Raw material processing stage
Wood chip conveying system: In the process of conveying wood chips to the cooking pot, a screw conveyor is usually used. An electric gate valve will be installed on the pipeline between the discharge port of the screw conveyor and the feed port of the cooking pot. This valve can accurately control the feeding speed of wood chips to avoid feeding too fast or too slow. When the cooking pot needs more raw materials, the opening of the electric gate valve increases so that the wood chips can enter quickly; when the feed amount needs to be controlled, the valve opening can be reduced.
Chemical addition during cooking: When cooking wood chips, chemicals such as sodium hydroxide and sodium sulfide need to be added. A metering valve will be installed on the chemical addition pipeline. The metering valve can accurately control the amount of chemicals added, because the amount of chemicals used during cooking has a great impact on the quality of pulp. For example, the precise amount of sodium hydroxide can ensure that the lignin in the wood is effectively dissolved, thereby obtaining good quality pulp.
Pulp washing and screening stage
Washing liquid circulation system: During the pulp washing process, the washing liquid needs to be circulated. A large number of butterfly valves are used on the circulation pipeline of the washing liquid. The butterfly valve is characterized by fast switching speed and can easily control the flow direction and flow rate of the washing liquid. For example, when washing different batches of pulp, the path of the washing liquid can be quickly switched through the butterfly valve so that the washing liquid passes through the filtering equipment first and then circulates back to the washing equipment.
Pulp screening equipment inlet and outlet: Pressure regulating valves and check valves are installed on the inlet and outlet pipelines of the pulp screening equipment. The pressure regulating valve can control the pressure of the pulp entering the screening equipment to ensure that the screening process is carried out at a suitable pressure to improve the screening efficiency. The check valve can prevent the screened pulp from flowing back to the unscreened pulp pipeline to ensure the screening quality.
Pulp flow system
Pulp mixing and dilution: Before the pulp is transported to the papermaking machine, the pulp needs to be mixed and diluted. Agitator-related valves and flow control valves are installed on the inlet and outlet pipelines of the pulp mixing tank. Agitator-related valves are used to control the operation of the agitator to ensure that the pulp is fully mixed in the mixing tank. The flow regulating valve is used to control the discharge flow of the mixed pulp so that it can enter the papermaking machine at a suitable speed. A proportional valve will also be installed on the pulp dilution pipeline to accurately control the ratio of diluent (such as water) to pulp to ensure that the concentration of the pulp meets the requirements of papermaking.
Flow pipeline to papermaking machine: A pressure stabilizing valve will be installed from the pulp flow pipeline to the entrance of the papermaking machine. The papermaking machine has certain requirements for the pressure of the pulp. The pressure stabilizing valve can ensure that the pressure of the pulp is stable when it enters the papermaking machine to prevent pressure fluctuations from affecting the forming quality of the paper. In addition, a degassing valve will be installed on the flow pipeline to remove air from the pulp, because air bubbles will affect the uniformity and strength of the paper.
Internal system of the papermaking machine
Net and press section: In the net and press section of the papermaking machine, a spray system will be used to clean the filter screen and blanket. A water-saving nozzle valve will be installed on the water supply pipeline of the spray system. These valves can control the water flow and angle of the nozzle, which can effectively clean the filter and blanket and save water. In the hydraulic system of the pressing section, there will be various hydraulic control valves to control the pressure of the pressing roller to ensure that the paper can be effectively dehydrated during the pressing process.
Drying section and winding section: In the drying section of the paper machine, steam regulating valves will be installed on the steam pipe. These valves can control the flow of steam, thereby adjusting the drying speed of the paper. In the winding section, tension control valves will be used to control the tension of the paper to ensure that the paper can be rolled into a paper roll flatly during the winding process, thereby improving the quality of the finished paper.
Wastewater collection and transportation system
Workshop wastewater collection pipeline: Manual ball valves will be installed on the collection pipelines for wastewater generated by various equipment in the papermaking workshop. These ball valves can be easily opened and closed to control the collection of wastewater from different equipment. For example, when the equipment is maintained or cleaned, the wastewater of a certain equipment can be collected separately through a manual ball valve. Check valves and flow monitoring valves will be installed on the main pipeline for transporting wastewater to the treatment plant. The check valve can prevent the treated wastewater from flowing back to the workshop, and the flow monitoring valve can monitor the flow of wastewater in real time to provide data support for subsequent treatment.
Pipeline system in the wastewater treatment plant: In the wastewater treatment plant, various regulating valves and gate valves are used on the connecting pipes between different treatment units. For example, a flow regulating valve will be installed on the water inlet pipe of the coagulation and sedimentation unit to control the water inlet flow and ensure that the coagulation and sedimentation process is carried out under appropriate conditions. A sludge return valve will be installed on the sludge return pipe to control the return ratio of sludge and improve the wastewater treatment effect.
