CN-224207709-U - Recovery processing device for methane in liquid nitrogen washing raw material gas

CN224207709UCN 224207709 UCN224207709 UCN 224207709UCN-224207709-U

Abstract

The utility model belongs to the technical field of chemical production equipment, and particularly relates to a recovery processing device for methane in liquid nitrogen washing raw material gas, which comprises a liquid nitrogen washing raw material gas system, a raw material gas separator, a nitrogen washing tower, a liquid methane pump, a high-pressure nitrogen cooler, a first raw material gas cooler, a second raw material gas cooler and a methane gas pipe network, wherein the liquid nitrogen washing raw material gas system is connected with the raw material gas separator through a raw material gas pipeline, the raw material gas pipeline passes through the first raw material gas cooler and the second raw material gas cooler, and the raw material gas separator is connected to the lower section of the nitrogen washing tower through a first outlet pipeline, and is connected to the inlet end of the liquid methane pump through a second outlet pipeline, and the nitrogen washing tower is connected to the second outlet pipeline through a first methane pipeline, and the outlet end of the liquid methane pump is connected to a methane gas pipe network through a second methane pipeline. The device solves the defect of large energy consumption in the prior art, can greatly reduce the energy consumption, reduces the production cost and achieves the purpose of energy conservation.

Inventors

YANG LIANGLIANG
LI PENG
YAN LULU
SONG YUWEI
CHEN CHEN

Assignees

河南晋控天庆煤化工有限责任公司

Dates

Publication Date: 20260508
Application Date: 20250228

Claims (1)

1. The recovery processing device for methane in liquid nitrogen washing raw gas comprises a liquid nitrogen washing raw gas system, a raw gas separator, a nitrogen washing tower, a liquid methane pump, a high-pressure nitrogen cooler, a first raw gas cooler, a second raw gas cooler, a methane gas pipe network, a high-pressure nitrogen system, a synthesis system, a fuel gas separator, a fuel gas system, a separator and an exhaust fan, and is characterized in that the liquid nitrogen washing raw gas system is connected with an inlet of the raw gas separator through a raw gas pipeline, the raw gas pipeline sequentially passes through the first raw gas cooler and the second raw gas cooler, the top of the raw gas separator is connected to the lower section of the nitrogen washing tower through a first outlet pipeline, the bottom of the raw gas separator is connected to the inlet end of the liquid methane pump through a second outlet pipeline, the outlet end of the liquid methane pump is connected to the methane gas pipe network through a second methane pipeline, and the second methane pipeline sequentially passes through the second raw gas cooler, the first raw gas cooler and the high-pressure nitrogen cooler; The high-pressure nitrogen system is connected to the upper section of the nitrogen washing tower through a first nitrogen pipeline, the first nitrogen pipeline sequentially passes through the high-pressure nitrogen cooler, the first raw material gas cooler and the second raw material gas cooler, the top of the nitrogen washing tower is connected to the synthesis system through a second nitrogen pipeline, and the second nitrogen pipeline sequentially passes through the second raw material gas cooler, the first raw material gas cooler and the high-pressure nitrogen cooler; The inlet of the fuel gas separator is connected to the lower section of the nitrogen scrubber through a first fuel gas pipeline, the outlet of the fuel gas separator is connected to the fuel gas system through a second fuel gas pipeline, and the second fuel gas pipeline sequentially passes through a second raw material gas cooler, a first raw material gas cooler and a high-pressure nitrogen cooler; The inlet of the liquid nitrogen separator is connected with a liquid nitrogen pipeline, the outlet of the liquid nitrogen separator is connected to the exhaust fan through a third nitrogen pipeline, and the third nitrogen pipeline sequentially passes through the second raw material gas cooler, the first raw material gas cooler and the high-pressure nitrogen cooler; the liquid nitrogen separator is also connected with a circulating pipeline, and the circulating pipeline passes through the second raw material gas cooler.

Description

Recovery processing device for methane in liquid nitrogen washing raw material gas Technical Field The utility model belongs to the technical field of chemical production equipment, and particularly relates to a recovery processing device for methane in liquid nitrogen washing feed gas. Background The liquid nitrogen washing raw gas also contains impurity gases such as CO, CH 4, ar and the like after entering the cold box, in order to finally prepare pure synthesis gas with the hydrogen-nitrogen ratio of 3:1, the impurity gases such as CO, CH 4, ar and the like are removed in the cold box, and the removed CO, CH4 and the like are decompressed, separated and reheated, and the gas phase returns to an upstream conversion section. The CH 4 gas treatment mode in the liquid nitrogen washing raw gas is that the raw gas is sent to a No. 1 raw gas cooler and a No. 2 raw gas cooler in a cold box, cooled by the nitrogen washing gas, the fuel gas and the methane fraction which are returned, flows out along with the gas flow in the No. 2 raw gas cooler, enters a raw gas separation tank to separate the liquid methane fraction therein, returns to the No. 2 raw gas cooler for continuous cooling, then enters the lower section of a nitrogen washing tower, and the separated liquid methane and the liquid methane which comes out from the lower part of the raw gas separation tank are mixed in a methane-rich gas separator, are sent to a methane-rich compressor after the cold energy is recovered by reheating, and the gas of 40Kpa is pressurized to 5.5Mpa by the methane-rich compressor and sent to a natural gas pipe network. However, after the liquid methane in the liquid nitrogen washing feed gas in the original process device is separated, the liquid methane is gasified firstly and then is subjected to a large amount of work through a motor or steam to be finally sent into a natural gas pipe network, and a large amount of electric energy is consumed in the process, so that the energy consumption is high and the cost is high. For this reason, there is a need for a recovery processing device for methane in liquid nitrogen-washed feed gas to solve the above-mentioned problems. Disclosure of utility model In order to overcome the defects in the prior art, the utility model provides a recovery treatment device for methane in liquid nitrogen washing raw gas, which comprises a liquid nitrogen washing raw gas system, a raw gas separator, a nitrogen washing tower, a liquid methane pump, a high-pressure nitrogen cooler, a first raw gas cooler, a second raw gas cooler and a methane pipe network, wherein the liquid nitrogen washing raw gas system is connected with an inlet of the raw gas separator through a raw gas pipeline, the raw gas pipeline sequentially passes through the first raw gas cooler and the second raw gas cooler, the raw gas pipeline is also connected with a raw gas branch pipeline, the top of the raw gas separator is connected to the lower section of the nitrogen washing tower through a first outlet pipeline, more than 90% of the lower section of the nitrogen washing tower is liquid methane, a small part of the liquid nitrogen and liquid carbon monoxide are also connected to the inlet end of the liquid methane pump through a second outlet pipeline, the outlet end of the liquid methane pump is connected to the methane pipe network through a second methane pipeline, and the second methane pipeline sequentially passes through the second raw gas cooler, the first raw gas cooler and the high-pressure nitrogen cooler. Optionally, the recovery processing device of methane in the liquid nitrogen washing raw material gas is provided with a high-pressure nitrogen system and a synthesis system, the high-pressure nitrogen system is connected to the upper section of the nitrogen washing tower through a first nitrogen pipeline, the first nitrogen pipeline sequentially passes through a high-pressure nitrogen cooler, a first raw material gas cooler and a second raw material gas cooler, the top of the nitrogen washing tower is connected to the synthesis system through a second nitrogen pipeline, and the second nitrogen pipeline sequentially passes through the second raw material gas cooler, the first raw material gas cooler and the high-pressure nitrogen cooler. Optionally, the recovery processing device for methane in the liquid nitrogen washing raw gas is provided with a fuel gas separator and a fuel gas system, wherein an inlet of the fuel gas separator is connected to the lower section of the nitrogen washing tower through a first fuel gas pipeline, an outlet of the fuel gas separator is connected to the fuel gas system through a second fuel gas pipeline, and the second fuel gas pipeline sequentially passes through the second raw gas cooler, the first raw gas cooler and the high-pressure nitrogen cooler. Optionally, the recovery processing device of methane in the liquid nitrogen washing raw material gas is further provided with a liquid