Gasification catalyst

In general, utilization of high-sulfur char as a boiler fuel does not appear to be economically attractive. Char may be utilized as a gasifier feedstock this possibility is particularly attractive when the char contains gasification catalyst used as a coal pretreatment prior to hydrocarbonization. Finally, as noted above, it is possible to optimize hydrocarbonization processes for the production of no net char. 

Ce02 with fluorite-type structure is a component in N02 dissociation catalysts [57] and biomass gasification catalysts [58],... 

Four deactivation processes can be considered for dehydrogenation catalysts. First is coke deposition, which can be minimized by gasification with steam at high temperature. In this regard potassium is very important as K2CO3 is believed to be the gasification catalyst. 

Reactivity results for the 1273 K chars reacted in 0.1 MPa CO2 and 3.1 kPa steam at 1053 K are shown in Figures 3 and 4, respectively. The same trends evident for the 1273 K chars reacted in 0.1 MPa air are also seen in these reactant gases. Two regions of reactivity behavior are present in both cases. Calcium is seen to be a good char gasification catalyst, while Mg has very little catalytic effect. 

By using potassium as a carbon gasification catalyst, it is possible to obtain activated carbons of large adsorption capacity (large micropore volume), but with micropores of small dimensions. Nevertheless, these materials could not be converted into carbon molecular sieves by carbon deposition from benzene pyrolysis. Success was achieved with chars which were activated only to a limited extent [16]. 

Interactions with the carbon surface can make the recovery of certain solvents, such as ketones and chlorinated hydrocarbons, difficult. Ketones and aldehydes can polymerize, releasing large amounts of heat. When this happens in a part of the bed with poor heat transfer, the temperature can reach the ignition point of the solvent. Fires always start with hot-spots in parts of the bed where the airflow is reduced due to poor design. The susceptibility of the carbon bed to autoignition can be reduced by removing soluble alkali sodium and potassium salts, that may be present as impurities in the activated carbon and which can function as combustion and gasification catalysts [29]. 

In the Arrhenius diagram in Fig. 10 the straw char reactivity is compared to some other chars. Compared to the other chars the combustion reactivity of the straw char is relatively high, but this fact is not reproduced during gasification in CO2. This is astonishing. The straw char contains the intrinsic ash with much potassium, which is reported to be a very efficient gasification catalyst. 

Wood ash and CaO are reasonably effective gasification catalysts for pellets. The effectiveness apparently depends on their incorporation into the wood matrix. 

Fredriksson, H.O.A., Lancee, R.J., Thiine, PC. et al. (2013) Olivine as tar removal catalyst in biomass gasification catalyst dynamics under model conditions. Applied Catalysis B Environmental, 130-131, 168-177. 

Mixed plastics automobile shredded 3 wt% chlorine Energy and Environmental Research Corporation and US EPA, pilot scale, spouted bed fluidized regime ablative gasification, 500-800°C Fe203 active gasification catalyst and sorbent for HCl Petrochemical feedstocks 381b... 

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