Potassium carbon gasification

Direct hydrogen cyanide (HCN) gas in a fuel oil gasification plant to a combustion unit to prevent its release. 4. Consider using purge gases from the synthesis process to fire the reformer strip condensates to reduce ammonia and methanol. 5. Use carbon dioxide removal processes that do not release toxics to the environment. When monoethanolamine (MEA) or other processes, such as hot potassium carbonate, are used in carbon dioxide removal, proper operation and maintenance procedures should be followed to minimize releases to the environment. 

CCG [Catalytic Coal Gasification] A generic name. All such processes require very cheap catalysts. Exxon Engineering Corporation developed such a process in the 1980s, which used a catalyst based on potassium carbonate. Tohoku University, Japan developed another process using iron salts deposited on coal. 

The formation of the mixed compounds is reflected in the activity of the potassium promoted system, which is below that of, e.g. potassium/iron-on-magnesia [3], The absence of both potassium ferrite, believed to be the active phase, and potassium carbonate, necessary for gasification of deposited carbon, might be responsible for the observed behavior. 

Potassium carbonate is a well-known catalyst for the steam gasification of carbonaceous materials. We discuss the use of in situ high temperature X-ray diffraction to demonstrate that intercalation compound-like structures are not involved as stable intermediates. 

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]. 

The two series studied have been prepared from chars with different ash contents, as a result of the acid- and water-washing treatments at which the starting material was submitted. The inorganic matter is constituted mainly by potassium salts and, to a lesser extent, also by sodium and calcium salts, which are known catalysts for the carbon gasification reaction with CO2. Figure 1 plots... 

Since catalysis is of such current interest, this paper presents a review of some of the literature which deals with the catalytic gasification of biomass. It also summarizes the preliminary results of a bench-scale fluid bed gasification study which employed Canadian hybrid poplar. The effect of such catalysts as potassium carbonate and calcium oxide on wood gasification is reported. Hybrid poplar was selected due to its rapid growth and, therefore, its relevance to the concept of wood energy plantations. 

Alkali carbonates such as sodium carbonate and potassium carbonate were studied intensively during early gasification research prior to World War II. White and Fox (2) noted that sodium carbonate increased graphite gasification rates, increased net gas yields and altered the gas product distribution in favor of carbon monoxide and hydrogen over carbon dioxide and methane. 

Subsequent graphite gasification research by White and his group (3,4) found potassium carbonate to be an excellent catalyst at an optimum proportion of 20 percent (by weight) of the carbonaceous fuel feed. White and Weiss (3J noted that alkali carbonates also catalyzed the water-gas shift reaction when steam was injected during gasification ... 

In 1953, Lewis, Gilliland and Hipkin (5) investigated the rate of gasification of wood charcoal catalyzed with potassium carbonate (10% by weight) at 650°C. The reaction rates at 650°C with the catalyst were approximately equal to the non-catalyzed rates at 870°C. 

Cox and co-workers (7, 8, 9) catalyzed the gasification of wood, coal, paper, sludge, manure and municipal refuse with potassium carbonate. They found that alkali carbonates promoted the steam-carbon and steam-hydrocarbon reactions and concluded ... 

Table II summarizes the catalyzed gasification results of the hybrid poplar in the presence of potassium carbonate and calcium oxide. Both of these catalysts increased the liquid and gas yield at the expense of the solid. Both catalysts promoted a final product which was approximately fifty percent (50%) gaseous. The remainder of the product was thirty percent (30%) liquid and twenty percent (20%) solid.

The process is based on the concept that alkali metal salts (such as potassium carbonate, sodium carbonate, potassium sulfide, sodium sulfide, and the like) will catalyze the steam gasification of coal. In addition, tests with potassium carbonate showed that this material also acts as a catalyst for... 

Freriks, I. L. C., van Wechem, H. M. H., Stuiver, J. C. M., Bouwman, R. (1981). Potassium-catalysed gasification of carbon with steam a temperature-programmed desorption and fourier transform infrared study. Fuel, 60, 463—470. 

Jiang, M., Hu, J., Wang, J. (2013). Calcium-promoted catalytic activity of potassium carbonate for steam gasification of coal char effect of hydrothermal pretreatment. Fuel, 109, 14-20. 

Wang, J., Sakanishi, K., Saito, I., Takarada, T., Morishita, K. (2005). High-yield hydrogen production hy steam gasification of hypercoal (ash-free coal extract) with potassium carbonate comparison with raw coal. Energy Fuel, 19, 2114—2120. 

Snoeck, J.-W., Froment, G. F., and Fowles, M. 2002. Steam/C02 reforming of methane. Carbon formation and gasification on catalysts with various potassium contents. Ind. Eng. Chem. Res. 41 3548-56. 

In this work we developed a methodology to produce activated carbons of high adsorption capacity and with controlled pore size, based on the KOH catalysed gasification with CO2 of a coconut shell char. To study the effect of potassium in the activation step two series of activated carbons were prepared, with (CK1173) and without KOH (DC1173), The results obtained show that the size of the micropores is much smaller in the series CKl 173. 

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