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Karrick process


The Karrick process is a low temperature carbonization (LTC) of coal, shale, lignite or any carbonaceous materials. These are heated at 680 °F to 1380 °F (360 °C to 749 °C) in the absence of air to distill out oil and gas. The process was the work of oil shale technologist Lewis C. Karrick at the U.S. Bureau of Mines in the 1920s.

China has announced high volume commercial coal liquefaction production in late 2007[1], after a successful trial, starting a process that could rapidly free China from dependency upon external OPEC oil imports. The process is reported to have '60-meter-high cylindrical structures' and to be a direct coal liquefaction process. While lacking formal confirmation, the process described seems identical to the Karrick process, and appears to be a re-engineering, based upon the 1930s patents. At the time of writing (2007) America does not have an equivalent oil self sufficiency strategy in place.



Karrick processing of 1 short ton of coal yields up to 1 barrel of coal tars (12% by weight), richer in lighter hydrocarbons than normal coal tar and suitable for processing into fuels, 3000 cubic feet of rich fuel gas and 1500 pounds of solid smokeless char or semi-coke (for one metric ton, 0.175 m³ of coal tars, 95 m³ of gas, and 750 kg of semi-coke). Smokeless char can be used for utility boilers and cooking coal in steel smelters, yields more heat than raw coal and can be converted to water gas. Water gas can be converted to oil by the Fischer-Tropsch process. Coal gas from Karrick LTC yields greater energy content than natural gas. Phenolic wastes are used by the chemical industry as feedstock for plastics, etc. Electrical power can be cogenerated at nominal cost. Karrick LTC process generates carbon dioxide. (See "Carbon/CO2 sequestration" in "See also" below).


Karrick did not invent coal LTC but perfected it in his now expired patents, issued from 1931 to 1942. Dozens of American facilities had previously produced oil, gas, grease and paraffin from coal, but by 1873, cheap petroleum caused the last coal oil plant to close. America is today experiencing a revival of the art in response to crude oil prices of up to or exceeding $80 per barrel, geopolitical and economic considerations. (See "Fischer-Tropsch process" below)

The Karrick low temperature carbonization process


A Karrick LTC pilot plant was constructed at the University of Utah in the 1930s, and below are some findings:

  • Bergius (HTC) liquefaction is too costly and approximately one-half of the thermal value of coal is destroyed.
  • Bergius process requires substantial volumes of water.
  • Karrick process, including conversion of the oil to motor fuel, destroys only 25% of the thermal value, or one-half that of the Bergius process.


  • Gasoline obtained from coal LTC liquefaction is equal in quality to tetraethyl lead gasolines.
  • More power is developed in internal combustion engines and an increase in fuel economy of approximately 20% is obtainable under identical operating conditions.


  • Yields by volume of approximately 25% gasoline, 10% kerosene and 20% good quality fuel oil are obtainable from coal.
  • The smokeless fuel, when burned in an open grate or in boilers, delivers 20% to 25% more heat than raw coal.
  • The oil can be converted to liquid fuels while the smokeless fuel is excellent for steam boilers.
  • The coal gas should deliver more heat than natural gas per heat unit contained due to the greater quantity of combined carbon and lower dilution of the combustion gases with water vapor.
  • The cheapest liquid fuel from coal will come when processed by LTC for both liquid fuels and electric power, which should yield the least expensive electricity.
  • The gasoline, fuel oil, and other oil products would be a small percentage of imported petroleum products and should therefore find a ready and enthusiastic market.


  • As a tertiary product of the coal distilling process, electrical energy can be generated at a minimum cost.
  • A Karrick LTC plant with 1 kiloton of daily coal capacity produces sufficient steam to generate 100,000 kilowatt hours of electrical power at no extra cost excepting capital investment for electrical equipment and loss of steam temperature passing through turbines.
  • The process steam cost could be low since this steam could be derived from off-peak boiler capacity or from turbines in central electric stations. Fuel for steam and superheating would subsequently be reduced in cost.


  • No difficulties whatsoever were encountered during the successful operation of the plant.
  • A 30 ton plant and oil refinery will show a profit over and above all operating and capital costs and the products will sell at attractive prices for equivalent products.
  • The private sector should require no subsidies, but not in competition with those who skim off the oil from coal and sell the residual smokeless fuel to power plants.


  • Commercial Karrick LTC process plants would fail due to mechanical problems, a postulation based on previous failures of other plants using different processes under different conditions.
  • Markets for the described coal products are limited, making such a venture economically unsound.

Coal reserves

The United States has 26% of Earth's known coal reserves. This is sufficient to last hundreds of years by the lowest estimates and accounts for 90% of U.S. energy reserves. Coal is, of course, a fossil fuel and as such is therefore subject to possible depletion within a few hundred years. In terms of energy obtained, coal peaked in 1998 and though production volumes have increased, the net energy has not, which could be explained by decreasing production of high quality coal, such as bituminous and anthracite. U.S. reserves are approximately 50% bituminous and anthracite.

The energy value of all the world's known recoverable coal is 27 zettajoules, which is expected to last 164 years. (See "Coal")

Of that, U.S. reserves alone comprise 7.02 zettajoules. The U.S. DOE estimates coal reserves at 1,081,279 million short tons (9.81 × 1014 kg), or about 4,786 billion (4.7 trillion) barrels of oil eqivalent. The amount of coal burned during 2001 was calculated as 2.337 gigatonnes of oil equivalent, or about 46 million barrels of oil equivalent per day. Were consumption to continue at that rate, those reserves would last about 285 years.

Production of synthetic fuels from U.S. coal assets represents an effective means towards decreasing U.S. reliance on imported oil, reducing trade deficits and providing more economical energy than current markets offer. (See "Princeton University: Increased Automobile Fuel Efficiency and Synthetic Fuels; Alternatives for Reducing Oil Imports" below)

Economic viability

Oils, including petroleum, have long been extracted from coal. Production plants were merely shut down in the 1880s because crude oil became cheaper than coal liquefaction. The capability itself, however, has never disappeared. Eight years of pilot plant tests by Karrick attest that states, cities or even smaller towns, could make their own gas and generate their own electricity.

John Winslow, Laboratories Technology Manager for Coal Fuels at the U.S. DOE National Energy Technology Laboratory (NETL), estimates that a plant producing 30,000 barrels of liquid coal per day (4,800 m³/d) can keep costs to $35-$40 per barrel. This finding was presented at the Coal Utilization Technologies Workshop, September 22 2004, at the National Research Center for Coal & Energy, Morgantown, WV. This meeting was part of the Energy Roadmap Workshop Series commissioned by West Virginia Governor Bob Wise.

Potential market size is substantial, U.S. importation of petroleum products alone for 2005 being a record $251.6 Billion, and $302.5 Billion for 2006, another record. Figures for 2007 are not yet available but are certain to be substantially higher still. (See "U.S. Census Bureau 2006 Foreign Trade Statistics" below).

Congressional funding

In 1980, the U.S. Congress approved a $20 billion synfuel program authorizing an Energy Mobilization Board to expedite high priority projects such as facilities to produce oil from coal and shale.

However, the DOE placed great emphasis on the Bergius process of direct liquefaction of coal by hydrogenation to produce synfuel. The Bergius process combines coal with heated hydrogen at 3000-5000 psi (20 to 35 MPa) to produce oil. Synthesis requires 7000 cubic feet of hydrogen per barrel of oil produced plus 1500 cubic feet of hydrogen per 1000 cubic feet of synfuel produced.

The Bergius process has been criticized both economically and ecologically as untenable, and given the shortcomings of the Bergius process, the prudence of that Congressional funding allocation has been questioned.

U.S. patents

Reference U.S. Patents issued to L.C. Karrick:

  • U.S. Patent 1,835,878  U.S. Patent 1,894,691  U.S. Patent 1,899,154 
  • U.S. Patent 1,901,169  U.S. Patent 1,901,170  U.S. Patent 1,906,755 
  • U.S. Patent 1,913,395  U.S. Patent 1,919,636  U.S. Patent 1,923,213 
  • U.S. Patent 1,938,596  U.S. Patent 1,942,650  U.S. Patent 1,945,530 
  • U.S. Patent 1,950,558  U.S. Patent 1,958,918  U.S. Patent 2,011,054 
  • U.S. Patent 2,268,989  U.S. Patent 2,283,556 

CO2-Related/Sequestration Patents:

2007217981, 2007051615, 2007081924, 2007144747, 2007261947, 2007253886, 2005180910, 2005169825, 2005180910, 2004200393, 7043920, 2004161364, 6945029, 6667022, 6976362, 7132090, 6598398, 6667171, 6763886, 6736215, 6871707, 2001015061, 6648949, 6447437, 6115672, 6148602, 6190301, 6170264, 2007028848, 2002035307, WO 2005108297, WO 0198313, WO 2007106372, WO 2007077139, WO 2007106883, WO2007071633, WO2007077137, WO2007003013, WO2007015689, WO03103805, WO0175277, WO2007106372, WO2007077138, CA2122200, CA2541681, CA2507946, CA2537383, CA2523135, CA2503655, CA2531181, FR2872566, KR20030011693, MXPA06008537, EP1801346, EP1350766, CN1898010, CN1884140, AU2003235033, JP62081478

See also

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Karrick_process". A list of authors is available in Wikipedia.
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