Views: 0 Author: Site Editor Publish Time: 2022-07-27 Origin: Site
Before cooking or refining, the papermaking raw materials are pretreated and processed according to the requirements of the cooking or refining process. They are divided into non-wood fiber preparation equipment and wood fiber preparation equipment. The former includes grass cutters, reed cutters, and sugarcane depidders, while the latter includes peelers and chippers.
The chipper is a machine that cuts the logs required for the production of wood pulp into wood chips of a certain size. It is divided into two types: disc type and drum type. The equipment for fiber is divided into two types: intermittent type and continuous type; wood grinder is the equipment for producing ground wood pulp, which can be divided into intermittent type and continuous type according to the production method, and can be divided into two types according to the pressurization method of the log. There are two types of hydraulic pressurization and mechanical pressurization;
It is the equipment used in the process of separating plant raw materials into fibers. Pulping methods can be divided into chemical methods, mechanical methods and chemical mechanical methods. The corresponding pulping equipment includes digesters, wood grinders, thermal mills, pulp washers, pulp bleaching machines, pulping machines and waste liquid recovery equipment.
After the wood chips are preheated by steam, the pulp that is ground in a high pressure state is called hot wood chip ground wood pulp. The machine for making hot wood chip ground wood pulp is a thermal mill. Utilizing the heat energy in the refining process is the key problem of the thermal mill; the pulp washer is a mechanical device that separates the cooked pulp from the black liquor. According to the extraction rate of the black liquor, there are two categories of high-concentration and low-concentration extraction.
The purpose of pulp bleaching is to remove the residual lignin and pigment in the pulp after cooking, improve the whiteness of the pulp, and make the pulp have a white color. The pulp bleaching machine is a commonly used bleaching equipment, which is composed of the screw propeller of the pulp bleaching tank, the washing drum and other components. The pulp and bleach are placed in the tank and continuously added to the washing water, and circulated in the tank with the help of the screw propeller to complete the process of mixing and chemical reaction. The water with bleaching products and residual bleach is discharged through the inner cavity of the drum, resulting in a white pulp.
It is a complete set of equipment that makes the pulp into the paper web, including the headbox, wire section, press section, drying section, calender, reel, and transmission section. , heat recovery and other auxiliary systems. The wire part that forms the wet paper web is the core of the paper machine, so the paper machine can be divided into fourdrinier wire paper machine, clip wire paper machine and rotary wire paper machine according to the structure of the wire part.
The headbox is a device that uniformly and stably sends the slurry of appropriate concentration to the net through the pulp distributor, rectifier, weir tank, weir plate nozzle and other components, also known as the head box; the slurry is sprayed from the headbox to the copper After the wire, the wet paper sheet is formed on the wire part and dehydrated; after that, the pressing, that is, the moisture of the wet paper sheet from the wire part is mechanically squeezed out, the dryness of the paper sheet is improved, and the surface properties of the paper sheet are improved at the same time. , eliminate the net marks and increase the smoothness, tightness and strength; then enter the drying section to further dehydrate the wet paper sheet after pressing, so that the paper sheet shrinks, the fibers are tightly combined and the strength is increased.
After the paper sheet coming out of the drying section is calendered by the calender, the smoothness, gloss and tightness of the paper sheet can be improved, the thickness of the paper sheet can be uniform across the whole width, and the air permeability can be reduced; Rolling into paper rolls completes the main process of papermaking. In order to meet different needs in the future, there are also calenders, rewinders, paper cutters, etc. behind the reel in the paper workshop.
The paper industry consumes a lot of raw materials, water, electricity and chemicals, and produces a lot of waste water and waste residue. Therefore, the future of papermaking machinery will develop towards the use of a wide range of papermaking raw materials, reducing material and energy consumption in the papermaking process, and reducing environmental pollution.