Distillation coal liquids

Operation of the FDU with coal-derived residuum was preceded by tests on pure compounds and distillable coal liquids using n-pentane as the supercritical fluid ( ). The results of tests with the coal-derived distillate showed that the FDU was basically performing as expected. Liquid reflux was generated by means of the hot finger when the device was operated at a temperature slightly above the critical temperature of the transport fluid. When reflux was established, fractionation based upon volatility was observed. Poorer separation was achieved in the absence of reflux. 

The widespread use of combustion turbines in industry and by electric utilities, as well as the generating efficiency improvement offered by new combined cycle plants in conjunction with combustion turbines, represents an attractive market opportunity for SRC-II distillate coal liquids. 

Heck, R. H., Stein, T. R., "Kinetics of Hydroprocessing Distillate Coal Liquids, Symposium on Refining of Synthetic Crudes, Chicago, (1977). 

Another method for the analysis of nitrogen-containing compounds includes the formation of fluo-roamide derivatives for amino polycyclic aromatic compounds in coal liquids [28]. Quantitative analysis of amine-rich isolates of an SRC-II heavy distillate coal liquid with trifiuoroacetyl or pentafluoropropyl... 

Cumene (isopropylhenzene), a liquid, is soluble in many organic solvents hut not in water. It is present in low concentrations in light refinery streams (such as reformates) and coal liquids. It may he obtained by distilling (cumene s B.P. is 152.7°C) these fractions. 

The principle of donor hydrogen reaction with coal has been applied in various ways in processes for coal liquefaction. In one application, hydrogen donor solvent is generated from the coal itself. The solvent, usually a distillate fraction of the coal liquid product, is hydrogenated and recycled to the coal liquefaction reaction. 

Catalytie synthesis from CO and Hj Natural gas Petroleum gas Distillation of liquid from eoal pyrolysis Catalytic synthesis from CO and Hj Distillation of liquid from wood pyrolysis Gaseous products from biomass gasification Synthetic gas from biomass and coal... 

None of these terms appears to be completely satisfactory. The concept of "mobility in NMR spectroscopy is quite different from that in the field of separation science, where mobility generally requires a measurable degree of solubility and/or distillability in liquid or gaseous media, respectively. For example, polymethylene-like moieties, such as found in some coal components (0, are highly "mobile in NMR terms (1), without necessarily being extractable by solvents or distillable by nondestructive heating. 

Bitumens occur naturally or are formed as the residue in the distillation of coal tar, petroleum, etc. Industrially, the two most important bitumens are asphalt and coal tar. Asphalt is a brown to black tarlike variety of bitumen that again occurs naturally or is the residue of distillation. Coal tar is the black, thick liquid obtained as the residue from the distillation of bituminous coal. 

Coal liquids, petroleum crudes, and their distillation cuts have been separated into four or five fractions by SEC (5 15). The SEC fractions were analyzed by use of GC. The procedure was performed manually. It was inefficient, and susceptible to human error. The automated fraction collection followed by injection of the fraction into the GC reduces analysis time, and offers an option for collection of the desired number of fractions at predetermined time intervals. The manual collection of up to 10 one-ml fractions is also used in order to study the effectiveness of the automated method. 

The British, French Italians during WWII used mixtures of heavy and light petroleum distillates with a density of about 0.86 at 15°. The Germans used various mixtures of petroleum distillates, coal tar fractions, and sometimes such liquids as methanol, acetone or even ether. The density of such mixtures was usually about 0.96 at 15°. One of the first American mixtures contained 70% water-gas tar (flash point 122° and d 1,044) and 30% "benzene heads (fl p 26° and d 0.756). The resulting mixture had d 1.02. 

Solid/liquid separation is usually required at the interface of the primary and secondary stages to allow optional upgrading of the crude coal liquids of the primary liquefaction stage, by removing mineral matter, unreacted coal, heavy products, and catalysts (111, 112). Distillation, anti-solvent extraction, and centrifugation have been conventionally employed in liquefaction processes (113, 114). 

A single-step reaction at 430°C for 3 hr eliminated only 30% of the nitrogen from the heavy distillate of a Wandoan coal liquid (bp 350-500°C) as shown in Table 11. In marked contrast, a 100% denitrogenation was... 

The authors reported an example of such solvent effects in the catalytic two-step denitrogenation of coal liquid distillates. With large quantities of added 1-methylnaphthalene or 20% added pyrene or fluoranthene, no additional catalyst is necessary for the second step to achieve high levels of denitrogenation. 

Shale Oils. As indicated by the data in Table II, only cut I of the shale oils contains a considerable amount of material boiling below 470°F, as would be expected from the low boiling range of this fraction (Table V). This distillate was fractionated into saturates, aromatics, and olefins by preparative FIA techniques, but a GLC analysis of these fractions proved unfruitful for the same problems mentioned above for the coal liquids. 

Distillations. The upgraded coal liquids were distilled with a metal-mesh-spinning-band still under the conditions shown in Figure 1 to produce cuts at 200°, 325°, and 425° C. Asphaltenes were then precipitated from each >425° C residuum dissolved in benzene by addition of 50 volumes of normal pentane (15). Further distillations on the asphaltene-free materials, at 202° C and 4 micron pressure using a wiped-wall molecular still, produced 425° to 540° C distillate cuts and residua fractions. 

Figure 2. Separation and analysis scheme for < 200° C coal liquid distillates...

Table III lists the specific gravity, nitrogen content, and sulfur content of the various distillation fractions obtained from each of the eight coal liquids. Nitrogen content increased for the higher-boiling distillates as expected. All sulfur values were low as expected. Nitrogen contents of the asphaltenes from the bituminous-coal liquids were higher than those from the lower-rank-coal liquids.

Separation, Characterization and Analysis of the Distillate Fractions. Results from the analyses of the <200° C coal-liquid distillates (after removal of trace quantities of acids and bases) are summarized in Table IV. Results from the dual silica-gel/alu-mina-gel adsorption chromatography separations of the 200° to 325° C, 325° to 425° C, and 425° to 540° C coal-liquid distillates are summarized in Table V. Data for the acid and base extracts of the polyaromatic-polar adsorption fractions are also included in Table V. Summary data on analysis of the saturate fractions are listed in Table VI. Data in Table VI show a trend toward higher percentages of zero- and one-ring saturates in lower-rank coals. 

Adsorption Chromatographic Fractions. Examination of the data of Table V shows a tendency for distillates of lower-rank-coal liquids to contain more saturate material and less polyaromatic-... 

Table III. Distillation Fractions of Upgraded Coal Liquids... 

Table IV. Composition of the < 200 °C Distillate Hydrocarbons from Eight Coal Liquids, Weight Percent Total Coal Liquid Basis...

Acid Fractions. The acid contents, as shown in Table V, account for about 0.4 to 0.6 percent of the 325° to 425° C coal liquid distillates except for the lignite liquid (0.76). The acid content for the 425° to 540° C distillates mostly fall in the range of 0.50 to 0.59 percent except for Pittsburgh (0.29) and Wyodak run 1 (0.34). The total acids from the 325° to 425° C and the 425° to 540° C distillates plus the oxygenate material from the 200° to 325° C distillate (19) expressed on a total liquid basis, correlated fairly well with the total coal liquid oxygen content (Table II) (correlation coefficient 0.82). The data are plotted in Figure 5. 

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