Method of preparing coarse paper pulp by using plant straws

Abstract

The invention belongs to the field of papermaking, and relates to a method of preparing coarse paper pulp by using plant straws and a method of preparing finished product paper pulp by virtue of the method. The method comprises the following steps: (1) cutting: cutting plant straws into 10-20mm small sections, and removing mud and sand and sundries; (2) screening: screening 10-20mm materials and removing dust; (3) washing and impregnating: washing with water to remove ash foreign matters, and performing dehydration after water absorption to swell; (4) mechanical rubbing: mechanically rubbing the materials to dissociate and broom fiber bundles; (5) detonation treatment: putting the materials in a closed pressure container, introducing high-pressure steam, keeping an air pressure of 1.0-2.5MPa for 4-15 minutes, releasing the materials and steam within 60-75ms to constant pressure, and detonating the materials; and (6) devillicating and rubbing: feeding the materials into a splitting machine to be extruded, ground, torn and rubbed to obtain the coarse pulp. The method provided by the invention for preparing finished product paper pulp is efficient in bleaching, low in cost, high in yield and free of black liquid, and is suitable for annual forage straws and perennial plant waste branches.

Description

technical field [0001] The invention belongs to the technical field of papermaking, in particular to a method for preparing papermaking coarse stock with plant straws and a method for preparing finished paper pulp by using the method, especially suitable for papermaking pulping of annual grass plant raw materials and crop straw plant raw materials. Background technique [0002] As a widespread plant biomass resource, crop waste straw has great biological utilization value. As a large agricultural country, my country produces a large amount of waste crop straw every year, but the utilization efficiency of straw is very low, and most of the straw is directly burned, causing serious environmental pollution and waste of resources. The main component of crop waste straw is lignocellulose, and its components include lignin, cellulose and hemicellulose, and pectin is also contained in plant raw materials. [0003] Compared with woody plants, annual non-woody fiber grasses and crop...

AI Technical Summary

Problems solved by technology

Cooking under high alkali, high temperature and high pressure conditions, the conventional strong alkali dosage is 8-18% of the weight of plant raw materials, the cooking temperature is 155-185°C, the pressure reaches 0.6-0.8MPa, the lignin dissolved in the cooking waste liquid is alkaline Lignin exists in the form of high silicon content, resulting in high viscosity and dark color of cooking waste liquid, which increases the process difficulty of bleaching, evaporation concentration and alkali recovery

The pre-cooking process and the process between cooking and bleaching in the existing alkaline pulping process have almost no correlation with the core cooking and bleaching process. They just do some simple physical cutting and cleaning for the core process, and the technical pressure is all Concentrate on the cooking process, so it is difficult to take into account the multi-faceted technical requirements

The alkali recovery technology in the above-mentioned pulping process is relatively mature for woody paper pulping black liquor, but there are great technical obstacles for herbaceous paper pulping black liquor. The reason is that the straw pulp waste liquor High silicon content, high viscosity, and poor filterability. When the lime alkali recovery method is used, high silicon content will significantly reduce the availability of active lime. Moreover, the fluidity is poor, it is difficult to transport, and it will also cause scaling problems in the delivery pipe.