A cellulose production method

Abstract

The invention relates to the chemical industry, namely to the production method of cellulose from all types of plant cellulose-containing raw material. The method includes raw material impregnation and hydrolysis in a hydrolysis solution, cellulose filtration, washing with water, filtration and drying, accompanied with the use of cycles that include heating of the material to a temperature of 115° C. or less, high-speed impulse action of vacuum with a pressure change in the range up to 5 mm Hg for a time of less than 10 seconds, followed by exposure under vacuum and vacuum relief. Both solution of nitric or sulphuric acids, their mixture and alkaline solution can be used as hydrolysis solution. Technical result of the claimed method consists in. reducing the duration of the cellulose hydrolysis process, reducing the temperature of the processes while obtaining the required chemical and structural homogeneity of the cellulose.

What is claimed is: 
     
         1 . A cellulose production method by processing a cellulose-containing raw material comprising
 impregnating and hydrolysis of the raw material in a hydrolysis solution,   filtration the resulting cellulose,   subsequent washing with water,   filtration and drying, wherein,   the impregnation and hydrolysis of the raw material in the hydrolysis solution, filtration of the resulting cellulose, washing with water, filtration and drying are carried out with the use of cycles involving the heating of the material to a temperature of 115° C. or less, high-speed vacuum-impulse action with a pressure change in the range up to 5 mm Hg for a time of less than 10 seconds, followed by exposure under vacuum and vacuum relief.   
     
     
         2 . The method as claimed in  claim 1 , wherein as a hydrolysis solution, a solution of nitric or sulphuric acids or mixtures of nitric and sulphuric acids with a solution concentration of not more than 15.0% is used at a ratio of the cellulose-containing raw material to the hydrolysis solution not more than 1:15 is used. 
     
     
         3 . The method as claimed in  claim 1 , wherein an alkaline solution with a concentration of less than 30 grams/liter is used as the hydrolysis solution at a ratio of the cellulose-containing raw material to the hydrolysis solution of not more than 1:15. 
     
     
         4 . The method as claimed in  claim 1 , wherein a solution of spent acids from nitrocellulose production is used. 
     
     
         5 . The method as claimed in  claim 1 , wherein a one-year cellulose-containing plant raw material is subjected to defibration after being impregnated in a hydrolysis solution. 
     
     
         6 . The method as claimed in  claim 1 , wherein the hydrolysis of the raw material in the hydrolysis solution is carried out simultaneously with raw material disintegration to increase the homogeneity of the cellulose and intensify subsequent operations. 
     
     
         7 . The method as claimed in  claim 1 , wherein the dissolved in a spent hydrolysis solution impurities are separated. 
     
     
         8 . The method as claimed in  claim 1 , wherein after cellulose washing and filtration the washing water is regenerated to organize water rotation. 
     
     
         9 . The method as claimed in  claim 1 , wherein after washing the cellulose, its bleaching is carried out using cycles that include heating of the material to a temperature of 115° C. or less, high-speed impulse action of vacuum with a pressure change in the range up to 5 mm Hg for a time of less than 30 seconds, followed by exposure under vacuum and vacuum relief. 
     
     
         10 . The method as claimed in  claim 1 , wherein after cellulose washing with water and filtration to maintain the integrity of the fiber length to the maximum, the cellulose is squeezed out on the mesh or fabric filters with pressure-exerting rollers by water vacuum-impulse suction and with passing the air heating medium through the cellulose fiber layer and the mesh until the required moisture is achieved, followed by loosening of the packed cellulose.