Deutscher Verein des Gas- und Wasserfaches (DVGW)-Research Center at the Engler-Bunte-Institut of Karlsruhe Institute of Technology (KIT), Engler-Bunte-Ring 1, 76131, Karlsruhe, Germany.
Karlsruhe Institute of Technology (KIT), Engler-Bunte-Institut, Engler-Bunte-Ring 9a, 76131, Karlsruhe, Germany.
Bioprocess Biosyst Eng. 2018 Nov;41(11):1561-1571. doi: 10.1007/s00449-018-1983-3. Epub 2018 Jul 12.
For an undisturbed operation of two-stage high-pressure fermentation up to 100 bar, a particle-free hydrolysate appears to be necessary. This is even more important if the second stage, i.e., the methane reactor, is designed as fixed bed. Here, we present the potential of microfiltration membranes as separation unit after the first stage, which is the hydrolysis. The study included the selection of membrane material, membrane performance investigations, and long-term-behavior during the filtration period. In a series of experiments, the optimum type of membrane material and the mode of operation [either crossflow (CF) or submerged (S)] were determined. Ceramic membranes proved to be the better option to treat the process stream due to their chemical and temperature resistance. The crossflow filtration achieved a sustainable flux of up to 33 L/(m h), while long-term experiments with the submerged membranes confirmed a critical flux of 7 L/(m h). Comparative analyses of hydrolysate and permeate showed that the rejected chemical oxygen demand (COD) as well as total organic carbon (TOC) fraction and thereby the loss of organic carbon in the permeate does not reduce the methane yield.
为了实现两段式高压发酵（最高可达 100 巴）的无干扰运行，似乎需要无颗粒的水解产物。如果第二阶段（即甲烷反应器）设计为固定床，则这一点更为重要。在这里，我们展示了微滤膜在第一阶段（即水解）之后作为分离单元的潜力。该研究包括膜材料的选择、膜性能的研究以及过滤期间的长期行为。在一系列实验中，确定了最佳的膜材料类型和操作模式（错流 [CF] 或浸没 [S]）。陶瓷膜因其耐化学性和耐高温性而被证明是处理工艺流的更好选择。错流过滤可实现可持续的通量高达 33 L/（m·h），而浸没膜的长期实验证实了 7 L/（m·h）的临界通量。对水解产物和渗透物的比较分析表明，被截留的化学需氧量（COD）以及总有机碳（TOC）分数，从而使有机碳在渗透物中的损失不会降低甲烷产量。
