490 / 2018-09-09 10:32:58

An overview on the control strategies for agglomeration, slagging, fouling and corrosion in biomass blends-fired power plant

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As is well-known, biomass energy is an important renewable energy, its share of the world's total energy consumed is increasing year by year. Extensive research has been carried out on the compositions and reaction kinetics of pyrolysis, gasification and combustion of biomass and its blends, including the emission of alkali metal and chloride, sintering and melt temperature and slagging tendency; However, biomass is different from the traditional fossil fuels, its high water and oxygen contents, molding difficult, energy dispersive and high cost for collecting, and high contents of alkali metal and chloride, all these results in many different sizes of furnace, such as reciprocating grate (RG), bubbling fluidized bed (BFB), CFB and like-pulverized coal suspended combustion etc, and sintering, agglomeration in combustion chamber, deposits and fouling, and corrosion on the surface of heat exchanger. It is the critical factors that the sintering temperature under different ambient atmosphere in a special furnace, such as grate, bubbling bed and cycle fluidized bed. However, it is responsible for the fouling on the tube surface that the particle viscosity and surface tension, wetting-contact angles, and the particle kinetic energy. Although we have known that alkali metal and chloride are responsible for the sintering and fouling of biomass burning, there is no practical illustration of K, Na and Cl removal by washing or pickling before combustion, it is widely used that biomass burning blended with coal or other fuel for adjusting the ash composition.
Therefore, ash compositions, operation temperature, the ratio of fuel to air flow rate constitute the main design and operation parameters for the control of sintering temperature; it is the best example that biomass burning blended with coal or additives; it also play an important role for the inhibition of fouling on the tube surface.
Furthermore, the detection of ash deposits and fouling has made a better progress. It is also a challenge that the economic utility of biomass is compared with fossil fuel.