Secondary Gasification

Secondary gasification usually involves the gasification of char from the primary gasifier. This is usually done by reacting the hot char with water vapor to produce carbon monoxide and hydrogen  

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For high-ash coals in particular, the integration of the sensible heat of the bottom product is essential for high efficiencies. Thus, the secondary gasification agent should be at the lowest possible temperature to gain maximum heat while... 

The mass flow of the secondary gasification agent is controlled to achieve a superficial gas velocity above the moving bed of 0.25 m/s. 

Baker, E. Mudge, L. Brown, M., Steam gasification of biomass with nickel secondary catalysts. Industrial and Engineering Chemistry Research 1987, 26, 1335-1339. 

High-temperature processes, based on pyrolysis, gasification or combustion of biomass are the preferred conversion routes for non-food competing biomass conversion processes to secondary energy. 

Gasification. The extent of carbon removal from coal by pyrolysis is relatively limited. As a result, the yields of secondary fuels having increased H/C ratio are not large. Essentially complete control of the amount of carbon removed can be achieved, however, by complete gasification of coal with an oxygen-containing gas and steam ... 

Water shift gas reactions form CO2 and H2 using water and CO at elevated temperature, as shown in equation 1.4. The reaction may be used with catalysts, which can become poisoned by S if concentrations are high in the feed gas. The water shift gas reaction is used as a secondary means of processing syngas when greater amounts of H2 are desired from gasification. 

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