Hydroliquefaction processes

Hydrocarbonization, or low-temperature carbonization under hydrogen pressure, is representative of a class of coal conversion processes distinctly different from the slurry hydroliquefaction processes and processes which synthesize liquid fuels from cr 1-derived synthesis gas. Hydrocarbonization technology is reviewed, and major process alternatives and problem areas are discussed. The present status and future prospects for hydrocarbonization are assessed. 

A large number of pyrolysis and hydroliquefaction processes have been and continue to be developed. Pyrolysis is commercial today in the sense that metallurgical coke production is a pyrolysis process. Hydroliquefaction is not commercial, because the economics today are unfavorable. 

Different types of other coal liquefaction processes have been also developed to convert coals to liqnid hydrocarbon fnels. These include high-temperature solvent extraction processes in which no catalyst is added. The solvent is usually a hydroaromatic hydrogen donor, whereas molecnlar hydrogen is added as a secondary source of hydrogen. Similar but catalytic liquefaction processes use zinc chloride and other catalysts, usually under forceful conditions (375-425°C, 100-200 atm). In our own research, superacidic HF-BFo-induced hydroliquefaction of coals, which involves depolymerization-ionic hydrogenation, was found to be highly effective at relatively modest temperatnres (150-170°C). 

Since the earliest days of coal liquefaction processing and research, the need for correlations of coal properties with coal reactivity under direct hydroliquefaction conditions has been recognized by coal scientists. This article traces the history of reactivity correlations from the earliest work of Bergius through the classic work at the Bruceton Bureau of Mines during the 1940 s to the most recent advances in this subject. Particular emphasis in this review is placed on an examination of the contributions of Professor Peter Given and his co-workers. Reactivity methodologies and techniques for correlation are presented and critically evaluated for utility and applicability as predictive tools. 

The conversion of polar asphaltenes (lumped with non-eluted asphaltenes) as a function of process severity, expressed by hydrogen content in the liquid product, is shown in Figure 7. Amocat IB and HDS-1443 show a significantly high conversion of polar asphaltenes at a given process severity. It is worth noting that Amocat IB and HDS-1442, the Co-Mo version of HDS-1443, have been found to be active catalysts for coal hydroliquefaction (4). 

Many reaction schemes have been proposed to interpret the results of hydroliquefaction experiments following the pioneering work of Weller et al. in 1951 (9). Factors to be taken into account when considering the complex liquefaction process include... 

The hydroliquefaction of coal in the Bergius process is not a simple reaction or process in fact, it involves a series of organometallic transformation, such as insertion, migration, and reductive elimination. Therefore, only a small part of the reaction scheme is displayed here to show a possible conversion. 

Bergins (1) A coal liquefaction process (also called hydroliquefaction) invented in Germany in 1913 by F. Bergius and subsequently developed by IG Farbenindustrie. The inventor, together with C. Bosch, was awarded the Nobel Prize for chemistry for this invention in 1931. A pilot plant was operated at Rheinau near... 

There are many references that discuss and evaluate processes for the production of chemicals from coal. A typical flow sheet for a plant is shown in Fig. 17.34. This Coal Refinery used hydroliquefaction, pyrolysis, and gasification and produces a product slate as shown in Fig. 17.35. The acronym POGO refers to Power Oil Gas Other, a project of the U.S. Department of Energy. 

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