Numerical Simulation And Experimental Research Of Heat Loss In Circulating Fluidized Bed Boiler

Because the essence of heat loss in circulating fluidized bed boiler is determined by the insulation performance and the rationality of the insulation structure. In this paper, we took the 200t/h circulating fluidized bed boiler of a running power plant as the research object. The aim is to analysis the simulation and experimental study of thermal insulation material, insulation construction and the outside wall temperature to obtain the law of furnace wall heat transfer and thermal insulation performance. It was discussed that the influence on heat loss when the thermal insulation material and insulation construction were changed, and the economic thickness of a variety of thermal insulation materials and insulation construction were given.First of all, the physical model and mathematical model of circulating fluidized bed boiler were established. The Comsol software was used to numerically simulate the heat transfer process of a variety of thermal insulation materials and insulation construction to calculate and obtain the heat transfer process law of furnace wall temperature distributions, the characteristics of outside wall temperature distribution and the economic thickness of them. Through the analysis of simulation result, it was showed that the economic thickness of different thermal insulation materials and insulation construction were different under the same condition and the temperature when the thickness of thermal insulation materials are same was different. They had some influence on the thermal insulation performance. The simulation results provided a theoretical basis for engineering practice.Secondly, on the basis of numerical simulation, the hot state test bench of the heat transfer of circulating fluidized bed furnace wall was designed and set up for the research. By means of the heat preservation testing to a variety of thermal insulation materials and insulation construction to obtain the law of outside wall temperature distribution and outside wall temperature. Through the analysis and the regulation on the thickness to achieve the reasonable value of outer wall temperature, and make heat loss minimum.Finally, combining with the experimental test results to verify some simulation schemes and the causes of differences are analyzed. Combined with the results of numerical simulation and experimental results, they were concluded that the economic thickness of the aluminum silicate fiber mat and the rock wool is 110 mm, the economic thickness of phenolic mineral wool and composite materials is 130 mm, for the chamber of a stove or furnace, and the economic thickness of aluminum silicate refractory fiber felt is 57 mm, the economic thickness of aluminum silicate fiber blanket is 155 mm, the economic thickness of cement slabs of expanded vermiculite blocks is 58 mm for cyclone separator, and the highest average withstanded temperature is 396℃ and 386℃ for the tail flue in the two design schemes. Therefore, the heat loss in circulating fluidized bed boiler can be reduced by finding the economic thickness of thermal insulation material for furnace type, at the same time saving the cost of circulating fluidized bed operation and the construction cost and providing a reference for engineering practice.