Dosing Control Online pH Controller for Paper Mill

During the papermaking process, 99% of the water is removed from the pulp, exposing 1% of the paper material. Therefore, the process is very water-intensive. But the potential for gray water reuse is huge. Maximizing the use of wastewater (white water) can achieve economic and environmental benefits. With minor processing and adjustments, white water can be reused within the plant for a variety of applications, including stream dilution, machine operation, cleaning and chemical replenishment. In most process sections of paper mills, pH analyzers are required to adjust and control the pH value. The online pH analyzer developed and produced by Daruifuno includes a Ph Controller and Ph Sensor, which can continuously monitor the pH value of water quality in real time. The pH controller has two programmable SPST relays, which can set high and low alarms, control the dosing pump, and maintain the pH of the solution within a certain range. The 3.2-inch LCD screen can display the pH value of water quality in real time, allowing you to understand the p value of water quality faster for adjustment.

Specification

Fiber recycling
White water can contain up to 30% of the feed fiber, so operating it at the top of the plant is a good approach. Fibers can be reintroduced into the pulp stream. Water is required to operate a beater, which turns the raw material into pulp and dilutes the pulp stream to create a constant flow rate. Consistency in pulp flow is key to the efficiency of mill operations. To maintain consistency, it is necessary to remove the filler content before pouring the plain water back into the plant heads. The filler content is typically a fine-grained mineral content, much smaller than that of a dewatering screen, and enters the white water at a higher rate than pulp fibers. Instead of returning the filler with the paper fibers, high pH precipitation is used to remove the filler content and recycle it. This method concentrates the mineral content. Returns white water flow with minimal filler content, eliminating the need for advanced dosing control of filler.

Application for clean water reuse
Reusing water in applications such as heating and cooling systems or chemical replenishment requires fiber-free water. Equipment called holding units are used to remove fibers and fillers, both to recycle raw materials and to simplify wastewater treatment in the production line. First, long fiber particles are easily captured by the drum screen, and then other solid components are removed through sedimentation. In order to achieve a higher solids removal rate than previous removal of filler content, the full-efficiency process measures the pH value through a pH sensor and then automatically adjusts the pH value through a pH controller to flocculate the water through slow mixing after precipitation. The solids are then removed by settling in a gravity clarifier.

In some applications, higher solids removal rates are required, such as water sprayed through nozzles. Once clarified and sent to a clean well, the water is further passed through a cartridge filter to capture remaining fine particulate matter. Finally, to use regenerated water in contact systems such as steam boilers or vacuum pumps, the water must also be treated to prevent metal corrosion, which also requires control with a pH analyzer.

After production is complete, all water used in paper mills is treated before being discharged. Because discharge requirements are higher than the treatment requirements for most whitewater reuse in paper mills, reuse reduces the overall material and energy costs of water treatment. At the main wastewater outlet of a paper mill, it is usually necessary to monitor parameters such as pH, COD, ammonia nitrogen, total nitrogen, total phosphorus, flow, SS, and color. Delfino company focuses on the research, development and production of water quality instruments. Our main products include Ph Orp Analyzer, Conductivity Analyzer, Turbidity Analyzer, Cod Analyzer, Dissolved Oxygen Analyzer, ammonium analyzer, chlorine analyzer, etc. If you are interested in our products, please contact us!