The dust in the coal conveying system of coal-fired boilers is mainly coal dust. Dust will be produced during coal screening, crushing and transportation. If no measures are taken, it will pollute the environment and atmosphere of the coal transportation site. At the same time, coal dust contains free silica. The smaller the dust particles, the less likely they are to settle. They floated in the air for a long time. Once inhaled and deposited in the lungs, it will cause fibrous lesions, gradually harden lung tissue, cause various lung diseases, and seriously endanger the health of workers.
In addition, dust falls on the rotating parts of the machinery, which accelerates the mechanical wear; If it falls on electrical equipment, it will cause poor contact of electrical equipment and make the control of electrical equipment invalid; Excessive dust accumulation on site will also cause adverse consequences such as dust spontaneous combustion. In order to ensure the health of coal conveying personnel, ensure the safe production of thermal power plant and prolong the service life of equipment, it is necessary to carry out comprehensive dust control on coal conveying system of thermal power plant.
At present, the existing dust removal devices on the belt conveyor usually add a spray device in the conveying process or at the exit to spray water into the dust removal space in the form of mist particles, and reduce dust pollution by means of water mist dust removal. This method needs a lot of water resources.
Another way is to add a dust bag to the belt conveyor, which includes a body, a dust inlet, an air outlet, a flower board and a plurality of evenly distributed filter bags connected with the flower board. The dust falls back to the coal conveying belt after being filtered by the filter bag, which reduces the dust pollution of the coal conveying belt. However, this requires a supporting fan, and the filter bag needs regular maintenance and replacement. Usually, a coal conveying belt uses a large number of filter bags, which are frequently replaced and have high daily maintenance costs.
In addition to the above two kinds of dust-proof devices, there is also a fully transparent dust-proof cover for coal conveying, which has won national patents, is energy-saving and environmentally friendly, and has lower operation and maintenance costs. The dust-proof effect of this fully transparent dust-proof cover device is over 95%, and the whole process of coal conveyor is visible and controllable, with simple cleaning and low maintenance cost. Installing a fully transparent dust cover on the coal conveying belt of a coal-fired boiler not only solves the dust pollution caused by lignite belt transportation and the noise pollution caused by the belt conveyor, but also greatly reduces the fire hazard at the coal conveying site, reduces dust and is more environmentally friendly!
At present, the dust cover device has been installed in Shanghai Waigaoqiao No.2 and No.3 power plants. After installation, the dust concentration outside the hood reached below the national standard of 4mg/m3 in the process of coal transportation in Indonesia, and no spontaneous combustion or flash explosion occurred after two years of operation, with remarkable environmental protection effect.