The Study On 300MW Oxy-enriched Combustion CFB Furnace Heat Transfer Character And Notional Designation

Making an analysis and research to the heat transfer character of circulating fluidized bed under oxy-enriched atmosphere. Under different oxygen concentration(such as 30%, 50%, 70% oxygen concentration), studied impact parameters such as gas composition, particle diameter, flue gas temperature, voidage matter, gas concentration, furnace height etc. how to effect the gas-solid phase flowing in boiler, diffusion and combustion of volatile and coke combustion, and get the effect curve of CFB heat transfer under oxy-enriched condition. Thereinto the combustion model combined isopycnic shrinkage nuclear model and the isodiametric shrinkage nuclear model, brought in the ash layer resistance diffusion rates which is relevant to coal category, and dynamic reaction rate brought in general lithotype theory. By comparing with the results of normal air condition, proving the veracity. Get the main conclusions: in the oxy-enriched atmosphere compared to normal air condition, the coefficient of heat transfer can be influenced by gas composition but not very much, the change of heat transfer characteristics is not a lot, it is feasible to transform the normal boilers into oxy-enriched ones by some easy remaking. Choose an example of 300MW circulating fluidized bed unit to discuss boiler inner heat transfer character, and designed the CFB boiler under oxy-enriched atmosphere according to the results. Calculated the heating area ratio and absorbing heat ratio of furnace under the concentration of 30%, 50%, 70% , compared to get the furnace profile of oxy-enriched conditions. Concluded the evolution of the CFB boiler size, flowing situation and heat transfer character with the increasing of oxygen concentration, and made a notional designation.