CIRCULAR UTILIZATION METHOD OF STRAW IN PULPING AND PAPERMAKING PROCESS

摘要

A circular utilization method of straw in a pulping and papermaking processes comprises the following steps of: obtaining straw raw material for pulping and its waste through stock preparation; obtaining primary pulp by digesting the straw raw material according to the ammonium sulfite method; obtaining pulp and concentrated black liquid by extruding the primary pulp; obtaining paper pulp for preparing a paper product and diluted black liquid by washing and post-processing; mixing the concentrated black liquid and the diluted black liquid, and then evaporating and concentrating; obtaining contaminated condensate by reclaiming the evaporated liquid, and using a residual concentrate as raw material of fertilizer or the concentrated black liquid for preparing a fertilizer; mixing the contaminated condensate with one or more of the group of the waste material obtained from stock preparation, a crop byproduct or organic waste, and obtaining base material or fertilizer by fermenting the nitrogen source of the contaminated condensate or ammonium sulfite, or using the contaminated condensate for desulfurizing flue gas, wherein ammonia and flue gas are reacted to obtain the ammonium sulfite as a digestion agent; and using the recycled water from the mid-phase water processing to corresponding phases in the whole pulping process.