Chemicals from Coal Gasification
Less than one percent of the total coal mined in the United States is used to make chemicals from coal gasification, but the technology provides important products that consumers use every day. Gasification is different than combustion of coal to make heat for electric power. Instead of burning the coal, the feed coal is combined with water in a slurry. The slurry is heated into steam, and oxygen is added in a thermal-chemical process which breaks down the matrix molecules in the coal. The produced "syngas" consists mainly of carbon monoxide (CO), hydrogen (H2), water vapor (H2O), and some other minor gases. These gases can then be separated through chemical processes and used as chemical feedstocks or products. Coal gasification can also be used to provide electricity in Integrated Gasification Combined Cycle (IGCC) plants.
A good example of coal gasification used to produce chemicals from coal is the Eastman Chemical plant in Kingsport, Tennessee. At the Kingsport plant, coal or a mixture of coal and pet-coke is gasified and particulate material is removed from the resulting syngas stream. Next, the syngas is purified through the removal of mercury (Hg), sulfuric acids (H2S), and carbon dioxide (CO2). The sulfuric acids are treated to form raw sulfur (S). Next, the cleaned syngas is separated into carbon monoxide (CO) and hydrogen (H2), which by themselves, are chemical products. Further treatment results in methanol (CH3OH), which is the source material for many important chemicals. One of those chemicals is methyl acetate, which is used in the production of acetic acid and acetic anhydride. The main function of the Kingsport plant is the production of acetic anhydride, which is used to make photographic film, synthetic textiles, and other products (Trapp, 2001; Eastman Chemical, 2003).
Other Uses of Coal:
- Coal for Electricity Generation
- Coal to Make Coke and Steel
- Coal for Industry and Residential Markets
- Rare Earth Elements from Coal
References for Chemicals from Coal Gasification
- American Chemical Society, 1995, National historic landmark: Chemicals from coal facility, Eastman Chemical Company, Kingsport, Tennessee: American Chemical Society Division of the History of Chemistry, Office of Public Outreach, 8 p.
- Eastman Chemical Company, 2003, Project data on Eastman Chemical Company’s chemicals-from-coal complex in Kingsport, TN: U.S. Department of Energy, National Energy Technology Laboratory, Cooperative Agreement DE-FC22-92PC90543, 30 p.
- National Energy Technology Laboratory (NETL), no date, Chemicals (from gasification): U.S. Department of Energy, NETL website, https://www.netl.doe.gov/research/Coal/energy-systems/gasification/gasifipedia/chemicals, accessed 2016.
- Trapp, B., 2001, Eastman and gasification–The next step–Building on past success: Gasification Technologies 2001 Conference, pdf slide show, http://www.gasification-syngas.org/uploads/eventLibrary/GTC01011.pdf
- U.S. Department of Energy, no date, Gasification: U.S. DOE website, http://energy.gov/fe/science-innovation/clean-coal-research/gasification, accessed 2016.
- U.S. Department of Health and Human Services, 2016, Household product database; USDHHS website, https://hpd.nlm.nih.gov/cgi-bin/household/search?tbl=TblChemicals&queryx=50-00-0, accessed 2016.
- Zoeller, J.R., 2004, Eastman Chemical Company’s “Chemicals from Coal” program: The first quarter century: American Chemical Society Division Fuel Chemistry, v. 49, no. 2, p. 623-624.