improving working conditions. All existing and construction facilities are equipped with automation tools.
Transportation of petroleum products continuous production requiring close attention to the issues of reliable operation, construction and reconstruction of oil pumping facilities, overhaul of equipment. At present, the main task of transporting petroleum products is to increase the efficiency and quality of the transport system. To accomplish this task, the construction of new and modernization of existing oil pipelines, the widespread introduction of automation, telemechanics and automated control systems for the transport of petroleum products are envisaged. At the same time, it is necessary to improve the reliability and efficiency of oil pipeline transport.
The automation system of the linear production dispatch service (LPDS) is designed to control, protect and control the equipment of the oil pipeline. It should provide autonomous maintenance of the set operating mode of the pumping station and its change by commands from the operator's console of the LPDS and from a higher level of control - the district control center (RDP).
The urgency of creating automation of control systems at LPDS "Cherkassy" has increased due to the low level of automation, the presence of obsolete relay circuits, low reliability and complexity of maintenance. This requires the replacement of existing systems with a microprocessor-based automation system.
The purpose of the diploma project is: increasing the reliability and survivability of technological equipment and automation equipment for LPDS; expansion of functionality; increase in frequency Maintenance and repair stations.
The objectives of the graduation project are:
Automation is the highest level of mechanization of production and is used in the complex of technological control. production processes. It opens up tremendous opportunities for increasing labor productivity, rapid growth in the rate of development of production, as well as the safety of production processes.
1 Linear production dispatching station "Cherkasy"
1.1 Brief description of the linear production dispatching station "Cherkasy"
LPDS "Cherkassy" of the Ufa production department of OAO "Uraltransnefteprodukt" was established in 1957 with the commissioning of the Ufa Petropavlovsk MNPP, pumping station No. 1 and the tank farm RVS-5000 in the amount of 20 units with a total capacity of about 57.0 thousand tons. The station was established as the second site of the NPS "Cherkassy" of the Ufimsky regional oil pipeline department, which is part of the Department of the Ural-Siberian main oil pipelines.
1.2 Characteristics of technological equipment
The technological equipment of LPDS "Cherkasy" includes:
Three main pumps NM 1250-260 for a nominal flow of 1250 m/h with a head of 260 m, with electric motors STD 1250/2 with a power of N=1250 kW, n=3000 rpm and one main pump NM 1250-400 for a nominal flow of 1250 m /h with a head of 400 m, with an electric motor AZMP-1600 with a power of N=2000 kW, n=3000 rpm, located in a common shelter and separated by a firewall wall;
Pressure control system consisting of three pressure regulators;
Oil system for forced lubrication of bearings of pumping units, consisting of two oil pumps, two oil tanks, an accumulation tank, two oil filters, two oil coolers;
Circulating water supply system, consisting of two water pumps;
Leak collection and pumping system, consisting of four tanks and two pumps for pumping leaks;
Ventilation system consisting of supply- exhaust ventilation pump compartments (two supply and two exhaust fans); retaining ventilation of the electric motor compartment (one fan is existing, the installation of the second one is planned for the future to perform emergency switching on of the reserve (ATS)); retaining ventilation of bespromvalny chambers (two fans); exhaust ventilation of the chamber of pressure regulators (one fan is existing, the installation of the second one is planned for the future to perform ATS); exhaust ventilation of the chamber for pumping out leaks (one fan is existing, the installation of the second one is considered for the future for performing ATS);
Electric gate valves on technological pipelines;
Filter system consisting of a dirt filter and two fine filters;
Power supply system;
Automatic fire extinguishing system.
Pressure regulator chamber protected area: brick walls. There are 3 pressure regulators in this room.
Leak chamber protected area: brick walls. There are 2 pumps for pumping out leaks in this room.
All actuators that ensure automatic operation of the substation must be equipped with electric drives. Shutoff valves of pipelines must be equipped with sensors for signaling extreme positions (open, closed). The automated equipment is equipped
devices for the installation of control sensors and actuators.
The flow diagram of the main pumping station MNPP "Ufa-Western Direction" No. 2 LPDS "Cherkassy" is shown in Figure 1.1.
1.3 Characteristics of technological premises
The general shelter of the pump house consists of a pump section and an electric motor section separated by a firewall wall. The pump room belongs to the explosive zone B-1a in accordance with the Electrical Installation Rules of the PUE, (class 1 zone in accordance with GOST R 51330.3-99), in terms of fire hazard to category A in accordance with Fire Safety Standards NPB 105-95, in terms of functional hazard to category F5.1 in accordance with Building Regulations and Rules SNiP 21-01-97. The room is subject to automatic fire extinguishing.
The space of the electric motor compartment does not belong to the hazardous area. In terms of fire hazard, the room of the electric motor compartment belongs to category D. In the electric motor compartment there is an oil receiver, which belongs to category B in terms of fire hazard in accordance with NPB 105-95. The oil receiver is subject to automatic fire extinguishing. According to the functional hazard, the electric motor compartment belongs to category F5.1 according to SNiP 21-01-97.
Pressure regulator chamber protected area: brick walls. There are 3 pressure regulators in this room. The space inside the premises belongs to the explosive zone B-1a according to the PUE (zone class 1 according to GOST R 51330.3-99). According to functional hazard - to category F 5.1 according to SNiP 21-01-97). According to fire hazard to category A according to NPB 105-95. The pressure regulator chamber is subject to automatic fire extinguishing. Supply pipeline extinguishing agent not provided. The automation system provides for the implementation of automatic fire extinguishing of the chamber of pressure regulators.
Leakage chamber - protected premises: brick walls. There are 2 pumps for pumping out leaks in this room. The space inside the premises belongs to the explosive zone B-1a according to the PUE (class 1 zone according to GOST R 51330.3-99), according to functional hazard to category F5.1 according to SNiP 21-01-97, according to fire hazard to category A according to NPB 105-95. The fire extinguishing agent supply pipeline is not provided. The automation system provides for the implementation of automatic fire extinguishing of the leakage pumping chamber.
1.4 Operating modes of LPDS "Cherkasy"
The automation system should provide the following control modes for pumping stations:
- "telemechanical";
- "not telemechanical".
The choice of the mode is carried out from the automated workstation (AWS) of the operator-technologist of the pumping station LPDS "Cherkasy".
Each selected mode must exclude the other.
Switching from mode to mode should be carried out without stopping the operating units and the station as a whole.
In the "telemechanical" mode, the following types of telecontrol (TC) are provided from the RDP of the oil product pipeline via the telemechanics system:
Start-up and shutdown of auxiliary systems of the pumping station;
Opening and closing valves at the entrance and exit of the station;
Start-up and shutdown of mainline pumping units according to the start-up and shutdown programs of the mainline unit.
The control of units and systems, including auxiliary systems and gate valves at the inlet and outlet of the station, by the telemechanics system must be accompanied, in addition to the message on the status (position) of the unit, by the message "Enabled - disabled by the pipeline manager" on the screen of the operator's workstation and recorded in the event log.
In the “non-telemechanical” mode, control of process valves, booster and main pumping units, units of auxiliary systems of the pumping station is provided by common commands “soft start”, “software stop” of main pumping units and auxiliary equipment.
Table 1.1 shows the technological parameters of the station. Table 1.1 - Technological parameters of the operation of LPDS "Cherkasy"
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Parameter |
Meaning |
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Location of the station along the MNPP highway, km |
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Elevation mark, m |
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Maximum allowable operating pressure at the pump discharge (on the manifold, up to the control devices), MPa |
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Maximum allowable working pressure at the station discharge (after control devices), MPa |
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Minimum and maximum allowable working pressure at the pump intake, MPa |
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The lowest and highest viscosity of the oil product pumped into the pipeline, mm/s |
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Limit of temperature change of injected oil product from reservoirs in MNPP, С |
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Type and purpose of the pump |
HM1250-260 No. 1 main HM1250-260 No. 2 main HM1250-400 No. 3 main HM1250-400 No. 4 main |
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Impeller diameter, mm |
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Motor type |
STD-1250/2 №1 STD-1250/2 №2 STD-1250/2 №3 4AZMP- 1600/6000 No. 4 |
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Minimum pressure at station intake, MPa |
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Maximum pressure in MNPP at the outlet of the station, MPa |
1.5 Main pump unit
Each MPU contains the following objects: pump, electric motor.
The pump of the NM 1250-260 brand and the electric motor of the STD-1250/2 type, and one pump of the NM 1250-400 brand with the AZMP-1600 electric motor are used as MPA equipment.
Centrifugal pumps are the main type of pressure equipment for pumping oil through main oil product pipelines. They meet the requirements for MND for pumping significant volumes of oil over long distances. Main pumps must be pressurized at the inlet. This pressure is to prevent the dangerous phenomenon cavitation that can occur inside the pump as a result of a decrease in pressure in a fast moving fluid.
Cavitation consists in the formation of bubbles filled with vapors of the pumped liquid. When these bubbles enter an area of high pressure, they collapse, developing huge point pressures. Cavitation leads to rapid wear of parts of the supercharger and reduces its efficiency. The used pump NM is intended for transportation of oil and oil products through main pipelines with temperatures from minus 5 to +80C, with a content of mechanical impurities by volume of not more than 0.05% and a size of not more than 0.02 mm. The pump is horizontal, sectional, multi-stage, single-casing or double-casing NM, with impellers of one-way entry, with plain bearings (with forced lubrication), with end seals of the mechanical type, driven by an electric motor.
As a drive of the pumping unit, an electric motor of the STD type with a power of 1250 kW in explosion-proof design is used. It is installed in the common room with the supercharger. Explosion-proof design of the electric motor is achieved by forced air injection ventilation system under protective cover drive to maintain excess pressure (excluding penetration of oil vapor into the engine), as well as the use of a flameproof shell.
High voltage asynchronous electric motors are also used as a drive to the pumps. However, when using asynchronous motors with a power of 2.5 to 8.0 MW, it is required to install expensive static power capacitors in the pump room (which often fail when the station load and ambient temperature fluctuate), as well as a complex of high-voltage equipment that complicates the power supply circuit.
Synchronous electric motors have better stability indicators than asynchronous ones, which is especially important when there are voltage drops in the network.
In terms of cost, synchronous electric motors are usually more expensive than similar asynchronous ones, but they have better energy characteristics, which makes their use efficient. It is believed that the coefficient of performance (COP) of a synchronous motor changes insignificantly at loads close to the nominal power of the motor. With loads ranging from 0.5 to 0.7 rated power, the efficiency of synchronous motors is significantly reduced. The practice of operating oil pipelines has shown that in conditions of a constantly changing level of loading of pipeline systems, it is advisable to use adjustable drives of pumping units. By adjusting the speed of the blower impeller, it is possible to smoothly change its hydraulic and energy characteristics, adjusting the operation of the pump to changing loads. DC motors allow you to control the speed by simply changing the resistance (for example, by introducing a rheostat into the motor rotor circuit), but for such motors the control range is relatively narrow. Engines alternating current allow regulation of the number of revolutions by changing the frequency of the supply current (from the industrial frequency of 50 Hz to a higher or lower value, depending on whether it is required to increase the number of revolutions of the rotor shaft or decrease, respectively).
1.6 Piping of pumps LPDS "Cherkasy"
Piping of pumps can be carried out in series, in parallel and in a combined way (Figures 1.2 1.4).
Figure 1.2 Series piping of pumps
Figure 1.3 Parallel piping of pumps
Figure 1.4 Combined pump piping
A serial connection of pumps is used to increase the pressure, and a parallel connection is used to increase the flow of the pumping station LPDS "Cherkassy" includes four main pumping units with electric motors located in a common shelter of the oil pumping station. To increase the pressure at the outlet of the station, the pumps are connected in series (Figure 1.6), so that at the same supply, the pressures created by the pumps are summed up. The piping of the pumps ensures the operation of the LPDS when any of the station's units goes into reserve. A gate valve is installed on the suction and discharge of each pump, and a check valve is installed in parallel with the pump.
Figure 1.5 Piping of pumps at the substation
check valve, separating the suction and discharge lines of each pump, allows liquid to flow in only one direction. When the pump is running, the pressure acting on the valve flap on the left (discharge pressure) is greater than the pressure acting on this flap on the right (suction pressure), as a result of which the flap is closed and oil flows through the pump. When the pump is idle, the pressure to the right of the valve flap is greater than the pressure to the left of it, as a result of which the flap is open, and the oil product flows through KO-1 to the next pump, bypassing the idle one.
1.7 Analysis of the existing automation scheme for LPDS "Cherkassy"
Automated equipment is equipped with devices for installing control sensors and actuators.
All actuators are equipped with actuators with electrical control signals. The shut-off valves of the pipelines of the external and internal piping of the LPDS are equipped with sensors for signaling the extreme positions (open, closed).
When implementing the automation system, the following tasks are performed:
Analysis of the modes of technological equipment;
Control of technological parameters;
Management and control of gate valves;
Control of readiness for launch of main and booster pumping units;
Processing of limit values of parameters for the main pumping unit;
Management and control of the main and booster pumping units;
Management and control of the receiving valve of the main pumping unit;
Correction of the control setpoint at the start of the main unit;
Setting of control settings;
Pressure regulation;
Management and control of oil pumps;
Management and control of the supply fan of the pump room;
Management and control of the exhaust fan of the pump room;
Management and control of the pump of pumping out of leaks;
Processing of measured parameters;
Accept and transmit signals to telemechanics systems.
The status and operation parameters of the LPDS equipment are displayed on the screen of the LPDS operator's workstation in the form of the following video frames:
General scheme pumping station;
Scheme of individual main units and auxiliary systems;
Energy Scheme;
Scheme of adjacent sections of the route.
The manual control unit (BRU) LPDS installed in the control room (SCHSU) provides for:
Light signaling from:
1) emergency pressure sensors at the inlet, in the collector and at the outlet of the LPDS;
Channels of the fire alarm system;
2) channels of means of gas contamination;
3) overflow sensor of the collection tank;
4) sensor of flooding of the pumping house;
5) ZRU alarm relay;
Buttons for issuing control commands:
Emergency shutdown of LPDS;
Shutdown of main and pumping units;
Inclusion of main and pumping units;
Opening and closing gate valves for connecting the station.
At present, with a constant decrease in oil production, the volume of pumped oil is decreasing. In this regard, a system of automatic control of the pumping mode is used. The system is designed to control and regulate the pressure at the inlet and outlet of pumping stations of oil trunk pipelines. The system uses electrically actuated control dampers to control the pressure at the inlet and outlet of oil pipelines by throttling the outlet flow.
2 Patent study
2.1 Selection and justification of the subject of the search
In the graduation project, the project of modernization of the process control system for the linear production dispatching station of the LPDS "Cherkasy" OJSC "Uraltransnefteprodukt" is considered.
One of the measured parameters of the pumping unit of the linear production dispatching station is vibration. At LPDS, for these purposes, I propose to use the Cascade vibration measurement system, therefore, when conducting a patent search, attention was paid to the search and analysis of piezoelectric sensors for measuring vibration in technological objects of the oil and gas industry.
2.2 Patent search regulations
The patent search was carried out using the USPTU fund on the sources of patent documentation of the Russian Federation.
Search depth five years (2007-2011). The search was performed on the index of the international patent classification (IPC) G01P15/09 “Measurement of acceleration and deceleration; measurement of acceleration pulses using a piezoelectric sensor”.
The following sources of patent information were used:
Documents of reference and search apparatus;
Full descriptions to Russian patents;
Official Bulletin of the Russian Agency for Patents and Trademarks.
2.3 Patent search results
The results of viewing the sources of patent information are shown in Table 2.1.
Table 2.1 Patent Search Results
2.4 Analysis of patent search results
Piezoelectric accelerometer according to patent No. 2301424 contains a multilayer package of piezoceramic plates, consisting of three sections. Sections include groups of three plates. The end plates in the group are provided with diametral grooves filled with switching busbars. One of the middle plates is polarized entirely in thickness, the other two middle plates contain segments polarized in thickness in opposite directions. Sections with segmented plates are rotated relative to each other by 90° around the longitudinal axis of the package. EFFECT: expanding functionality by measuring vibration acceleration in three mutually perpendicular directions.
The vibration sensor according to patent No. 2331076 contains a piezoceramic tubular rod with electrodes, fixed in the housing with one end on the base with electrical contacts perpendicular to its surface, and at the other end of the rod, an inertial element is fixed, made in the form of a mass-structure, which consists of a thin-walled cylinder, the cavity of which filled with a fluid damping medium (for example, low-viscosity oil) and single spherical weights, with the possibility of their free movement, while the spherical weights have different masses. Inside the housing there is a damping element, which is also used as a fluid damping medium. The technical result is to expand the measurement range while increasing the sensitivity of the sensor.
The vibration transducer according to patent No. 2347228 contains a housing with a piezoelectric element fixed in it, made in the form cuboid with a square base and with charge removal elements in the form of electrically conductive surfaces fixed on its faces and electrically isolated from each other, conductors for removing charges and a dielectric substrate on which a square base of the piezoelectric element is installed, the polar axis of which is perpendicular to the plane of its attachment to the substrate. Each electrically conductive surface is made in the form of a plate with a lobe protruding on one of its sides beyond the corresponding face of the parallelepiped, made of isotropic copper foil and fixed on the face of the parallelepiped by means of a polymerizable thermosetting conductive material, while on each pair of adjacent plates the petals are oriented to different edges of the parallelepiped , each leaf has a notch for attaching a conductor to remove charges, and the axis of each leaf coincides with one of the symmetry planes of the corresponding plate. This design of the transducer makes it possible to bring the attachment points of the conductors to the charge removal elements, as the most pronounced stress concentrators, beyond the limits of the charge removal surfaces of the sensitive element and makes it possible to implement the technologies for manufacturing parts and mounting the piezoelectric package in an industrial way, which minimizes inhomogeneity and mechanical stresses on the edges of the piezoelectric element.
The three-component oscillatory acceleration sensor according to patent No. 2383025 contains a housing that is rigidly fixed to the base base and is closed with a cap. The case is made of metal in the form of a trihedral pyramid with three orthogonal planes, on each of which one sensitive element is fixed in a cantilever manner. The sensitive elements are made in the form of piezoelectric or bimorph plates.
The device for measuring vibration according to patent No. 2382368 contains a piezoelectric transducer, an instrumentation amplifier and an operational amplifier, the output of which is the output of the device. The outputs of the piezoelectric transducer are connected to the direct and inverse inputs of the instrumental amplifier, the first gain setting input of which is connected to the first output of the first resistor. The output of the operational amplifier is connected to its inverted input through a capacitor. The inverse input of the operational amplifier is connected through a second resistor to the output of the instrumentation amplifier. The direct input of the operational amplifier is connected to a common bus. An inductance is introduced into the device, which is connected between the second output of the first resistor and the second input of the instrumental amplifier gain setting, and the third resistor is connected in parallel with the capacitor. The direct and inverse inputs of the instrumentation amplifier can be connected to a common bus through the first and second auxiliary resistors.
The essence of the piezoelectric transducer according to patent No. 2400867 is that it contains a piezoelectric transducer and a preamplifier. The first part of the preamplifier is located in the transducer housing and includes an amplification stage on a field effect transistor and three resistors. The second part of the preamplifier is located outside the housing and includes a decoupling capacitor and a current-stabilizing diode, the cathode of which and the first terminal of the decoupling capacitor are connected to the source of the field-effect transistor. The second terminal of the separating capacitor and the anode of the current-stabilizing diode are connected respectively to the registrar and the power source, the common point of which is connected to the drain of the field-effect transistor. The converter also contains the first and second diodes connected in series. The cathode of the first and the anode of the second diode are connected respectively to the source and drain of the field-effect transistor. Their middle point is connected to the gate of the field-effect transistor, to the first electrode of the piezoelectric transducer by the first terminal of the first resistor, the second terminal of which is connected to the first terminals of the second and third resistors. The second output of the second resistor is connected to the source of the field effect transistor. The second output of the third resistor is connected to the second electrode of the piezoelectric transducer and to the drain of the field-effect transistor. Technical result: simplification electrical circuit, noise reduction and FET breakdown protection.
Patent studies have shown that today there are a fairly large number of piezoelectric vibration measuring instruments, which are diverse in their design and have both advantages and disadvantages.
Thus, the use of sensors that make it possible to determine vibration based on the properties of piezoelectric crystals is quite relevant.
Automation of a pumping station includes control of main pumping units in start-stop modes, automatic control, protection and signaling of pumping units and, in general, stations according to controlled parameters, automatic start-stop, control, protection and signaling for auxiliary installations of pumping stations.
The control system of pumping units operates in the modes of remote step-by-step control, program start of pumps, program stop of pumps and emergency stop.
In modes remote control from the control room panel, the oil pump is started, the ventilation of the pump room is controlled, and the valves on the suction and discharge lines of the main pumping units are opened and closed.
In the MHA program start and stop mode, all start-up operations are performed automatically. The starting mode of the electric motor depends on its type (synchronous or asynchronous) and is carried out by starting stations.
In general, starting the main pumping unit is quite simple. When the electric motor reaches the nominal speed, the suction and discharge valves open, and the unit starts to work. The oil supply system at a modern pumping station is centralized, common to all units, which eliminates the control of the oil system pumps and seals during the start-stop of the unit.
For the pumping LPDS, the software launch of the MPU is important. There are various schemes for starting pumps, depending on the characteristics of the pumps, power supply schemes and other factors. The programs for sequentially opening the valves and starting the main electric motor of the unit differ.
Units transferred to the standby position for the ATS system can also be switched on according to a program in which both gate valves are opened in advance when the unit is switched to standby, and the main electric motor starts when the operating unit is turned off and the ATS system is triggered. This program of turning on the unit is the best from the point of view of the hydraulic conditions of the main pipeline, since with such switching of the units, the pressures at the suction and discharge of the stations change very slightly and the linear part of the main pipeline practically does not experience any loads due to pressure waves.
The shutdown program of the unit, as a rule, provides for the simultaneous shutdown of the main electric motor and the inclusion of both valves to close. In this case, the command to close the valves is usually given by a short impulse (Figure 3.1).
Protection of the pump unit in terms of the parameters of the pumped liquid is provided by pressure sensors 1-1, 1-2, 7-1, 7-2 (Sapphire-22MT), which control the pressure in the suction and discharge pipelines. Sensors 1-1, 1-2, installed on the suction pipeline at the inlet valve, are adjusted to the pressure characterizing the cavitation mode of the pump. Protection against the minimum suction pressure is carried out with a time delay, which eliminates the reaction to short-term pressure drops when the pumps are turned on and small ones pass through the pipeline. air locks. Sensors 7-1, 7-2, installed on the discharge pipeline at the outlet valves, protect against the maximum discharge pressure. The maximum contact of sensor 7-1 gives a signal to the control circuit of the unit, interrupting the start-up process in case of exceeding the allowable pressure after opening the valve. Maximum sensor contact 7-1 provides automatic stop of the unit if a signal is sent to the control circuit of the unit, interrupting the start process in case of exceeding the allowable pressure after opening
start-up process in case of exceeding the permissible pressure after opening the valve.
The maximum contact of sensor 7-1 provides automatic shutdown of the unit if the pressure in the discharge pipeline exceeds the allowable value due to the mechanical strength of the equipment, fittings and pipeline.
In operation, there may be cases of pump operation with a very low flow, which is accompanied by a rapid increase in the temperature of the liquid in the pump housing, which is unacceptable.
Protection against rising oil temperature in the pump housing is provided by a resistance thermal converter 9 installed on the pump housing. Violation of the tightness of the pump shaft seal devices requires an immediate shutdown of the unit. Leak control is reduced to level control in the chamber through which leaks are discharged. Exceeding the permissible level is recorded by the level gauge 3-1.
Protection against temperature excess of bearings 2-1, 2-2, 2-3, 2-4 is carried out by a resistance thermal converter of the TSMT type. An alarm is triggered in the control room, and the unit is turned off by protection by means of a control signal from the controller.
Protection against temperature increase of the stator core windings is carried out by a resistance thermometer 10 TES-P.-1. The air temperature in the motor housing is controlled and signaled by means of a control signal from the controller.
The pressure in the systems of sealing liquid and circulating lubrication of the pump and motor bearings is controlled by the pressure sensor Sapfir-22MT and the controller.
Vibration signaling equipment 4-1, 4-2, 4-3, 4-4 controls the vibration of the pump and motor bearings, and when it increases to unacceptable values, it turns off the unit.
Table 3.1 List of selected MPA equipment
|
Positional designation |
Name |
Note |
|
|
Pressure sensor type Sapphire-22MT |
|||
|
Manometer showing type EKM |
|||
|
Resistance thermal converter platinum type TSP100 |
|||
|
Level indicator type OMYuV 05-1 |
|||
|
Vibration control equipment "Cascade" |
The emergency stop of the unit occurs when the devices and protection devices are triggered. There are emergency stops that allow the unit to restart and those that do not. In the latter case, the reason that caused the stop is established and eliminated, and only after that it becomes possible to restart the unit. A stop with restart permission occurs when a start has failed, i.e. if the stop was due to the temperature of the product in the pump casing. An emergency stop with a prohibition of restarting the unit occurs with the following parameters: an increase in the temperature of the bearings of the electric motor, pump and intermediate shaft; increased vibration of the unit; increased leakage from pump shaft seals; an increase in the temperature of the cooling air at the inlet to the electric motor; increasing the temperature difference between the incoming and outgoing air cooling the electric motor; triggered devices electrical protection electric motor.
The sequence of operations when the units are stopped by the signals of protective automation does not differ from the sequence during a normal program stop.
In general, the pumping station also has a warning and emergency protection system for the following parameters: fire, flooding of the pumping station, unacceptable pressures on the suction and discharge lines, etc.
Automatic shutdown of the station units occurs sequentially according to the program, with the exception of the case of gas protection. With an increased concentration of oil vapors in the pump room, all electrical consumers are simultaneously turned off, except for fans and control devices. The automation scheme of the pumping station provides for fire protection (sensors are installed that respond to the appearance of smoke, flame or elevated temperature in the room), when they are triggered, all consumers of electricity are turned off without exception.
The list of devices used to automate the main pumping unit is given in Table 3.2.
Table 3.2 Instruments used to automate MND
|
script |
Positional designation |
Trigger condition |
Action |
|
Pump Front Bearing Overtemperature |
ED speed reduction |
||
|
Pump Rear Bearing Temperature Excess |
ED speed reduction |
||
|
Exceeding the temperature of the oil product in the pump housing |
ED speed reduction |
||
|
Exceeding the temperature of the front bearings ED |
ED speed reduction |
||
|
Exceeding the temperature of the stator core windings |
ED speed reduction |
||
|
Exceeding the temperature of the rear bearings ED |
ED speed reduction |
||
|
Exceeding the vibration of the front bearings ED |
ED speed reduction |
||
|
excess vibration of the rear bearings ED |
ED speed reduction |
||
|
excessive vibration of the rear bearings of the pump |
ED speed reduction |
||
|
excessive vibration of pump front bearings |
ED speed reduction |
3.2 Safety system
The reliability of the functioning of safety systems for hazardous industrial facilities depends entirely on the state of electronic and programmable electronic systems related to security. These systems are called the emergency protection system (SIS). Such systems must be able to maintain their operability even in the event of failure of other functions of the APCS of the oil pumping station.
Consider the main tasks assigned to such systems:
Prevention of accidents and minimization of the consequences of accidents;
Blocking (preventing) intentional or unintentional interference in the technology of an object that could lead to development dangerous situation and initiate the operation of the ESD.
For some protections, there is a delay between the detection of an alarm and the safety shutdown. Disabling the main auxiliary systems, closing the valves for connecting the PS to the MN.
The pumping unit is continuously monitored for a number of technological parameters, the emergency values of which require shutdown and blocking of the unit. Depending on the parameter or condition on which the protection was triggered, the following can be performed:
Shutdown of the electric motor;
Closing of aggregate valves;
Starting the backup unit.
For all protection parameters, a test mode is provided. In the test mode, the protection flag is set, an entry in the protection array, and a message is transmitted to the operator, but control actions on the process equipment are not formed.
Depending on which controlled parameter triggers the plant-wide protection associated with the shutdown of pumping units, the system must carry out:
Shutdown of one of the working MHA, the first in the course of oil;
Simultaneous or sequential shutdown of all operating MHAs;
Simultaneous shutdown of all working PNA;
Closing of the NPS connection valves;
Closing of FGU valves;
Disabling certain auxiliary systems;
Turning on light and sound signaling devices.
Aggregate protection MNA and PNA must ensure its trouble-free operation and shutdown when the controlled parameters go beyond the established limits.
The algorithmic content of the PAZ functions consists in the implementation next condition: when the values of certain technological parameters that characterize the state of the process or equipment go beyond the established (permissible) limits, the corresponding unit or the entire station should be switched off (stopped).
input information for a group of emergency protection functions, they contain signals about the current values of the controlled technological parameters coming to the logic blocks (programmable controllers) from the corresponding primary measuring transducers, and digital data about the permissible limit values of these parameters coming to the controllers from the operator's workstation of the PS. The output information of the emergency protection functions is represented by a set of control signals sent by the controllers to the executive bodies of the protection systems.
The presence of feedback greatly simplifies the process of developing processor targets and user applications. On the other hand, this increases the invariance of the reaction of logical and computational algorithms to the test action carried out when checking emergency protection.
Such a check cannot guarantee the repeatability of test results, since the state of the processor's memory under feedback control under all the same test conditions will not be the same at different points in time.
3.3 APCS based on Modicon TSX Quantum controllers
The automated process control system (APCS) of oil pumping stations is based on the Modicon TSX Quantum series of programmable controllers, which is a good solution for control tasks based on high-performance programmable controllers. The Quantum-based system combines compactness, providing cost-effective and reliable installation even in the most difficult industrial environments. At the same time, Quantum systems are easy to install and configure, and have a wide range of applications, which provides a lower cost compared to other solutions. Support is also provided installed products by sharing legacy technologies with this latest management platform. Modicon TSX Quantum programmable controllers are designed to save space in the switchboard. With a depth of only 4 inches (including the screen), these controllers do not require large shields; they are housed in a standard 6" electrical cabinet, saving up to 50% on the cost of conventional control panels. Despite their small size, Quantum controllers maintain a high level of performance and reliability. Control systems using Modicon TSX Quantum programmable controllers support various options solutions ranging from a single I/O rack (up to 448 I/Os) to redundant branched I/O processors with up to 64,000 I/O lines as needed. In addition, a memory capacity of 256 KB to 2 MB is sufficient for the most complex schemes management. By using advanced processor devices based on Intel chips, the Quantum series controllers are fast and I/O capable enough to meet demanding speed requirements. These controllers also use high-performance math co-processors to provide the best algorithm and math speed required to ensure the continuity and quality of the controlled process.
The combination of performance, flexibility and expandability makes the Quantum series best solution for the most complex applications and at the same time economical enough for simpler automation tasks. The ability to connect to enterprise networks and field buses is implemented for eight types of networks from Ethernet to INTERBUS-S.
Quantum supports five programming languages conforming to the IEC 1131-3 standard. In addition to these languages, Quantum controllers can execute programs written in the Modicon 984 Ladder Diagram Language, the Modicon Status Language, and third-party application-specific languages.
In addition to the IEC languages, the Quantum system takes advantage of the enhanced 984 instruction set to run applications written in Modsoft or translated with SY/Mate on the Quantum controller. It is possible to connect backbone communication networks Ethernet, Modbus and Modbus Plus to the Quantum controller.
No system architecture meets the needs of today's control market like the Modicon TSX Quantum series of programmable controllers. It provides an alternative system where the I/O nodes are sized, spaced and configured to reduce the cost of cabling connecting the I/O nodes to sensors and actuators. The Quantum controller has the flexibility to combine local, remote, distributed I/O, peer-to-peer, and fieldbus I/O configurations. This flexibility makes Quantum unique solution capable of meeting all automation needs. With only one series of I/O modules, the Quantum system can be configured for all architectures and is thus suitable for continuous process control, plant control or distributed control.
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Vibrodiagnostics allows you to control technical condition main and retaining units in the mode of continuous monitoring of the vibration level.
Basic requirements for monitoring and measuring vibrations of pumping units:
1. All mainline and booster pumping units must be equipped with stationary monitoring and signaling vibration equipment (KSA) with the possibility of continuous monitoring of the current vibration parameters in the operator room. The automation system of the PS should provide light and sound alarms in the control room in case of increased vibration, as well as automatic shutdown of the units when the emergency vibration value is reached.
2. Sensors of the control and signal vibration equipment are installed on each bearing support of the main and horizontal booster pumps to control vibration in the vertical direction. (fig) On vertical booster pumps, sensors are installed on the housing of the thrust bearing assembly to monitor vibration in the vertical (axial) and horizontal-transverse directions. (fig)
Drawing. Measuring points on the bearing pedestal
Drawing. Vibration measuring points on the vertical pump unit
The automation system must be configured to issue a signal when the warning and emergency levels of pump vibration at controlled points are reached. The measured and normalized vibration parameter is the mean square value (RMS) of the vibration velocity in the operating frequency band of 10…1000 Hz.
3. The values of the alarm and protection settings for excessive vibration are set according to the approved process protection settings map depending on the rotor size, pump operation mode (supply) and vibration standards.
Vibration standards for main and booster pumps for nominal operating modes
Vibration standards for main and booster pumps for non-rated operating modes
With a vibration value of 7.1 mm/s to 11.2 mm/s, the duration of operation of the main and booster pumps should not exceed 168 hours.
The nominal mode of operation of the pumping unit is the supply from 0.8 to 1.2 of the nominal supply (Q nom) of the corresponding rotor (impeller).
When turning on and off the pumping unit, the protection of this unit and other operating units should be blocked due to excessive vibration for the duration of the program for starting (stopping) the pumping units.
4. Warning signaling in the operator's room of the local control room in terms of the "increased vibration" parameter corresponds to the RMS value of 5.5 mm/s (nominal mode) and 8.0 mm/s (non-nominal mode).
Signal "emergency vibration" - RMS 7.1 mm/s and 11.2 mm/s, immediate shutdown of the pumping unit.
5. Vibration control of auxiliary pumps (oil pumps, pumps for pumping out leaks, water supply, fire extinguishing, heating systems) should be carried out once a month and before being taken out for maintenance using portable equipment.
6. To obtain additional information during vibration diagnostics of main and retaining units, as well as for the period of temporary absence of permanently installed means for measuring and monitoring vibration (verification, calibration, modernization), portable portable vibration equipment is used.
Each measurement of vibration by portable equipment is carried out at strictly fixed points.
7. When using portable vibration equipment, the vertical component of the vibration is measured on the top of the bearing cap above the middle of the bearing shell length.
The horizontal-transverse and horizontal-axial vibration components of horizontal pumping units are measured 2…3 mm lower from the axis of the pump shaft opposite the middle of the length of the support insert (Fig.).
Vibration measurement points on the vertical pump unit correspond to points 1, 2, 3, 4, 5, 6 (fig.).
Drawing. Vibration measuring points on the pump bearing housing without outriggers
For pumps that do not have remote bearing units (such as CNS, NGPNA), vibration is measured on the housing above the bearing as close as possible to the axis of rotation of the rotor (Fig.).
8. To assess the rigidity of the frame attachment to the foundation, vibration is measured on all elements of the pump attachment to the foundation. The measurement is made in the vertical direction on the anchor bolts (heads) or next to them on the foundation at a distance of no more than 100 mm from them. The measurement is carried out with planned and unscheduled vibration diagnostics control.
9. To carry out vibration diagnostic control, equipment is used to measure the root-mean-square value of vibration and universal vibration-analyzing equipment with the ability to measure the spectral components of vibration and amplitude-phase characteristics.
As mentioned above, on the main oil pipeline, production workers are exposed to many harmful and dangerous factors. In this section, the most harmful factor of the head oil pumping station, which adversely affects the body, will be considered - vibration.
When working in vibration conditions, labor productivity decreases, and the number of injuries increases. At some workplaces, vibrations exceed the normalized values, and in some cases they are close to the limit. Usually, low-frequency vibrations that negatively affect the body predominate in the vibration spectrum. Some types of vibration adversely affect the nervous and cardiovascular systems, the vestibular apparatus. The most harmful effect on the human body is exerted by vibration, the frequency of which coincides with the frequency of natural vibrations of individual organs.
Industrial vibration, characterized by a significant amplitude and duration of action, causes irritability, insomnia, headache, aching pains in the hands of people dealing with a vibrating instrument. With prolonged exposure to vibration, the bone tissue is rebuilt: on radiographs, you can see stripes that look like traces of a fracture - areas of greatest stress, where the bone tissue softens. The permeability of small blood vessels increases, the nervous regulation is disturbed, the sensitivity of the skin changes. When working with a manual mechanized tool, acroasphyxia (a symptom of dead fingers) may occur - loss of sensitivity, whitening of fingers, hands. When exposed to general vibration, changes from the side of the central nervous system: dizziness, tinnitus, memory impairment, impaired coordination of movements, vestibular disorders, weight loss appear.
Vibration control methods are based on the analysis of equations describing vibrations of machines and units in production conditions. These equations are complicated because any kind of technological equipment (as well as its individual structural elements) is a system with many degrees of mobility and has a number of resonant frequencies.
where m is the mass of the system;
q - system stiffness coefficient;
X - current value of vibration displacement;
Current value of vibration velocity;
Current value of vibration acceleration;
The amplitude of the driving force;
Angular frequency of the driving force.
The general solution of this equation contains two terms: the first term corresponds to the free oscillations of the system, which in this case are damped due to the presence of friction in the system; the second - corresponds to forced vibrations. the main role- forced vibrations.
Expressing vibration displacement in complex form and substituting the corresponding values and into formula (5.1) we find expressions for the relationship between the amplitudes of the vibration velocity and the driving force:
The denominator of the expression characterizes the resistance that the system provides to the driving variable force, and is called the total mechanical impedance of the oscillatory system. The value is active, and the value is the reactive part of this resistance. The latter consists of two resistances - elastic and inertial -.
The reactance is zero at resonance, which corresponds to the frequency
In this case, the system resists the driving force only due to active losses in the system. The amplitude of oscillations in this mode increases sharply.
Thus, from the analysis of the equations of forced vibrations of a system with one degree of freedom, it follows that the main methods for combating vibrations of machines and equipment are:
1. Reducing the vibration activity of machines: achieved by changing technological process, the use of machines with such kinematic schemes in which the dynamic processes caused by impacts, accelerations, etc. would be excluded or reduced to the maximum.
replacement of riveting by welding;
dynamic and static balancing mechanisms;
lubrication and cleanliness of the processing of interacting surfaces;
the use of kinematic gearings of reduced vibration activity, for example, herringbone and helical gears instead of spur gears;
replacement of rolling bearings with plain bearings;
application construction materials with increased internal friction.
2. Detuning from resonant frequencies: consists in changing the operating modes of the machine and, accordingly, the frequency of the disturbing vibration force; natural vibration frequency of the machine by changing the stiffness of the system.
installation of stiffeners or changing the mass of the system by attaching additional masses to the machine.
3. Vibration damping: a method of reducing vibration by strengthening friction processes in the structure that dissipate vibrational energy as a result of its irreversible conversion into heat during deformations that occur in the materials from which the structure is made.
application of a layer of elastic-viscous materials on vibrating surfaces with large losses due to internal friction: soft coatings (rubber, polystyrene PVC-9, VD17-59 mastic, Anti-vibrate mastic) and hard coatings (sheet plastics, glass isol, hydroisol, aluminum sheets );
the use of surface friction (for example, plates adjacent to each other, like springs);
installation of special dampers.
4. Vibration isolation: reducing the transmission of vibrations from the source to the protected object with the help of devices placed between them. The effectiveness of vibration isolators is estimated by the transmission coefficient KP, equal to the ratio of the vibration displacement amplitude, vibration velocity, vibration acceleration of the protected object, or the force acting on it to the corresponding parameter of the vibration source. Vibration isolation only reduces vibration when the gearbox< 1. Чем меньше КП, тем эффективнее виброизоляция.
· the use of anti-vibration supports such as elastic pads, springs, or combinations thereof.
5. Vibration damping - an increase in the mass of the system. Vibration damping is most effective at medium and high vibration frequencies. This method has found wide application in the installation of heavy equipment (hammers, presses, fans, pumps, etc.).
installation of units on a massive foundation.
6. Personal protective equipment.
Since it is irrational to apply collective protection methods due to their high cost intensity (for this, it is necessary to completely revise the plans for upgrading the equipment of the enterprise), in this section we will consider and carry out calculations on the use of personal protective equipment to reduce the impact of vibrations on the body of production personnel servicing the pumping systems of the head oil pumping station.
As a means of protection against vibration during work, we will choose anti-vibration gloves and special shoes.
Thus, to reduce the impact of vibration, the worker must use the following personal protective equipment:
Distinctive characteristics: unique vibration-protective gloves from the widest range of low-frequency and high-frequency vibrations. Cuffs: driver's leggings with Velcro. Special resistance to abrasion, tearing. Oil and petrol repellent. Excellent dry and wet (oiled) grip. Antistatic. Antibacterial treatment. Lining: filler "Gelform". Percentage reduction of vibration to a safe level (removal of vibration syndrome of the hand-forearm system): low-frequency vibrations from 8 to 31.5 Hz - by 83%, medium-frequency vibrations from 31.5 to 200 Hz - by 74%, high-frequency vibrations from 200 up to 1000 Hz - by 38%. Operation at temperatures from +40°С to -20°С. GOST 12.4.002-97, GOST 12.4.124-83. Model 7-112
Coating material: butadiene rubber (nitrile). Length: 240 mm
Sizes: 10, 11. Price - 610.0 rubles per pair.
Anti-vibration ankle boots have a multi-layered rubber sole. Such, for example, as Boots RANK CLASSIC, which are recommended for oil and gas enterprises and industries where aggressive substances are used. The upper is made of high quality natural water-repellent leather. Wear-resistant MBS, KShchS sole. Goodyear sole attachment method. Side loops for easy donning. A metal toe cap with an impact strength of 200 J protects the foot from impacts and pressure. Reflective elements on the shaft visually indicate the presence of a person when working in conditions of poor visibility or at night. GOST 12.4.137-84, GOST 28507-90, EN ISO 20345:2004. Upper material: genuine grain leather, VO. Sole: monolithic multi-layered rubber. Price - 3800.0 per pair.
Thus, using these personal protective equipment, it is possible to reduce the impact of vibration on the worker's body. If 4 pairs of gloves and one pair of anti-vibration boots are issued for one year, then the enterprise will additionally spend approximately 2,000.0 rubles per employee per month. These expenses can be considered economically justified, since they are the prevention of occupational diseases. Such as, for example, vibration disease, which is the reason for putting an employee on disability.
In addition, it is also rational to observe the working hours. Thus, the duration of work with vibrating equipment should not exceed 2/3 of the work shift. Operations are distributed among workers so that the duration of the continuous action of vibration, including micropauses, does not exceed 15 ... 20 minutes. It is recommended to take breaks for 20 minutes 1-2 hours after the start of the shift and for 30 minutes 2 hours after lunch.
During breaks, a special set of gymnastic exercises and hydroprocedures should be performed - baths at a water temperature of 38 ° C, as well as self-massage of the limbs.
If the vibration of the machine exceeds the permissible value, then the contact time of the person working with this machine is limited.
To increase the protective properties of the body, working capacity and labor activity, special industrial gymnastics complexes, vitamin prophylaxis (twice a year a complex of vitamins C, B, nicotinic acid), special nutrition should be used.
Comprehensively applying the above methods, it is possible to reduce the influence of such a harmful factor as vibration and prevent its transition from the category of harmful to the category of dangerous factors.
Thus, in this section, the working conditions of a fitter of the 5th category of technological installations of the LPDS "Perm" OJSC "North-Western Oil Lines" are considered.
most dangerous and harmful factors at this workplace are: noise, vibration, evaporation of oil products, the possibility of infection with encephalitis and borreliosis in the spring and summer. The most dangerous of these is the impact of vibration. In this regard, recommendations were implemented aimed at eliminating the negative impact of this factor. To do this, it is rational to provide the working staff with personal protective equipment in the amount (per person) of 4 pairs of anti-vibration gloves and one pair of anti-vibration boots for a period of 12 months, which will reduce the influence of this factor several times.
General and local vibration affect the human body in different ways, therefore, various maximum permissible values are also established for them.
The normalized parameters of general vibration are the rms values of the vibrational speed in octave frequency bands or the amplitude of movements excited by the operation of equipment (machines, machine tools, electric motors, fans, etc.) and transmitted to workplaces in industrial premises(floor, work platforms, seat). The regulated parameters are introduced by sanitary norms SN 245-71. They do not apply to vehicles and self-propelled machines in motion.
The permissible values of vibration parameters given in the norms (Table 12) are intended for permanent workplaces in industrial premises with continuous exposure during the working day (8 hours).
Table 12
If the duration of exposure to vibrations is less than 4 hours during the working day, the permissible values of the vibration parameters indicated in the table should be increased by 1.4 times (by 3 dB); when exposed to less than 2 hours - twice (by 6 dB); when exposed to less than 2 hours, three times (by 9 dB). The duration of exposure to vibrations must be justified by calculation or confirmed by technical documentation.
For manual machines, the maximum permissible vibration levels were introduced by GOST 17770-72. Their parameters determine: the effective values of the vibrational speed or their levels in octave frequency bands at the points of contact of the machines with the hands of the worker; the force of pressing (feed) applied in the process of work to the manual machine by the hands of the worker; the mass of a manual machine or its parts, perceived in the process of work by the hands of the worker.
Permissible values of vibrational speed and their levels in octave frequency bands are given in Table. 13.
Table 13
Note. In the octave band with a geometric mean frequency of 8 Hz, the control of vibrational speed values should be carried out only for manual machines with a number of revolutions or beats per second less than 11.2.
The standards for manual machines also define the pressing force and the mass of the machine, and for pneumatic actuators - the magnitude of the applied force.
The force of pressing (feed), applied by the hands of a worker to a manual machine and necessary for stable and productive work, is established by standards and specifications for individual types of machines; it should not exceed 200 N.
The mass of a manual machine or its parts, perceived by the hands, the force of gravity or its component, transmitted to the hands of the worker in the process of work, should not exceed 100 N.
The surfaces of the machines in the places of their contact with the hands of the worker must have a thermal conductivity coefficient of not more than 0.5 W / (m * K). General requirements manual pneumatic machines are equipped with GOST 12.2.010-75, which contains safety requirements for the design and operation of machines, as well as requirements for vibration parameters control methods.
The design of the machine must comply with the requirements of GOST 17770-72 with the following additions: the design of the machine must provide vibration protection for both hands of the operator; to have protections of the working tool; the location of the exhaust openings is such that the exhaust air does not interfere with the work of the operator. Percussion machines must be equipped with devices that prevent spontaneous flight of the working tool during idle impacts.
The use of machines to perform operations not provided for by their main purpose is allowed. However, if at the same time the vibration exceeds the established levels (GOST 17770-72), then the duration of the work of one operator should not exceed the established "Recommendations for the development of working conditions for workers in vibration-hazardous professions" approved by the USSR Ministry of Health, the USSR State Committee for Labor and Wages and the All-Union Central Council of Trade Unions 1-XII 1971
On manual controls of pneumatic actuators and devices, the amount of effort should not exceed during operation: with the hand - 10 N; arm to the elbow - 40 N; with the whole hand - 150 N; two hands -250 N.
Controls (handles, flywheels, etc.), with the exception of remote remote controls, must be placed relative to the platform from which control is performed, at a height of 1000-1600 mm when servicing drives while standing and 600-1200 mm when servicing while sitting.
Technical requirements for measuring and monitoring vibrations at workplaces are established by GOST 12.4.012-75.
Measuring instruments must ensure the measurement and control of the vibration characteristics of workplaces (seat, working platform) and controls under operating conditions, as well as the determination of the mean square value of the vibration velocity averaged over the measurement time in absolute and relative values. Measurement of root-mean-square values of vibration acceleration in absolute and relative values and vibration displacement in absolute values is allowed.
Measuring instruments must ensure the determination of vibration in the octave and third octave frequency bands. The characteristics of octave and third octave filters are accepted in accordance with GOST 12.4.012-75, but the dynamic range of the filter must be at least 40 dB.
Measuring instruments must ensure the determination in octave frequency bands of root-mean-square values of vibration velocity relative to 5 * 10 -8 m / s in accordance with Table. 14 and vibration acceleration relative to 3*10 -4 m/s 2 in accordance with the table. 15.
Table 14
Table 15
Measuring instruments are carried out in the form of portable devices.
