Process for the preparation of synthesis gas from black liquor

摘要

A process for the adjustment of the composition of a synthesis gas produced in a high temperature black liquor gasifier, comprising the steps of(a) generating a gasifier effluent stream from black liquor in said gasifier by means of a blast and optionally an atomising stream;(b) optionally quenching the gasifier effluent stream with a gas stream to form a gas quenched effluent stream;(c) quenching the gasifier effluent of step (a) or the gas quenched effluent gas stream of step (b) with a water stream to form a raw synthesis gas;(d) further cooling and cleaning and separating the raw synthesis gas to form a purified unprocessed synthesis gas with an appropriate H2/CO ratio;(e) partly converting the purified synthesis gas to dimethyl ether in a synthesis section, producing at least a product stream of DME and a hydrogen rich purge stream of processed.(f) splitting and recycling individual or combinations of split streams of the processed or the unprocessed synthesis gas to step a and/or step (b);.andrecycling a by-product stream of CO2 being further generated in step (e) in part or completely to step (a) and/or step (b).