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

FIELD: gas industry.

SUBSTANCE: The 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 Far 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 (ASI) in the separator of the first separation stage, after whereby the mixture of UGC and ASI from the bottom part of this separator is diverted to a liquid separator (LS), and the gas condensate mixture from the outlet of the same separator of the first separation stage is divided into two streams and cooled in the first sections of recuperative heat exchangers (HE) "gas-gas" and "gas-condensate". The flow entering the "gas-condensate" HE goes through the gas condensate mixture flow rate control valve (CV), which regulates 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" HE, 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 ASI, 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 into the LS, in which UGC, ASI and weathering gas are separated, after which UGC is fed using a pump unit into the main condensate pipeline - MCP, the flow of released gas - weathering gas from the LS is transported for disposal or compression and supply to the main gas pipeline - MGP, ASI is sent to the inhibitor regeneration workshop. The cold dry 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 gas-gas HE, and the second to the bypass of this section, equipped with a gas flow control valve, which changes the ratio of gas flows passing through the HE and bypass, providing real-time correction of the gas temperature to the set values ​​required by the technological regulations 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 the mode of its operation using the initially set values ​​of the settings of the controlled parameters, which are entered into the database (DB) of the APCS before the plant is put into operation. As soon as the APCS detects the output of one of the controlled parameters beyond the established limits of its allowable variations relative to the setpoint, violating the technological regulations for the operation of the unit, the APCS step by step changes the value of the allowable pressure setting of the produced gas condensate mixture at the inlet of the installation by a value of in the interval determined by the inequality where is the minimum allowable, and is the maximum allowable value of the allowable pressure setting of the gas condensate mixture at the unit inlet. The value is assigned from the ratio where n is the number of allowable steps for changing the setpoint and this change in the setpoint is carried out by the APCS in the direction that ensures the elimination of the detected violation, and after each step it keeps the process control mode of the plant with a new setpoint value for a time interval of not less than , sufficient to complete transient processes in the system and which is an individual characteristic of the installation, determined experimentally. 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 gas condensate mixture pressure setpoint at the unit inlet as a working one and generates a message to the operator about the automatic change of the operating mode and its new characteristics, and then the automated process control system implements the newly selected mode of operation 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 installation and the efficiency of the process of preparing gas and gas condensate for long-distance transport.

3 cl, 2 dwg