For the dark fermentation (DF) most studies focus on either high productivity or high yield without investigating the impact it has on the technical and economical feasibility of the two-step biological process, which is what is covered in the present study. The Methogen from biomass production process, including pretreatment and gas up-grading (ammine-based), was investigated using the commercial flowsheeting software AspenPlus and the costing tool Aspen Process Economic Analyzer. Three Methogen base cases with different focus for the DF (high yield, high productivity and low nutrient) and one reference case with methane as the sole product are studied based on literature data as well as experimental data from partners at Lund University. A sensitivity analysis of important process conditions has also been performed.
The results from the study give new and important insights on the economical feasibility of the individual steps as well as the integrated process and a path forward will be presented.