Research & Development

http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/13_4_NEW%20YORK_09-69_0185.pdf

 

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.

 

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?

http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/26_1_ATLANTA_03-81_0094.pdf

 

We have previously cited the USDOE's Bockrath and Noceti, of the Pittsburgh, PA, Energy Technology Center, relative to their research into the practical liquefaction of coal, and herein is more documentation of their work, and their accomplishments.

 

Though the following excerpts from the enclosed link might seem lengthy, they are just an abbreviated example of what is available;.we were compelled to edited out much overly-technical detail. 

 

With comment appended:

 

"Evaluation of the Donor Ability of Coal Liquefaction Solvents

 

Bradley C. Bockrath and Richard P. Noceti

 

United States Department of Energy
Pittsburgh Energy Technology Center
P. 0. Box 10940
Pittsburgh, Pennsylvania 15236  

Hydrogen donor solvents are used in most processes for the direct liquefaction of coal. The overall performance of these solvents depends on several qualities, including. the abilities to physically solvate coal and its liquefaction products, to hold coal particles in suspension, to assist transfer of hydrogen from the gas phase to coal by dissolving molecular hydrogen or undergoing hydrogenation/dehydrogenation cycles (hydrogen shuttling), and to donate hydrogen directly to coal. Unknown factors may also be involved. In addition, in the case of commercial application, the solvents must be derived from coal and be suitable for recycle operation as well. In order to fully understand the function and importance of liquefaction solvents, the influence of each property must be studied separately. As a step towards this goal,we have developed a method by which the relative hydrogen donor ability of liquefaction solvents may be evaluated.

 

Our method of evaluation is based on a generally accepted hypothesis -of the mechanism of coal liquefaction that has been used to rationalize the kinetics of coal liquefaction (1,2) and has been discussed several times in recent reports (for example (3,4,5). According to this mechanism, the initial act is rupture of the weaker covalent bonds in coal. This produces two free radicals in close proximity. These radicals may either abstract hydrogen from any available source (donor solvent, coal or molecular hydrogen), undergo
rearrangement, or add to some other site on either coal or solvent. Recbmbination or addition may lead to production of insoluble or char-like residues that are dearly undesirable. One critical function of the donor solvent is to provide a source of hydrogen. Abstraction of hydrogen by coal-derived free radicals prevents retrogressive reactions that lead to higher molecular weight products, and it directs more coal along the desired pathways to lower molecular weight products. Thus, donors with high potential for hydrogen
transfer are regarded as beneficial to increased liquefaction yields.

 

Our approach to evaluation of the donor property was to devise a test that embodies the main features of the free radical mechanism of coal liquefaction. The basic idea is shown in Figure 1. Benzyl radicals are generated by the thermolysis of' a convenient precursor at relatively low temperatures. These radicals then behave like the free radicals generated by the thermolysis of coal at liquefaction temperatures. When benzyl radicals are generated in a donor solvent, the relafive amounts of toluene and bibenzyl produced reflect the relative ability of the solvent to donate hydrogen and to prevent reco'mbination. A variable amount of benzyl radical is also lost, which presumably represents that amount which adds to or combines with the solvent.

 

Other methods have been used in the past to provide a "solvent quality index. ... Notably, measurement of liquefaction yields produced under specified conditions and with a specified coal has been used to provide a direct empirical evaluation of solvent quality.

 

Various spectroscopic methods have also been used to estimate the relative amount of benzylic or hydroaromatic hydrogen available for transfer (10,11,l2). These methods serve their intended purposes well. In the present work, we airn at developing a better understanding of the chemistry of liquefaction and the overall performance of liquefactionsolvents by isolating the hydrogen donor ability and free radical scavenger ability for study.

 

RESULTS AND DISCUSSION

 

Since many of the cornpounds to be tested as rnodel hydrogen donors are solids at room temperature, it was worthwhile to use an inert liquid as a diluent. Tert-butylbenzene served this purpose well. It possesses only relatively inert aromatic and primary aliphatic hydrogen and sufficient solvent power to dissolve most of the donor solvents to be tested. Decomposition of either benzyl radical precursor in lert-butylbenzene solution produced only srnall yields of toluene.

 

Material balance studies showed that not all of the benzyl radical present in the precursor was recovered as either toluene or bibenzyl. A sizeable fraction is apparently rernoved by side reactions with the solvent. In pure t-butylbenzene, this accounted for 24% of the benzyl radical, while in a 50/50 wt mixture of

t-butylbenzene and tetralin, it accounted for 32%. In the gas chromatograms of the decornposition products, new peaks appeared which were due to high boiling compounds. In the case of runs done in the
presence of tetralin, GC/MS analyses indicated that three of these peaks had the correct molecular weights for benzyltetralins, benzylnaphihalene and bitetralyl. These products must arise from radical combination and addition reactions.

 

The appearance of solvent combination and addition products is in accord with some recently reporteq results from other groups. Collins et. al. (13) reported that after they heated coal with 4C labeled tetralin at 400’ C for I hour, the pyridine solubles were 1.6 1 t. percent tetralin and the residue 2.6 wt. percent tetralin. In pother experirnent (13), “C labeled 1,3 -dipheriylpropane was heated with tetraliri at 400 C for 1 hour. Toluene and ethylbenzene were major products. In addition, methylnaphthalenes, mcthyldihy-dronap!ithalenes, phenylethyltetralins, and phenylcthylnaphthalenes were found. A mechanism was proposed that involved cornbination of phenylethyl with tetralyl radical, followed by further thermolysis to produce methyl substituted .tetralins and: naphthalenes.

Thus at higher temperatures, radical addition to solvent may he followed by (unintelligible) of the newly formed bridge. Evidence for the addition and subsequent dissociation of benzyl radical with tetrafin at temperatures of 400-450°C has also been reported by workers at Gulf (14). Another piece of evidence showing the importance of addition reactions is the report (15) that -negative solvent balances were found during preheater studies. These findings were interpreted to mean that during the initial phase of liquefaction (300’ -4OO0C), coal-derived solvent became bound to the coal so tightly that it could not be Jreed by either distillation or solvent extraction. Subsequent reaction after reaching 450 C changed the solvent balance to positive. Processes analogous to the addition/dissociation reactions described by Collins rnay Pe involved.

 

The three solvent indices were determined for the decomposition of dibenzylmercury for several solvent mixtures made from different amounts of tetralin .in t-butylbenzene. The data contained in Figure 2 show that the donor index increases with increasing tetralin concentration. Also shown in this figure are data taken from reference (16).for conversign of a bituminous coal to pyridine soluble material after reaction for three minutes at 427 F in mixtures of tetralin with methylnaphthalene, cresol, and picoline. Conversion as well as the donor index goes up as the tetralin concentration in the solvent increases. This comparison is made only to point out the qualitative similarity between the two results since we assume that both coal conversion and toluene yield are related to the relative hydrogen donor ability of the solvent. In both cases the greatest increase in conversion or toluene yield comes at relatively low tetralin concentration.

 

Tetrahydroquinoline's superior quality has been attributed to a unique combination of readily donatable hydrogen with a heightenedability to solvate coal and its liquefaction products ... an additional reason for the superior liquefaction performance of tetrahydroquinoline may be its ability to add to or combine with
free radicals initially produced by the thermolytic reactions of coal.

 

Comparison of the donor indices with other available quality criteria is made with two sets of solvents. The DCD series are recycle solvents derived from Blacksville coal under different processing conditions in the 1000 Ib/day liquefaction unit at PETC. The values of ... distillation residue from a lightly hydrogenated recycle oil made in the Wilsonville SRC pilot plant from Wyodak coal. F-14is a lightly hydrogenated recycle oil made in the Tacoma SRC pilot plant from Kentucky coal. F-16 is a coal gasification tar from an in situ gasification project near Manna, Wyoming.  

 

REFERENCES
1) G. P. Curran, R. T. Struck and E. Gorin, Ind. Eng. Chem., Process Des. Dev. -6, 166 (1967).
2) W. H. Wiser, Fuel, E,475 (1968).
3) D. D. Vhitehurst, T. 0. Mitchell, M. Farcasiu and 3. J. Dickert, Jr., "The Nature and Origin of Asphaltenes in Processed Coals," EPRl Final Report AF-1298 (1979).
4) R. C. Neavel, Fuel, 55, 237 (1976).
5) I. Wender and 5. Friedman, Proc. 13th. IECEC (Sin Diego, CA., Augut, 1978) Vol. 1, p. 457.
6) B. K. Bandlish, A. W. Garner, M. 1.Hodges and J. W. Timberlake, J. Am. Chem. SOC., 97,5855 (1975).
7) K. C. Bass, J. Organometal, Chern., 2,l(1965).
8) Method No. 43080-60, Analytical Department, Catalytic, Inc.,Wilsonville, Alabama.
9) 3. A. Kleinpeter, F. P. Burke, P. J. Dudt and D. C. Jones, "Process Development for Improved SRC Options," EPRl Interim Report, AF-1158, August, 1979, Palo Alto, Calif.
IO) C. H. Wright and D. E. Severson, Preprints Am. Cliem. Soc., Div. Fuel Chem-16(2), 68 (1972).
11) I<. S. Seshadri, R. G. Ruberto, D. M. Jewell and tl. P. Malone, Fuel, 57, 549 (1978). 
12) B. T. Fant, "EDS Coal Liquefaction Process Developmcnt: Phasc IIIA," Annual Technical Report, 1 Jan -31 Dec 1976, ERDA No. FE-2353-9 (1977).
13) Am. Chem. SOC., Fuel Div., g(5), 98 (1977). C. 3. Collins, B.M. Benjamin, V.F. Raaen, P. H. hlaupin and V. H.Roark, Preprints,
14) Eng. Chem., Fundam., E, 195 (1979). C. Cronauer, D. M. Jewell, Y. T. Shah, R. J. Alodi and K. Seshadri, Ind.
15) hl. G.Thomas and R. K. Traeger, Preprints, Am. Chem. SOC., Fuel Div., 2(3), 223 (1979).
16) D. D. IVhitehurst, T. 0.Mitchell, bi. Farcasiu and J. J. Dickert, Jr., "The Nature and Origin of Asphaltenes in Processed Coals, Volume I," EPKI Final Report AF-1298, pg. 1-46 (1979).
17) G. Koclling, Rrennstoff-Cherr$ie, g,23 (1965).
18) D. Hausigk, G. Koelling and F. Ztegler, Brennsroff-Chrmie, 50, S, (19b9).
19) Petrakis and D. W. Grandy, Fuel, 2,227 (1980). 
20) F. Silver and R. J. Hurtubisc, "Effect of Solvent Characteristics on Wyodak Coal Liquefaction," Final Technical Progress Report," Department of Energy Report FE-2367-9 (1979).  

21) G. Cohen, S. J. Groszos and D. Sparrow, J. Am. Chem. SOC., 72, 3947 (1950). 

22) J. R. Shelton and C. K. Liang, Synthesis, 204 (1971)."

 

First of all, an early quote: "Hydrogen donor solvents are used in most processes for the direct liquefaction of coal".

 

Did you, did anyone in Coal Country, know that there was such a multiplicity of coal liquefaction technologies that a statement like "most processes for the direct liquefaction of coal" could even be used?

 

Second, in a similar vein, note how, in an offhand manner, it is revealed that there were a number of coal liquefaction operations underway around the United States, as in:"Comparison of the donor indices with other available quality criteria is made with two sets of solvents. The DCD series are recycle solvents derived from Blacksville coal under different processing conditions in the 1000 Ib/day liquefaction unit at PETC. The values of distillation residue from a lightly hydrogenated recycle oil made in the Wilsonville SRC pilot plant from Wyodak coal. F-14 is a lightly hydrogenated recycle oil made in the Tacoma SRC pilot plant from Kentucky coal. F-16 is a coal gasification tar from an in situ gasification project near Manna, Wyoming."

 

In the above exert, they note that WV - "Blacksville" - coal was liquefied in Pittsburgh. Another coal was liquefied in Alabama, in the "Wilsonville SRC" we have documented for you previously. And, coal was shipped all the way from Kentucky to be liquefied in the "Tacoma", Washington, "SRC pilot plant", another US Government coal conversion facility about which we have reported.

 

They also document "Tetrahydroquinoline's superior quality" as a coal liquefaction solvent. Also known as "Tetralin", that material is a key part of WVU's "West Virginia Process" for direct coal liquefaction.

 

Finally, make note of the sheer volume of coal liquefaction references they include.

 

The knowledge, the technology, is real. Why aren't we using it?