COMPACT METHOD OF PRODUCING PRELIMINARILY HYDROLYSED CELLULOSE Russian patent published in 2015 - IPC D21C1/02 

FIELD: chemistry.

SUBSTANCE: to prevent problems of formation of resin which plugs output nets, and ensure clear ending of the stage of preliminarily hydrolysis, as well as thorough alkaline soaking before the stage of sulphate cooking, an alkali is added into the mixture of preliminarily hydrolysed material in such amount that the residual concentration of the alkali after the neutralisation of the product of acid hydrolysis exceeds 20 g/l of an effective alkali in the form of NaOH, and the temperature of the resulting solution for the alkaline processing of the preliminarily hydrolysed material decreases by 10% in comparison with the temperature at the stage of preliminary hydrolysis. Addition of the alkali prevents the re-sedimentation of hemicellulose, dissolved at the stage of preliminary hydrolysis and abruptly brings a mixture of a wood material into an alkaline medium, favourable for the stage of alkaline soaking at a reduced temperature before the final stage of sulphate cooking. The main part of hemicellulose, contained in the cellulose material, is extracted at the said stage of soaking.

EFFECT: improved compact method of the soluble cellulose production in the process of sulphate cooking with preliminary hydrolysis.

13 cl, 12 dwg