| 摘要 |
The invention relates to a process for producing biogas from predominantly animal excrements, in particular liquid manure or chicken manure, individually or as a mixture. Proceeding from the disadvantages of the prior art, a process is to be provided which is distinguished by a higher yield of crude gas or biogas and also a higher content of methane in the crude gas and enables an economically improved mode of operation. In addition, the biogas produced is intended to have a very low fraction of nitrogen. The proposed process relates, inter alia, to the following measures: - fermentation substrate is mixed with reduced-ammonia fermentation liquid supplied at least in an amount via which a loading of 2.5 g of NH47I or below is set in the fermentation substrate, - the resultant fermentation substrate is subjected to a first fermentation during a time period from one to four days at a pH of below 6.5, wherein a hydrolysis and acidogenesis take place and a weak gas is produced as first biogas stream, - the fermented fermentation substrate is then pumped into a following fermenter and in this is subjected to a further fermentation, wherein further acidogenesis, acetogenesis and methanogenesis take place and in this process a second biogas stream having a lower hydrogen sulphide content than the weak gas is generated. |
