Methanol Production from Cow Dung

Abstract

The amount of agricultural biodegradable wastes generated in Nigeria is constantly on the increase. These wastes are mainly cellulosic materials from reared animal (feaces) and plants. The environmental awareness of most Nigerians is also far better than it used to be in about 30 years back. Accordingly, the paper considers economical use of one of this agricultural wastes-cow dung. The waste was anaerobically digested and acid treated in sequence to produce storable form of alternative energy, while the left over sludge could be used as a good quality farmland fertilizer. The quantities/qualities of methane gas and methanol produced were found to depend on slurry concentration, incubation period, pH value, operating temperature and carbon/nitrogen ratio of the dung. The gas chromatographic analysis conducted indicated that the unrefined biogas was determined to contain 57.23 mol% CH₄, 42.65mol% CO₂, 0.21mol% H₂S, 0.07mol% NH₃ and others. The refined biogas was analyzed and the composition was established to be: 59.45mol% CH₄, 14.65mol% CO₂, 0.11mol% H₂S, 0.04mol% NH₃ and others. This refinement was found to enhance the C/N ratio, making the organic component readily available for the acidic reaction. Spectroscopic analysis of the obtained liquid sample indicated formation of methanol. The purity of methanol produce was determined to be 92.5%, which compared slightly favorably with literature value of 98.9%. The boiling point and heat of combustion were found to compare favorably with literature values. The C/N ratio determined after the demethanization was found to be lower compared to the starting C/N ratio and the gang served as good source of manure.

Keywords- biomass, cow dung, fertilizer, methanol, renewable energy, methane, manure