Coal gasification commercialization

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Coal gasification is a process whereby a hydrocarbon feedstock (coal) is converted into gaseous components by applying heat under pressure in the presence of steam. Rather than burning, most of the carbon-containing feedstock is broken apart by chemical reactions that produce "syngas." Syngas is primarily hydrogen and carbon monoxide, but the exact composition can vary. In Integrated Gasification Combined Cycle (IGCC) systems, the syngas is cleaned and burned as fuel in a combustion turbine which then drives an electric generator. Exhaust heat from the combustion turbine is recovered and used to create steam for a steam turbine-generator. The use of these two types of turbines in combination is one reason why gasification-based power systems can achieve high power generation efficiencies. Currently, commercially available gasification-based systems can operate at around 40% efficiencies. [1] Syngas, however, emits more greenhouse gases than natural gas, and almost twice as much carbon as a coal plant. Coal gasification is also water-intensive. [2]

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According to the Gasification and Syngas Technologies Council, a trade association, there are globally 272 operating gasification plants with 686 gasifiers and 74 plants with 238 gasifiers under construction. Most of them use coal as feedstock. [3]

As of 2017 large scale expansion of the coal gasification industry was occurring only in China where local governments and energy companies promote the industry for the sake of jobs and a market for coal. The central government is aware of the conflict with environmental goals. For the most part the plants are located in remote coal rich areas. In addition to producing a great deal of carbon dioxide the plants use a great deal of water in areas where water is scarce. [4]

Wabash River IGCC [5]

Bituminous coal gasification to produce electricity

The Wabash River Coal Gasification Repowering Project was a demonstration of advanced integrated gasification combined cycle (IGCC) technology, a joint venture between the Wabash River Coal Gasification Project Joint Venture and the U.S. Department of Energy. [6] The term “repowering” refers to the IGCC plant’s replacing a dated conventional pulverized coal power plant. Construction began in July 1993 near West Terre Haute, Indiana, followed by operational startup in November 1995. The project demonstration phase was completed and turned over for commercial operation in December 1999.

The gasification technology utilized at Wabash River IGCC was developed originally by Dow Chemical, and was subsequently transferred to Destec, a partially held subsidiary of Dow Chemical. The technology was later acquired by ConocoPhillips. CB&I currently licenses this process technology under the name E-GAS™. [7]

The Wabash River IGCC Power Plant is designed to use a variety of local coals, including high-sulfur Midwestern bituminous coals such as Illinois No. 6. In addition, petroleum coke and blends of coal and coke are consumed, in the range of about 2,500 TPD to generate about 262 MWe net output of electricity. [8]

Plant design was conducted with the goal of outperforming the Clean Air Act (CAA) emission standards, which limit sulfur dioxide (SO2) at 1.2 lb/million Btu of fuel input and NOx at 0.15 lb/million Btu. Demonstrated emissions are far better than these targets. Despite power generation at the Wabash River complex being almost three times that of the original unit, the total emissions are a fraction of the pre-powering values as a result of the IGCC system. Particulate emissions are negligible.

Tampa Electric IGCC [9]

Bituminous coal gasification to produce electricity

Construction began on this IGCC unit at Tampa Electric Company's Polk Power Station (Polk County, Florida) in October 1994, followed by operational startup in September 1996. The project ran for four years as a demonstration, and continues to operate as a power production facility for Tampa Electric. The plant uses GE Energy's (formerly owned by Texaco), entrained-flow, oxygen-blown gasifier [10] to produce syngas from coal or petroleum coke which feeds a combined-cycle turbine system to produce electricity. The IGCC unit consumes 2,200 TPD of bituminous coal, producing 260 MW of electricity.

The following table [11] quantifies the emissions from the Polk Power Station, with comparison to emissions associated with conventional technologies for electricity generation from coal. Typical of electricity generation based on coal gasification with combined cycle generation, emissions of pollutants are far lower than those of conventional technologies. For example, notwithstanding the IGCC unit is fueled by high-sulfur coal and/or petroleum coke, sulfur emissions are very low as a benefit of the MDEA amine gas treating system that removes H2S from the syngas fueling the combustion turbine. [12]

Pollutant (lbs/MWhour)Pulverized coal-basedAtmospheric Fluidized Bed Combustor-basedPolk (Permit)Polk (Steady-state)
SO22.23.31.41.0
NOx3.61.80.90.7
Particulate0.80.20.07<0.01

Duke Energy Edwardsport IGCC Project [13]

Bituminous coal gasification to produce electricity

Duke Energy began construction on an IGCC plant in Edwardsport, Indiana in 2008, which began commercial operations in June 2013. The IGCC-based unit at Edwardsport will consume 1.7-1.9 million tons of coal per year to generate 618 MW of base-load electricity. It uses GE gasification technology, GE 7FB combustion turbines, and a GE steam turbine. The IGCC plant replaces a now demolished 160 MW coal-fired power plant at the site, and while it can produce nearly four times the power of the unit it replaced, it has far lower emissions of SO2, NOx, and particulates. There is potential for carbon capture and geologic sequestration in the context of the Edwardsport IGCC project, with space reserved at the site for CO2 capture equipment. Also, Duke initiated a front-end engineering and design study for carbon capture and filed a $121 million request with Indiana Utility Regulatory Commission for detailed characterization of deep saline aquifers, depleted oil or gas fields, and enhanced oil recovery. Schlumberger Carbon Services is to begin site assessment for deep saline sequestration near the plant.

Eastman Chemical Company Kingsport Plant [14]

Coal gasification to produce chemicals

One of the earliest and most notable coal gasification-based chemical plants in the United States is owned and operated by Eastman Chemical Company and based in Kingsport, Tennessee. Known as the Eastman Integrated Coal Gasification facility, it first opened in 1983 and is designed to process syngas from the gasification of Southwest Virginia and Eastern Kentucky coal, using Texaco gasifiers (now GE gasifier technology [15] ). The intermediate products of syngas conversion are methanol and CO; these are further converted into products consisting of 500 million pounds per year of acetyl chemicals including acetic anhydride and acetic acid, enough to supply half of Eastman’s raw acetyl needs. Acetyl chemicals are important to many of Eastman’s products, but especially those at the Kingsport site, where five of seven manufacturing divisions rely on acetyls as a raw material. The success of the operation led to a decision to expand the plant capacity to an excess of 1 billion pounds per year to meet all of Eastman's needs.

The process configuration at Eastman is fairly complex, as a consequence of the feedstock requirements associated with multiple chemical syntheses involved. Part of the syngas resulting from the gasification of feed coal is shifted, and a Rectisol process is utilized for sulfur removal and CO2 removal. Recovered CO2 is sold for use in making carbonated beverages. [16]

Great Plains Synfuels Plant

Lignite gasification to produce synthetic natural gas or ammonia

The Great Plains Synfuels Plant (GPSP) in Beulah, North Dakota has been in operation since 1984 producing synthetic natural gas (SNG) from lignite coal, [17] and remains the only coal-to-SNG facility in the United States. GSPS is operated by the Dakota Gasification Company. In addition to the production of SNG, the plant also produces high purity carbon dioxide, which is distributed through a pipeline to end users in Saskatchewan, Canada (Apache Canada at the Midale field and Cenovus Energy at the Weyburn field, until that asset was sold to Whitecap Resources in 2017 [18] ) for enhanced oil recovery operations.

Operational profitability of the GPSP is affected by the market price of natural gas, with which SNG competes. In response, an anhydrous ammonia synthesis unit was added to the process train at the plant in the 1990s, [19] diversifying the plant's product line away from synthetic fuels (SNG), with a substantial capacity to produce anhydrous ammonia, a feedstock for fertilizer production. The plant can shift production to higher value products, depending on fluctuating market conditions.

Kemper County Energy Facility [20]

Lignite coal gasification to produce electricity

Southern Company Services/Mississippi Power started construction on a new IGCC plant located in Kemper County, Mississippi in December 2010. Construction for the Kemper project is 75% complete as of January 2013. [21] Start of commercial operations for the plant is scheduled for 2016, in which the plant will convert 12,000 tons of local Mississippi low-rank coal per day (large reserves of 4 billion tons of mineable lignite are located near the plant) to produce 582 MW (net) of electricity. The new plant will utilize KBR's TRIG™ gasifier technology, [22] suitable for utilization of the local lignite resources; two of the gasifiers will operate in air-blown mode at the Kemper County plant.

TRIG™ and related systems for gasification of low-rank coal had been developed by KBR and Southern Company in conjunction with DOE at the Power Systems Development Facility (PSDF) in Wilsonville, Alabama, which comprised an engineering-scale demonstration of TRIG™ and associated critical subsystems. This provided the engineering and operational basis for the full-scale plant now being constructed in Kemper County.

The plant will capture and sequester 65% of the CO2 it produces through enhanced oil recovery. Emissions controls will remove over 99% SO2 and P25, at least 90% Hg, and limit NOx emissions to less than 0.07 lb/million Btu.

The Kemper County IGCC project is estimated to cost $4.7 billion, but the Kemper plant will be the cheapest plant to operate once it's up and running. Mississippi Power has received a $270 million grant from the Department of Energy and $412 million in investment tax credits approved by the IRS through the National Energy Policy Act of 2005 and the Energy Improvement and Extension Act of 2008.

The Gasifier component of this project has been canceled.

Sasol

Sasol, in South Africa, operates commercial gasification plants in Secunda, Mpumalanga and in Sasolburg. [23]

Proposed Coal Gasification

During the 2011 session of the Illinois legislature proposals to provide financial support for state-of-the-art coal gasification plants in Chicago and Southern Illinois were considered. The bills require Illinois utilities to purchase gas at fixed rates from the plants for 30 years. The Chicago plant to be built by Chicago Clean Energy, a subsidiary of Leucadia National Corporation, is budgeted to cost $3 billion. It would be located in an existing industrial area on the Southeast Side on Burley Avenue near 116th Street. In addition to coal the plant would use coke, an oil refinery byproduct, as feed stock. Carbon dioxide produced during the project would be sequestered. [24] The bill to build the Chicago plant was passed by the legislature but vetoed by the Illinois governor Pat Quinn who cited cost issues. Due to uncertainty about natural gas supplies and prices alternative financing is doubtful. Another plant, Indiana Gasification, LLC also a Leucadia National Corporation subsidiary and with a similar business plan, is proposed for Rockport, Indiana where the state has agreed to purchase gas for 30 years at a fixed price. [25] [26]

During sometime in late 2011 to early 2012, around 18 coal exploitation licenses were given by the coal association to create new coal gasification plants around the island of Great Britain, with the largest being in Swansea Bay, where up to 1bn tonnes of coal sits underneath the water.[ citation needed ] If these licenses pass, The UK could be a major coal power in the world once more.

Since 2012 Ukraine is gradually switching from natural gas-based to coal gasification technologies developed by China. [27]

Related Research Articles

<span class="mw-page-title-main">Coal</span> Combustible sedimentary rock composed primarily of carbon

Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is a type of fossil fuel, formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian) and Permian times.

Southern Company is an American gas and electric utility holding company based in the southern United States. It is headquartered in Atlanta, Georgia, with executive offices also located in Birmingham, Alabama. The company is the second largest utility company in the U.S. in terms of customer base, as of 2021. Through its subsidiaries it serves 9 million gas and electric utility customers in 6 states. Southern Company's regulated regional electric utilities serve a 120,000-square-mile (310,000 km2) territory with 27,000 miles (43,000 km) of distribution lines.

Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide, in various ratios. The gas often contains some carbon dioxide and methane. It is principally used for producing ammonia or methanol. Syngas is combustible and can be used as a fuel. Historically, it has been used as a replacement for gasoline, when gasoline supply has been limited; for example, wood gas was used to power cars in Europe during WWII.

<span class="mw-page-title-main">Gasification</span> Form of energy conversion

Gasification is a process that converts biomass- or fossil fuel-based carbonaceous materials into gases, including as the largest fractions: nitrogen (N2), carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2). This is achieved by reacting the feedstock material at high temperatures (typically >700 °C), without combustion, via controlling the amount of oxygen and/or steam present in the reaction. The resulting gas mixture is called syngas (from synthesis gas) or producer gas and is itself a fuel due to the flammability of the H2 and CO of which the gas is largely composed. Power can be derived from the subsequent combustion of the resultant gas, and is considered to be a source of renewable energy if the gasified compounds were obtained from biomass feedstock.

In industrial chemistry, coal gasification is the process of producing syngas—a mixture consisting primarily of carbon monoxide (CO), hydrogen, carbon dioxide, methane, and water vapour —from coal and water, air and/or oxygen.

Substitute natural gas (SNG), or synthetic natural gas, is a fuel gas (predominantly methane, CH4) that can be produced from fossil fuels such as lignite coal, oil shale, or from biofuels (when it is named bio-SNG) or using electricity with power-to-gas systems.

<span class="mw-page-title-main">Fuel gas</span> Fuels which under ordinary conditions, are gaseous

Fuel gas is one of a number of fuels that under ordinary conditions are gaseous. Most fuel gases are composed of hydrocarbons, hydrogen, carbon monoxide, or mixtures thereof. Such gases are sources of energy that can be readily transmitted and distributed through pipes.

Coal liquefaction is a process of converting coal into liquid hydrocarbons: liquid fuels and petrochemicals. This process is often known as "Coal to X" or "Carbon to X", where X can be many different hydrocarbon-based products. However, the most common process chain is "Coal to Liquid Fuels" (CTL).

<span class="mw-page-title-main">Synthetic fuel</span> Fuel from carbon monoxide and hydrogen

Synthetic fuel or synfuel is a liquid fuel, or sometimes gaseous fuel, obtained from syngas, a mixture of carbon monoxide and hydrogen, in which the syngas was derived from gasification of solid feedstocks such as coal or biomass or by reforming of natural gas.

Underground coal gasification (UCG) is an industrial process which converts coal into product gas. UCG is an in-situ gasification process, carried out in non-mined coal seams using injection of oxidants and steam. The product gas is brought to the surface through production wells drilled from the surface.

An integrated gasification combined cycle (IGCC) is a technology using a high pressure gasifier to turn coal and other carbon based fuels into pressurized gas—synthesis gas (syngas). It can then remove impurities from the syngas prior to the electricity generation cycle. Some of these pollutants, such as sulfur, can be turned into re-usable byproducts through the Claus process. This results in lower emissions of sulfur dioxide, particulates, mercury, and in some cases carbon dioxide. With additional process equipment, a water-gas shift reaction can increase gasification efficiency and reduce carbon monoxide emissions by converting it to carbon dioxide. The resulting carbon dioxide from the shift reaction can be separated, compressed, and stored through sequestration. Excess heat from the primary combustion and syngas fired generation is then passed to a steam cycle, similar to a combined cycle gas turbine. This process results in improved thermodynamic efficiency, compared to conventional pulverized coal combustion.

<span class="mw-page-title-main">Waste-to-energy</span> Process of generating energy from the primary treatment of waste

Waste-to-energy (WtE) or energy-from-waste (EfW) is the process of generating energy in the form of electricity and/or heat from the primary treatment of waste, or the processing of waste into a fuel source. WtE is a form of energy recovery. Most WtE processes generate electricity and/or heat directly through combustion, or produce a combustible fuel commodity, such as methane, methanol, ethanol or synthetic fuels, often derived from the product syngas.

<span class="mw-page-title-main">Mississippi Power</span> Investor-owned electric utility

Mississippi Power is an investor-owned electric utility and a wholly owned subsidiary of Atlanta-based Southern Company. Mississippi Power Company (MPC) is headquartered in Gulfport, Mississippi.

Second-generation biofuels, also known as advanced biofuels, are fuels that can be manufactured from various types of non-food biomass. Biomass in this context means plant materials and animal waste used especially as a source of fuel.

Edwardsport Power Station is a 618 MW Integrated gasification combined cycle (IGCC) coal based power plant in Vigo Township, Knox County, near the town of Edwardsport, Indiana. The integrated gasification combined cycle power plant construction started in June 2008 by Duke Energy near the site of an older 160 MW coal-fired electrical power plant, which was decommissioned in 2010.

GreenGen is a project in Tianjin, China that aims to research and develop high-tech low-emissions coal-based power generation plants.

<span class="mw-page-title-main">Kemper Project</span> Power station in Mississippi, US

The Kemper Project, also called the Kemper County energy facility or Plant Ratcliffe, is a natural gas-fired electrical generating station currently under construction in Kemper County, Mississippi. Mississippi Power, a subsidiary of Southern Company, began construction of the plant in 2010. The initial, coal-fired project was central to President Obama's Climate Plan, as it was to be based on "clean coal" and was being considered for more support from the Congress and the incoming Trump Administration in late 2016. If it had become operational with coal, the Kemper Project would have been a first-of-its-kind electricity plant to employ gasification and carbon capture technologies at this scale.

Lower-temperature fuel cell types such as the proton exchange membrane fuel cell, phosphoric acid fuel cell, and alkaline fuel cell require pure hydrogen as fuel, typically produced from external reforming of natural gas. However, fuels cells operating at high temperature such as the solid oxide fuel cell (SOFC) are not poisoned by carbon monoxide and carbon dioxide, and in fact can accept hydrogen, carbon monoxide, carbon dioxide, steam, and methane mixtures as fuel directly, because of their internal shift and reforming capabilities. This opens up the possibility of efficient fuel cell-based power cycles consuming solid fuels such as coal and biomass, the gasification of which results in syngas containing mostly hydrogen, carbon monoxide and methane which can be cleaned and fed directly to the SOFCs without the added cost and complexity of methane reforming, water gas shifting and hydrogen separation operations which would otherwise be needed to isolate pure hydrogen as fuel. A power cycle based on gasification of solid fuel and SOFCs is called an Integrated Gasification Fuel Cell (IGFC) cycle; the IGFC power plant is analogous to an integrated gasification combined cycle power plant, but with the gas turbine power generation unit replaced with a fuel cell power generation unit. By taking advantage of intrinsically high energy efficiency of SOFCs and process integration, exceptionally high power plant efficiencies are possible. Furthermore, SOFCs in the IGFC cycle can be operated so as to isolate a carbon dioxide-rich anodic exhaust stream, allowing efficient carbon capture to address greenhouse gas emissions concerns of coal-based power generation.

<span class="mw-page-title-main">UBC Biomass Research and Demonstration Facility</span>

The Biomass Research and Demonstration Facility uses biomass to create clean heat and energy. This facility is located at 2329 West Mall in Vancouver at the University of British Columbia's West Point Grey Campus. Official operation began in September 2012, by combining syngas and gasification conditioning systems with a Jenbacher engine. The highest potential output of this system is 2 MWe (megawatts) of electricity and 9600 lbs of steam per hour. This system is the first of its type in all of Canada, and it was put together by the cooperation of three parties: General Electric (GE), Nexterra, and the University of British Columbia (UBC).

References

  1. ↑ "HOW COAL GASIFICATION POWER PLANTS WORK". Archived from the original on 13 January 2017. Retrieved 10 January 2017.
  2. ↑ "Coal gasification: The clean energy of the future?" . Retrieved 10 January 2017.
  3. ↑ "The Gasification Industry". Gasification and Syngas Technologies Council. 2016. Retrieved 2016-05-10.
  4. ↑ Edward Wong (February 8, 2017). "'Irrational' Coal Plants May Hamper China's Climate Change Efforts". The New York Times. Retrieved February 8, 2017.
  5. ↑ "Wabash River Coal Gasification Repowering Project".[ permanent dead link ]
  6. ↑ "Topical Report Number 20 – The Wabash River Coal Gasification Repowering Project: An Update" (PDF). U.S. Department of Energy & Wabash River Coal Gasification Project Joint Venture. Archived from the original (PDF) on February 22, 2014. Retrieved July 18, 2013.
  7. ↑ "CB&I E-Gas™ Technology". Archived from the original on 2014-08-23. Retrieved 2014-08-16.
  8. ↑ "Operational Experience at the Wabash River Project" (PDF). Thomas A. Lynch, ConocoPhillips. Archived from the original (PDF) on May 2, 2014. Retrieved July 18, 2013.
  9. ↑ "Tampa Electric Integrated Gasification Combined-Cycle Project".
  10. ↑ "GE Energy Gasifier".
  11. ↑ "Polk Power Station IGCC" (PDF). TECO Energy. Archived from the original (PDF) on May 12, 2013. Retrieved July 22, 2013.
  12. ↑ "Tampa Electric Integrated Gasification Combined Cycle Project" (PDF). U.S. Department of Energy. Archived from the original (PDF) on March 3, 2016. Retrieved August 7, 2013.
  13. ↑ "Edwardsport IGCC Project". Archived from the original on 2014-03-17. Retrieved 2014-08-16.
  14. ↑ "Commercial Examples of Gasification-based Chemicals Production".
  15. ↑ "GE Energy (formerly Chevron Texaco) Gasifier".
  16. ↑ "Acetyl Chemicals from Coal Gasification - National Historic Chemical Landmark". American Chemical Society. Retrieved August 7, 2013.
  17. ↑ "Project Examples – Great Plains Synfuels Plant". Gasifipedia. U.S. Department of Energy, NETL. Retrieved July 19, 2013.
  18. ↑ "Cenovus selling majority stake in Weyburn oil project". CBC News. November 13, 2017. Retrieved January 29, 2018.
  19. ↑ "Ammonia Plant: Coproduct yields agricultural benefit". Dakota Gasification Company. Retrieved July 19, 2013.
  20. ↑ "Kemper County IGCC Project". Archived from the original on 2014-03-17. Retrieved 2014-08-16.
  21. ↑ Mississippi Power (January 2013). "Kemper County Energy Facility Progress Report January 2013" (PDF). Retrieved July 22, 2013.
  22. ↑ KBR (2012). "Coal Gasification, KBR Technology" (PDF). Archived from the original (PDF) on October 18, 2012. Retrieved July 22, 2013.
  23. ↑ "Unlocking the potential wealth of coal" (PDF). Archived from the original (PDF) on November 7, 2012. Retrieved May 6, 2013.
  24. ↑ Lydersen, Kari (March 10, 2011). "Clean-Coal Debate Focuses on Gasification Plant". The New York Times. Retrieved March 16, 2011.
  25. ↑ Lydersen, Kari (March 15, 2011). "'Clean Coal' Faces Uncertain Local Future". Chicago News Cooperative. Archived from the original on July 18, 2011. Retrieved March 16, 2011. Our investments in clean coal must not come at the expense of consumers
  26. ↑ Bradner, Eric (December 16, 2010). "State, developers reach agreement on Rockport, Ind., gasification plant". Evansville Courier & Press. Retrieved March 16, 2011.
  27. ↑ Kyiv’s gas strategy: closer cooperation with Gazprom or a genuine diversification Archived October 23, 2013, at the Wayback Machine , Centre for Eastern Studies (15 July 2013)
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