METHOD FOR AUTOMATIC MAINTENANCE OF THE TEMPERATURE CONDITION ON LOW-TEMPERATURE GAS SEPARATION INSTALLATIONS WITH AIR COOLING APPARATUS IN THE EXTREME 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 automatically maintaining the temperature regime at low-temperature gas separation units with air coolers (AC) in the Far North of the Russian Federation includes preliminary cleaning of the produced gas condensate mixture from mechanical impurities and partial separation of a mixture of unstable gas condensate (UGC) and an aqueous solution of an inhibitor (ASI) in the separator of the first separation stage, after which 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 separator outlet of the first separation stage is fed to the air cooler inlet, which is put into operation by the automatic process control system (APCS) at achievement of the specified temperature difference between the gas condensate mixture and atmospheric air, by applying an appropriate signal to the input of the automatic control system (ACS) of the air cooler, which controls the operation of the air cooler, providing a decrease in the temperature of the gas condensate mixture at its outlet to the specified values ​​necessary to maintain the required temperature in the low-temperature separator, after which the gas condensate mixture pre-cooled in the air cooler is divided into two streams, the first of which is sent to the pipe space of the first section of the recuperative heat exchanger (HE) "gas-gas", where it is cooled by a counter-flow of dried gas coming from a low-temperature separator and passing through the second section of the HE "gas-gas", and the second flow through the valve-regulator (VR) is fed into the pipe space of the first section of the HE "gas-condensate", where it is cooled by a counter-flow of a mixture of UGC and ASI, discharged from the bottom part of the low-temperature separator and passing through the second section of the "gas-condensate" HE. The flow rate of the gas condensate mixture along these flows is distributed by the automated process control system using the VR installed at the inlet of the first section of the gas-condensate HE, so that the temperature of the oil and gas condensate supplied to the main condensate pipeline (MCP) is within the range specified by the technological regulations. After the gas condensate mixture flows out of the first sections of the HE "gas-gas" and HE "gas-condensate" they are combined and fed to the VR, which acts as a controlled reducer, passing through which it experiences adiabatic expansion and corresponding cooling, after which it is sent to a sensor-equipped low-temperature separator, in which the final separation of the gas condensate mixture into dried cold gas and a mixture of UGC with ASI is carried out, which is fed from the bottom of the low-temperature separator to the inlet of the second section of the HE "gas-condensate" and further into the LS, in which UGC, ASI and weathering gas, after which the UGC is fed to the MCP using a pumping unit, the ASI is sent to the plant inhibitor regeneration shop, the weathering gas is sent for utilization or injection into the main gas pipeline (MGP). 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 gas-gas HE, and the second to the bypass of this section, equipped with a gas flow control valve, with the help of which the process control system regulates the ratio of flows dried gas passing through the second section of the gas-to-gas VR and bypass, providing real-time correction of the temperature of the dried gas to the set values ​​required by the technological regulations of the installation when gas is supplied to the MGP. APCS in tandem with ACS AC from the moment the unit is put into operation provide a given flow rate of oil and gas supplied to the MCP, for which they use the initially set values ​​of the settings of the controlled parameters and the limits of their permissible deviations from the values ​​of the settings. As soon as the APCS detects the output of one of the controlled parameters beyond the established limits, violating the technological schedule of the plant operation, the APCS changes by one step the value of the pressure setting P_in of the gas condensate mixture at the inlet of the installation by the value ΔP_IN in the interval determined by the inequality where P_min is the minimum allowable, and P_max is the maximum allowable value of the gas condensate mixture pressure setpoint at the unit inlet. The value of ΔP_IN is assigned from the ratio where n is the number of allowed steps for changing the P_in setpoint, and this change in the setpoint of the automated process control system is carried out in the direction that allows stopping the violation that has occurred. At the same time, the automated process control system monitors that the working body of the VR, which controls the pressure at the inlet of the installation, is within the allowable limits of its movement, and keeps the control mode of the technological processes of the installation with a new setpoint value for a time interval of at least τ_const, which is an individual characteristic of the installation determined experimentally. If other controlled parameters of the technological process during this time return within the limits set for them, then the automated process control system fixes this value as a new setpoint to maintain the specified flow rate of oil and gas supplied to the MCP, and generates a message to the operator about the automatic change of the operating mode of the installation and its new characteristics, and further APCS in tandem with ACS AC implement this 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