Song Wu

Abstract: A system is proposed to use the combustible waste gas as a supplementary fuel in coal‐fired boilers. The combustion air can be partially or fully substituted by ventilation air methane or diluted combustible waste gases. The recommended volume fraction of combustible waste gas in combustion air is no more than 1.0%. The effect of waste gas introduction on thermodynamic parameters of boiler is evaluated through thermal calculation based on material balance, heat balance, and heat transfer principles. A case study is conducted by referring to a 600 MW supercritical pressure boiler. The results show that no retrofit of boiler is required. The operation of boiler is scarcely influenced, and the original forced and induced draft fans can meet the requirement. With increasing volume fraction of combustible waste gas, the flue gas temperature at the furnace exit decreases monotonically, resulting in an increment of heat absorption in furnace and a decrement of heat transferred in convective heating surfaces. When 1.0% volume fraction of hydrocarbon gas is introduced, the thermal efficiency of boiler is increased by 0.5%, and the coal consumption rate is reduced by 25.4%. The cost analysis of the proposed system is conducted, and break‐even curves are given as references for the utilization of waste gas as a supplementary fuel. The economic velocity of the combustion air is suggested to be 18.2 m s−1.

TL;DR: Considering the severe fouling of high temperature convection pass in the boilers using high-sodium coals, a novel boiler design with a furnace exit gas temperature (FEGT) below 800 °C was proposed in this article.

TL;DR: In this paper, a numerical simulation coupled with the user-defined function (UDF) is conducted on a cyclone-fired boiler, and the thermal boundary condition is established for the cyclone barrel.

TL;DR: In this article, a multilayer wall model considering the heat transfer from flame to working fluid in the water-cooled tubes was proposed and a judgment criterion was established to evaluate the adaptability of cyclone barrel to slag film.