Combustion, biomass advantages

The first option is to remove the ammonia from the fuel gas before combustion. The advantage of ammonia removal at this stage is that the volume of the gas leaving the gasifier is much smaller than the flue gas volume. Conventional ammonia removal methods, involving condensation and absorption in water, may be used in biomass IGCC plants. These methods are associated with cooling and potential loss of sensible heat from the gas. Also the absorbed ammonia has to be disposed of. 

Although the gasifier product itself has low levels of NOx, the total systems emissions of this product must be carefully scrutinized. When clean biogas is eventually burned, NOx will be produced, as it is in most combustion systems with all fuels. The use of biogas rather than solid biomass fuels provides the opportunity to better control the combustion process, which can potentially result in lower NOx emissions. As such, gasification offers potential environmental emissions advantages over combustion alternatives. However, NOx may still occur as the gas is burned, and appropriate NOx control technologies may be needed. 

The low concentration of sulfur in biomass offers potential advantages for some applications. In cofiring applications, for example, the cleaner combustion gases from biomass dilute those from coal, and the overall concentrations of sulfur per unit of combustion gas are reduced. In most applications... 

Biomass has some advantageous chemical properties for use in current energy conversion systems. Compared to other carbon-based fuels, it has low ash content and high reactivity. Biomass combustion is a series of chemical reactions by which carbon is oxidized to carbon dioxide, and hydrogen is oxidized to water. Oxygen deficiency leads to incomplete combustion and the formation of many products of incomplete combustion. Excess air cools the system. The air requirements depend on the chemical and physical characteristics of the fuel. The combustion of the biomass relates to the fuel bum rate, the combustion products, the required excess air for complete combustion, and the fire temperatures. 

The biomass pyrolysis is attractive because sohd biomass and wastes can be readily converted into hquid products. These liquids, as crade bio-oil or slurry of charcoal of water or oil, have advantages in transport, storage, combustion, retrofitting and flexibihty in production and marketing. 

Other advanced combustion systems for solid biomass fuels also offer considerable advantages over conventional designs and are in commercial use or under development. A few of them are described here. 

For large-scale biomass conversion 400-1000 MW, ) the biomass Integrated Gasification Combined Cycle (BIGCC) is a well-known concept [4], Coii ared with combustion the system has some clear advantages ... 

In comparison with coal, combustion of biomass fuels and fuel mixture of biomass and coal has advantages with lower sulphur emissions and less tendency for slag formation. 

Fluidised bed combustion has been chosen to study the pollution emission for these advantages is adequate for large variety of biomass with different physical-chenucal characteristics, high combustion efficiency and low pollution emission. 

The advantage of ash separation within this combined combustion of coal and biomass offers a separate ash utilisation. While the ash utilisation of pure coal ash is technically approved and economically feasible already, different kinds of utilisation of biomass ash have to be proved. The utilisation of mixed ashes in building industry, which is the main market for ashes from coal combustion, is not foreseen in the legislation of the European Union. The investigated pre-treatment process is a suitable alternative for biomass co-combustion. 

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