Enzymatic straw material pulping process

Abstract

The enzymatic straw material pulping process includes three stages of mechanical pre-treatment, enzyme treatment and chemical pulping or chemical-mechanical pulping. After being pretreated mechanically in a pulp grinder, the straw material is treated with hemicellulase liquid or mixed enzyme liquid comprising hemicellulase and lignin peroxidase at pH 3.5-6.5 and 40-60 deg.c for 1-10 hr. In chemical pulping, the material is presoaked with waste pulp-making liquor before extruding out wastes liquor and digested; and in chemical-mechanical pulping, the material is first treated with EDTA, NaOH and H2O2 at 40-80 deg.c for 30-120 min and then ground to form the pulp. The present invention is used in papermaking enterprises with straw as material and has the advantages of low pollution load, high, paper pulp quality, easy-to-process waste liquor, etc.

Description

(1) Technical field [0001] The invention relates to an enzymatic pulping method, in particular to a method for enzymatic pulping using grass raw materials. (2) Background technology [0002] Grass raw materials, such as wheat straw, are the main raw materials of my country's paper industry, accounting for more than 50% of the raw materials of my country's paper industry, which are mainly used to produce chemical pulp. However, the traditional chemical pulping process, such as caustic soda method, sulfate method, etc., is used to produce straw chemical pulp, and a large amount of black liquor produced in the production process has high viscosity, low organic content, high silicon content, and low calorific value. characteristics, making it difficult to effectively recycle, causing serious environmental pollution problems. According to statistics, in 1998, the chemical oxygen demand (COD) in the wastewater discharged by my country's pulp and paper industry accounted for about...

AI Technical Summary

Problems solved by technology

Due to the large difference in chemical composition and structure between grass raw materials and wood raw materials, the biopulping process researched and developed with wood as raw materials is not suitable for grass raw materials

In addition, in terms of biological treatment methods, existing biological treatment processes, such as the invention patent "biomechanical straw pulp process and its special equipment" (application number 96115824.7), the invention patent "biological delignification-mechanical pulping technology" ( Application No. 97101537.6), invention patent "Technology for Biological Pretreatment of Chemi-Mechanical Pulp Straw Pulp" (Application No. 01107892.8), etc., all use microorganisms to directly process raw materials. Their main disadvantages are: (1) The biological treatment cycle is long, and generally It takes a few days; (2) before the microbial treatment, the raw materials should be sterilized, which increases the production cost and may reduce the quality of the raw materials; (3) the biological treatment process is difficult to effectively control, and often occurs Poor quality uniformity, severe carbohydrate degradation and other problems lead to a reduction in pulping yield; (4) The poor quality uniformity of raw materials after biological treatment also directly affects the quality of pulp, thereby affecting the quality of the final product; (5) Production by the above method Compared with chemical pulp, straw mechanical pulp and chemical mechanical pulp have poor physical properties and bleaching properties, and cannot be used to produce high-brightness, high-strength paper, so they can only be used to produce low-grade paper. products, unable to meet the needs of high-end products for pulp quality, which limits the use of final products