Nowadays, the coal cost of the thermal power plant accounts for 70% of the total cost, and with the increase in coal prices, this ratio is still expanding. Therefore, the sampling of representative coal samples is of great significance in controlling the cost of coal and protecting the interests of power plants. At present, the thermal power plants usually adopt the mechanical sampling equipment. Compared with the manual sampling, mechanical sampling has high precision and representativeness, but there are some problems during the use of mechanical sampling equipment. In the article Problems and Solutions of the Coal Sampling Machine Operation System in Thermal Power Plant, we talked about some technical requirements of the sampling machine and some problems and solutions during the operation. Next, we will continue with these contents.
Problems and Solutions in Operation
The Crusher Inlet of the Coal Sampling System is Blocked
The inlet size of the coal crusher is very small. If it encounters the wet and viscous coal samples, the fine coal slurry in the coal crusher will be splashed on the wall of the falling coal tube. Normally, they will be piled up and cause the coal falling tube blocked after the coal sampling machine running for one to two hours. This problem is difficult to be detected because the device is still operating after the coal falling tube is blocked. However, there is a simple method that can help us in solving this problem. The only thing we need is a little vibrating motor. The coal slurry accumulated on the wall of the coal falling tube would be shaken off by setting up a vibrating motor outside the coal falling tube to avoid blockage and ensure the operation efficiency of the sampling equipment.
The Feed Belt of the Coal Sampling Machine is Pressed Tightly
When the crusher is blocked, it will send out the fault signal of the coal sampling machine to stop the operation. However, if other parts of the equipment are blocked, the crushing machine and the sampler will not stop running. The coal sample will be continuously transported to the coal falling tube, thus the feeding belt will be pressed. For solving this problem, we can install the fault signal device on other equipment of the sampling system. If one of the devices fails, the signal will be sent immediately. All devices will terminate the operation at the same time to avoid the above problems.
The Moisture Loss from Coal Samples
The coal sampling equipment with the belt-type division machine used to store the coal samples in the iron coal tub. Coal samples will be directly in contact with the air, resulting in the water loss. The testing of coal samples requires that the moisture loss rate should not be higher than 1%, but because of the different coal types and the interference of weather factors, the water loss of coal samples is often more than 1%. In this way, the calorific value of coal after sample preparation is larger than the actual value, and the coal consumption will increase by 7g/ KWH -9g/ KWH. In order to solve this problem, we can add a funnel under the division machine. The insurance plastic film will be used to collect the coal sample at the bottom of the funnel. In the process of sample changing, we can seal the coal sample with plastic film, so as to reduce the moisture loss rate.
In short, in the process of coal sampling, coal blockage and leakage are the common problems. On the one hand, it is caused by the quality of the coal itself; on the other hand, it is caused by the operation problem of the sampling machine. Based on this, it is suggested to scientifically design the sampling system to avoid these problems becoming the bottleneck of the whole system.
TopSampler, as a coal sampling system manufacturer in China, produces the auger sampling system for railcar, the auger sampling system for truck and the cross belt sampling system. If you are interested, please feel free to contact us.