Biogas Plant Concepts

Biogas Plant Concepts Danish Cooperative Biogas Plant Differences in WW characteristics for different product processing W.W Unit Ethanol COD mg/l 250,000 180,000 90,000 BOD5 mg/l 100,000 4.4 pH Distillery Palm Palm Starch Starch 32,000 16,000 8,500 50,000 30,000 20,000 8,000 5,000 4.5 4.5 4.0 3.9 Food 2,500 5.4 UASB Principle Schematic diagram of fixed bed reactor Fixed Film Reactor The Covered Lagoon at a Pig Farm Aerobic treatment after the covered lagoon Plug Flow Digester and UASB at a Thai Pig Farm Screening of WW from Starch Processing Starch WW after Screening Anaerobic Covered Lagoon Starch Mill Sludge Settling in Covered Lagoons Digester efficiency COD/CH4 Recommended HRT kg COD/kg biomass 60-70 % (1 stage digester) 0.32 m3 CH4/kg COD 25 days ~ 0.93 kg/kg WW flow in m3 * (COD inlet - COD outlet) - m3 CH4/0.32 = If the difference between COD in, and COD out, is not converted to CH4, sludge is building up in the digester ~ 0.93 kg biomass/kg COD not removed or converted, will build up and slowly reduce the active volume of the digester Biogas system at Asian Palm Oil Fluidized Sludge Bed Reactor Palm Oil Mill Effluent (POME) Advanced Agitated Covered Lagoon Flowmaker to keep Solids Suspended Distillery Effluent Distillery Biogas Plant Industrial WW digestion problems Problem Solution Too high COD of your WW at the digester inlet will give your digester constipation Equalization tank with mixing of digested WW Too Low pH value at the digester inlet, Equalization tank with mixing of will inhibit/kill the anaerobic bacteria in digested WW the digester Your EQ tank smells like your old sports shoes Forming of long chained fatty acids, like butyric acid, will inhibit the anaerobic digestion The HRT in your EQ tank is too long, results in the forming of long chained fatty acids Reduce the EQ tank seize Sludge build up in your digester Keep solids suspended Make circulation between outlet and inlet, High Sulfate content in the WW at the Aerate the WW with e.g disk digester inlet, will create H2S and aerators, before the EQ tank; inhibit the COD turnover in the digester collect and flare the H2S produced COD turnover and gas production in the digester will increase Danish average is 25 m3 of digested manure/ha each crop Thank You for Your Attention ... Biogas system at Asian Palm Oil Fluidized Sludge Bed Reactor Palm Oil Mill Effluent (POME) Advanced Agitated Covered Lagoon Flowmaker to keep Solids Suspended Distillery Effluent Distillery Biogas. ..Danish Cooperative Biogas Plant Differences in WW characteristics for different product processing W.W Unit Ethanol