Method and device for operating a fermentation plant

摘要

A method for operating a fermentation plant with at least one digester (1) that is supplied with a substrate (1a). The substrate (1a) is percolated using a percolate (2a) from a percolate container (2) and biogas that is generated via the percolation process in the digester (1) or/and in the percolate container (2) is drawn off. The drawn off biogas is treated in a biogas treatment device (3) and the CO2-containing exhaust gas that is generated during the treatment is introduced into the digester (1) using a purge line (4), for forcing out and drawing off the biogas that was generated in the digester (1). Alternatively CO2-containing biogas that was generated in an additional digester (1) in a different fermentation process can be introduced into the digester (1) using a purge line (4) for forcing out and drawing off the biogas that was generated in the digester (1). The CO2-containing purge gas is supplied to the digester (1) such that the CO2-containing purge gas is forced to pass through the substrate (1a) dislodging any trapped biogas.

主权项

1. A method for operating a fermentation plant with at least one digester (1) into which a substrate to be digested (1a) is supplied, the method comprising:
percolating the substrate (1a) with a percolate (2a) from a percolate container (2), withdrawing biogas, containing methane and CO2, that is generated in the digester (1) or/and in the percolate container (2) during a fermentation period, treating the withdrawn methane and CO2-containing biogas in a biogas treatment device (3) to separate predominantly CO2-containing exhaust gas from said methane and CO2-containing biogas, and introducing said predominantly CO2-containing exhaust gas that is generated during treatment of the withdrawn biogas in the treatment device (3) into the digester (1) after the fermentation period, using a purge line (4), as CO2-containing purge gas, wherein the CO2-containing purge gas is introduced under pressure into a bottom region of the digester (1) and thus into a bottom region of the substrate (1a) through one or more purge ports such that any biogas that is present in the substrate (1a) is dislodged into the substrate-free volume (1b) of the digester (1) above the substrate (1a) for subsequent collection and removal.