RU1830091C - Method of lignocellulose material making - Google Patents

Abstract

The inventive crushed lignocellulosic material is treated with an aqueous solution of methyl or ethyl alcohol at a concentration of 81-98 vol.% In the presence of an additive - chloride or magnesium nitride, or calcium, or a mixture thereof in an amount of 0.003-0.050 mol / l aqueous solution and 0.0001- 0.0090 n solution of an acidic reagent - inorganic or organic acid or aluminum chloride or tin at a temperature of 190-220 ° C, a weight ratio of cooking liquid and lignocellulosic material of at least 4: 1 and a pressure of 285-320 bar. As an inorganic acid, hydrochloric, sulfuric or sulfuric acid is used, and as an organic acid, salicylic, oxalic or acetic acid. After cooking, the apparatus is cooled, the pulp is unloaded, washed and dried. 2 wpp, 3 tab.

Description

The invention relates to a technology for the cooking of lignocellulosic materials, for example wood chips, using organic solvents and is intended for use in the pulp and paper industry in the manufacture of pulp for paper and paperboard.

The aim of the invention is to increase the selectivity of the delignification process.

The goal is achieved in that the processing of lignocellulosic material is carried out under a pressure of 285-320 bar, while using an aqueous solution of methyl or ethyl alcohol with a concentration of 81-98 vol.%.

The specified cooking is carried out in the presence of an additive - chloride or magnesium or calcium nitrate, or a mixture thereof in an amount of 0.003-0.050 mol / l aqueous solution and

0.0001-0.0090 n of a solution and a solution of an acidic reagent - an inorganic or organic acid or aluminum chloride or tin at a temperature of 190-220 ° C and a mass ratio of cooking liquid and lignocellulosic material of at least 4: 1.

As an inorganic acid, hydrochloric, sulfuric or sulfuric acid is used, and as an organic acid, salicylic, oxalic or acetic acid.

In the proposed method, by combining the use of high concentration alcohol and high pressure, increased delignification selectivity is provided with a lower degree of decomposition of carbohydrates, characterized by a higher viscosity of the pulp. This in turn helps speed up the delignisle process.

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fication of lignocellulosic material in the processing of wood of various species and improving the quality of the resulting pulp.

Example. The method of cooking lignocellulosic material is carried out as follows. Wood spruce shavings are loaded into a solution containing magnesium or calcium chloride or nitrate or a mixture thereof as a catalyst, as well as an acid reagent. Organic or inorganic acid or aluminum chloride or tin chloride is used as the acid reagent. The tightly closed apparatus was quickly brought to a cooking temperature of 190-220 ° C, and this temperature was kept constant during cooking.

At the end of cooking, the apparatus is rapidly cooled and the cooking solution is decanted. The pulp is then washed, air-dried to constant weight, and then the yield, Kappa number and viscosity are determined by TAPPI.

The specific values of the technological parameters of the cooking, as well as the characteristics of the resulting pulp are given in table 1.

Table 2 presents data characterizing the parameters of cellulose when using solutions of acidic reagents and additives taken at different concentrations.

Table 8 presents data characterizing the influence of alcohol concentration and overpressure on the cooking process and the quality of pulp.

From the above table. 1-3 data shows that the proposed method for

10

With these parameter values it is possible to increase the selectivity of the delignification of lignocellulosic material, thereby reducing the duration of the pulp production process and to improve its quality indicators.

Claims (3)

1. The method of cooking lignocellulosic material by processing the specified crushed material with an aqueous solution of methyl or ethyl alcohol in the presence of an additive - chloride or magnesium or calcium nitrate, or a mixture thereof in an amount 15 0.003-0.050 mol / L aqueous solution and 0.0001-0.009 n. a solution of an acidic reagent, an inorganic or organic acid or aluminum chloride, or tin at 190-220 ° C, a weight ratio of cooking liquid and lignocellulosic material of at least 4: 1 and elevated pressure, characterized in that. in order to increase the selectivity of the delignification process, the processing of lignocellulosic material is carried out under a pressure of 285-320 bar, using an aqueous solution of methyl or ethyl alcohol with a concentration of 81-98 vol.%. 2. A method according to claim 1, characterized in that hydrochloric, sulfuric or sulfuric acid are used as the inorganic acid. 3. The method according to claim 1, characterized in that salicylic, oxalic or acetic acid is used as the organic acid. twenty 25 thirty 35 Table 1 table 2 Table 3