Karrick process

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Karrick Process, from U.S. Patent #1,958,918.
Karrick Process, from U.S. Patent #1,958,918.

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.

Contents

[edit] Process

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 boasts 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" below).

[edit] History

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 $78 per barrel, geopolitical and economic considerations. (See "Fischer-Tropsch process" below)

[edit] Karrick LTC comparative

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.

[edit] Karrick LTC gasoline

  • 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.

[edit] Karrick LTC byproducts

  • 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.

[edit] Karrick LTC thermals

  • 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 megawatt 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.

[edit] Karrick LTC viability

  • 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.

[edit] Karrick LTC criticisms

  • 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.

[edit] Coal reserves

The United States has 26% of Earth's known coal reserves. This is sufficient to last hundreds of years by the most conservative estimates and accounts for 90% of U.S. energy reserves. Coal is a logical resource towards achieving energy independence but the environmental hazards associated with burning coal preclude its combustion in raw form. To paraphrase, "Pollution is a misallocated resource." (See "Learn about Coal" and "USDOE estimates of worldwide coal reserves" below)

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)

[edit] Economic viability

Oils, including petroleum, have long been extracted from coal. Production plants were merely shut down in the 1980s 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 for 2005 alone being $251.6 Billion. (See "U.S. Census Bureau 2005 Foreign Trade Statistics" below).

[edit] 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.

[edit] U.S. patents

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

[edit] See also

[edit] External links

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