RU2743869C1 - Method for automatic load distribution between low-temperature gas separation lines at gas treatment plants using air cooling units, oil and gas condensate fields of northern russia - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.SUBSTANCE: invention relates to the field of extraction and preparation of natural gas for long-distance transportation at complex gas treatment plants (CGTP) of oil and gas condensate fields (OGCF) of Northern Russia. Proposed method includes control of a number of parameters by means of an automated process control system (APCS) of the CGTP. Among them is the flow of dried gas supplied to the main gas pipeline (MGP) and the flow of unstable gas condensate (UGC) supplied to the main condensate line (MCL). APCS maintains temperature of gas separation in each low-temperature separator and controls mode of its operation at specified value of gas flow therefrom. APCS, having received the task on production volume of CGTP UGC, executes it by means of PID-regulator of flow rate maintenance of UGC in MCL, implemented on the basis of APCS. At the SP input, this proportional-integral-derivative controller (PID) controller of the APCS PID controller controls the dispatcher setting signal, and at the same time to its feedback input the PV signals the current flow rate of the UGC to the MCL. Comparing the setpoint and current flow rate of the UGC, this PID controller generates a CV at its output CV, which sends the PID regulators of all process lines (PL) of low-temperature separation (LTS) of the gas, which are also implemented on the basis of APCS. To the PV feedback input of these PID-controllers APCS transmits the signal of actual flow of dried gas to CGTP. Also, at the input of CV of PID-controllers of each LTS TL, a signal of the coefficient of the proportionality factor Cp_i, (where i is the LTS TL number), which determines the degree of action of this PID-controller on the control valve (CV) of the gas flow rate through it LTS TL. Value of the coefficient of proportionality Cp_iis determined for each LTS TL by its proportionality coefficient calculation unit depending on the cooling capacity of its air cooling apparatus (ACA), installed after separator of first stage of separation, and its operation is controlled by individual automatic control system - ACS. At that, ACS in accordance with APCS task, which is generated taking into account current process parameters in each low-temperature separator and state of environment, controls cooling capacity of ACA gas and sends its corresponding signal to unit for calculation of coefficient of proportionality of its LTS TL.EFFECT: use of said method enables to provide a given degree of extraction of UGC from natural gas to CGTP at stages of constant, falling and final stages of operation of OGCF at compliance with norms and restrictions on process technological parameters, which are set by process procedure of installation.4 cl, 2 dwg

Description

The invention relates to the field of production and preparation of natural gas from Valanginian deposits (hereinafter natural gas) for long-distance transport at integrated gas treatment units (CTP) of oil and gas condensate fields (NGKM) in the North of the Russian Federation.

At the oil and gas condensate field of the North of the Russian Federation, the Valanginian deposits are being developed, located at a depth of about 3500 ÷ 3600 m, the formation gas of which contains a significant amount of condensate, reaching 300 ÷ 350 g / cubic meter [see, for example, p. 360, Andreev E.B. and other Automation of technological processes of oil and gas production and preparation: textbook for universities. - M .: LLC "Nedra-Business Center", 2008. - 399 p.]. The preparation of gas from Valanginian deposits for long-distance transport at the oil and gas condensate field of the North of the Russian Federation is carried out by the method of low-temperature separation (LTS) or low-temperature absorption (LTS), which are reduced to cooling natural gas with subsequent separation of the gas-condensate mixture into liquid and gas phases.

The technology of field processing of natural gases from the oil and gas condensate field of the North of the Russian Federation is characterized by a low degree of recovery of liquid hydrocarbons: ethane - about 10, propane-butanes - 30, heavy hydrocarbon components С _{5 + в} - 95 wt. % of their potential content in reservoir gas [for example, see p. 371, Gritsenko A.I. and other Collection, field preparation of gas in the northern fields of Russia. - M .: JSC "Publishing house" Nedra ", 1999. - 473 p.]. It is the relatively low level of hydrocarbon recovery in the field conditions of the oil and gas condensate field of the North of the Russian Federation that stimulated the widespread use of the LTS technological process with a temperature level of up to minus 30 ° C at the gas processing plant [for example, see 371-403, Gritsenko A.I. and other Collection, field preparation of gas in the northern fields of Russia. - M .: JSC "Publishing house" Nedra ", 1999. - 473 p.].

At the GPP, natural gas is dried for moisture and hydrocarbons to certain conditions in accordance with the requirements and standards for natural gas in a cold climatic zone according to OST 51.40-93 "Natural combustible gases supplied and transported through main gas pipelines", and unstable gas condensate (commercial) according to STO Gazprom 5.11-2008 “Unstable gas condensate”. In order to comply with the norms and requirements of these regulatory documents, as well as to obtain the temperature of the dried gas at the outlet of the gas treatment plant close to the ground temperature, which ensures a steady state of the "pipeline-permafrost" system, the temperature in the low-temperature separator must be maintained in the range of minus 23-30 ° С [ for example, see p. 778, Vyakhirev R.I., Gritsenko A.I., Ter-Sarkisov PM Development and operation of gas fields. - M .: LLC "Nedra-Business Center", 2002. - 880 p.].

To obtain low temperatures, the gas treatment plant uses reservoir energy of natural gas or its artificial cooling. In the first case, the temperature of natural gas decreases as a result of adiabatic expansion (throttling), in the second - due to external sources of cold - air coolers (AVO) in the cold season, and turboexpander units (TDA) in the warm season.

The duration of the cold period of the year, i.e. the low ambient temperature in the north lasts from September to May, which makes it possible to widely use the AVO for cooling natural gas at the GPP.

The technological process of collecting and preparing natural gas for long-distance transport provides for its supply from the clusters of production wells to the switching valve building of the UKPG. From it, through a common collector, the produced gas is distributed over several (up to 8, and in the future - and more) identical technological lines (TL) LTS [see. p. 361, Andreev E.B. and other Automation of technological processes of oil and gas production and preparation: textbook for universities. - M .: LLC "Nedra-Business Center", 2008. - 399 p.]. For example, at the Zapolyarnoye oil and gas condensate field, the gas treatment plant uses four LTS TLs.

During operation, for various reasons, for example, due to burst outbursts of water and sand production in wells arising from natural gas production, due to corrosion of equipment, etc., there is a change in the state of equipment TL LTS, leading to a deterioration in the quality of its operation. ... All this together reduces the separating properties of separators, increasing the carryover of dropping liquid and mechanical impurities from them. There is a decrease in the efficiency of the AVO and recuperative heat exchangers (HE) due to contamination of the surface of their heat exchange tubes, i.e. their thermal efficiency decreases. The formation of hydrate and other deposits in the units of the UKPG leads to a change in the pressure drop in them, which ultimately also affects the efficiency of their work.

It is obvious that the change in the state of the equipment of TL NTS at the GPP does not proceed in the same way. Therefore, the actual state of the equipment of TL NTS in terms of operability will differ from each other. Consequently, in order to increase the efficiency of the process of preparing natural gas for long-distance transport, the distribution of the load between the TL NTS of the UKPG in real mode of operation should be carried out taking into account the actual state of the equipment of each line. This will make it possible to significantly improve the quality of prepared natural gas for long-distance transport, subject to the norms and restrictions of the technological regulations of the CGTP.

The quality of marketable products in the process of low-temperature fusion is significantly influenced by the change in temperature in the low-temperature separator [for example, see, A.V. Kravtsov et al. Analysis of the influence of technological parameters and optimization of low-temperature separation processes. Bulletin of the Tomsk Polytechnic University. 2009. T. 315. No. 3, pp. 57-60]. Therefore, when preparing natural gas for long-distance transport, maintaining the set temperature in the low-temperature separator, regulated by the technological regulations of the UKPG, is of paramount importance. Those. to obtain unstable gas condensate (NTK) at the outlet of the gas treatment plant with the specified characteristics, it is necessary to strictly observe the operating temperature of the low-temperature separator within the limits of the settings provided for by the technological regulations of the unit. It is known that a decrease in the temperature in a low-temperature separator below the minimum setting T _min will cause the release of light fractions of condensate, which can lead to problems during its transportation, and an increase in temperature in it above the maximum setting T _max will lead to unjustified losses of valuable condensate components.

A known method of automatic control of natural gas preparation on TL LTS gas for long-distance transport, which allows you to automatically maintain the temperature of gas separation in a low-temperature separator, at a given value of gas flow rate on TL LTS, by changing the degree of gas throttling on the fittings facing these separators [see. , pp. 111-112, B.F. Taranenko, V.T. Hermann. Automatic control of gas production facilities. M., "Nedra", 1976, 213 p.].

The disadvantage of this method is that it does not take into account the actual state of the equipment in the distribution of the load between TL NTS. In addition, this method uses technological schemes for obtaining cold by throttling gas at the choke installed in front of the low-temperature separator, which is applicable only in the initial and increasing stages of oil and gas condensate field operation. These factors reduce the effectiveness of this cooling method, because it is not applicable for the preparation of natural gas for long-distance transport at the stages of constant, falling and final stages of oil and gas condensate field operation.

The closest in technical essence to the claimed invention is a method for automatic control of gas preparation on TL LTS gas for long-distance transport, which allows you to automatically maintain the temperature of gas separation in a low-temperature separator at a given value of gas consumption by using TDA in LTS gas schemes [see. p. 312, Bekirov T.M., Lanchakov G.A. Gas and condensate processing technology. M .: LLC "Nedra-Business Center". 1999. - 596 p.]

A significant disadvantage of this method is that in it, as in the analogue, the changes in the state of the equipment TL LTS occurring during operation are not taken into account when distributing the load between them.

The aim of the present invention is to improve the efficiency of the process of preparing natural gas for long-distance transport, which allows to improve the quality of prepared products (dried gas and STC) supplied to consumers at the constant, declining and final stages of oil and gas condensate field operation.

The technical result achieved from the implementation of the present invention is to ensure a predetermined degree of extraction of STC from natural gas at the GPP while observing the norms and restrictions on the technological parameters of the processes established by the technological regulations of the installation, ensuring the specified quality of preparation of natural gas and STC for long-distance transport, while taking into account the actual the condition of the equipment of each TL NTS.

The specified problem is solved, and the technical result is achieved due to the fact that the method of automatic load distribution between the TL LTS of gas at the GPP, with the use of AVO, NGKM of the North of the Russian Federation, includes control by means of an automated process control system (APCS) of the UKPG of a number of parameters. Among them is the consumption of dried gas entering the main gas pipeline (MGP) and STC entering the main condensate pipeline (MCP). The APCS maintains the gas separation temperature in each low-temperature separator and controls the mode of its operation at a given value of the gas flow through it.

This goal is achieved due to the fact that the automated process control system, having received the task for the production volume of the STC UKPG, performs it with the help of a proportionally integral differentiating (PID) regulator for maintaining the STC flow rate in the MCP. The APCS sends the dispatcher's task signal to the SP reference input of this PID controller, and at the same time, the PV feeds the current flow rate signal of the NTC to the MCP to its feedback input. Comparing the reference and the current flow rate of the NTC, this PID controller generates a reference signal at its output CV, which feeds the input of the reference SP of the PID regulators of all TL NTS. The ACS TP provides a signal of the actual dry gas flow rate through the GTP to the PV feedback input of these GHID-regulators. _{Also, at the same time, a signal of the proportionality coefficient value K p_i} (where i is the number of TL LTS) is fed to the input Кр of the PID controller installed at the input of the low-temperature separator of each TL LTS, which determines the degree of influence of this PID controller on the flow control valve (KR) controlled by it gas on its TL NTS. In this case, the value of the proportionality coefficient K _{p_i} is determined by the unit for calculating the proportionality coefficient of TL LTS, depending on the refrigerating capacity of its AVO, installed after the separator of the first stage of separation of TL LTS. The AVO operation is controlled by the AVO individual automatic control system (ACS).

Cooling capacity of AVO depends on the ambient temperature and the volume of air transported by its fans. It is characterized by the current value of the current consumed by the AVO electric motors, expressed as a percentage of the sum of the currents of the nominal rating values of the AVO electric motors.

In this case, the ACS, in accordance with the task of the ACS TP, taking into account the current values of the parameters of the technological process in each low-temperature separator and the state of the environment, changes the refrigerating capacity of the AVO gas in the required way and sends a signal corresponding to its value to the unit for calculating the proportionality coefficient of its TL LTS.

The proportionality coefficient K _p for the PID controller of each TL NTS determines its block for calculating the proportionality coefficient using the current value of the cooling capacity of the AVO gas of this line according to the following formulas:

if the production of STC for a given STL of STC needs to be increased, i.e. F _plan -F _fact > 0, then:

if the production of STC under this STL TL needs to be reduced, i.e. F _plan -F _fact <0, then:

where W _i - the current value of the cooling capacity of the AVO i-th TL LTS, coming from the ACS AVO, in the form of a signal to input I. _{1 of the} unit for calculating the proportionality coefficient of this line;

K _{p_max_i} is the setting of the maximum value of the proportionality coefficient of the PID controller of the i-th TL NTS, entering the input I. _{4 of} its blocks for calculating the proportionality coefficient;

K _{p_min_i} is the setting of the minimum value of the proportionality coefficient of the PID controller of the i-th TL NTS, entering the input I. _{5 of} its block for calculating the proportionality coefficient of this line.

W _{max_i} - the setting of the maximum cooling capacity of the AVO, supplied as a signal to input I. ₂ blocks for calculating the proportionality coefficient of the i-th TL NTS;

W _{min_i} is the setting of the minimum cooling capacity of the AVO, which is supplied as a signal to input I. ₃ blocks for calculating the proportionality coefficient of the i-th TL NTS;

In this case, the calculation of K _{p_i} according to formulas (1) and (2) is limited by the following conditions:

if K _{p_i} <K _{p_min_i} , then K _{p_i} = K _{p_min_i} ,

if K _{p_i} > K _{p_max_i} , then K _{p_i} = K _{p_max_i} .

The values of K _{p_min_i} and K K _{p_max_i} for each PID controller are set when setting up the control system by the service personnel based on the state of the equipment of the TL NTS at the time of starting the system, taking into account the technological norms and restrictions provided for by the technological regulations of the installation.

The values of W _{max_i} and W _{min_i} are set when setting up the management system for service personnel for each TL NTS based on the state of the equipment of a particular TL NTS at the time the system is launched, taking into account the AVO passport data.

If in the course of the technological process the value of the cooling capacity of the AVO at least one of the TL _LTS goes beyond W max_i or W _{min_i} indicated in the technological regulations of the UKPG, then the ACS of the AVO through the APCS generates a message about this to the plant operator to assess the current situation and make a decision on changing the technological operating mode of the installation.

If in the course of the technological process the value of the dew point temperature of the dried gas entering the MHP reaches the upper permissible limit determined by the technological regulations of the installation, the APCS generates a message about this to the operator of the installation to make a decision on changing the operating mode of the installation.

The use of this method makes it possible to provide a given degree of NTK extraction from natural gas at the CGTP at the stages of constant, falling and final stages of operation of the NGKF, subject to the norms and restrictions on the technological parameters of the process, imposed by the technological regulations of the unit. At the same time, the specified quality of natural gas and gas condensate preparation for long-distance transport is ensured by taking into account the actual condition of the gas treatment plant equipment.

FIG. 1 shows an enlarged schematic flow diagram of the GPP, and Fig. 2 block diagram of automatic control of load distribution between TL NTS UKPG.

FIG. 1, the following designations are used:

1 - raw gas collector;

2 _i - input line of the i-th LNV TL (i is the number of the LNV TL, i = 1, 2, ..., n, where n is the number of LNV TL at the GPP);

3 _i - separator of the first stage of separation of the i-th TL LTS;

4 _i - liquid separator of the i-th TL NTS;

5 _i - air cooler of the i-th TL NTS

6 _i - ACS AVO of the i-th TL NTS;

7 - gas condensate flow sensor for the UKPG;

8 _i - recuperative TO gas-condensate of the i-th TL NTS;

9 _i - recuperative TO gas-gas of the i-th TL LTS;

10 _i - intermediate separator of the i-th TL NTS;

11 _i - KP flow rate of the gas condensate mixture of the i-th TL LTS;

12 _i - low-temperature separator of the i-th TL NTS;

13 _i - temperature sensors in the low-temperature separator of the i-th TL NTS;

14 _i - flow sensor of dried gas of the i-th TL NTS;

15 - dry gas dew point temperature sensor;

16 - ACS TP UKPG;

For simplicity, FIG. 1 shows the connections of the sensors and KR with the APCS only for the 1st TL NTS.

FIG. 2, the following notation is used:

17 - signal of the actual flow rate of the NTC at the UKPG, the value of which is determined by the APCS according to the readings of the sensor 7;

18 - signal of the STC production plan for the GTP, set by the plant operator based on the daily production plan for the GTP, set by the dispatcher of the oil and gas production company;

19 - signal of the actual flow rate of dried gas at the UKPG, the value of which is determined by the APCS by summing the readings of the sensors 14 _i ;

20 _i - signal of the actual cooling capacity of AVO 5 _i for cold W _i i-th TL NTS;

21 _i - signal of the setpoint for the maximum cooling capacity of AVO 5 _i for cold W _{max_i of the} i-th TL NTS;

22 _i - setpoint signal for the minimum cooling capacity of AVO 5 _i for cold W _{min_i of the} i-th TL NTS;

23 _i - setpoint signal K _{p_max_i of the} maximum value of the proportionality coefficient of the PID controller 27 _{i of the} i-th TL NTS;

24 _i - setpoint signal K _{p_min_i of the} minimum value of the proportionality coefficient of the PID controller 27 _{i of the} i-th TL NTS;

25 - PID-regulator for maintaining the level of production of NTK at the UKPG;

26 _i - block for calculating the proportionality coefficient of the i-th TL NTS;

27, - PID-regulator that controls the production level of STC according to the i-th STL STC;

28 _i - control signal supplied to KR 11 _{i of the} gas-condensate mixture flow rate according to the i-th TL LNV.

The process of preparing natural gas for long-distance transport on the LTS TL, shown in Fig. 1, provides:

- primary separation of natural gas in the inlet separator 3 _i ;

- cooling of the extracted gas-condensate mixture in the air cooler 5 _i ;

- cooling the input flow of the gas-condensate mixture in the recuperative TO gas-gas 9 _i with the flow of cooled gas and gas-condensate 8 _i with the flow of cooled condensate;

- intermediate separation of the gas-condensate mixture in the separator 10 _i for its subsequent separation;

- partial cooling of the gas-condensate mixture by throttling the flow on the KP11 _i ;

- final separation of the cooled gas-condensate mixture in the low-temperature separator 12 _i .

The PID controller 25 for maintaining the production level of the STC at the UKPG, the blocks for calculating the proportionality coefficient 26 and the PID regulators 27 that control the production volume of the STC for each TL of the STC are implemented on the basis of the APCS.

The method of automatic distribution of the load between the TL LTS of gas at the GPP, using the AVO, NGKM of the North of the Russian Federation, is implemented as follows.

The produced natural gas from the clusters of production wells enters the building of the switching valves of the UKPG, from where it is distributed through the raw gas collector 1 between all TL LTS. For the i-th TL LTS, through its inlet line 2 _{i, the} produced gas is supplied to the separator 3 _{i of the} first separation stage, where the liquid phase is separated (formation water with a dissolved inhibitor and condensed hydrocarbon condensate). The separated gas-condensate mixture is fed to the AVO 5 _i , controlled by its ACS 6 _i , where it is pre-cooled to a temperature that provides a given technological mode in the low-temperature separator 12 (if the ambient temperature guarantees its implementation). From the outlet of AVO 5 _{i, the} gas-condensate mixture is divided into two streams, which are directed to the recuperative 9 _i gas-gas and TO 8 _i gas-condensate, to recover cold from the dried gas stream coming from the low-temperature separator 12 _i , and the gas-liquid phase with condensate removed from the intermediate separator 10 _i and the low-temperature separator 12 _i . To prevent hydrate formation, a hydrate inhibitor (not shown in Fig. 1) is injected into the _{mixture stream before TO 8 i} and TO 9 _i. Further, the flows of the cooled gas-liquid mixture from the outlets TO 8 _i "gas-condensate" and TO 9 _i "gas-gas" are combined and the total flow enters the inlet of the intermediate separator 10 _i , where further separation of the liquid phase takes place. From the outlet of the intermediate separator 10 _{i, the} gas-liquid mixture through KP 11 _i , which regulates the volume of condensate production according to the i-th TL of the LTS, enters the low-temperature separator 12 _i , where condensed liquid hydrocarbons and an aqueous solution of an inhibitor (VRI) of hydrate formation are finally separated from the mixture stream.

Maintaining the set temperature of the gas-condensate mixture in the low-temperature separator 12 is due to the regulation of the temperature of the gas-liquid mixture in the AVO 5, and the throttling of the gas at the KP 11 _i . At the same time, the maintenance of the required temperature in the low-temperature separator 12 _{i is} carried out by the ACS 16 by controlling the cooling capacity of the AVO 6 _i based on the readings of the temperature sensor 13, in the low-temperature separator of the i-th TL NTS.

The dried gas from the low-temperature separator 12 _i passes through the recuperative TO 9 _i , where it is heated and sent to the MGP equipped with a gas flow sensor 14 _i . The NGK leaving the low-temperature separator 12 _i and the intermediate separator 10 _i passes through the recuperative TO 8 _i and heats up. After that, it is mixed with the liquid phase withdrawn from the separator 3 _i , and enters the three-phase separator of liquids 4 _i . From the liquid separator 4, the weathering gas is sent either to the torch or used for own needs. VRI, withdrawn from the lower part of the three-phase separator of liquids 4 _i , is sent for regeneration to the regeneration shop of the inhibitor of the UKPG. NTK is fed to MCP for further transportation to consumers.

NTK is considered to be a more valuable product in comparison with dried gas, therefore, at the GPP, first of all, the level of production of NTK is maintained.

The ASU TP 16 supports the task of the dispatcher of the gas production company by the production level of STC by regulating the flow of natural gas at the GPP using the PID controller 25. For this, the APCS 16 sends a signal 18 to the input of the SP task of the PID controller 25, which corresponds to the production plan of the STC at the GPP. At the same time, the ACS TP 16 at the feedback input PV of the same PID controller from the sensor 7 sends a signal 17 of the value of the actual flow rate of the NTC at the UKPG. Comparing these two signals, the PID controller 25 at its CV output generates a control signal that provides a predetermined production level of the STC at the GTP, which is fed to the input of the SP setting of the PID controller 27 _{i of} each TL LTV. At the same time, to the PV feedback input of each PID controller 27 _{i, the} APCS 16 sends a common signal 19 for all, corresponding to the value of the actual total consumption of dried gas for all TL LTS UKPG, determined by summing the readings of their gas flow sensors 14 _i . Also, at the same time, the signal of the value of the proportionality coefficient K _{p_i} is fed to the input Кр of the PID controllers 27 _i , which determines the degree of influence of this PID controller on the КР 11 _{i of the} flow rate of the gas-liquid mixture along the i-th TL LTS. The value of the proportionality coefficient K _{p_i} for the PID controller 27 _i TL LTS is determined by its block for calculating the proportionality coefficient 26 _i , depending on the current cooling capacity of AVO 5 _i , the value of which in the form of a signal 20 _i comes from the ACS AVO 6 _i to input I. ₁ of the calculation block 26 _i .

The PID controller 25 for maintaining the production level of the STC continuously monitors the difference in values between the production plan of the STC at the GPP, coming from the plant operator, which is set on the basis of the daily production plan by the dispatcher of the oil and gas production company F the _plan and its actual value F _fact coming from the sensor 5. If As a result of the comparison, it _{turns out that F plan} - Fact> 0, then at the output of the PID controller 25 a control signal will be generated to increase the flow of natural gas through the installation. If F _plan -F _fact <0, then the output of the PID controller 25 will generate a control signal to reduce the flow of natural gas through the installation. This signal as a reference will go to the input SP of the reference of each PID controller 27 _i . As a result, the production of STC UKPG will increase in the first case, or decrease in the second case by the PID regulators 27 _i until the planned target is reached, characterized by the ratio F _plan -F _fact = 0. In this case, the proportionality coefficients K _{p_i} for each PID controller 27 _i will be calculated in its block 24, according to the following formulas:

If the production of STC needs to be increased, i.e. F _plan -F _fact > 0, then:

if the production of STC needs to be reduced, i.e. F _plan -F _fact <0, then:

where W _i is the current value of the cooling capacity of AVO 5 _i , supplied from the ACS AVO 6 _i , in the form of a signal 20, to the input I. _{1 of the} unit for calculating the proportionality coefficient 26 _i ;

W _{max_i} - the setting of the maximum cooling capacity of AVO 5 _i , supplied in the form of a signal 21 _i to input I. ₂ blocks for calculating the proportionality coefficient 26 _i ;

W _{min_i} is the setting of the minimum cooling capacity of AVO 5 _i , which is supplied in the form of a signal 22 _i to input I. ₃ blocks for calculating the proportionality coefficient 26 _i ;

K _{p_max_i} is the setting of the maximum value of the proportionality coefficient of the PID controller 27 _i , which is fed in the form of a signal 23 _i to the input I. ₄ blocks for calculating the proportionality coefficient 26 _i ;

K _{p_min_i} is the setting of the minimum value of the proportionality coefficient of the PID controller 27 _i , supplied in the form of a signal 24 _i to the input I. _{5 of the} unit for calculating the proportionality coefficient 26 _i ;

Calculation of K _{p_i} according to formulas (1) and (2) is limited by the following conditions:

if K _{p_i} <K _{p_min_i} , then K _{p_i} = K _{p_min_i} ,

if K _{p_i} > K _{p_max_i} , then K _{p_i} = K _{p_max_i} .

The values K _{p_min_i} and K _{p_max_i} for the PID controller are set when setting up the control system by the service personnel based on the state of the equipment of the i-th TL STC at the time of the system startup, taking into account the technological standards and restrictions provided for by the technological regulations of the installation.

The values of W _{max_i} and W _{min_i} are set when setting up the management system for service personnel based on the state of the equipment of the i-th TL at the time of starting the system, taking into account the passport data of AVO 5 _i .

This method of controlling the productivity of the unit for the production of STC allows you to distribute the load between TL STS, taking into account the state of their equipment, depending on the value of the current refrigerating capacity of AVO 5 _i , which, in turn, leads to the production of STC and gas with more stable quality characteristics.

ACS AVO 6 _i through ACS TP 16 strictly monitors the temperature regime of the low-temperature separator 12 _i . If in the course of the technological process the value of the cooling capacity of AVO 5 _i goes beyond W _{max_i} or W _{min_i} , (for example, in the event of warming or cooling of the atmosphere), then the ACS AVO 6 _i through the ACS TP 16 generates a message about this to the installation operator to assess the situation and make a decision on changing the technological mode of operation of the installation.

ACS TP 16 in real time monitors the parameters of the dew point temperature using the readings of the sensor 15. If the dew point temperature of the dried gas entering the MGP _reaches its upper limit T p_max, determined by the technological regulations of the installation, the ACS TP 16 generates a message about this to the installation operator to make a decision on changing the installation operating mode.

The tuning of the used PID controllers is carried out by the maintenance personnel at the time of starting the system into operation for a specific operating mode of the installation according to the method set forth, for example, in the "Encyclopedia of ACS TP", p. 5.5, PID controller, resource:

http://www.bookasutp.ru/Chapter5_5.aspx#HandTiming.

The method of automatic load distribution between TL LTS gas at the GPP using AVO, oil and gas condensate field of the North of the Russian Federation was implemented in PJSC Gazprom, OOO Gazprom dobycha Yamburg at the Zapolyarnoye oil and gas condensate field at GPP 1 V, UKPG 2 V. The results of operation showed its high efficiency. The claimed invention can be widely used in other operating and newly developed gas condensate fields in the Russian Federation.

The use of this method makes it possible to provide a given degree of NTK extraction from natural gas at the GPP at the constant, declining and final stages of the oil and gas condensate field operation, subject to the norms and restrictions on the technological parameters of the process determined by the technological regulations of the installation, with a given quality of natural gas preparation for long-distance transport, while taking into account the actual state of the equipment of TL NTS and the use of energy (cold) of the environment to save reservoir energy of the produced gas.

Claims (17)

1. Method of automatic load distribution between technological lines - TL of low-temperature separation - LTS of gas at integrated gas treatment plants - UKPG, using air coolers - AVO, oil and gas condensate fields of the North of the Russian Federation, including control by means of an automated process control system - ACS TP UKPG consumption of dried gas entering the main gas pipeline - MGP, the flow rate of unstable gas condensate - NTC, entering the main condensate pipeline - MKP, automatic maintenance of the gas separation temperature in the low-temperature separator at a given value of the gas flow through it, characterized in that the task of the dispatcher of the gas production enterprise by volume production STC enters the APCS, which performs the task with the help of the PID controller for maintaining the STC flow rate in the MCP, implemented on the basis of the APCS, to the SP input of which the APCS sends a dispatcher's task signal, and at the same time to its th feedback input PV sends a signal of the current flow rate of the NTC to the MCP, comparing which, this PID controller forms a reference signal at its output CV, which feeds the input of the reference SP of the PID controllers of all TL NTS, and controllers of the automated process control system sends a signal of the actual flow rate of dried gas through the gas treatment plant, and at the same time an individual signal of the value of the proportionality coefficient Kp is supplied to the input Kp of the PID controller of each TL LTS, which determines the degree of influence of this PID controller on the valve-regulator controlled by it - KP of the gas flow rate by its TL LTS, while the value of the proportionality coefficient Kp is determined individually for each TL LTS by its proportionality coefficient calculation unit, depending on the current refrigerating capacity for cooling its AVO gas, installed after the separator of the first stage of gas separation TL LTS and controlled by an individual automatic control system - ACS, which on the instructions of the APCS produced from Taking into account the current parameters of the technological process in each low-temperature separator and the state of the environment, it controls the refrigerating capacity of the AVO gas of each TL LTS and sends a signal corresponding only to it to the unit for calculating the proportionality coefficient of its TL LTS. 2. The method according to claim 1, characterized in that the proportionality coefficient K _{p_i} for the PID controller of the i-th TL NTS determines its block for calculating the proportionality coefficient, using the current value of the cooling capacity of the AVO gas of this TL, according to the following formulas: if production of NTS needs to be increased, i.e. F _plan -F _fact > 0, then

if the production of NTS needs to be reduced, i.e. F _plan -F _fact <0, then

where W _i - the current value of the cooling capacity of the AVO i-th TL LTS, coming from the ACS AVO in the form of a signal to input I. _{1 of the} unit for calculating the proportionality coefficient of this line; W _{max_i} - the setting of the maximum cooling capacity of the AVO, supplied as a signal to input I. ₂ blocks for calculating the proportionality coefficient for the i-th TL LTS; W _{min_i} is the setting of the minimum cooling capacity of the AVO, which is supplied as a signal to input I. ₃ blocks for calculating the proportionality coefficient for the i-th TL NTS; K _{p_max_i} is the setting of the maximum value of the proportionality coefficient of the PID controller for this TL NTS, which is supplied as a signal to the input I.4 of the block for calculating the proportionality coefficient of the i-th TLNTS; K _{p_min_i} is the setting of the minimum value of the proportionality coefficient of the PID controller for the i-th TL NTS, which is supplied as a signal to input I. _{5 of the} block for calculating the proportionality coefficient of this TL NTS, in this case, the calculation of K _P by formulas (1) and (2) is limited by the following conditions: if K _{p_i} <K _{p_min_i} , then K _{p_i} = K _{p_min_i} , if K _{p_i} > K _{p_max_i} , then K _{p_i} = K _{p_max_i} , at the same time, the values of K _{p_min_i} and K _{p_max_i} for each PID regulator of the TL NTS are set when setting up the control system by the service personnel, taking into account the current state of the equipment of the lines, technological standards and restrictions provided for by the technological regulations of the installation, and the values of W _{max_i} and W _{min_i} are set when setting up the system control for each TL NTS by the service personnel based on the state of the equipment at the time of the system startup, taking into account the passport data of the AVO. 3. The method according to claim 1, characterized in that if during the technological process the value of the cooling capacity of the AVO of at least one of the TL _LTS goes beyond the boundaries of W max_i or W _{min_i} indicated in the technological regulations of the UKPG, then the APCS generates a message about this to the plant operator to assess the current situation at a specific TL LTS and make a decision on changing the technological mode of operation of the installation. 4. The method according to claim 1, characterized in that if during the technological process the value of the dew point temperature of the dried gas entering the MGP reaches the upper permissible limit determined by the technological regulations of the installation, the APCS generates a message about this to the operator of the installation for making a decision on changing the operating mode of the installation.

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