Advisor(s) - Committee Chair
Laurence Boucher, Alan Leff, Rita Hessley, William Lloyd
Department of Chemistry
Master of Science
Low-temperature pyrolysis is the thermal degradation of coal in an inert atmosphere at temperatures below 700°C. Coal pyrolysis is well-studied, being a complex mix of many reactions. Pyrolysis is affected by changes in many different process variables, such as temperature, pressure and heating rate. Low-temperature pyrolysis is an old and well-studied process.
Chemical pretreatments have been used to beneficiate conversion processes, inducln pyrolysis. Nitration has not been one of them. Pyrolyzing a nitrated coal would, hopefully, rapidly devolatilize the coal and break up the matrix into more commercially usable products. The nitration procedure developed by The Standard Oil Company minimizes oxidation of the coal, reducing the adverse affects of such a treatment.
Lignite, both untreated and nitrated at two different levels, was pyrolyzed at temperatures of 250, 425 and 600°C, helium pressures of 0, 500, and 1000 psig, with sample masses of about 1, 3, and 5 grams. Residence times of 0.5, 1.5 and 2.5 hours were used. The yields of volatiles (gas), oils,asphaltenes, preasphaltenes, and char were monitored. The char was subjected to elemental analysis, and the pyrolysis gas was analyzed by gas chromatography.
Nitration does not appear to improve lignite lowtemperature pyrolysis substantially. Nitrated and untreated lignites the char nitrogen content is hydrogen content of the char not cause the expected rapid produce similar char and oil yields. After nitration raised substantially, and the is decreased. Nitration does devolatilization, nor does it substantially improve the quality of the off-gas. Nitration does de-ash and desulfurize the coal.
Chemistry | Physical Sciences and Mathematics
Spears, Dennis, "The Low-Temperature Pyrolysis of a Nitrated North Dakota Lignite" (1984). Masters Theses & Specialist Projects. Paper 2869.