Coal Gasification Robert Nagai AP Environmental Science Period 3

Uses of Coal Gasification  Clean way to convert coal (or any carbon based material) into energy  Electricity Production  Lighting, Heating, and Cooking Fuels  Energy-Efficient Fuel Cell Technology  Ammonia and Hydrogen Production  Transportation Fuel (gasoline, diesel, methanol, liquefied natural gas)  Road Tar, Creosote (wood preservative), phenol (plastics), cresols (disinfectants), dyes, and medicines

Efficiency  Combined cycle  Coal gases are fired into a gas turbine and creates electricity  Steam is produced from the gasification process and the heat made by the gas turbine  Gross power generation is 50% efficiency  Net generation is 40% efficient  With improvements in high pressure solid fuel cell technology, efficiency is expected to rise to 60%

Cost of Coal Gasification  Costs vary widely depending on plant design and type as well as quality of coal  Capital costs: $ /GigaJoule (GJ)*  Synthesis Gas (Syngas) production: $ /GJ* *based on data from US based plants in 2005

Gasification Extraction and Usage  Coal (or other bio mass) is broken down into its basic chemical constituents by:  Exposure to steam  Controlled amounts of oxygen  High temperature and pressure  Process yields carbon monoxide, hydrogen, and other fuel gases

Gasification Extraction and Usage

Gasification Extraction and Usage (continued)  Underground Coal Gasification (UCG) gasifies un-mined coal deposits while still underground  UCG technology was first proposed by Sir William Siemens in 1868 and developed extensively by the USSR under Lenin and Stalin  The US conducted UCG research form 1974 to 1989, but abandoned development due to a drop in oil prices  China, Australia, and South Africa continue to develop UCG technology

Gasification Extraction and Usage (continued)  China has the largest UCG program with more than 16 plants built since 1991

Gasification Consumption/Usage  The United States started using modern gasification in 1984  20 plants are in operation in the US as of 2002 with 10 more scheduled to be built  Worldwide, there are 117 plants in operation with 35 additional plants in development  36% of these plants generate fuels, 19% generate electricity, and 42% generate chemical feedstock.  These plants account for 24,000 megawatts of electricity with an annual growth rate of 10%

Gasification Advantages  Gasification yields a wide variety of useful products beyond electricity such as sulfur and ammonia  The process is 17% more efficient than conventional coal burning plants  Converting coal into a gaseous state allows easier removal of polluting compounds

Gasification Disadvantages  Installation and maintenance costs are higher than conventional coal burning plants  Process produces more greenhouse gases than petroleum  The environmental impact of coal mining is not reduced by gasification

Gasification—Ecological Problems  Gasification waste products may pollute the groundwater surrounding the plant  Gasification products are highly toxic and pose a health and environment threat should a leak occur  Gasification does not reduce the demand for coal, nor does it make coal mining more environmentally friendly

Gasification Installations  The first modern coal gasification plant in the US was built in 1984 in Beulah, North Dakota  Facilities in Barstow, California; West Terre Haute, Indiana; and Lakeland, Florida are among the more than 20 active plants in the US  China is building more than 50 gasification plants in its northwestern region in order to reduce smog (despite the large amount of greenhouse gases produced by gasification)

Sources   research/gasification  gasification/   kemper-idUSL2N0F723N  Bell, D. A., Brian F. Towler, and Maohong Fan. "Chapter 7." Coal Gasification and Its Applications. Oxford, U.K.: William Andrew/Elsevier, 2011, pages