METHOD FOR PRODUCING PURE METHANE Russian patent published in 2007 - IPC F25J3/02 

FIELD: chemical or oil industry.

SUBSTANCE: method comprises removing mechanical admixtures and water droplets from main-line natural gas, absorbing drying, cooling in the heat exchanger, and rectifying to produce pure methane. Downstream of the heat exchanger, the gas is supplied to a double rectification tower where it is separated into the mixture of methane and nitrogen and vat liquid. The vat liquid is mixed with the liquid nitrogen supplied from a cryogenic tank, and the mixture is supplied to the condenser-evaporator. The liquid mixture of methane and nitrogen is supplied to the top rectification tower from the pockets of the bottom condenser-evaporator. The pure gas methane is removed from the bottom condenser-evaporator. The flow in the heat exchanger is cooled by heating vapor from the top condenser-evaporator and gas methane produced. According to the second version, the gas mixture of methane and nitrogen is supplied from the bottom condenser-evaporator to the top rectification tower and the vat liquid from the bottom tower is mixed with the liquid nitrogen supplied from the cryogenic tank and is directed to the top condenser-evaporator. The pure liquid methane is removed from the bottom condenser-evaporator. The direct flow in the heat exchanger is cooled by heating vapor from the top condenser-evaporator.

EFFECT: enhanced efficiency.

4 cl, 1 dwg