PROCESS FOR PRODUCING FURFURAL, FORMIC ACID AND ACETIC ACID FROM SPENT PULP-COOKING LIQUOR

摘要

The invention relates to a process for producing furfural, for forming formic and acetic acids and for recovering formic and acetic acids in a pulp making process, in which an acid mixture containing mainly formic and acetic acids is used as a cooking chemical. The process of the invention is characterized by utilizing reactive evaporation and recycling of spent cooking liquors in evaporators in the recovering stage of the cooking chemicals. Thus it is possible to form effectively more furfural, formic acid and acetic acid from the dissolved organic matter contained in the cooking liquor and/or chemically bound acids contained therein.