Synthoil process

Effect of Processing Options and Coal on the Product Composition from the H-Coal Process 

Liquid feed throughout 140 0b/h)/ft reactor volume Slurry feed 45 coal + 55 recycle oil (w/w) 

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In the Energy Research and Development Administration s SYNTHOIL process, slurries of coal in recycle oil are hydrotreated on Co-Mo/Si02 Al203 catalyst in turbulent flow, packed-bed reactors. The reaction is conducted at 2,000 to 4,000 psi and about 450° C under which conditions coal is converted to low-sulfur liquid hydrocarbons and sulfur is eliminated as E2S. 

Akhtar, Sayeed, Lacey, James J., Weintraub, Murray, Reznik, Alan A., and Yavorsky, Paul M. The SYNTHOIL Process—Material Balance and Thermal Efficiency. Presented at the 67th Annual AIChE Meeting, December 1-5, 1974, Washington, D.C. 

Akhtar, Sayeed, Mazzocco, Nestor J., Weintraub, Murray, and Yavorsky, Paul M. SYNTHOIL Process for Converting Coal to Nonpolluting Fuel Oil. Presented at the 4th Synthetic Fuels from Coal Conference of the Oklahoma State University, Stillwater, Oklahoma, May 6-7, 1974. 

The objective of this work was to study the activity of the Monolith catalyst for removing sulfur and nitrogen from a Synthoil process liquid (heavy stock) and Raw Anthracene Oil (light feedstock), and to make a preliminary assessment of the advantages and/or disadvantages of the Monolith catalyst over a commercial catalyst used in the petroleum industry. 

Removal of asphaltenes and preasphaltenes was easier than heteroatoms. At an increase of a hydrogen-to-carbon atomic ratio by 0.16, they were 80% removed. A comparison can be made with Synthoil process product of hydrogen-to-carbon atomic ratio equal to 1.04 which was hydrotreated to hydrogen-to-carbon atomic ratio equal to 1.24. The asphaltenes and preasphaltenes were 77% and 99% removed, respectively (7). Squires (8) concluded that the preasphaltenes can be converted to asphaltenes and oils with very little consumption of hydrogen. Asphaltenes are the major consumers of hydrogen. Although Squires conclusions were based on donor-solvent coal liquefaction, similar results were reported... 

Microstructure. The characterization of coal-derived asphaltene is quite similar to that of petroleum-derived asphaltene. Since it is anticipated that coal-derived asphaltene will have acid/neutral and base characteristics (26, 36), the average structure of both must be considered. In Table III, Structure I is amphoteric (or slightly basic), and Structure II is an acid/neutral representation. A mixture of both may be typical of the average structure of a coal-derived asphaltene. At present, we will illustrate this by an asphaltene obtained from coal liquid of the Synthoil process. (The coal is hvAb, West Kentucky, Homestead Seam the coal liquid is obtained by catalytic hydrogenation at 450° C and 4000 psig having %C, 86.7 %H, 8.38 %N, 0.93 %S, 0.09 %Q, 3.2 and %Ash, 0.7.)... 

The differences reflected in the two methods indicate the presence of amphoteric asphaltene compounds, an observation that is at odds with that reported by Sternberg et al. (7) for asphaltenes from the Synthoil process. The bases isolated by this ion exchange method correspond closely in amount to those isolated by the phosphotungstic acid scheme. 

Coal Liquids. Coal liquids from three feed coals and three liquefaction products from the Synthoil process were analyzed for PNA content (17). Data obtained from these coal liquids are presented in Table VII. Here, as in the case of the petroleum materials, the concentrations are in the ppm level. In general, liquefaction appears to decrease the level of 5-ring PNAs but significantly, at least in the case of Kentucky Homestead and Clearfield, Pennsylvania, coal, to increase the concentration of pyrene. 

The Synthoil process (Akhtar et al., 1975) (Figure 19.15) is a hydrodesulfurization process in which crushed, partially dried coal is mixed with process oil to form a slurry (35%-50% w/w coal) which is combined with hydrogen and charged (after preheating) to a fixed-bed reactor to produce a low-sulfur liquid product (Table 19.9). 

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