METHANOL PURIFICATION FROM STRIPPER OFF GAS PRODUCED DURING THE KRAFT PULPING PROCESS AND APPARATUS

摘要

Disclosed is a method to recover and purify methanol from a stripped off gas stream, comprising the steps of: obtaining, at a controlled rate, a foul gas feed comprising no more than approximately 40 weight per cent methanol; condensing said foul gas feed; removing immiscible contaminants from said condensed foul gas feed; heating said condensed foul gas feed in the presence of an acid to evaporate volatile components, leaving a contaminated methanol feed, said acid being supplied at an entry point below an input point of said condensed foul gas feed; refining said contaminated methanol feed by heating to evaporate methanol from said contaminated methanol feed; and further refining said evaporated methanol by heating to evaporate remaining volatile components and to produce purified methanol and impure condensate.