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Title: Flash hydropyrolysis of coal. Progress report No. 7, July 1-December 31, 1978

Technical Report ·
DOI:https://doi.org/10.2172/5970669· OSTI ID:5970669

A considerable number of runs on the flash hydropyrolysis of lignite has been made and the data used in correlating the parametric study of the process chemistry. The production of gaseous hydrocarbons (methane and ethane) was studied as a function of the feed hydrogen to coal ratio. The gaseous yield was observed to vary with this ratio to the 0.18 power at pressures of both 1000 psi and 2500 psi. The rate of increase of gaseous yield was shown to be approximately 2 to 2.5% in yield for each 100 psi increase in pressure for H/coal ratios of both 1 and 0.25. The higher H/coal ratio produced an approximately 20% greater overall conversion than the lower ratio. Methane concentrations as high as 34.4% were produced in the process stream at a H/coal ratio of 0.23 and a temperature and pressure of 875/sup 0/C plus 2500 psi. This high methane concentration is 60% of the thermodynamic equilibrium concentrations under these temperatures and pressures. Further attempts were made to operate the system at pressures of 3000 psi where plugging of the unit had been experienced earlier using lignite. Two runs were conducted, one at 750/sup 0/C and the other at 825/sup 0/C and although in both cases the reactor eventually plugged, sufficient data had been collected to consider the experiment completed. The data generated by the parametric study of lignite has been correlated and activation energies for a first approximation of the reaction scheme are presented. These range from 88 Kcal/mol for the formation of ethane and 62 Kcal/mol for the formation of benzene to 29 Kcal/mol for the formation of methane, all from the feed coal. The mechanism appears to be largely chemical reaction rate controlled as opposed to diffusion controlled.

Research Organization:
Brookhaven National Lab. (BNL), Upton, NY (United States)
DOE Contract Number:
EY-76-C-02-0016
OSTI ID:
5970669
Report Number(s):
BNL-51010
Country of Publication:
United States
Language:
English