| As an abatement of smoke and dust equipment, electrostatic precipitators (ESP) are widely used in thermal power generation, steel, nonferrous metallurgy, chemicals, building materials, machinery, electronics and other industries. It is a very important practical significance to protection and improvements of the environment. Nowadays, there is a common problem in the process of the operation of the ESP:the insulating material of the cathode of the ESP that plays the role of load-bearing and insulation is frequently ruptured, which leads to the abnormal operation of the ESP, affects the collection efficiency seriously, destroys the normal order of production and increases the cost of production. To solve this problem, one of the measures taken is to keep the temperature of the insulating material above the dew point of the flue gas by the incubator, which prevents the condensation of the flue gas. However, due to the high dew point of the flue gas, the conventional heating mode by electricity can't meet the requirements and seriously affect the stability and continuous production. So a new and efficient heating source is in urgent need of developing.Based on solving common problem that is frequently ruptured of the cathode insulation of ESP in the actual operation of the ESP, the microwave heating airflow technology was introduced in this paper. It takes full advantage of its unique properties, solves the output problem of the high temperature air, achieves purpose of energy conservation, and has important economic significance and environmental significance to normal running of ESP. The specific content of this paper is as follows:The theory heat supplied by the hot air was calculated through the establishment of the solution of mathematical models and designing of microwave high-temperature hot air system. Also, common forms of heat exchangers and comparative analysis were introduced. The required heating power by the microwave air heating technology under the condition that the incubators of the industry and experiment use maintain 240℃were respectively calculated to be 1482W through the establishment and the solution of mathematical models. SiC is the suitable material of the strengthening heat transfer of microwave resonant cavity structure. Three structural forms of the strengthening heat transfer of microwave resonant cavity structure are single honeycomb straight-tube flow cell, dual honeycomb straight-tube flow cell and partition type.The experimental results of microwave hot air system show that, in the small-scale experiment, the temperature of the incubator was up to 235℃when the microwave power is 3KW. Better temperature-rising, better equilibrium temperature are obtained at 190V Voltage and 2.18m/s air speed; in the pilot-scale experiment, the best operating conditions is to adjust the power to 9KW before warming 55min under microwave power of 32KW and then the insulator temperature rose to 260℃.On the basis of GAMBIT modeling, meshing, boundary conditions established, FLUENT are adopted to simulate for temperature and flow field inside of insulators. The comparison between experiment results and simulation results showed that it is feasible and authentic for simulation. The indication error is in the allowable range and its main reason is analyzed. In the semi-industrial experiment, the best operating conditions is to warm the insulator for 120min under microwave power of 33KW, adjust the power to 28.5KW, and then insulator minimum temperature rose to 180℃.It is feasible to use the microwave air heating technology to solve the common problem that is frequently ruptured of the cathode insulation of ESP in the actual operation through the researches. This paper provides the new way and the new program for the solution to this common problem and extremely expands the microwave heating technology research. The research is greatly significant in the practical production and application. |
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