Integrating prehydrolysis kraft pulping of softwood and viscose fibre manufacturing

• This work investigates the potential to integrate modern viscose manufacturing with prehydrolysis kraft pulping in order to improve the economic and environmental feasibility for production of regenerate cellulose fibers from wood. The study is largely based on calculations from literature data, but key stages are also tested experimentally. It is concluded that a kraft pulp mill can supply the acid demands of the viscose plant via acetic acid formed in the prehydrolysis and sulphuric acid for coagulation, with alkali for mercerization and dissolution, and it can also take care of spent liquors from the viscose plant. The pulp used for regenerated cellulose manufacture is delivered as wet pulp from the pulp mill, no drying is needed and a considerable amount of energy is saved. However, in an integrated production the viscose mill cannot use the whole production of cellulose from the kraft mill. One method of removing zinc ions from the coagulation bath effluents, based on precipitation of zinc sulphide via a well-controlled addition of green liquor from the pulp mill, has been studied.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering (hsv//eng)

Keyword

biorefinery

integrated production

pre-hydrolysis kraft pulping

regenerated cellulose

viscose process.

Chemical Engineering

Kemiteknik

Publication and Content Type

ref (subject category)

art (subject category)