Influence of Aeration Rate on the Physio-Chemical Characteristics of Biodried Dairy Manure - Wheat Straw Mixture
2012
Sharara, M.A. | Sadaka, S. | Costello, T.A. | VanDevender, K.
Animal manure is a prime candidate for thermochemical conversion (co-firing, gasification, and pyrolysis) except for its high moisture content. Biodrying is a promising solution to reduce manure moisture with minimum energy input. This study investigated the effects of different aeration rates; low (0.05 L/min/kg VM ), medium (0.80 L/min/kg VM ), and high (1.50 L/min/kg VM ), on the biodrying of dairy manure mixed with wheat straw. The moisture content dropped in 21 days from 56% to 28%, 34%, and 35% wb under high, medium, and low aeration rates, respectively. The heating value of the mixture decreased from 16.19 MJ/kg dry to 14.31, 13.79, and 13.83 MJ/kg dry under high, medium, and low aeration, respectively. Evaluation of energy consumption to remove a unit mass of moisture showed that high aeration levels required the least energy input, 7.84 MJ/kg H2O , followed by low aeration at 7.93 MJ/ kg H2O , while the medium aeration had a relatively high energy cost for water removal, 9.09 MJ/ kg H2O . The high aeration level was superior in terms of both drying energy and time requirements to the other rates considered. Comparison showed that high aeration level biodrying (1.50 L/min/kg VM ) exceeded the range of conventional drying energy demand. However, the ratio of external fossil fuel demand was much lower in biodrying (due to the auto-thermal effect) than in conventional drying.
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