Automation of the process of formation and drying of viscose fiber

Cellulose is treated with working alkali in a continuous mercerization unit. The pulp is weighed on a scale before entering the mercerizer, then the entire bale is transferred to the sheet feeding machine, which continuously feeds the pulp into the mercerizer tank. The working lye enters the mercerizer from the 30 m³ working lye tank by a centrifugal pump through a heater. After the heater, the alkali temperature comes out at a temperature of 60 °C. The mercerizer is a vertical cylindrical vessel equipped with an agitator with blades and beaters, with the help of which the cellulose is mixed with the alkali and forms alkaline cellulose.

During the mercerization of cellulose, the following basic chemical and physicochemical processes occur:

- swelling of cellulose in alkali;

- Production of a new chemical compound – alkaline cellulose according to the following scheme:

(C6H10O5)n + nNaOH (C6H9O5Na)n + nH2O

- destruction of alkaline cellulose;

- Additional cellulose refining.

- Flushing of hemicelluloses

The intensity of these processes depends on the time of processing the cellulose with alkali, the temperature and concentration of the working solution of the alkali and the mercerization module.

Simultaneously with the formation of a new chemical compound – alkaline cellulose – cellulose swells in the mercerizer, which contributes to the leaching of hemicelluloses and the uniform diffusion of carbon disulphide into the cellulose fiber during the further process of xanthogenization. In addition, in the process of mercerization, the molecular weight of cellulose is reduced due to oxidative destruction, and low-molecular compounds, such as hemicellulose and cellulose destruction products with a polymerization degree below 150-200, which adversely affect the mechanical properties of the fiber, are washed out.