Sub-department of Environmental Technology, Wageningen University, Bomenweg 2, Wageningen, The Netherlands.
Water Sci Technol. 2011;64(3):647-53. doi: 10.2166/wst.2011.664.
Conventional anaerobic digestion is a widely applied technology to produce biogas from organic wastes and residues. The biogas calorific value depends on the CH, content which generally ranges between 55 and 65%. Biogas upgrading to so-called 'green gas', with natural gas quality, generally proceeds with add-on technologies, applicable only for biogas flows > 100 m3/h. In the concept of autogenerative high pressure digestion (AHPD), methanogenic biomass builds up pressure inside the reactor. Since CO2 has a higher solubility than CH4, it will proportion more to the liquid phase at higher pressures. Therefore, AHPD biogas is characterised by a high CH4 content, reaching equilibrium values between 90 and 95% at a pressure of 3-90 bar. In addition, also H2S and NH3 are theoretically more soluble in the bulk liquid than CO2. Moreover, the water content of the already compressed biogas is calculated to have a dew point <--10 degrees C. Ideally, high-quality biogas can be directly used for electricity and heat generation, or injected in a local natural gas distribution net. In the present study, using sodium acetate as substrate and anaerobic granular sludge as inoculum, batch-fed reactors showed a pressure increase up to 90 bars, the maximum allowable value for our used reactors. However, the specific methanogenic activity (SMA) of the sludge decreased on average by 30% compared to digestion at ambient pressure (1 bar). Other results show no effect of pressure exposure on the SMA assessed under atmospheric conditions. These first results show that the proposed AHPD process is a highly promising technology for anaerobic digestion and biogas upgrading in a single step reactor system.
传统的厌氧消化是一种广泛应用的技术，可从有机废物和残渣中生产沼气。沼气的热值取决于 CH4 的含量，一般在 55%至 65%之间。沼气升级为所谓的“绿色气体”，具有天然气质量，通常需要附加技术，仅适用于> 100m3/h 的沼气流量。在自增压高压消化（AHPD）的概念中，产甲烷生物质在反应器内建立压力。由于 CO2 的溶解度高于 CH4，因此在较高压力下，它将更多地分配到液相中。因此，AHPD 沼气的 CH4 含量较高，在 3-90 巴的压力下达到 90-95%的平衡值。此外，H2S 和 NH3 理论上在主体液体中的溶解度也高于 CO2。此外，已经压缩的沼气的含水量计算出露点<--10°C。理想情况下，高质量的沼气可直接用于发电和供热，或注入当地的天然气分配网络。在本研究中，使用乙酸钠作为底物和厌氧颗粒污泥作为接种物，分批进料反应器的压力增加到 90 巴，这是我们使用的反应器的最大允许值。然而，与在环境压力（1 巴）下消化相比，污泥的特定产甲烷活性（SMA）平均下降了 30%。其他结果表明，在大气条件下评估的压力暴露对 SMA 没有影响。这些初步结果表明，所提出的 AHPD 工艺是一种在单步反应器系统中进行厌氧消化和沼气升级的极具前景的技术。
