Papermaking machinery is a general term, actually composed of many different types of components with different functions. Today, let the editor of China Paper Industry Network introduce the material preparation equipment and pulping equipment in papermaking machinery:
Material preparation equipment
It is equipment used for pre-treatment and processing of papermaking raw materials before cooking and pulping, according to the requirements of cooking and pulping processes. It is divided into non-wood fiber raw material preparation equipment and wood fiber raw material preparation equipment. The former includes lawn mowers, reed machines, and sugarcane pulpers, while the latter includes peelers and shredders.
A wood chipper is a machine that cuts logs into wood chips of a specific size for wood pulp production; it can be divided into disc type and drum type. A digester is a device that dissolves lignin in papermaking raw materials into cooking liquor and separates the raw materials into fibers; it can be divided into batch type and continuous type. A wood grinder is a type of equipment for producing wood pulp; from the perspective of production method, it can be divided into batch type and continuous type; according to the method of log compression, it can be divided into hydraulic type and mechanical type.
Pulping equipment
It is a device used to separate plant materials into fibers. Pulping methods are divided into chemical, mechanical, and chemimechanical methods. Corresponding pulping equipment includes digesters, wood grinders, thermomills, washing machines, bleaching machines, beaters, and waste liquor recovery equipment.
Pulp preheated with steam and then ground under high pressure is called hot-chip milled pulp. The machine used to produce hot pulp is a thermomill, which consumes a large amount of electricity. Therefore, making full use of the heat energy in the pulping process is a key issue for thermomills. A washing machine is a device used to separate cooked pulp from black liquor. Mechanical equipment can be divided into two categories according to the black liquor extraction rate: high concentration and low concentration.
The purpose of pulp bleaching is to remove residual lignin and pigments from the pulp after cooking, thereby increasing its whiteness and giving it a clean white color. A pulp bleaching machine is a widely used bleaching device, consisting of a bleaching tank, a screw propeller, and a washing drum. The pulp and bleaching agent are placed in the tank, and wash water is continuously added. The agitation and chemical reaction process is completed in the tank with the help of the screw propeller. The water containing bleaching products and residual bleaching solution is discharged through the inner cavity of the washing drum, thus whitening the pulp.
