We have recently been reporting on the "Karrick Process" of coal liquefaction, also known, more technically, as the "low-temperature carbonization", or LTC, of coal, which, as we have documented, is being experimented with and developed in other nations, now that the original patents, assigned to US Bureau of Mines scientist Lewis Karrick and a few of his colleagues, early in the last century, have expired.
As we have documented, a number of Big Oil petroleum monopolists were inexplicably entrusted by our Federal Government, over the course of decades, with the oversight of several research and development projects that were, for the sake of public perception at least, intended to develop technologies that would enable the United States to convert her abundant coal into needed liquid fuels.
Several oil companies, after gaining experience through government-funded projects, conducted additional research on their own.
Herein, one of them, Ashland Oil, is documented to have followed up on their CTL development work with the government by demonstrating, and confirming overseas research we have already reported to you, that the carbonaceous residue left behind by the low-temperature carbonization, i.e. Karrick, processing of coal, to obtain liquid hydrocarbons suitable for refining into petroleum replacements, can itself be further processed to obtain even more hydrocarbon liquids amenable to refining. That, even though the focus of Ashland's work in this case was, or was intended to seem, focused on the extraction of a somewhat useful commercial by-product of low-temperature coal carbonization.
Excerpt as follows; emphases added, with comment interspersed and appended:
"CARBON BLACK FEEDSTOCK FROM LOW TEMPERATURE CARBONIZATION TAR
Donald C. Berkebile, Harold N. Hicks, and W. Sidney Green
Ashland Oil and Refining Company
1409 Winchester Avenue, Ashland, Kentucky 41101
About three years ago Ashland Oil and Refining Company management initiated a modest coal liquids research program. This program was aimed at accumulating basic technology and at providing a basis for more extensive studies. During the early stages research consisted primarily of literature surveys and scouting experiments. It was concluded from this initial work that low temperature carbonization (LTC) of coal could supply coal liquids at attractive values when considering the current economic conditions.
Discussions with FMC Corporation established' their willingness to cooperate in supplying tar from their LTC-pilot plant for experimental work. The FMC unit was constructed under sponsorship of the Office of Coal Research (OCR) . This project is designated as Char-Oil-Energy-Development and has the acronym of COED.
(So, "FMC Corporation" also had a coal conversion program? How many of those were there, anyway? And, why haven't we been informed?)
The COED process utilizes multiple stage, fludized-bed pyrolysis with increasing stage temperatures to drive off the volatile matter at controlled rates and temperatures so that a high percentage of the coal is converted to gas and condensable oil products. Coal is crushed and dried and fed to the first stage vessel, where it is fluidized in hot recycle gases generated from combustion of some of the product gas or char. The coal then proceeds from the first stage, which is nominally at 600°F, to the subsequent stages where it is subjected to increasing temperatures of 850, 1000 and 1600OF. Heat for the second and third stages comes from burning some of the char with oxygen in the fourth stage. The gases from the fourth stage flow countercurrent to the solids through the third stage to the second stage, from which most of the volatile products are collected. A small percentage of the volatiles comes from the first .stage. A small amount of char is recycled to the third and to the second stage to help provide the heat necessary to maintain the vessel temperatures. The volatile products from the pyrolysis are condensed and separated.
(Note that a part of the Karrick LTC process, as we've earlier documented from other sources, is exothermic. It can provide energy to help drive the conversion process, and, as we have also documented, be harnessed to generate some electricity as a by-product.)
The project COED tar that was the feedstock for all work described in this paper was derived from Illinois #6 coal.
Ashland's position as a supplier of refinery products and carbon black--through the United Carbon division--had a significant influence on the selection of the research program goals for processing of LTC tar.
(We bet it did.)
The primary objective of this program was to produce carbon black feedstock from all or a portion of the LTC coal liquids. A product of this nature would require a minimum amount of upgrading and would utilize heretofore unmarketable fractions of the coal liquids. Secondly, emphasis was placed on converting the fractions unsuitable for carbon black feedstock into products compatible with normal refinery operations.
(In other words, there were marketable, as opposed to "unmarketable" ... "coal liquids".)
Other researchers have tried many techniques to upgrade LW tar including coking, thermal cracking and hydrogenation. Products ranging from coke to gasoline with some intermediate chemicals are commonly reported in the literature. Probably the point most 'common to the work of these various groups was the fact that the processes were uneconomical. Processes to produce chemicals from LTC coal liquids failed because these materials could not be obtained by simple processing schemes.
(So, "products" such as "gasoline" can be obtained from carbonaceous LTC tar residues, but the "processes were uneconomical". We wonder if WVU's West Virginia Process for direct coal liquefaction, using the hydrogen donor, tetralin, if applied to LTC residues, already processed, and porous, as they are, might have more economic success. And, petroleum economics have changed dramatically in the decades since this report was published - to use the term "published" very loosely.)
DISCUSSION
An initial quantity of project COED full range coal liquids was obtained from FMC for characterization.
Initial Processing Scheme: The tar was-heated until fluid and blended with benzene in a 1:1 volume ratio in order to reduce the tar viscosity sufficiently to permit centrifugation for solids removal and for a subsequent distillation to remove the water.
(A lengthy description of processing details is contained in the report. We are not excerpting them, but the processes were focused not only on obtaining carbon black, but on evaluating "the product as a potential refinery reformer charge stock". As it happens, it didn't work too well for carbon black, but was a productive source of additional liquid hydrocarbons when appropriately processed, as revealed following.)
Hydrotreating-Microreactor
Because of the high oxygen content of the dry, solids-free tar and its detrimental effect on carbon black yield, it was decided to attempt to selectively hydrotreat the tar with the objective of removing the oxygen, nitrogen and sulfur without ring saturation. Fixed bed, catalytic hydrotreatment of the tar was conducted at a moderate temperature and intermediate pressure in a 3/4 inch diameter reactor. The process was studied by evaluation of composited reactor effluent and off-gas samples from consecutive test periods of 19 to 24 hours duration.
A hydrocarbon liquid yield on feed of about 86 weight percent and an aqueous yield of about 3%were obtained. Hetero atom removal based on the feed and composited effluent samples was over 90%for sulfur, over 60% for oxygen, and nearly 40% for nitrogen. Hydrogen consumption for this level of processing was estimated at 1200 to 1500 SCF/bbl. of feed. Material balance data indicated that hetero atom removal accounted for the largest portion of the hydrogen consumed with most of the remaining hydrogen used appearing as cracked products in the off gas.
(So, they didn't get the carbon black they were originally, supposedly, looking for, but: "86 ... percent" of the LTC residue feed was converted into, yielded "hydrocarbon liquid".)
The hydrotreated composited product was fractionated into ... refinery feedstock and a carbon black feedstock.
(There was additional, significant, benefit attributed to the process for the "refinery feedstock", as follows.)
Hetero atom (Sulfur and other contaminants.) concentrations have been reduced sufficiently by this operation to permit processing of the material in conventional refinery units.
ECONOMICS
The preliminary economics of a commercial scale LTC tar processing facility have been estimated based on a pilot plant and laboratory data. The economics assume a 10,000 ton/day coal car-
bonization unit is located adjacent to the tar processing facility. This unit, while not directly included in the economics, supplies a low cost source of 11,906 bbl/day of full-range LTC tar.
bonization unit is located adjacent to the tar processing facility. This unit, while not directly included in the economics, supplies a low cost source of 11,906 bbl/day of full-range LTC tar.
A capital investment of $13,100,000 has been estimated for the processing units shown in Figure 3, with the exception of the carbon black facility, which is not included in the economics. A discounted cash flow of 20% can be realized on this investment with full-range LTC tar valued at $1.62/bbl. and the following values placed on the various products:
Carbon Black Feedstock -7C/gallon
Rt2 Fuel oil -9$/gallon
Gasoline Blending Stock -14C/gallon (102+ Octane No.)
Benzene -23C/gallon
Naphthalene -4.5$/lb.
H2 Consumed or Generated -30$/1000 SCF
(NOTE: Unless we misread this, when all the products and economics are considered, a "102+ Octane" "Gasoline Blending Stock" was produced from coal LTC residue at a cost of 14 cents per gallon.)
The technical feasibility of hydrotreating full-range LX tar to produce a highly aromatic residue boiling above 600°F, with low hetero atom (Sulfur, etc. - JtM) content, has been demonstrated.
The lower boiling material from hydrotreating ... is a highly aromatic material ideally suited for processing in conventional refinery equipment to yield valuable products.
Preliminary economics, based on pilot plant data, indicate the overall LTC tar processing scheme can realize a good DCF rate of return on investment, when reasonable product values are assumed."
----------------
So, according to Ashland Oil, we can use USBM scientist Lewis Karrick's LTC process to make liquid petroleum fuel replacements from coal. And, we can further convert the "waste", the carbonaceous residue, from that LTC process into a "material ideally suited for processing" in a conventional oil refinery, at a cost, at the time of this report, of 14 cents per gallon, for "stock" from which gasoline can be blended.
Do we have that all about right? And, doesn't the answer to that question spur the birth of a whole bunch of other questions?