RU2743870C1 - Method for automatic load distribution between low-temperature gas separation lines at gas treatment plants of 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. Method includes monitoring by means of automatic process control system (APCS) of CGTP, flow rate of dried gas supplied to main gas pipeline (MGP), flow rate of unstable gas condensate (UGC) supplied to main condensate line (MCL), automatic maintenance of gas separation temperature in low-temperature separator of each technological line (TL) of low-temperature gas separation (LTGS) at a given gas flow rate therefrom by varying the degree of gas throttling on the union facing the separator. Task of the dispatcher of the gas producing company as per the volume of production of UGC is sent to the automated control system, which executes the task with the help of a proportional integral differentiating (PID) controller for maintaining the flow rate of UGC in the MCL, which is implemented on the basis of APCS. To the SP setting input of this PID-controller APCS sets the dispatcher setting signal. Simultaneously, APCS sends to its PV feedback input a signal of current flow rate of UGC in MCL. 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. Simultaneously, to the PV feedback input of these PID controllers, the APCS sends a signal of actual flow of the dried gas to the CGTP. 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 for each LTS TL by its proportionality coefficient calculation unit depending on the current temperature in the low-temperature separator of said lines by the readings recorded by the ACS with the help of a corresponding temperature sensor.

EFFECT: method provides a given degree of UGC extraction from natural gas at the CGTP in the initial and increasing stages of the OGCF operation with observance of the norms and restrictions on the process technological parameters, which are set by the process regulations of the installation, guaranteeing the specified quality of natural gas treatment for long-distance transport with simultaneous consideration of actual condition of the equipment of the plant.

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, Valanginian deposits are being developed, located at a depth of about 3500 ÷ 3600 m, formation gas which contains a significant amount of condensate, reaching 300 ÷ 350 g / cubic meter [see, for example, p. 360, Andreev Ye.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.]. At high reservoir pressures, which are typical for Valanginian deposits, gas preparation for long-distance transport is carried out by low-temperature separation (LTS) or low-temperature absorption methods, which are reduced to natural gas cooling with subsequent separation of the gas-condensate mixture into liquid and gas phases.

The technology of field processing of natural gases at the oil and gas condensate field 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 C _{5 + B} - 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 in the North of the Russian Federation that 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 pp. 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. This mode of operation of the low-temperature separator ensures that the temperature of the dried gas at the outlet of the GPP is close to the temperature of the soil, which in the North guarantees the stationarity of the state of the pipeline system - permafrost [for example, see p. 778, Vyakhirev RI, Gritsenko AI. , Ter-Sarkisov PM Development and operation of gas fields. - M .: LLC "Nedra-Business Center", 2002. - 880 p.].

To obtain low temperatures, the gas processing unit uses reservoir energy of natural gas or 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 cooling units, turbo expander units). In the initial and increasing stages of oil and gas condensate field operation, as a rule, technological schemes are used with obtaining cold due to gas throttling at the choke.

According to the technological process of collecting and preparing natural gas for long-distance transport, natural gas from the clusters of production wells enters the GPP - the switching valve building. From it, gas through a common collector 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 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 work, including the deterioration of the separation properties of separators. This increases the carryover of dropping liquid and mechanical impurities from them, which leads to a decrease in the efficiency of recuperative heat exchangers (HE) due to contamination of the surface of their heat exchange tubes. The formation of hydrate and other deposits in the units of the CGTP occurs, which leads to a change in the pressure drop in them and, ultimately, 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 over time will differ from each other. Consequently, in order to increase the efficiency of the process of preparing natural gas for long-distance transport, it is necessary to distribute the load between the TL NTS of the UKPG in the real mode of its operation, taking into account the actual state of each line. This will significantly improve the quality of the prepared natural gas for long-distance transport, while observing the norms and restrictions of the technological regulations of the CGTP.

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. This means that in order to obtain unstable gas condensate (NGK) at the outlet of the GPP 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. Indeed, a decrease in the temperature in the low-temperature separator below the minimum setting T _min causes 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.

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. This factor reduces the efficiency of the gas-condensate mixture separation process and leads to a deterioration in the quality of both the prepared gas and the NGK for long-distance transport.

The closest in technical essence to the claimed invention is a method of 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 flow through it by changing the degree of gas throttling at the fittings facing these separators [see. p. 404, Isakovich R.Ya., Loginov V.I., Popadko V.E. Automation of production processes in the oil and gas industry. Textbook for universities. M., nedra, 1983, 424 p.]

A significant disadvantage of this method is that it, like in the analogue, does not take into account the changes in the state of the equipment of the TL NTS, which occur during operation and which must be taken into account when distributing the load between the TL NTS. This factor reduces the efficiency of the gas-condensate mixture separation process and leads to a deterioration in the quality of both the prepared gas and the NGK for long-distance transport.

The aim of the present invention is to improve the efficiency of the process of preparing natural gas and oil and gas condensate for long-distance transport and improve the quality of prepared products for delivery to consumers.

The technical result achieved from the implementation of the present invention is to provide a predetermined degree of oil and gas recovery from natural gas at the gas processing plant, subject to the norms and restrictions on the technological parameters of the process established by the technological regulations of the installation, while taking into account the actual state of its equipment to optimize the LTS gas processes.

The specified problem is solved, and the technical result is achieved due to the fact that the method of automatic load distribution between TL LTS at the gas processing plant of the oil and gas condensate field in the North of the Russian Federation includes control by means of an automated process control system (APCS) of the gas processing plant:

- consumption of dried gas entering the main gas pipeline (MGP);

- the consumption of NGK entering the main condensate pipeline (MCP);

- automatic maintenance of the gas separation temperature in the low-temperature separator of each TL NTS at a given value of the gas flow through it by changing the degree of gas throttling at the choke in front of this separator.

This goal is achieved due to the fact that the task of the dispatcher of the gas production company in terms of oil and gas production volume is sent to the automated process control system of the gas processing plant, which performs the task using a proportionally integral differentiating (PID) regulator for maintaining the oil and gas production in the MCP, implemented on the basis of the automated process control system. The control signal of the dispatcher is sent to the SP reference input of this PID-controller of the ACS TP. At the same time, the APCS sends a signal of the current flow rate of the oil and gas condensate to the MCP to its PV feedback input. The PID controller compares these parameters and generates a reference signal at its CV output, which feeds the SP reference input of the PID controllers of all LPNC gas TLs. At the same time, to the PV feedback input of these PID controllers, the ACS sends a signal of the actual dry gas flow rate at the gas treatment plant. Also, at the same time, the values of the proportionality coefficient K _{p_i are} fed to the input Kp of the PID controller of each TL NTS, where i is the TL NTS number, which determines the degree of influence of this PID controller on the gas flow rate regulator (KR) controlled by it according to 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 the TL LTS, depending on the current temperature in the low-temperature separator of this line according to the readings recorded by the APCS using the appropriate temperature 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 T _i is the current value of the temperature in the low-temperature separator of the i-th TL NTS, entering the input Ii of its block for calculating the proportionality coefficient;

T _{max_i} is the setting of the maximum allowable temperature in the low-temperature separator of the i-th TL LTS, entering the input I. _{2 of} its block for calculating the proportionality coefficient;

T _{min_i} is the setting of the minimum permissible temperature in the low-temperature separator of the i-th TL LTS, entering the input I. _{3 of} its blocks for calculating the proportionality coefficient;

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 24 _i .

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} , K _{p_max_i} , _{Tmax_i} and _{Tmin_i} are set when setting up the control system for the operating personnel, taking into account the technological standards and restrictions provided for by the technological regulations of the installation.

If, during the technological process, the temperature in the low-temperature separator by one of the TL LTS goes beyond the boundaries of T _max or T _min 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 on a specific TL LTS and make a decision to change technological mode of operation 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.

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 is the 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 - gas condensate flow sensor for the UKPG;

6 _i - recuperative heat exchanger (TO) gas-condensate of the i-th TL LTS;

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

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

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

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

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

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

13 - dry gas dew point temperature sensors;

14 - 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:

15 - signal of the actual consumption of NGK at the UKPG, generated by the APCS according to the readings of the sensor 5;

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

17 - signal of the actual consumption of dried gas for the UKPG, the value of which is determined by the APCS by summing the readings of the sensors 12 _i ;

18 _i - signal of the actual gas temperature measured by the sensor 11 _i in the low-temperature separator 10 _{i of the} i-th TL LTS;

19 _i - T _{max_i} - setting of the maximum allowable temperature in the low-temperature separator 10 _{i of the} i-th TL NTS;

20 _i - T _{min_i} is the setting of the minimum allowable temperature in the low-temperature separator 10 _{i of the} i-th TL NTS;

21 _i - K _{p_max_i} is the setting of the maximum value of the proportionality coefficient of the PID controller 25 _{i of the} i-th TL NTS;

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

23 - PID-regulator for maintaining the oil and gas production level at the GPP;

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

25 _i - PID-regulator, which ensures the level of oil and gas production according to the i-th TL STS;

26 _i - control signal supplied to the KR of natural gas flow rate 9 _i i-th TL NTS, supplied from the PID controller 25 _i .

The process of preparing natural gas for long-distance transport on the i-th TL LTS, 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 7 _i with the flow of cooled gas and gas-condensate 6 _i with the flow of cooled condensate;

- intermediate separation of the gas-condensate mixture in the separator 8 _i for its subsequent separation;

- cooling of the gas-condensate mixture by throttling the flow to KP 9 _i ;

- final separation of the cooled gas-condensate mixture in the low-temperature separator 10 _i .

The PID controller 23 for maintaining the oil and gas complex production at the GPP, the proportionality coefficient calculation blocks 24 and the PID controllers 25 that ensure the production level of the STC are implemented on the basis of an automated process control system.

The method of automatic load distribution between TL NTS at the gas processing plant of the oil and gas condensate field in the north of the Russian Federation is implemented as follows.

Natural gas from the clusters of production wells enters the GPP - to the switching valve building, 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 , where it separates the liquid phase (formation water from dissolved inhibitor and condensed hydrocarbon condensate). The separated gas-condensate mixture is divided into two streams, one of which is directed to the recuperative TO gas-gas 7 _i , and the second to the TO gas-condensate 6 _i , to recover cold from the throttled gas flow and separated condensate. To prevent hydrate formation, a hydrate inhibitor (not shown in Fig. 1) is injected into the mixture stream before TO. Further, the flows of the cooled gas-liquid mixture from the outputs of TO 6 _i "gas-condensate" and 7 _i "gas-gas" are combined and the combined flow enters the inlet of the intermediate separator 8 _i , where further separation of the liquid phase takes place. From the outlet of the intermediate separator 8 _{i, the} gas-liquid mixture through the KR flow rate 9 _i enters the low-temperature separator 10 _i , where condensed liquid hydrocarbons and an aqueous solution of the hydrate formation inhibitor (VRI) are finally separated from the mixture flow.

The decrease in the temperature of the gas-condensate mixture in the low-temperature separator 10 _i occurs due to the throttling of the gas at the KP flow rate 9 _i .

The dried gas from the low-temperature separator 10 _i passes through the recuperative TO 7 _i , where it is heated. From the outlet of TO 7 _i, it is fed to the MGP equipped with a gas flow sensor 12 _i . The liquid phase - NGK from the low-temperature separator 10 _i and the intermediate separator 8 _i , passing through the recuperative TO 6 _i, is heated and mixed with the liquid phase withdrawn from the separator 3 _i . This combined flow enters the 3-phase liquid separator 4 _i . From it, the weathering gas is sent either to a 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 inhibitor regeneration workshop of the UKPG, and the NGK is supplied to the MCP for further transportation to consumers.

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

The task of the dispatcher of the gas production company by the production level of the oil and gas complex ACS 14 supports by regulating the flow of natural gas at the gas processing plant using the PID controller 23. For this, the automated process control system 14 sends a signal 16 to the input of the task SP of the PID regulator 23, corresponding to the production plan of the oil and gas complex at the gas processing plant. At the same time, the APCS sends a signal 15 from sensor 5 to the PV feedback input of the same PID controller, which corresponds to the value of the actual flow rate of the NGK at the GPP. Comparing these two signals, the PID regulator 23 at its output CV forms a control signal that provides a predetermined level of oil and gas production at the GTP, which feeds the input of the set SP of the PID regulators 25 of all TL LTS. At the same time, a common signal 17 for all is fed to the feedback input of the PV PID controllers 25 of the APCS 14 - the value of the total consumption of dried gas for all TL LTS UKPG, which is determined by summing up the readings of the gas flow sensors 12 _i installed on each i-th TL LTS ... Also, at the same time, to the input Kp of each PID controller 25, an individual signal of the value of the proportionality coefficient K _{p_i is supplied} , which determines the degree of influence of the PID controller 25 _i on the KP 9 _{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 the blocks for calculating the proportionality coefficient 24 _i , depending on the current temperature in the low-temperature separators 10 _i , recorded by the temperature sensor 11 _i .

The PID controller 23 for maintaining the oil and gas production level continuously monitors the difference in values between the oil and gas production plan for the gas treatment plant received 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 - F _fact > 0, then at the output of the PID controller 23 a control signal will be generated to increase the gas flow through the installation, if F _plan - F _fact <0, then a control signal will be formed at the output of the PID controller 23 signal to reduce gas flow through the installation. This signal is fed to the SP reference input of each PID controller 25 _i . As a result, the productivity of the NGK GPPG will be increased in the first case, or reduced in the second case by the PID controllers 25 _i to the planned target, which is determined by the ratio F _plan - F _fact = 0. In this case, the proportionality coefficient K _{p_i} for each PID controller 25 _i will be calculated in its block 24 _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 T _i is the current temperature value coming from the temperature sensor 11 _i in the low-temperature separator 10 _i , which is fed in the form of a signal 18 _i to the input I. _{1 of the} unit for calculating the proportionality coefficient 24 _i ;

T _{max_i} is the setting of the maximum allowable temperature in the separator 10 _i , supplied in the form of a signal 19 _i to input I. _{2 of the} block for calculating the proportionality coefficient 24 _i ;

T _{min_i} is the setting of the minimum permissible temperature in the separator 10 _i , which is received as a signal 20 _i at input I. ₃ blocks for calculating the proportionality coefficient 24 _i ;

K _{p_max_i} is the setting of the maximum value of the proportionality coefficient of the PID controller 25 _i , supplied in the form of a signal 21 _i to the input I. ₄ blocks for calculating the proportionality coefficient 24 _i ;

K _{p_min_i} is the setting of the minimum value of the proportionality coefficient, supplied in the form of a signal 22 _i to input I. _{5 of the} block for calculating the proportionality coefficient 24 _i ;

Calculation of К _{п_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} , K _{p_max_i} , _{Tmax_i} and _{Tmin_i} are set when setting up the control system for the operating personnel, taking into account the technological standards and restrictions provided for by the technological regulations of the installation.

This method of controlling the performance of the installation allows you to distribute the load between TL LTS, taking into account their state, depending on the temperature in the low-temperature separator 10 _i , which, in turn, leads to the production of NGK and gas with significantly more stable quality characteristics.

If during the technological process the temperature in the low-temperature separator 10 _i goes beyond T _{max_i} or T _{min_i} , indicated in the process regulations of the UKPG, then the APCS 14 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 14 in real time monitors the parameters of the dew point temperature using the readings of the sensor 13. If the dew point temperature reaches its upper (T _{p_max} ) limit determined by the technological regulations of the installation, the ACS 14 generates a message about this to the operator of the installation for making a decision to change the operating mode of the installation.

The tuning of the PID controllers used 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#HandTuning.

The method of automatic load distribution between TL NTS at the GPP of the oil and gas condensate field was implemented in PJSC Gazprom, OOO Gazprom dobycha Yamburg at the Zapolyarnoye oil and gas condensate field, at the GPP 1V, GPP 2V. Operational results 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 oil and gas recovery from natural gas at the gas processing plant in the initial and increasing stages of oil and gas condensate field operation, subject to the norms and restrictions on the technological parameters of the process set forth by the technological regulations of the plant, ensuring the specified quality of natural gas preparation for long-distance transport, while taking into account the actual state installation equipment.

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 of oil and gas condensate fields in the North of the Russian Federation, including control by means of an automated process control system - ACS TP of UKPG of dried gas flow entering the main gas pipeline - MGP , the flow rate of unstable gas condensate - NGK, entering the main condensate pipeline - MCP, automatic maintenance of the gas separation temperature in the low-temperature separator at a given value of the gas flow through it by changing the degree of gas throttling at the choke in front of this separator, characterized in that the task of the gas producer of the enterprise in terms of oil and gas production volume enters the APCS, which performs the task with the help of the PID controller for maintaining the NGK flow rate in the MCP, implemented on the basis of the APCS, to the SP input of which the APCS sends a signal set the dispatcher and at the same time to its feedback input PV sends a signal of the current flow rate of the NGK to the MCP, comparing which, this PID controller forms a reference signal at its CV output, which feeds the SP reference input of the PID controllers of all TL LTS gas, and to the input feedback PV of these PID-controllers of the APCS sends a signal of the actual flow rate of dried gas through the gas processing unit, and simultaneously to the input Kp of the PID-controller of each TL _{LTS, the signal of the proportionality coefficient value Kp_i is supplied} , which determines the degree of influence of this PID-controller on the valve-regulator controlled by it - KR of the gas flow rate according to its TL NTS, while the value of the proportionality coefficient K _{p_i} is determined by the unit for calculating the proportionality coefficient of the TL NTS depending on the current temperature in the low-temperature separator of this TL NTS according to the readings recorded by the APCS using the appropriate temperature sensor. 2. The method according to claim 1, characterized in that the value of the proportionality coefficient K _{p_i} for the PID controller of each TL LTS determines its proportionality coefficient calculation unit, using the current temperature value in its low-temperature separator of this line, 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 T _i is the current value of the temperature in the low-temperature separator of the i-th TL LTS, entering the input I. _{1 of} its block for calculating the proportionality coefficient; T _{max_i} is the setting of the maximum allowable temperature in the low-temperature separator of the i-th TL LTS, supplied to input I. _{2 of} its block for calculating the proportionality coefficient; T _{min_i} is the setting of the minimum allowable temperature in the low-temperature separator of the i-th TL LTS, supplied to input I. _{3 of} its blocks for calculating the proportionality coefficient; K _{p_max_i} is the setting of the maximum value of the proportionality coefficient of the PID regulator of the i-th TL NTS, which is fed to 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, which is fed to input I. _{5 of} its block for calculating the proportionality coefficient; 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} and the values K _{p_min_i} , K _{p_max_i} , _{Tmax_i} and _{Tmin_i} are set when setting up the control system for the operating personnel, taking into account the technological standards and restrictions provided for by the technological regulations of the installation. 3. The method according to claim 1, characterized in that if, during the technological process, the temperature in the low-temperature separator of one of the TL _LTS goes beyond the boundaries of T max_i or T _{min_i} indicated in the technological regulations of the UKPG, then the APCS generates a message about this to the plant operator for assessing the current situation at a specific TL LTS and making 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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