Coking plant co-production method of methanol and liquefied natural gas

Abstract

The invention belongs to the technical field of comprehensive utilization of coke oven gas, in particular to a method for co-producing methanol and liquefied natural gas (LNG) in a coking plant. Coke oven gas is purified by temperature swing adsorption (TSA), desulfurization, vacuum pressure swing adsorption (VPSA), etc., and then cryogenically liquefied and separated to obtain liquefied natural gas (LNG) products. The main components of the unliquefied part are (CO+H 2 ), used as methanol synthesis gas for the production of methanol, the insufficient carbon component as H 2 As the benchmark, it is supplemented by the continuous oxygen-enriched atmospheric pressure gasifier of 7-24mm chopped coke. The present invention realizes CH, one of the main components of coke oven gas 4 The direct utilization of , (CO+H 2 ) is directly used in methanol synthesis, and the insufficient carbon source uses atmospheric pressure gas-making furnace, and the gas-making raw material is self-produced mixed coke in the coking plant, which reduces the main energy-consuming sections such as intermolecular conversion and high-investment devices, and the overall process flow is simplified. The comprehensive energy consumption of methanol and liquefied natural gas (LNG) is low, which can improve the overall economic efficiency of coking enterprises and save investment.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of coke oven gas, in particular to a method for co-producing methanol and liquefied natural gas (LNG) in a coking plant. Background technique [0002] my country is a large country of coke production, and a large amount of coke oven gas is produced by-product in the coke production process. Large-scale coking plants, especially independent coking plants, must be equipped with feasible and effective coke oven gas comprehensive utilization devices. The composition of coke oven gas is relatively complex and unstable. Generally, the low calorific value of the purified coke oven gas is 17580-18420kJ / m 3 , the density is 0.45~0.48kg / m 3 , the main characteristics of the components are more hydrogen and less carbon. According to the volume fraction, CH in coke oven gas 4 Nearly 25%, CO, CO 2 、CH 4 , CnHm total about 40%, H 2 Can be as high as 60%. [0003] According to the composi...

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Problems solved by technology

[0010] The problems of this process are: in order to increase the methanol production, most of the coke oven gas needs to be converted into methanol synthesis gas. First, the coke oven gas needs to be converted into methanol synthesis gas through the conversion process. The requirements are high, and there is no "molecular economy"; the second is that the conversion section needs pure oxygen, and a large-scale air separation unit needs to be built, which greatly increases the investment. segment investment accounts for about 1 / 3 of the entire fixed asset investment

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