Pyrolysis behaviour of the black liquor derived from soda-AQ and soda-oxygen pulping for rice straw at different reaction endpoints

摘要

Black liquor(BL)with inorganic cooking chemicals and combustible material is the alkali and power resources for pulping.For rice straw pulping,BL obtained from Soda-AQ pulp(SABL)could hardly be combusted in traditional recovery furnace,because of the involvement of a great deal of silica in it.On the contrary,Soda-oxygen pulping may have majority of the silica depositing in pulp owing to the oxidation,instead of its dissolution in the BL(SOBL).The pyrolysis behavior of SOBL was investigated in this paper,composition and thermal degradation were comparatively studied by elemental analysis and TG analysis.The reaction mechanism of pyrolysis of SOBL at different pulping endpoints were firstly revealed.The results suggested that SOBL had reasonable silicon content about 1/8 of the SABL,and the volatiles can be easily released at lower temperature from pyrolysis process.