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Title: Deuterium and carbon-13 tagging studies of the plasma pyrolysis of coal

Conference · · Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States)
OSTI ID:7269947

When coal is pyrolyzed in a high temperature plasma, acetylene is the principal hydrocarbon product formed; it was found, furthermore, that yields of acetylene in a hydrogen plasma are greater than in an argon plasma. In order to separate the process of hydrocarbon formation during coal pyrolysis from the subsequent quenching step, acetylene decomposition studies were carried out. Acetylene was injected into plasma streams of argon, helium, nitrogen, and hydrogen. In a hydrogen plasma virtually all the acetylene is preserved whereas in the other plasma streams more than half the acetylene is decomposed to carbon. In order to determine the role of hydrogen in preserving acetylene at high temperature, deuterium, as a chemically similar plasma, was used; it was found that ''acetylene'' in its C/sub 2/H/sub 2/, C/sub 2/HD, and C/sub 2/D/sub 2/ forms, was present in the same total concentration as when hydrogen was used as the plasma gas. In addition, tests with mixtures of C/sub 2//sup 12/H/sub 2/ and C/sub 2//sup 13/H/sub 2/ injected into a hydrogen plasma were made, and again identical ''acetylene'' concentrations were measured. The deuterium and C/sup 13/ experiments indicate that both C-H and C-C exchange occurs at high temperature and that hydrogen acts as a chemical preserver of acetylene during collision of acetylenic fragments on molecules during the quenching step. A statistical collisional process that occurs during the quenching of the acetylene or coal pyrolysis mixture explains the experimental results.

OSTI ID:
7269947
Journal Information:
Am. Chem. Soc., Div. Fuel Chem., Prepr.; (United States), Vol. 18:1; Conference: 165. meeting of the American Chemical Society, Dallas, TX, USA, 8 Apr 1973; Other Information: See CONF-730403--P1
Country of Publication:
United States
Language:
English