| 摘要 |
<p>PURPOSE:To improve the yield ratio of methane in an anaerobic digesting tank, by operating a means for removing carbonic acid gas in response to each of values detected by a means for detecting the concentration of carbonic acid gas in digestive gas and a means for detecting the alkalinity of bicarbonate in digested sludge. CONSTITUTION:Sludge is supplied to a primary digesting tank 2 and left standing for 10-30 days under an anaerobic condition, so that it is decomposed by the action of anaerobes to form methane and carbonic acid gases. The digestive gas from which carbonic acid gas is removed by a means F4 for removing carbonic acid gas is circulated through a gas-circulating pipe 14 to the primary digesting tank 2 by a gas-circulating compressor 15. The concentration of carbonic acid gas in the digestive gas is detected by a densitometer 16 for carbonic acid gas, while the alkalinity of bicarbonate in the digested sludge is detected by an alkalimeter 17 for bicarbonate. The detected values of the concentration of carbonic acid gas and the alkalinity of bicarbonate are dispatched to a controller 18 to drive the means 4 for removing carbonic acid gas and a pump 19 for injecting a chemical liquid.</p> |
