A NEW METHOD TO EVALUATE DELIGNIFICATION SELECTIVITY AND ITS APPLICATION TO ALKALINE SULFITE-QUINONE COOKING

A new method is proposed to evaluate delignification selectivity durin g various wood cooking processes. By this method, rates of delignifica tion and lessening of carbohydrate yields, which are independently giv en, are used for the simulation of delignification selectivity at give n delignification rates, and to determine carbohydrate yields during v arious cooking processes, which are compared with each other. This met hod was applied to the comparison of delignification selectivity of al kaline sulfite-quinone cooking and soda-quinone cooking. Delignificati on selectivity for Picea jezoensis Carr. during alkaline sulfite-quino ne cooking was better than that during soda-quinone cooking. That is, the carbohydrate yield of the former was 1.5-2.0% higher at a given de lignification. For Fagus crenata Bl., although that during the former was slightly better, the increase of the carbohydrate yield was smalle r than in the case of P. jezoensis.