Operating temperature and retention time effects on the thermochemical conversion process of swine manure

A thermochemical conversion (TCC) reactor was developed to process swine ma nure for waste reduction and energy production. The operating temperature a nd retention time are the two key parameters affecting the process. Carbon monoxide (CO) was employed as the reductive reagent. The investigated range s of the operating temperature and retention time were 275 degreesC similar to 350 degreesC (corresponding operating pressures were 7 similar to 18 MP a) and 5 similar to 120 min, respectively. The pH value of the fresh swine manure (pH = 6.1), CO to VS ratio (CO: VS = 0.07 by weight or CO initial pr essure P-ini = 690 kPa), and total solids content (TS = 20%) were kept cons tant for all the experiments in this study. No extra catalyst was added in the experiments because of the presence of plentiful minerals and carbonate s. The operating temperature was the most important factor affecting the TC C process. No substantial oil product yield was achieved unless the tempera ture reached 285 degreesC or above. Temperature higher than 335 degreesC le d to solid char formation. Retention time affected the completeness of the TCC process. The retention time for achieving high oil yield and quality wa s largely dependent upon the operating temperature levels. The suggested op erating temperature and retention time for the TCC process are 295 degreesC to 305 degreesC and 15 to 30 min, respectively.