METHOD FOR AUTOMATIC CONTROL OF A LOW-TEMPERATURE GAS SEPARATION UNIT OPERATING IN THE CONDITIONS OF THE NORTH OF THE RUSSIAN FEDERATION Russian patent published in 2022 - IPC E21B43/34 F17D3/01 F25J3/08 

FIELD: gas industry.

SUBSTANCE: invention relates to the field of production and preparation of gas and gas condensate for long-distance transport. A method for automatic control of a low-temperature gas separation unit (hereinafter referred to as the unit) operating in the conditions of the north of the Russian Federation includes preliminary cleaning of the produced gas condensate mixture from mechanical impurities with the separation of unstable gas condensate (UGC) and an aqueous inhibitor solution (AIS) in the separator of the first separation stage, after whereby the mixture of UGC and AIS from the bottom part of this separator is diverted to a liquid separator (LS), and the gas condensate mixture from the outlet of the separator of the first separation stage is divided into two streams and cooled in the first sections of recuperative heat exchangers (HE) "gas-gas" "gas- condensate". The flow entering the “gas-condensate” HT goes through the gas condensate mixture flow rate control valve (CV), which controls its flow, ensuring that the specified temperature of the oil and gas complex is maintained at the outlet of the second section of the “gas-condensate” HT, and then the flows leaving of the first sections of the HE "gas-gas" and HE "gas-condensate", are combined and fed through the CV, which acts as a controlled gearbox, on which the adiabatic expansion of the gas condensate mixture is carried out, and sent to a low-temperature separator equipped with a temperature sensor, where the final separation of the gas condensate is carried out mixture for dried gas and a mixture of UGC with AIS, which is fed from the bottom part of the low-temperature separator to the inlet of the second section of the HE "gas-condensate" and then to the LS, in which UGC, AIS and weathering gas are separated, after which UGC is fed using a pump unit into the main condensate pipeline - MGP, the flow of released gas - the weathering gas from the LS is transported for disposal or compression and supply to the main gas pipeline - MGP, AIS is sent to the inhibitor regeneration shop, and the cold dried gas leaving the low-temperature separator is divided into two streams, one of which is fed to the inlet of the second section of the HE "gas-gas", and the second - to the bypass of this section, equipped with a gas flow rate control valve, which changes the ratio of the gas flows passing through the HE and the bypass, providing real-time correction of the gas temperature to the set values ​​required by the technological schedule of the installation when gas is supplied to the MGP. From the moment the plant is put into operation, the automated process control system (APCS) implements its operation mode using the initially set values ​​of the settings of the controlled parameters, which are entered into the database - the APCS database before the plant is put into operation. As soon as the automated process control system detects that one of the controlled parameters goes beyond the established limits, violating the technological operation schedule of the unit, the automated process control system step by step changes the setting value of the flow rate plan for the produced gas condensate mixture Q_{GCM_PLAN} according to the installation by the value ΔQ_{GCM_PLAN} in the interval determined by the inequality Q_min__GCM≤ Q_{GCM_PLAN}≤Q_max__GCM, where Q_min__GCM is the minimum allowable, and Q_max__GCM is the maximum allowable flow rate of the produced gas condensate mixture at the installation. This change in the setpoint of the APCS is carried out in the direction that ensures the elimination of the detected violation, and after each step it keeps the process control mode of the installation with a new setpoint value for a certain time interval. If the values ​​of the other controlled parameters of the technological process during this time return within the limits of permissible variations established for them, then the process control system fixes this value of the new setpoint of the produced gas condensate mixture flow rate as a working one and generates a message to the operator about the automatic change of the operating mode and its new characteristics, and further, the automated process control systems implement the newly selected operating mode of the installation. Otherwise, the APCS changes the setpoint value by one more step in the same direction.

EFFECT: increasing the reliability of operation of the plant and the efficiency of the process of preparing gas and gas condensate for long-distance transport.

3 cl, 2 dwg