Gasification continued process

HTG has several advantages in the treatment of aqueous wastes due to high carbon gasification efficiencies, reduced land footprint and destruction of pathogens. However the technology is still very much at the research stage and requires continuing process... 

The high cost of coal handling and preparation and treatment of effluents, compounded by continuing low prices for cmde oil and natural gas, has precluded significant exploitation of coal as a feedstock for methanol. A small amount of methanol is made from coal in South Africa for local strategic reasons. Tennessee Eastman operates a 195,000-t/yr methanol plant in Tennessee based on the Texaco coal gasification process to make the methyl acetate intermediate for acetic anhydride production (15). 

Matsumura, Y. Minowa, T., Fundamental design of a continuous biomass gasification process using a supercritical water fluidized bed. Journal of Hydrogen Energy 2004, 29, 701. 

The continuing search for technical and economic improvements in the coal gasification areas has provided incentives to develop newer process concepts starting in 1979. The Joint Program for 1979 includes processes in the Process Development Unit (PDU) stage of development which promise technical and/or economic improvements. Gasification processes included in the 1979 program are ... 

After World War II, direct liquefaction of coal became uneconomical as the use of lower-cost petroleum products became more widespread. However, the German process of indirect coal liquefaction, the Fischer-Tropsch process, continued to hold some interest. The Fischer-Tropsch process first involved production of a carbon monoxide and hydrogen-rich synthesis gas by the controlled gasification of coal followed by a catalytic reaction process to yield a valuable mixture of hydrocarbon products. Simplified Fischer-Tropsch reactions are shown by the following equations ... 

In the Hybrid gasification process, a slurry of coal and residual oil is injected into the gasifier where it is pyrolyzed in the upper part of the reactor to produce gas and chars. The chars produced are then partially oxidized to ash. The ash is removed continuously from the bottom of the reactor. 

The gasification of hydrocarbons to produce hydrogen is a continuous, non-catalytic process (Figure 10-2) that involves partial oxidation of the hydrocarbon. Air or oxygen (with steam or carbon dioxide) is used as the oxidant at 1095— 1480°C (2000-2700°F). Any carbon produced (2-3 wt% of the feedstock) during the process is removed as a slurry in a carbon separator and pelleted for use either as a fuel or as raw material for carbon-based products. 

Hydrocarbon gasification process a continuous, noncatalytic process in which hydrocarbons are gasified to produce hydrogen by air or oxygen. 

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