Gasification accomplishment

If a fuel is in the liquid state, such as fuel oil, most of it must be vaporized to the gaseous state before combustion occurs. This vaporization can be accomplished by supplying heat from an outside source, but usually the liquid fuel is first atomized and then the finely divided fuel particles are sprayed into a hot combustion chamber to accomplish the gasification. 

Regeneration of coked catalysts may be accomplished by gasification with oxygen, steam, hydrogen, or carbon dioxide ... 

Sewage in vast quantities of billions of gallons per day could be recycled to produce a renewable source of hydrogen. This can be accomplished either by utilizing the non-photosynthetic bacteria that live in the digestive tracts and wastes of humans and other animals, or by pyrolysis-gasification methods. 

Gasification. Conversion of biomass to gaseous fuels can be accomplished by several methods only two are used by the biomass eneigy industry (ca 1992). One is thermal gasification in which LHV gas, ie, producer gas, is produced. The other process is anaerobic digestion, which yields an MHVgas. 

In addition 10 direct operations i<> remove or reduce sulfur content, coal liquefaction or gasification can accomplish similar results indirectly. 

The description given applies to DR processes that are based on the use of gaseous reductants in shaft furnaces, batch retorts, and fluidized beds. In the processes that use solid reductants, eg, coal (qv), the reduction is accomplished to a minor extent first by volatiles and reducing gases that are released as the coal is heated and then by CO that is formed by gasification of fixed carbon contained in the coal char with C02. Reduction by solid carbon and coal volatiles in kilns is insignificant. 

The challenge in developing lower cost SNG gasification processes is (1) to combine as many of these items as possible into each new process and (2) to accomplish this without adding so much additional cost in other parts of the processes so as to wipe out the savings. 

One of the more innovative pyrolytic gasification processes is an indirectly heated, fluid-hed system (c/. Alpert et al, 1972 Bailie, 1981 Paisley, Feldmann, and Appelbaum, 1984). This system uses two fluid-bed reactors containing sand as a heat transfer medium. Combustion of char formed in the pyrolysis reactor takes place with air within the combustion reactor. The heat released supplies the energy for pyrolysis of the combustible fraction in the pyrolysis reactor. Heat transfer is accomplished by flow of hot sand from the combustion reactor at 950°C to the pyrolysis reactor at 800°C and return of the sand to the combustion reactor (Fig. 9.5). This configuration separates the combustion... 

The accumulated operating experience amounts to about 8500 hours of gasification runs and about 3600 hours of operation as a fully integrated plant as per the end of 1999. The test runs have been very successful and the plant has been operated on different wood fuels as well as straw and RDF. One of the last tests included operation on 100% straw, which was accomplished without disturbances or problems. 

Technically speaking, gasification is the controlled thermal decomposition of organic material, producing a gaseous fuel and an inert solid ash residue. This controlled thermal processing can be accomplished through two types of reactions ... 

Gasification of solid waste can be accomplished in a variety of furnace designs. At Midland-Ross, we have selected the vertical shaft furnace primarily because of its uncomplicated material transport method—gravity—and its efficient counterflow of material and process gas. This furnace is shown on Figure 1. 

Conventional gasification requires separation of hydrogen and CO2 from the fuel gas mixture. This can be accomplished through chemical or physical sorbents or through membrane separation. As mentioned earlier, at low temperatures, physical and chemical adsorption is commonly used to separate hydrogen from the gas stream. Many of the zero-emission plants, however, could improve efficiency dramatically if CO2 capture could be achieved at high temperatures. Solid chemical sorbents, such as CaO, have been considered potential candidates. 

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