Gasification coal fuel

The types of reactions involving fluids and solids include combustion of solid fuel, coal gasification and liquefaction, calcination in a lime kiln, ore processing, iron production in a blast furnace, and regeneration of spent catalysts. Some examples are given in Sections 8.6.5 and 9.1.1. 

The catalyzed gasification (using steam) of carbon solids (coals, chars, organic solid waste, graphite) to H2, CO2, and CO is utilized to convert these materials to gaseous fuels (coal gasification) [23, 212]. Describe the process. 

Coal gasification, which is used intensively in parts of the world, is also based on partial oxidation. Often the hydrogen is, however, not separated from the syngas, e.g. in the production of synthetic fuels. Coal gasification plays a role as a sub-process especially for the so called Pre-Combustion CO2 Capture . 

See also Biofuels and Synthetic Fuels Coal Gasification Hazardous-Waste Disposal Hydroelectric Power Plants Industrial Pollution Control Petroleum Extraction and Processing Steam Energy Technology Wind Power Technologies. 

Fuel. Coal gasification produces a combustible fuel gas that is principally H2, CO, and sometimes CH4. This fuel is excellent for direct use in combustion turbines and is also an excellent industrial fuel gas. It can easily be processed and converted into pipeline-quality natural gas, or even premium liquid fuels such as methanol or gasoline. These uses of coal gas generally favor oxygen-blown coal gasification processes. Key issues are the supply and price of conventional fuels. Nevertheless, coal gasification sets the maximum price for these conventional fuels and assures an alternative fuel source. 

Gas-solid reactions play a major role in the technology of most industrialized nations. Gas-solid reactions encompass a very broad field including the extraction of metals from their ores (iron oxide reduction, the roasting of sulfide ores, etc.), the combustion of solid fuels, coal gasification, and the incineration of solid refuse, to cite but a few of the representative examples. Typical equipment used for effecting gas-solid reactions is also rather diverse, as seen from Figs. 1.1-1.3. 

Ammonia from coal gasification has been used for fertilizer production at Sasol since the beginning of operations in 1955. In 1964 a dedicated coal-based ammonia synthesis plant was brought on stream. This plant has now been deactivated, and is being replaced with a new faciUty with three times the production capacity. Nitric acid is produced by oxidation and is converted with additional ammonia into ammonium nitrate fertilizers. The products are marketed either as a Hquid or in a soHd form known as Limestone Ammonium Nitrate. Also, two types of explosives are produced from ammonium nitrate. The first is a mixture of fuel oil and porous ammonium nitrate granules. The second type is produced by emulsifying small droplets of ammonium nitrate solution in oil. 

Alternative feedstocks for petrochemicals have been the subject of much research and study over the past several decades, but have not yet become economically attractive. Chemical producers are expected to continue to use fossil fuels for energy and feedstock needs for the next 75 years. The most promising sources which have received the most attention include coal, tar sands, oil shale, and biomass. Near-term advances ia coal-gasification technology offer the greatest potential to replace oil- and gas-based feedstocks ia selected appHcations (10) (see Feedstocks, coal chemicals). 

The importance of coal gasification as a means of produciag fuel gas(es) for iadustrial use caimot be underplayed. But coal gasification systems also have undesirable features. A range of undesirable products are also produced which must be removed before the products are used to provide fuel and/or to generate electric power (see Power generation) (22,41). 

Chemistry. Coal gasification iavolves the thermal decomposition of coal and the reaction of the carbon ia the coal, and other pyrolysis products with oxygen, water, and hydrogen to produce fuel gases such as methane by internal hydrogen shifts... 

Indirect Hquefaction of coal and conversion of natural gas to synthetic Hquid fuels is defined by technology that involves an intermediate step to generate synthesis gas, CO +. The main reactions involved in the generation of synthesis gas are the coal gasification m2LC ions Combustion... 

Methanol, a clean burning fuel relative to conventional industrial fuels other than natural gas, can be used advantageously in stationary turbines and boilers because of its low flame luminosity and combustion temperature. Low NO emissions and virtually no sulfur or particulate emissions have been observed (83). Methanol is also considered for dual fuel (methanol plus oil or natural gas) combustion power boilers (84) as well as to fuel gas turbines in combined methanol / electric power production plants using coal gasification (85) (see Power generation). 

B. K. Schmid and D. M. Jackson, "The SRC-11 Process," paper presented at Third Annual International Conference on Coal Gasification and Eiquefaction. University of Pittsburgh, Aug. 3—5, 1976 D. M. Jackson and B. K. Schmid, "Production of Distillate Fuels by SRC-11," paper presented at ACS Div. of Ind. and Eng. Chem. Symposium, Colorado Spriags, Col., Feb. 12,1979. 

Partial oxidation of heavy Hquid hydrocarbons requires somewhat simpler environmental controls. The principal source of particulates is carbon, or soot, formed by the high temperature of the oxidation step. The soot is scmbbed from the raw synthesis gas and either recycled back to the gasifier, or recovered as soHd peUetized fuel. Sulfur and condensate treatment is similar in principle to that required for coal gasification, although the amounts of potential poUutants generated are usually less. 

C -Chemisty. A great deal of research has been undertaken on the development of PGM catalysts for the manufacture of chemicals and fuels from syngas, a mixture of CO and H2 obtained from coal gasification (see Coal conversion processes). 

Natural gas Naphtha Fuel oil Coal gasification Water electrolysis... 

G. W. Roberts, N. K. Dicciani, J. Klosek, Conference on Coal Gasification and Synthetic Fuels for Power Generator, San Francisco, Calif., Apr. 14—18,1985. 

In 1982, Texaco started up a 900 t/d gasifier at Southern California Edison s Cool Water faciUty. This was the first coal gasification plant to operate in an electric utihty environment, providing coal gas as fuel to a GE-frame 7E combustion turbine. The Cool Water gasification plant operated for over... 

Whereas near-term appHcation of coal gasification is expected to be in the production of electricity through combined cycle power generation systems, longer term appHcations show considerable potential for producing chemicals from coal using syngas chemistry (45). Products could include ammonia, methanol, synthetic natural gas, and conventional transportation fuels. 

Conventional Transportation Fuels. Synthesis gas produced from coal gasification or from natural gas by partial oxidation or steam reforming can be converted into a variety of transportation fuels, such as gasoline, aviation turbine fuel (see Aviation and other gas turbine fuels), and diesel fuel. A widely known process used for this appHcation is the Eischer-Tropsch process which converts synthesis gas into largely aHphatic hydrocarbons over an iron or cobalt catalyst. The process was operated successfully in Germany during World War II and is being used commercially at the Sasol plants in South Africa. 

W. V. Bush, K. R. Loos, and P. F. Russell, "Environmental Characteri2ation of the Shell Coal Gasification Process. I. Gaseous Effluent Streams," Fifteenth BiennialEow-Rank Fuels Symposium, St. Paul, Minn., May 22—25,1989. 

Natural gas requires no fuel treatment however, low-Btu gas, espeeially if derived from various coal gasification processes, requires various types of cleaners for use in a gas turbine. These cycles can get very complex as indicated by a typical system, which utilizes a steam bottoming cycle to achieve high efficiency. Vaporized fuel oil gas is already cleansed of its impurities in the vaporization process. 

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