Assessment of Hybrid Processes for Bio-Butanol Purification Applying Process Simulation

Bio-butanol production based on ABE (acetone-butanol-ethanol) fermentation is facing increasing interest as a transport fuel, since it offers significant advantages to other bio-fuels. However, to ensure an economic operation two bottlenecks has to be overcome: (1) high cost of the fermentation substrate, and (2) high energy demand for butanol purification via distillation due to low solvent concentration in fermentation broth. While first bottleneck might be overcome by the use of alternative feedstock like lignocelluloses or agro-food-wastes, the latter can be targeted by introducing hybrid purification concepts, combining in-situ removal techniques with distillation. Experimental and literature data based on lab-scale size experiments operated with synthetical fermentation broth are used to parameterize an Aspen Plus® simulation to predict the energy demand for biobutanol purification for three in-situ removal techniques coupled with distillation and to compare to a standalone distillation sequence: gas stripping, pervaporation and adsorption/desorption. Depending on the initial solvent content of fermentation broth, with 23.2 - 31.2 MJ/kg butanol the heat demand of the standalone distillation sequence is slightly below the energy content of butanol of about 36 MJ/kg. Applying gas-stripping and pervaporation before purification via distillation reduces the heat demand by 50 % to 13.6 - 16.8 MJ/kg and 12.0 - 14.5 MJ/kg butanol, respectively. Best result is shown by combining adsorption and distillation with an energy demand of 5.0 – 5.7 MJ/kg butanol. However, the advantageous low overall energy demand results from low efforts in the distillation step, only considering separation of butanol and water, but neglecting purification of acetone and ethanol obtained in ABE fermentation.European Union’s Horizon 202

Development of Honeycomb Methanation Catalyst and Its Application in Power to Gas Systems

Fluctuating energy sources require enhanced energy storage demand, in order to ensure safe energy supply. Power to gas offers a promising pathway for energy storage in existing natural gas infrastructure, if valid regulations are met. To improve interaction between energy supply and storage, a flexible power to gas process is necessary. An innovative multibed methanation concept, based on ceramic honeycomb catalysts combined with polyimide membrane gas upgrading, is presented in this study. Cordierite monoliths are coated with γ-Al2O3 and catalytically active nickel, and used in a two-stage methanation process at different operation conditions (p = 6–14 bar, GHSV = 3000–6000 h−1). To fulfill the requirements of the Austrian natural gas network, the product gas must achieve a CH4 content of ≥96 vol %. Hence, CH4 rich gas from methanation is fed to the subsequent gas upgrading unit, to separate remaining H2 and CO2. In the present study, two different membrane modules were investigated. The results of methanation and gas separation clearly indicate the high potential of the presented process. At preferred operation conditions, target concentration of 96 vol % CH4 can be achieved