Study Of Cleaning Process With Advanced Oxidation For Cotton Cellulose Production

Basing on the raw materials of cotton linter, traditional process for cotton cellulose production has operations of cooking under high temperature and alkali, bleaching with sodium hypochlorite, and so on. Cooking and bleaching are the two major operations of purified cotton production, and also the main processes of generating pollution. The black liquor from cooking section is with high value of COD, of high concentration of organic chemicals, high viscosity, high pH-value, deep colourity, low yielding, and uneasy to treat. Huge dioxin is generated from bleaching section, and such problems greatly hinder the national development of cotton pulping. How to give up the mode of end-administrating and transfer from traditional process to cleaning process is a difficulty faced to all researchers in aspect of practice and theory.This work studied the pulping process with advanced oxidation technology, and targeted at reduce pollution generating at the beginning, and decrease energy and water consumption, and finally save cost. This is an inevitable way of sustainable development for pulping industry. Advanced oxidation technology was applied to the process of pulping. Optimized technological conditions were determined for pulping. Agents were considered to promote pulp bleaching, and their combination schemes were selected out based on the indexes of yielding, polymerization degree, whiteness, and chemical oxygen demand.(1) With comparison of cleaning process using advanced oxidation for refined cotton production with traditional process, it was found that the new process need low liquid ratio, and realize high concentration of continuous pulping. The time of polymerization degree falling was cut down from150min to20min, and the highest temperature dropped down from160℃to100℃, achieving at soft reaction condition and energy consumption reduction. The generating chemical oxygen demand decreased from400kg to120kg per ton pulp.(2) The selected bleaching agents optimized the technological conditions, and increased the yielding of pulp from3%to6%, and improved the whiteness by9.5%ISO.(3) Several methods were used for experiment to treat cotton pulping waste water. The obtained results showed that the methods had their own limitation. Therefore, developing novel cleaning pulping process is urgent facing the rising problems of environment.(4) The characteristic results of waste water from new and old processes indicated that most chromophore and auxochromous groups of lignin were oxidized in the new process.