Gasification

The world is facing rapid growth in energy demand, persistently high energy prices, and a challenge to reduce carbon dioxide emissions from power generation and manufacturing. No single technology or resource can solve the problem, but gasification can be part of the solution along with renewable power sources such as wind and energy efficiency programs.

Gasification can enhance the U.S. and world energy portfolio while creating fewer air emissions, using less water, and generating less waste than most traditional energy technologies. Whether used for power generation, for production of substitute natural gas, or for production of a large number of energy intensive products, gasification has significant environmental benefits over conventional technologies.

Gasification provides significant environmental benefits

Gasification plants produce significantly lower quantities of air pollutants.
Gasification can reduce the environmental impact of waste disposal because it can use waste products as feedstock, generating valuable products from materials that would otherwise be disposed as wastes.
Gasification byproducts are non-hazardous and are readily marketable.
Gasification plants use significantly less water than traditional coal-based power generation, and can be designed so they recycle their process water, discharging none into the surrounding environment.
Carbon dioxide (CO2) can be captured from an industrial gasification plant using commercially proven technologies. In fact, since 2000, the Great Plains Substitute Natural Gas plant in North Dakota has been capturing the same amount of CO2 as a 400 MW coal power plant would produce and sending that CO2 via pipeline to Canada for Enhanced Oil Recovery.
Gasification offers the cleanest, most efficient means of producing electricity from coal and the lowest cost option for capturing CO2 from power generation, according to the U.S. Department of Energy.
Gasification can be accomplished using MASS BURN techniques which is in fact the most widely used methodology throughout the US and EU. High tech incineration as well as collection techniques from landfill gasses are effective and commonly employed due to their relative costs compared to plasma ( the most expensive) and pyrolysis.

ECONOMIC BENEFITS

Gasification can compete effectively in high-price energy environments to provide power and products.
Gasification can be used to turn lower-priced feedstock, such as petcoke and coal, into very valuable products like electricity, substitute natural gas, fuels, chemicals, and fertilizers. For example, a chemical plant can gasify petcoke or high sulfur coal instead of using high-priced natural gas, thereby reducing its operating costs.
While a gasification power plant is capital intensive (like any very large manufacturing plant), its operating costs are potentially lower than conventional processes or coal-fired plants because gasification plants are more efficient and require less back-end pollution control equipment. With continued research and development efforts and commercial operating experience, the cost of these units will continue to decrease.
Gasification offers wide fuel flexibility. A gasification plant can vary the mix of solid feedstock, or run on gas or liquid feedstock—giving it more freedom to adjust to the price and availability of its feedstock.
The ability to produce a number of high-value products at the same time (polygeneration) also helps a facility offset its capital and operating costs. In addition, the principal gasification byproducts (sulfur and slag) are readily marketable. For example, sulfur can be used as a fertilizer and slag can be used in roadbed construction or in roofing materials.
A state-of-the-art gasification power plant with commercially available technology can perform with efficiency in a range of 38-41 percent. Technology improvements now in advanced testing will boost efficiency to significantly higher levels.
Gasification can increase domestic investment and jobs in manufacturing industries that have recently been in decline because of high energy costs.
Many predict that coal-based power plants and other manufacturing facilities will be required to capture and store CO2, or participate in a carbon cap and trade market. In this scenario, gasification projects will have a cost advantage over conventional technologies. While CO2 capture and sequestration will increase the cost of all forms of power generation, an IGCC plant can capture and compress CO2 at one-half the cost of a traditional pulverized coal plant. Other gasification-based options, including production of motor fuels, chemicals, fertilizers, or hydrogen, to name a few, have even lower carbon capture and compression costs. This will provide a significant economic and environmental benefit in a carbon-constrained world. (See Carbon Capture & Compression Costs.)
Gasification can replace volatile natural gas as a fuel or a feedstock. Read more.
Gasification is being used around the world. Read more about gasification economics in practice.

PRODUCTS AND APPLICATIONS

Chemicals and Fertilizers
Modern gasification has been used in the chemical industry since the 1950s. Typically, the chemical industry uses gasification to produce methanol as well as chemicals, such as ammonia and urea, which form the foundation of nitrogen-based fertilizers. The majority of the operating gasification plants worldwide produce chemicals and fertilizers. And, as natural gas and oil prices continue to increase, the chemical industry is developing additional coal gasification plants to generate these basic chemical building blocks.

Eastman Chemical Company helped advance the use of coal gasification technology for chemicals production in the U.S. Eastman's coal-to-chemicals plant in Kingsport, Tennessee converts Appalachian coals to methanol and acetyl chemicals. The plant began operating in 1983 and has gasified approximately 10 million tons of coal with a 98 to 99 percent on-stream availability rate.

Power Generation with Gasification
Coal can be used as a feedstock to produce electricity via gasification, commonly referred to as Integrated Gasification Combined Cycle (IGCC). This particular coal-to-power technology allows the continued use of coal without the high level of air emissions associated with conventional coal-burning technologies. In gasification power plants, the pollutants in the syngas are removed before the syngas is combusted in the turbines. In contrast, conventional coal combustion technologies capture the pollutants after combustion, which requires cleaning a much larger volume of the exhaust gas. This increases costs, reduces reliability, and generates large volumes of sulfur-laden wastes that must be disposed of in landfills or lagoons.

Today, there are 15 gasification-based power plants operating successfully around the world. There are three such plants operating in the United States. Plants in Terre Haute, Indiana and Tampa, Florida provide baseload electric power, and the third, in Delaware City, Delaware provides electricity to a Valero refinery. (See World Gasification-Based Power Generating Capacity)

Substitute Natural Gas
Gasification can also be used to create substitute natural gas (SNG) from coal and other feedstocks, supplementing U.S. natural gas reserves. Using a "methanation" reaction, the coal-based syngas—chiefly carbon monoxide (CO) and hydrogen (H2)—can be profitably converted to methane (CH4). Nearly identical to conventional natural gas, the resulting SNG can be shipped in the U.S. natural gas pipeline system and used to generate electricity, produce chemicals/fertilizers, or heat homes and businesses. SNG will enhance domestic fuel security by displacing imported natural gas that is generally supplied in the form of Liquefied Natural Gas (LNG).

Hydrogen for Oil Refining
Hydrogen, one of the two major components of syngas, is used in the oil refining industry to strip impurities from gasoline, diesel fuel, and jet fuel, thereby producing the clean fuels required by state and federal clean air regulations. Hydrogen is also used to upgrade heavy crude oil. Historically, refineries have utilized natural gas to produce this hydrogen. Now, with the increasing price of natural gas, refineries are looking to alternative feedstocks to produce the needed hydrogen. Refineries can gasify low-value residuals, such as petroleum coke, asphalts, tars, and some oily wastes from the refining process, to generate both the required hydrogen and the power and steam needed to run the refinery.

Transportation Fuels
Gasification can be used to produce transportation fuels from oil sands, coal and biomass. Read more about each of these technologies.

GASIFICATION INDUSTRY

Gasification has been reliably used on a commercial scale worldwide for more than 50 years by the chemical, refining, and fertilizer industries and by the electric power industry for more than 35 years. Currently, there are more than 140 gasification plants—with more than 420 gasifiers—operating worldwide.

Nineteen of those gasification plants are located in the United States. (See Existing Gasification Plants in the U.S).

The Future of Gasification
Worldwide gasification capacity is projected to grow 70 percent by 2015, with 80 percent of the growth occurring in Asia. The prime movers behind this expected growth are the chemical, fertilizer, and coal-to-liquids industries in China, oil sands in Canada, polygeneration (hydrogen and power or chemicals) and substitute natural gas in the United States, and refining in Europe

The use of gasification is expanding. Several gasification projects are under development to provide steam and hydrogen to upgrade synthetic crude in the oil sands industry in Canada. In addition, the paper industry is exploring how gasification can be used to make their operations more efficient and reduce waste streams.
A number of factors contribute to a growing interest in gasification, including volatile oil and natural gas prices, more stringent environmental regulations, and a growing consensus that CO2 management will likely be required in power generation and energy production. (See U.S. Energy Prices).
China is expected to achieve the most rapid growth in gasification worldwide. Since 2004, 29 new gasification plants have been licensed and/or built in China. In contrast, no new gasification plants have begun operation in the United States since 2002.
The gasification industry is expected to grow significantly in the United States despite a number of challenges, including rising construction costs and uncertainty about policy incentives and regulations.

TRANSPORT FUELS

Transportation Fuels from Oil Sands
The "oil sands" in Alberta, Canada are estimated to contain as much recoverable oil (in the form of bitumen) as the vast oil fields in Saudi Arabia. However, to convert this raw material to saleable products requires mining the oil sands and refining the resulting bitumen to transportation fuels. The mining process involves massive amounts of steam to separate the bitumen from the sands and the refining process demands large quantities of hydrogen to upgrade the "crude oil" to finished products. Residuals from the upgrading process include petcoke, deasphalted bottoms, vacuum residuals, and asphalt/asphaltenes - all of which contain unused energy.

Traditionally, oil sands operators have utilized natural gas to produce the steam and hydrogen needed for the mining, upgrading, and refining processes. However, a number of operators will soon gasify petcoke to supply the necessary steam and hydrogen. Not only will gasification displace expensive natural gas as a feedstock, it will also enable the extraction of useable energy from what is otherwise a very low-value product (petcoke). In addition, black water from the mining and refining processes can be recycled to the gasifiers using a wet feed system, reducing fresh water usage and waste water management costs. (This is not inconsequential, since traditional oil sand operations consume large volumes of water.)

Transportation Fuels from Coal
Gasification is the foundation for converting coal and other solid feedstocks and natural gas into transportation fuels such as gasoline, ultra-clean diesel fuel, jet fuel, naphtha, and synthetic oils. Two basic paths are employed in converting coal to motor fuels via gasification. In the first, the syngas undergoes an additional process, the Fischer-Tropsch (FT) reaction, to convert it to a liquid petroleum product. The FT process, with coal as a feedstock, was invented in the 1920s, was used by Germany during World War II, and has been utilized in South Africa since the 1950s. Today, it is also used in Malaysia and the Middle East with natural gas as the feedstock.

In the second process, so-called Methanol- to-Gasoline (MTG), the syngas is first converted to methanol (a commercially used process) and the methanol is converted to gasoline by reacting it over a bed of catalysts. A commercial MTG plant successfully operated in the 1980s and early 1990s in New Zealand and plants are under development in China and in the U.S.

Transportation Fuels from Biomass
Gasification is also being used as a basis for converting biomass to transportation fuels. Biomass, (such as agricultural waste, switch grass, or wood waste) is converted to a synthesis gas via gasification. The synthesis gas is then passed over various proprietary catalysts and converted to transportation fuels, such as cellulosic ethanol or bio-diesel. Several biomass-to-liquids plants are now under development.

nformation with thanks to the "Gasification Technologies Council"

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