Wet ball mill is one of the important systems of desulfurization system in thermal power plant. Its operation output directly affects the environmental protection and economic operation of power plant units. Two fgdm3264 wet ball mills were used in the desulfurization system of Shengli Power Plant of Shengli Petroleum Administration Bureau to prepare limestone slurry. The rubber liner of ball mill a was replaced in March 2010, and the output of the mill changed from 0.8 T / h to 1.4 T / h. It is found that the reason of output change is related to the structure and size of root liner plate. Therefore, in order to ensure the mill to operate under the best working conditions, improve the mill output and reduce the steel and power consumption, we put forward the optimization measures and implemented them on Mill B, which has achieved good results and provided an effective solution for solving such problems.
1. Analysis of present situation of our factory
The limestone grinding system in our plant is a recirculating wet pulping system. The overflow ball mill is selected, which can operate continuously and discontinuously. The limestone (particle size < 20 mm) is sent from the limestone storage bin to the wet ball mill for grinding into slurry by the weighing feeder. The limestone slurry is pumped to the hydrocyclone. After separation, the large-scale material is recycled, and the overflow material is stored in the limestone slurry tank, and then sent to the absorption tower by the limestone slurry pump. Within the designed working capacity range, it can operate safely and stably for a long time and reach the specified fineness requirements. The annual operation hours of the equipment are 7500 hours. Fgdm3264 wet ball mill is used in the desulfurization system design of the plant.
The density of slurry tank in the common area is 1203.9, generally about 1200; the water material ratio is 1:2.6, - generally 1:2; the outlet diameter of cyclone is 40; the water injection for grinding head is 10m > / h, and the water injection for grinding tail is 32m3 / h. The average output of mill a is 16.1t/h after replacing rubber liner; the average output of mill B is 17.2t/h after replacing rubber liner; the output of two mills is about 17.5t/h after 200 hours of operation and 18.75t/h after 400H of operation, in which the output of mill B is slightly higher than that of mill a.
The original lining plate uses the products of Laizhou Jingcheng rubber products Co., Ltd., which can run for 4500 hours. After 4200 ~ 4600 hours of operation, the average wear of lifting strip is more than 70%, the average wear of lining plate is more than 55%, and the wear of cylinder body is 15% more than that of export.
4.1 the same point a. the rubber lining plates of ball mills provided by the two rubber products factories have the same model and layout, the same material, and the design continuous time is 4500 hours. B. the installation process and process of rubber lining plates of ball mills provided by the two rubber products factories are the same, and the installation of bottom rubber and rubber lining plates are all carried out by the same team. C. After the liner plate of AB mill was replaced, the new ball was added again.
4.2 different points and analysis: We conducted a simple experiment during the whole production and maintenance period. At first, the purpose was to study the internal working conditions of the mill, but unexpectedly found the influence of the output of the liner mill. The experiment is like this: different colored particles with certain mass (slightly smaller than stone and with certain buoyancy) are evenly fed into the running AB mill from the feeder at the same time, and the residence time in the mill is compared. The original test purpose is to study the internal working conditions of the mill. Therefore, there is no accurate calculation time in the test, and only a simple comparison of the residence time in the mill by adding colored particles for several times is recorded. A. Old liner structure: the old liner is seriously worn due to long-term use, especially on the side of the mill population. Some lifting bars expose the metal framework, and the wear of the outlet lifting strip is relatively light, and the wear of the lining plate is also much larger than that of the outlet, The stone is gradually made into small particles in the cylinder, which leads to the different wear of lining plates at different positions in the mill.