Patent DE-102007063091-A1 (DE)
Title: Method and device to produce biogas with high methane rate, by dosingly supplying hydrogen-producing bacteria, which are cultured in hydrogen and methane fermenter, and dosingly introducing gaseous hydrogen into methane fermenter
Inventor: AXMANN JUERGEN
IPC: C12P5/02
Filed: 2007-12-28
Abstract: The method and device for fermentatively producing biogas with high methane rate, comprise dosingly supplying hydrogen-producing bacteria (6d), which are cultured in a hydrogen fermenter (3) and in a methane fermenter (4), dosingly introducing gaseous hydrogen into the methane fermenter, dosingly supplying specially prepared organic material (6e) into the methane fermenter, which microfinely distributes the hydrogen and/or contains metastably bonded form, ensuring stable microorganisms with high loading rates (OLR greater than 2.5 kg(TS) m -> 3>d -> 1>) using an intelligent process controller. The method and device for fermentatively producing biogas with high methane rate, comprise dosingly supplying hydrogen-producing bacteria (6d), which are cultured in a hydrogen fermenter (3), and in a methane fermenter (4), dosingly introducing gaseous hydrogen into the methane fermenter, dosingly supplying specially prepared organic material (6e) into the methane fermenter, which microfinely distributes the hydrogen and/or contains metastably bonded form, ensuring stable microorganisms with high loading rates (OLR greater than 2.5 kg(TS) m -> 3>d -> 1>) and high specific gasification rate (GPR greater than 0.5 m 3>/kg(TS)) using an intelligent process controller, adjusting the organic supply, microorganism supply, additive supply and hydrogen introduction in a coordinated manner and ensuring stable microbiological situation using an adaptive controller, and carrying out an anaerobic fermentation using a combined pack-agitated anaerobic special hydrogen fermenter. The control is carried out on the basis of adaptive algorithms such as a model reference process using a self-tuning-regulator. The regulator uses the organic supply, microorganism supply, additive supply and hydrogen introduction into the methane fermenter, hydrogen gas concentration in the hydrogen fermenter and methane gas concentration in the methane fermenter as input parameters. The actual value of temperature or gas pressure is used as additional input parameters. The regulator uses the methane concentration and the total gas quantity at the exit of the methane fermenter and/or a post-fermenter (8) as priority target parameter, and uses the quantity and time intervals of the organic supply and the hydrogen introduction as priority correcting variables. The additive supply into the fermenters is used as secondary correcting variable, which receives with a weighting factor of less than 1 in the error computation of the control deviation. A high specific biogas gasification rate (GPR s p e zgreater than 0.5 m 3>/kg o(TS)) is reached with a hybrid fermenter with simultaneous low retention time (HRT less than 20 d), high loading rate (OLR greater than 3.0 kg o(TS) m -> 3>d -> 1>) and stable microbiological situation indicated by the pH value of 7.2-7.7. The hydrogen-producing microorganisms are Escherichia coliand/or Lactobacilli-containing mixed culturesand Clostridia-containing mixed cultures, which are selected, enriched and/or concentrated by a special conditioning process, and is cultured in the special hydrogen fermenter. The hydrogen fermenter is disposed over a fluidized bed construction present in the lower half of a container and over paddle stirring blades. The fluidized bed construction is flowed through with gas from downside. The gas is introduced over an injection device. The paddle stirring blades are placed on a vertically arranged agitator axis. One of the paddle stirring blades is positioned above the fluidized bed. The hydrogen fermenter is disposed to an inlet present in the bottom area of the container. A substrate is supplied over the inlet, so that the fluidized bed flows through from downside. An outlet is present itself in the upper third of the container. The process is a wet fermentation process. The hydrogen fermenter and the methane fermenter are coupled with one another regarding the substrate flow. The combination of the hydrogen fermenter and the methane fermenter is indicated as the hybrid fermenter. Several hydrogen fermenters are switched in rows. The base materials of the bacteria and the organic material are completely or partially injected into the subsequent hydrogen fermenter. The different hydrogen fermenters are exposed with different operational parameters (adjusted pH value, temperature, OLR and HRT) over the regulator. The organic material added into the methane fermenter consists of a mixture of organic acids or pure carbonic acids such as acetic acid and lactic acid, and cellulose. The added organic acids are fermentatively produced, and are produced from plant raw and residual material by fermenting biomass. The introduced hydrogen is produced from renewable sources by fermenting biomass. The introduction of the hydrogen into the methane fermenter is carried out in liquid-phase bonded form or in the gaseous state. The microbiological process stability is controlled over a laser-optical infrared sensor for on-line measurement of organic acids and content of dry substances.