Analysis On Attrition Of CFB In Mixture Combustion Of Coal And Coal Gangue

For CFB boiler, large amount of materials move rapidly in the furnace and gas with large ash density flows. That leads to the abrasion of metallic components and refractory inside the boiler. Abrasion is a factor which badly influences boiler normal operation, and is one of the most common reasons for boiler shut-down. In this dissertation, after having investigated the state of abrasion of CFB boilers'heating surface, refractory and other parts, and analyzed the concerning mechanism as well as the effecting factors.In this paper, it is analyzed that combustion characteristic of coal and coal gangue, with experiment research. analysis the combustion characteristic of mixture coal and coal gangue by TGA. It show that antagonism exist in the process of the mixture combustion. The ash of coal and coal gangue analysis by X-ray show that the effect of attrition by coal gangue depends on the content of Al2O3 in it .Al2O3 is very hard and heavy and unbreakable in high temperature, this leads to coal gangue attrition effect on surface of CFB boiler is more serious than coal .With the development of large-scale CFB boiler, the abrasion problem is becoming more and more serious day by day. Presently, analysis about abrasion of CFB boiler is focus on characteristic and technique of anti-attrition coatings .The anti-attrition ridge design almost depends on experience. Simulate of the process about flow and combustion in CFB boiler. in different design parameters of anti-attrition ridge, then calculate the volume of attrition in different condition in erosion model.In numerical simulation process, using numerical simulation software Fluent6.3 establishes three-dimensional numerical combustion model corresponding with the #4 boiler in Lian Zhou Power Plant. Selecting turbulence model as flow mathematical model, P-1 radiation model as radiation heat transfer, Non-Premixed Combustion model as combustion chemical reaction. Make the boundary condition as the operating parameters in Lian Zhou Power Plant. As the numerical simulation show that trapezoidal anti-attrition ridge is better than rectangle anti-attrition ridge, increase anti-attrition ridge width will promote the efficiency of anti-attrition, increase anti-attrition ridge number in CFB boiler will promote the efficiency of anti-attrition too. Otherwise, contrast condition B,G,H will find that when the coal gangue ration in mixture coal and coal gangue less than 20%,the temperature field uniform distributed, boiler can run safely . Contrast condition A,B will find that EB/EA less that 0.5, power plant come to the same situation, it show that the numerical simulation process is correct.