Anaerobic Digestion with CO2 separation¤
Introduction¤
Anaerobic digestion is a biochemical process that is used to break the biogenic carbon of wet biomass and release it in the form of biogas, a gaseous mixture of CH4 and CO2. Digestion of wet biomass under anaerobic conditions is realized with the aid of suitable bacteria and proceeds through a complex series of (bio-)chemical reactions that can be grouped in four main stages, namely hydrolysis, acidogenesis, acetogenesis and methanogenesis. A set of parameters including the temperature and pH are decisive for the efficient operation of anaerobic digestion. In particular, three types of bacteria are used depending on the temperature of operation: thermophilic (45-55 °C), mesophilic (25-45 °C) and cryophilic (below 25 °C). The production of methane is directly linked with the type of the employed bacteria and is positively affected by temperature; a direct compromise between methane production and energetic demands to sustain the operating temperature to levels above room temperature. Anaerobic digestion results also to a liquid by-product stream, the digestate, which contains all undigested biomass as well as the valuable nutrients originally in the feed stream. Due to the latter, digestate streams are mostly used nowadays as soil fertilizers. However, the high carbon content of this residual stream leaves room for additional retrieval in the form of fuels by hydrothermal treatment. The energy efficiency of anaerobic digestion greatly depends on both the nature of the digested biomass as well as the operating conditions. Together, they define the methane potential for each case (i.e. the produced volume of methane per mass unit of digestible matter). As the energetic content of methane is the only source of contained energy in the output biogas stream, the methane potential is a crucial parameter to define the energy efficiency of the process.
ES Model Parameters¤
All the parameters concerning the An. Dig. are listed in the table below.
| entry_key | value | unit | sets | source_reference |
|---|---|---|---|---|
| CO2_A (layer) | 1.0604 | kt/GWh | Pöschl, Martina; Ward, Shane; Owende, Philip, (2010): "Evaluation of Energy Efficiency of Various Biogas Production and Utilization Pathways" | |
| SNG (layer) | 1 | - | Pöschl, Martina; Ward, Shane; Owende, Philip, (2010): "Evaluation of Energy Efficiency of Various Biogas Production and Utilization Pathways" | |
| WET_BIOMASS (layer) | -3.3462 | - | Pöschl, Martina; Ward, Shane; Owende, Philip, (2010): "Evaluation of Energy Efficiency of Various Biogas Production and Utilization Pathways" | |
| c_inv | 1053 | MCHF/GW | Ro, Kyoung S.; Cantrell, Keri; Elliott, Douglas; Hunt, Patrick G., (2007): "Catalytic Wet Gasification of Municipal and Animal Wastes" | |
| c_maint | 93.91 | MCHF/GW/yr | Ro, Kyoung S.; Cantrell, Keri; Elliott, Douglas; Hunt, Patrick G., (2007): "Catalytic Wet Gasification of Municipal and Animal Wastes" | |
| c_p | 1 | - | Pöschl, Martina; Ward, Shane; Owende, Philip, (2010): "Evaluation of Energy Efficiency of Various Biogas Production and Utilization Pathways" | |
| gwp_constr | 0 | kt/GWh | Pöschl, Martina; Ward, Shane; Owende, Philip, (2010): "Evaluation of Energy Efficiency of Various Biogas Production and Utilization Pathways" | |
| lifetime | 25 | y | Pöschl, Martina; Ward, Shane; Owende, Philip, (2010): "Evaluation of Energy Efficiency of Various Biogas Production and Utilization Pathways" | |
| ref_size | 0.0004 | GW | Ro, Kyoung S.; Cantrell, Keri; Elliott, Douglas; Hunt, Patrick G., (2007): "Catalytic Wet Gasification of Municipal and Animal Wastes" | |
| trl | 9 | - | Pöschl, Martina; Ward, Shane; Owende, Philip, (2010): "Evaluation of Energy Efficiency of Various Biogas Production and Utilization Pathways" |
References¤
| Data Sources |
|---|
| Pöschl, Martina; Ward, Shane; Owende, Philip. (2010). "Evaluation of Energy Efficiency of Various Biogas Production and Utilization Pathways". Applied Energy. https://doi.org/10/fwz87p ⧉ |
| Ro, Kyoung S.; Cantrell, Keri; Elliott, Douglas; Hunt, Patrick G.. (2007). "Catalytic Wet Gasification of Municipal and Animal Wastes". Ind. Eng. Chem. Res.. https://doi.org/10/dwprds ⧉ |