Karrick Process

The Karrick process is a named low-temperature carbonization (LTC) route for coal, associated with Lewis Cass Karrick and documented in a source dossier. It heats coal below conventional coking temperatures to drive off volatiles, leaving a solid char together with condensable tar/oil and a combustible gas stream.

The dossier's own article states the attribution carefully: "Lewis Cass Karrick did not invent LTC of coal; he perfected it." Coal-oil plants predate him — the 1933 thesis records 55 coal-oil plants operating in the US by 1860, the largest distilling 6000 barrels of oil per day — and the wiki preserves the distinction rather than crediting Karrick as inventor.

Reported operating conditions and yields

The karric.htm article reports the following figures for the Karrick process. They are archive assertions, not independently verified measurements, and are given here with that attribution:

• Pyrolysis temperature of about 800 °F, in the absence of oxygen, applied to coal, shale, lignite or any other carbonaceous material (including garbage).
• Per ton of coal: up to one barrel of oil, 3000 cu. ft. of rich fuel gas, and 1500 lb. of solid smokeless char (semi-coke).
• A plant with a daily capacity of 1000 tons would produce enough steam to generate 100,000 kW-hours of electrical power per day, at no extra cost other than capital investment in electrical equipment and steam temperature losses in the turbines.

The article's economic framing is that "the oil is obtained for free," resting on the sale of the other product streams. It also claims the process "produces no pollutants other than carbon dioxide," while separately naming phenolic wastes as a stream used by the chemical industry as feedstock for plastics — an internal tension in the source's own text.

Claimed product slate

The archive presents the process as yielding several saleable streams from one coal feed:

• solid char (semi-coke), described as an excellent substitute for coal in utility boilers and for coking coal in steel smelters, yielding more heat than raw coal and convertible to water gas; also usable as smokeless fuel or feedstock;
• condensable tar/oil;
• combustible gas, claimed to yield more BTUs than natural gas because it contains more combined carbon and less dilution of the combustion gases with water vapor;
• and, in the archive's framing, a route to liquid fuel independent of petroleum.

The economic argument attached to the process is byproduct recovery — viability is claimed to rest on selling multiple products rather than one. See Byproduct Recovery in Carbonization. The source does not provide an independent cost or yield accounting.

Mechanism

The mechanism is thermal decomposition of coal under controlled, comparatively mild heating. Because the peak temperature is lower than in coking, volatiles are released with less severe cracking, and the solid residue retains more volatile matter than metallurgical coke. The characteristic LTC trade-off applies: a larger solid fraction and a smaller liquid fraction than hydrogenation or liquefaction routes. See Low-Temperature Carbonization (LTC) for the general mechanism and Coal Carbonization vs. Coal Liquefaction for the route comparison.

The 1933 thesis describes the heat-transfer arrangement used in its plant tests: exhaust steam from power-plant engines or turbines was superheated and then passed directly through bodies of sized, dust-free coal. The thesis credits an earlier 1920 study by the State of Utah and the Federal Government, which used steam as the heat-transfer fluid in destructive distillation and obtained "excellent yields and quality of oil."

Evidence status

The strongest evidence in the source text is the Jacobsen/Carter thesis — a dated, institutional, methodologically described plant-test program on Utah cannel coal slack, submitted to the University of Utah on 15 May 1933. It states its objects (minimize radiated heat losses; take temperature and heat-flow data throughout the coal charges and the apparatus; correlate products with the most economical use of heat), describes the apparatus and test procedure, and includes a heat calculation for Test Run #6. It is not peer-reviewed journal literature, and the capture omits several sections, but it is a documented experimental study rather than an archive assertion. See s-c-jacobsen and g-w-carter.

The karric.htm article reports pilot or demonstration-scale testing and commercial operation by the National Coal Carbonizing Co., Ltd. (NCCC), which it says ran five LTC retorts producing Rexco-brand smokeless fuel for 40 years, but supplies no peer-reviewed citation and no independent cost or yield accounting. The dossier also reports pilot or demonstration-scale testing typically attributed to U.S. Bureau of Mines work or company trials, likewise without peer-reviewed citation.

The archive additionally asserts that the process was commercially suppressed by petroleum and coking-coal interests, and that the government dismantled the Rifle, Colorado pilot plants once LTC proved cheaper than pumped oil. That is the archive's framing and is attributed here to the source, not stated as a documented finding. See Karrick Claims vs. Evidence: The Dossier's Assertions and the Absence of Test Data and US Bureau of Mines.

The source capture carries a moderate probability (0.28) of being partially truncated, so specific temperatures and yields are not reproduced here beyond those attributed above.

Related

• Lewis Cass Karrick — the process's associated developer.
• Byproduct Recovery in Carbonization — the economic claim structure.
• Semi-Coke — the solid product.
• Destructive Distillation — the underlying thermal method.
• cannel-coal — the feedstock used in the 1933 plant tests.
• Karrick Patent Set (Seven US Patent Drawings in the KLTCUSP Capture) — the patent drawings associated with the process.
• fuels, energy — topic guides.