Method for preparing hydrogen and LNG from coke oven gas

Abstract

The invention provides a method for preparing hydrogen and LNG from coke oven gas. The method comprises the following steps: electric decoking; boosting of the coke oven gas by a compression system; cooling of the raw gas coke oven gas by using the BOG gas (the BOG gas is a gas formed after the passive heating gasification of LNG) of LNG in order to further remove tar, benzene, naphthalene and like substances in the coke oven gas; and pretreatment using a TSA process to finely remove macromolecular impurities, such as tar, benzene, naphthalene and the like; wet and dry two-stage desulfurization for removing sulfides in the coke oven gas; two-stage low pressure shifting for a reaction of CO and water vapor to form CO2 and hydrogen; and pressurization using a compressor, an MDEA solution process for removing carbon dioxide, a membrane separation technology for separating hydrogen and methane, separation, concentration and purification of the hydrogen and methane, and dehydration, demercuration and liquefaction of the separated high-concentration methane to obtain the LNG. The coke oven gas is finally converted into the hydrogen and the LNG which have high values, so the energy of thecoke oven gas is fully used, and the environment is protected.

Description

technical field [0001] The invention relates to the technical field of coke oven gas treatment, in particular to a method for producing hydrogen and LNG from coke oven gas. Background technique [0002] Coke oven gas, also known as coke oven gas, has many combustible components and belongs to high calorific value gas, crude gas or raw gas. It is a combustible gas produced when coke and tar products are produced after high-temperature dry distillation of coking coal in the coking oven, and is a by-product of the coking industry. Its main components are hydrogen (55%-60%) and methane (23%-27%), and also contain a small amount of carbon monoxide (5%-8%), C 2 The above unsaturated hydrocarbons [0003] (2% ~ 4%), carbon dioxide (1.5% ~ 3%), oxygen (0.3% ~ 0.8%)), nitrogen (3% ~ 7%) and sulfides. Among them, hydrogen, methane, carbon monoxide, C 2 The above unsaturated hydrocarbons are combustible components, and carbon dioxide, nitrogen, and oxygen are non-flammable componen...

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Problems solved by technology

[0004] At present, part of coke oven gas is used to generate electricity, part is used to produce methanol and hydrogen, and a considerable part is directly burned and discharged. The energy

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