EFFECTS OF ALTERNATIVE PROCESS GASES ON THE THERMOCHEMICAL CONVERSION PROCESS OF SWINE MANURE

Abstract

A thermochemical conversion (TCC) process was developed to convert swine manure into an oil product in a hightemperature and pressure environment. The objective of this study was to examine the effects of different process gases,including CO, H2, CO2, N2, and compressed air, on the efficiencies of oil production and waste reduction, and to explore thepossibility of replacing costly reducing process gases, such as CO, with an inexpensive inert gas such as compressed air. Itwas found that the addition of a process gas to the reaction system before the experiment was critical for the TCC processto yield an oil product. Both reducing gases (such as CO and H2) and inert gases (such as CO2, N2, and compressed air) canbe used as a process gas. With the addition of reducing gases (i.e., CO and H2), the process yielded a better quality oil productand achieved a higher oil production efficiency. There were no significant differences in the chemical oxygen demandreduction rate among the five process gases mentioned above. The pressurized process created by water vapor alone did notyield an oil product. It is unclear why the inert gases of N2, CO2, and compressed air affected the oil product formation fromswine manure but water vapor did not.