Comparative Study of Products of Pyrolysis of Cow Dung and Poultry Litter

Abstract

In this work, comparative study of products of pyrolysis of cow dung and poultry waste was carried out and determined with a view to establishing their energy potentials.

A pyrolysis assembly that consists of brick furnace, condensate receiver, retort and gas collection unit was used. The moisture content of the residues and the weight of wood used for pyrolysis were determined. Sample of each residue was loaded into the retort and placed inside the furnace chamber for firing one at a time. The process of pyrolysis took 30 minutes. The products collected were each weighed and recorded. The pyrolytic gases collected were taken to laboratory for further analysis in order to establish the constituents of the gases.

The yields obtained for cow dung are 42.00 % for char, 35.66 % for the mixture of tar oil/pyroligneous   acid and 17.34 % for pyrogas. The corresponding values for the poultry litter in the order listed above are 47.33 %, 28.33 % and 24.34 % respectively. For the cow dung, the pyrogas consists of 56.67 % methane (CH₄) and 54.33 % propane (C₃H₈), while for the poultry litter the pyrogas consists of 22.89 % by volume of methane (CH₄), 17.35 % of propane (C₃H₈), 35.22 % of ethyne (C₂H₂) and 24.54% by volume of ethane (C₂H₈).The higher heating values obtained for the chars of cow dung and poultry litter were 32.42 and 39.30 MJ/kg respectively.

The results of this work showed that the two animal residues examined would make a good biomass fuel and they lent them easily to process of pyrolysis. However, findings show that the poultry litter indicates more positive attributes of biomass fuel than its cow dung counterpart. The poultry litter produced four different pyrogases as against the two produced by cow dung. Also, the higher heating value of poultry litter seems higher than the cow dung.