Coal liquefaction using donor solvents hydrogenated at low temperatures
Direct coal liquefaction proceeds initially through a complex series of bond breaking and hydrogen transfer reactions involving coal and a donor solvent. When the recycle solvent contains high amounts of donor solvent, the requirement for high hydrogen gas pressure in the initial stage of liquefaction is reduced and coal conversion is augmented. Effective tests for hydrogen donating ability of coal derived solvents often consist of GC/MS, proton NMR, catalytic dehydrogenation, as well as microautoclave coal liquefaction testing [1,2,3]. Microautoclave testing is an empirical measure of solvent quality for hydrogen donation using coal, a donor solvent and an inert gas instead of hydrogen. Previous studies [4] have investigated the hydrogen transfer cycle for direct liquefaction using Illinois {number_sign}6 high volatile bituminous coal and a distillate (650{degrees}F-770{degrees}F) derived from a coal liquefaction process solvent. The objective of this work is to determine the effects of donor solvent on coal conversions in microautoclave liquefaction experiments performed at 400{degrees}C with Wyodak coal. These tests used a heavy distillate solvent that had been hydrogenated with a synthesis gas (50% carbon monoxide:50% hydrogen) mixture and steam at low temperatures (300{degrees}C-325{degrees}C). The in situ water-gas shift (WGS) reaction provides an alternate source of hydrogen and has the potential of eliminating the need for high purity high pressure hydrogen for solvent hydrogenation. Hydrogenation at low temperatures can lead to increased donor content since larger amounts of hydroaromatics are produced at equilibrium with any given hydrogen pressure. Distillate solvents were hydrogenated at various weight hourly space velocities, using two different catalysts and used in microautoclave coal liquefaction tests to evaluate solvent pretreatment effects on coal solubility.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 10123748
- Report Number(s):
- SAND--92-2582C; CONF-930304--3; ON: DE93006292
- Country of Publication:
- United States
- Language:
- English
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