Abstract
Heat balance of the charcoal kilns was calculated based on the measurement of temperature variations within the kilns. Temperature in kilns of two kinds of carbonization methods, (one is ODC, One Day Carbonization; the other is TDC, Two Days Carbonization), was measured, and the reusable heat of those methods were compared. The results are as follows:HomePage
(1) In TDC, the carbonization cycle is 72 hours, the carbon yield is 15%, of raw wood and the maximum temperature of carbonization is 950oC; and in ODC, those values are 43 hours, 10% and 940oC, respectively.
(2) The heating rate in the pyrolysis stage of ODC is 0.47oC¥min-1 faster than that of TDC. It plays an important role on the charcoal harvest of ODC Iower than that of TDC.
(3) According to the results of heat balance analyses in the kilns, the amount of exhaust heat out of TDC is 54.9% of total heat. On the other hand, that of ODC is 49.9%.
(4) The reusable heat per unit time of ODC is 70% higher than that of TDC. From that, the heat supply of ODC is more stable than that of TDC for heating greenhouse in snowy cold area.
(5) The reusable heat per input wood from TDC is more effective than that from ODC based on the heat balance analyses.
From these results, it is available to reuse the heat exhausted out of the charcoal kiln.Keywords: kiln, unutilized energy, exhaust heat, heat balance of carbonization, heating load, snowy cold area, biomass