RU2743690C1 - Method for automatic load distribution between low-temperature gas separation lines with turbo-expander units at gas treatment facilities of northern russia - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention relates to production and preparation of natural gas of Valanginian deposits (hereinafter - natural gas) to long-distance transport at complex gas treatment plants (CGTP) of oil and gas condensate fields (OGCF) of Northern Russia. Proposed method comprises monitoring by means of automatic process control system (APCS) of CGTP by a number of parameters. Among them is the flow of dried gas supplied to the main gas pipeline (MGP) and consumption 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 by changing degree of adiabatic expansion of gas with performance of external mechanical work in turboexpander unit (TEU), standing in front of each low-temperature separator. APCS, having received the task by the CGTP UGC production volume, it executes with the help of the proportional-integral-differentiating (PID) regulator the UGC flow rate maintenance in the MCL based on the APCS. At the SP setting input of this PID controller, the APCS sends the dispatcher setting signal, and simultaneously to its feedback input PV supplies the UGC current flow signal to the MCL. Comparing the reference and the current flow rate of the UGC, this PID controller generates, at its output CV, a setting signal which supplies the PID control inputs of the PID regulators of all LTS TL gas to the input of the SP, which are also implemented based on APCS. And to the PV feedback input of these PID-controllers APCS sends a signal of actual flow of dried gas to CGTP -V. Also, at the input of CV of PID-controllers of each LTS TL, a signal of the coefficient of the proportionality factor C_{p_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 C_{p_i} is determined individually for each LTS TL by its unit for calculating the proportionality coefficient depending on the speed of rotation of the TEU rotor, which is recorded by the ACS with the help of a rotor rpm sensor. Application of this method allows to ensure the specified degree of UGC extraction from natural gas to CGTP at stages of constant, falling and finishing stages of OGCF operation at compliance with norms and restrictions on process technological parameters, which are set by process procedure of the installation.

EFFECT: preset quality of natural gas and gas condensate treatment for long-distance transport is ensured by taking into account actual condition of CGTP equipment.

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 in 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 a liquid and a gas phase.

The technology of field processing of natural gases from oil and gas condensate fields in 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.]. 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 has created the possibility of widespread use of the LTS technological process at temperatures up to minus 30 ° С 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”. To comply with the norms and requirements of these regulatory documents, the temperature in the low-temperature separator must be maintained at a level of minus 23-30 ° C. It is also necessary to obtain the temperature of the dried gas at the CGTP outlet close to the ground temperature in order to ensure the steady state of the pipeline system - permafrost in the North [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) and turboexpander units (TDA). As you know, in the conditions of constant, falling and final stages of operation of the oil and gas condensate field, as a rule, external sources are used to obtain cold at the gas processing plant - AVO (in the cold season) and TDA (in the warm season).

Cold period of the year, i.e. low ambient temperature - lasts from October to May and allows the use of AVO to cool natural gas at the gas processing plant operated in the northern regions of the Russian Federation. However, during the warm period of the year - from May to October, the maximum ambient temperature can reach + 24 - + 35 ° С (such cases are observed in the second half of July - in the first decade of August) [for example, see p. 49, Ananenkov A.G. and other ACS TP of gas production facilities. - M .: LLC "Nedra-Business Center", 2003. - 343 p.]. During this period, it is impossible to use AVO as an external source of cold when preparing natural gas for long-distance transport at the GPP. Therefore, in the warm season, TDA is widely used to cool natural gas at the gas processing plant.

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) of LTS gas [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 TL LTS of gas.

During operation, for various reasons, for example, due to burst outbursts of water and sand production in wells arising from the production of natural gas, due to corrosion of equipment, etc., the state of the equipment of the TL NTS changes, including the deterioration of the quality of work. separators. As a result, the entrainment of dropping liquid and mechanical impurities increases, which leads to a decrease in the efficiency of 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 LTS 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 each line. This makes it possible to significantly improve the quality of natural gas preparation for long-distance transport while observing the norms and limitations of the process regulations of the UKPG.

The quality of marketable products during the LTS process 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. This is due to the fact that lowering the temperature in the 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 unnecessary losses of condensate.

There is a 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 according to TL LTS, by changing the degree of gas throttling at the choke in front of this separator [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 the gas at the choke in front of the low-temperature separator, and this is possible only in the initial and increasing stages of oil and gas condensate field operation. These factors reduce the effectiveness of this method, and it is not applicable for the preparation of natural gas for long-distance transport at the stages of constant, declining and final stages of oil and gas condensate field operation in the warm season.

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 stages of 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 provide a predetermined degree of NTK extraction from natural gas at the GPP, subject to the norms and restrictions on the technological parameters of the process specified by the technological regulations of the installation. As a result, the specified quality of preparation of natural gas and STC for long-distance transport is ensured, taking into account the actual state of the technological equipment.

This problem is solved, and the technical result is achieved due to the fact that the method of automatic load distribution between TL LTS with TDA at the gas processing plant of the oil and gas condensate field of the North of the Russian Federation includes control by means of an automated process control system (APCS) of the gas processing plant 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 its operation mode by changing the degree of adiabatic expansion of the gas with the performance of external mechanical work in the TDA in front of each low-temperature separator.

At the same time, the APCS, having received the task for the production volume of the STC of the UKPG, executes it with the help of the proportional-integral-differentiating (PID) controller for maintaining the STC flow in the MCP, implemented on the basis of the APCS. The APCS sends a dispatcher's task signal to the SP setting input of this PID controller, and at the same time PV sends a signal of the current flow rate 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 LPG gas, which are also implemented on the basis of the APCS. And to the PV feedback input of these PID controllers, the APCS sends a signal of the actual dry gas flow rate at the CGTP. Also, at the same time, the signal of the value of the proportionality coefficient K _{p_i} (i is the line number) is sent to the input of the PID controller of each TL NTS, which determines the degree of influence of this PID controller on the gas flow rate controller (KR) controlled by it, according to its TL NTS, installed after separator of the first separation stage. In this case, the value of the proportionality coefficient K _{p_i} is determined for each TL LTS by its unit for calculating the proportionality coefficient, depending on the rotor speed of the TDA, recorded by the APCS using the rotor speed sensor according to the following formulas:

if productivity needs to be increased, i.e. F _plan -F _fact > 0, then:

if performance needs to be reduced, i.e. F _plan -F _fact <0, then:

where ST _i is the current value of the TDA rotor speed, supplied to input I. _{1 of the} unit for calculating the proportionality coefficient of the i-th TL NTS;

ST _{max_i} is the setting of the maximum rotor speed TDA supplied to input I. ₂ blocks for calculating the proportionality coefficient of the i-th TL NTS;

ST _{min_i} is the setting of the minimum rotor speed TDA supplied to input I. ₃ blocks for calculating the proportionality coefficient of the i-th TL NTS;

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

K _{p_min_i} is the setting of the minimum value of the proportionality coefficient of the PID controller, supplied to input I. _{5 of the} block 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 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, taking into account the technological standards and restrictions provided for by the technological regulations of the installation.

The values ST _{min_i} and ST _{max_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 of system startup, taking into account the TDA passport data.

If in the course of the technological process the value of the rotor speed of the TDA of the i-th TL _LTS goes beyond the boundaries of ST max_i or ST _{min_i} , then the APCS generates a message about this to the plant operator to assess the situation and make a decision to change the technological mode of the plant.

If in the course of the technological process the value of the dew point temperature of the dried gas entering the PGM 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.

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

6 - gas condensate flow sensor for the UKPG;

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

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

9 _i - intermediate separator for separation of the i-th TL LTS;

10 _i - TDA of the i-th TL NTS;

11 _i - rotor speed sensor TDA of the i-th TL NTS;

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

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

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

15 _i - KR for maintaining the rotor speed of the TDA of the i-th TL NTS;

16 - dry gas dew point temperature sensors;

17 - APCS of the 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:

18 - 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 5;

19 - signal of the STC production plan for the GTP, coming from the plant operator (set on the basis of the daily production plan for the GTP by the dispatcher of the oil and gas production company);

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

21 _i - signal of the actual rotation speed SP _{i of the} rotor TDA 10 _{i of the} i-th TL NTS, which is determined using the rotor speed sensor 11 _i ;

22 _i - signal of the setting of the maximum speed of rotation SP _{max_i of the} rotor TDA 10 _{i of the} i-th TL NTS;

23 _i - signal of the setting of the minimum rotation speed SP _{min_i of the} rotor TDA 10 _{i of the} i-th TL NTS;

24 _i - signal of the setting of the maximum value of the proportionality coefficient K _{p_max_i of the} PID controller 28 _{i of the} i-th TL NTS;

25 _i - signal of the setting of the minimum value of the proportionality coefficient K _{p_min_i of the} PID controller 28 _{i of the} i-th TL NTS;

26 - PID-regulator for maintaining the production level of NTK at the GPP;

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

28 _i - PID-regulator of the production level of STC according to the i-th STL STC;

29 _i - control signal supplied to KP 5 _{i of the} natural gas flow rate of the i-th TL LTS.

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 the input flow of the gas-condensate mixture in the recuperative TO gas-gas 8 _i with the flow of cooled gas and gas-condensate 7 _i with the flow of cooled condensate;

- intermediate separation of the gas-condensate mixture in the separator 9 _i for its subsequent separation;

- cooling of the gas-condensate mixture due to the operation of TDA 10 _i , in which adiabatic expansion of the gas occurs in the turbine section with energy transfer to the machine shaft, which makes it possible to obtain significant cooling of the mixture due to work in the compressor section;

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

The PID controller 26 for maintaining the production level of the STC at the GPP, the blocks for calculating the proportionality coefficient 27 _i and all the PID controllers 28 _i , which provide the total production level of the STC for the TL STC, are implemented on the basis of the APCS.

The method of automatic load distribution between TL LTS with TDA at the gas processing plant of the oil and gas condensate field of the North of the Russian Federation is implemented as follows.

Natural gas from the clusters of production wells enters the switching valve building of the UKPG, from where it is distributed through the raw gas collector 1 between the TL LTS and through the input lines 2 _i is fed to the separator of the first separation stage 3 _i . It separates the liquid phase (formation water with a dissolved inhibitor and condensed hydrocarbon condensate). The separated gas-condensate mixture passes through the flow control valve 5 _i , after which it is divided into two streams, which are sent to the recuperative TO gas-gas 8 _i and gas-condensate 7 _i , for cold recovery from the throttled gas and condensate flow removed from the intermediate separator 9 _i and 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 7 _i. Further, the flows of the cooled gas-liquid mixture from the outputs of TO 7 _i "gas-condensate" and 8 _i "gas-gas" are combined and their total flow enters the inlet of the intermediate separator 9 _i , where further separation of the liquid phase occurs. From the outlet of the intermediate separator 9 _{i, the} gas-liquid mixture is fed to the inlet of the turbine part of the TDA 10 _i equipped with a rotor speed sensor 11 _i . Further, from the outlet of the TDA 10 _i , the gas-condensate mixture 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 it.

The decrease in the temperature of the gas-condensate mixture in the low-temperature separator 12 _i occurs due to the expansion of the gas flow with the performance of external mechanical work in the TDA 10 _i . Gas expansion with energy removal leads to a significant decrease in its temperature, i.e. to the development of "cold". Maintaining the temperature within the specified limits in the low-temperature separator 12 is carried out by the automated process control system of the UKPG 17 by adjusting the rotor speed of the TDA 10 _i , carried out by the regulator valve 15 _i , maintaining the rotor speed of the TDA based on the readings of the sensor 11 _i of the rotor speed, as described in the patent on RF invention No. 2680532.

Dry gas from low temperature separator 12_i passes through recuperative TO 8_i, where it heats up and further, through KP 15_i for maintaining the rotor speed, the TDA is supplied through a branch pipe equipped with a gas flow sensor 14_i, in IHL. NTC streams from low-temperature separator 12_i and intermediate separator 9_i combine and pass through the recuperative TO 7_i, in which the total flow is heated, and after leaving it is mixed with the liquid phase removed from the separator 3_i, and enters a three-phase liquid separator 4_i... From it, the weathering gas is sent either to the torch or used for own needs. VRI output from the bottom of the three-phase liquid separator 4_i, is sent for regeneration to the inhibitor regeneration workshop of the UKPG, and the NTC is fed to the MCP for further transportation to consumers.

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

The ASU TP 17 supports the task of the dispatcher of the gas production company by the production level of STC by regulating the flow rate of natural gas at the GPP using the PID controller 26. For this, the APCS 17 at the input of the SP task of the PID regulator 26 sends a signal 19 of the STK production plan at the GPP. At the same time, the ACS TP 17 sends a signal 18 from the sensor 6 to the PV feedback input of the same PID controller, which measures the value of the actual flow rate of the NTC at the UKPG. Comparing these two signals, the PID controller 26 at its output CV generates a control signal that provides a predetermined level of production of the NTC at the GTP, which is fed to the input of the set point SP of the PID controller 28 _{i of} each TL NTS. At the same time, the ACS TP 17 sends a common signal 20 to the PV feedback input of each PID controller 28 _i - the value of the total dry gas flow rate for all TL LTS UKPG, which is determined by summing the readings of the gas flow sensors 14 _i for each TL LTS. Also, at the same time, the signal of the proportionality coefficient value K _{p_i} is fed to the input Kp of each PID controller 28 _i , (i is the number of lines), which sets the degree of influence of the PID controller on its KP 5 _{i of the} gas flow rate along the i-th TL LTS. In this case, the value of the proportionality coefficient K _{p_i} is determined for each TL LTS by its block for calculating the proportionality coefficient 27 _i , depending on the current rotor speed of the TDA 10 _i , measured by the sensor 11 _i , the signal 21 _i from which is fed to the input I. ₁ block for calculating the proportionality coefficient 27 _i .

The PID controller 26 for maintaining the production level of the STC continuously monitors the difference in values between the production _plan F, the STC plan for the GPP, coming from the plant operator, which is set by the dispatcher of the oil and gas production company based on the daily production plan and its actual value F _fact coming from the sensor 6. If in As a result of the comparison, it turns _{out that F plan -F fact} > 0, then at the output of the PID controller 26 a control signal will be generated to increase the flow rate of natural gas in the installation. And if F _plan -F _fact <0, then at the output of the PID controller 26 a control signal will be generated to reduce the consumption of natural gas in the installation. This signal, as a reference, is fed to the input of the SP reference of each PID controller 28. As a result, the productivity of the STC UKPG will increase in the first case, or decrease in the second case until reaching the planned task, at which F _plan -F _fact = 0, with this proportionality coefficients K _{p_i} for each PID controller 28 _i . will be calculated in its block 27 _i according to the following formulas:

If productivity needs to be increased, i.e. F _plan -F _fact > 0, then:

if performance needs to be reduced, i.e. F _plan -F _fact <0, then:

where ST _i is the current value of the rotor speed of the TDA 10 _i , coming from the sensor 11 _i , which is fed in the form of a signal 21 _i to the input I. _{1 of the} unit for calculating the proportionality coefficient 27 _i ;

ST _{max_i} is the setting of the maximum rotor speed of the TDA 10 _i , which is fed in the form of a signal 22 _i to input I. _{2 of the} unit for calculating the proportionality coefficient 27 _i ;

ST _{min_i} is the setting of the minimum rotor speed TDA 10 _i , which is fed in the form of a signal 23 _i to input I. ₃ blocks for calculating the proportionality coefficient 27 _i ;

K _{p_max_i} is the setting of the maximum value of the proportionality coefficient of the PID controller 28 _i , supplied in the form of a signal 24 _i to the input I. ₄ blocks for calculating the proportionality coefficient 27 _i ;

K _{p_min_i} is the setting of the minimum value of the proportionality coefficient of the PID controller 28 _i , supplied in the form of a signal 25 _i to the input I. _{5 of the} unit for calculating the proportionality coefficient 27 _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 ST _{min_i} and ST _{max_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 of system startup, taking into account the passport data TDA 10 _i .

The values of K _{p_min_i} and K _{p_max_i} for the PID controller 28 _i are set when setting up the control system by the operating personnel, taking into account the technological standards and restrictions provided for by the technological regulations of the installation.

This method of managing the plant's performance allows the load to be distributed between TL LTS, taking into account their state, depending on the workload of TDA 10 _i , which in turn ensures the production of LTS and gas with more stable quality characteristics.

ACS TP 17 strictly monitors the temperature regime of the low-temperature separator 12 _i . If during the technological process the value of the rotor speed of the TDA 12 _i goes beyond the boundaries of ST _{max_i} or ST _{min_i} , then the APCS 17 generates a message about this to the plant operator to assess the current situation and make a decision to change the technological mode of the plant.

ACS TP 17 in real time monitors the parameters of the dew point temperature, using the readings of the sensor 16. If the dew point temperature reaches its upper (T _{p_max} ) boundaries determined by the technological regulations of the installation, the ACS TP 17 generates a message about this to the operator of the installation to make a decision to change the operating mode of the installation.

The tuning of the used PID controllers is carried out by the maintenance personnel at the time of starting the system 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#HandTuning.

The method of automatic load distribution between TL LTS with TDA at the gas treatment plant of the 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 the gas treatment plant 1 V, the gas treatment plant 2 V. The results of operation have shown 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 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.

Claims (17)

1. Method of automatic load distribution between technological lines - TL of low-temperature separation - LTS of gas with turbo-expander units - TDA at integrated gas treatment plants - UKPG in the north of the Russian Federation, including control by means of an automated process control system - APCS of UKPG of dried gas flow entering the main gas pipeline - MGP, the flow rate of unstable gas condensate - NTC entering the main condensate pipeline - MKP, maintaining the gas separation temperature in each low-temperature separator and controlling its operation mode by changing the degree of adiabatic gas expansion with the performance of external mechanical work in the TDA facing each low-temperature separator , characterized in that the task of the dispatcher of the gas production enterprise in terms of the production volume of the STC is sent to the APCS, which executes it with the help of the PID controller for maintaining the STC flow in the MCP, implemented on the basis of the APCS, at the input d set SP of which the APCS sends a dispatcher's task signal, and at the same time, to its feedback input, PV sends a signal of the current flow rate of the NTC to the MCP, comparing which this PID controller generates a reference signal at its CV output, which feeds the SP reference input of the PID controllers of all TL LTS gas, also implemented on the basis of the APCS, and at the feedback input PV of these PID controllers, the APCS sends a signal of the actual dry gas flow rate through the UKPG-V, and simultaneously to the input of the PID controller of the PID controller of each TL LTS, the signal of the coefficient value proportionality K _{p_i} , which determines the degree of influence of this PID controller on the control valve controlled by it - KP of the gas flow rate along its TL LTS, installed after the separator of the first separation stage, while the value of the proportionality coefficient K _{p_i} is determined for each TL LTS by its proportionality coefficient calculation unit depending on the rotor speed of the TDA of this line, recorded by the APCS using the speed sensor rotation of the rotor. 2. The method according to claim 1, characterized in that the proportionality coefficient K _{p_i} for the PID controller of each TL NTS determines its block for calculating the proportionality coefficient using the current value of the rotor speed TDA of this TL NTS according to the following formulas: if productivity needs to be increased, i.e. F _plan -F _fact > 0, then:

if performance needs to be reduced, i.e. F _plan -F _fact <0, then:

where ST _i is the current value of the TDA rotor speed, supplied to input I. _{1 of the} unit for calculating the proportionality coefficient of the i-th TL NTS; ST _{max_i} is the setting of the maximum rotor speed TDA supplied to input I. ₂ blocks for calculating the proportionality coefficient of the i-th TLNTS; ST _{min_i} is the setting of the minimum rotor speed TDA supplied to input I. ₃ blocks for calculating the proportionality coefficient of the i-th TL NTS; K _{p_max_i} is the setting of the maximum value of the proportionality coefficient of the PID controller, supplied to input I. ₄ blocks for calculating the proportionality coefficient of the i-th TL NTS; K _{p_min_i} is the setting of the minimum value of the proportionality coefficient of the PID controller, which is fed to input I. _{5 of the} block for calculating the proportionality coefficient of the i-th TL NTS, in this case, the calculation of K _n 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} . and the values of Кп_min_i and _{Кп_max_i} for the PID controller are set when setting up the control system by the service personnel, taking into account the technological standards and restrictions provided for by the technological regulations of the installation, and the values ST _{min_i} and ST _{max_i} are set when setting up the control system of the service personnel for each TL STC based on the state equipment of a specific TL NTS at the time of launching the system, taking into account the passport data of the TDA. 3. The method according to claim 1, characterized in that if, during the technological process, the value of the rotor speed of the TDA of the i-th TL NTS goes beyond the boundaries of ST _{max_i} or ST _{min_i} , then the APCS generates a message about this to the installation operator to assess the current situation and making a decision to change the technological mode of operation of the installation. 4. The method according to claim 1, characterized in that if during the technological process the dew point temperature 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 to change the operating mode of the installation.

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