ADM1 simulations of hydrogen production

Hydrogen can be produced by fermentation of organic wastes as a renewable CO2 emission free fuel. The production potential as a function of feed composition is investigated using the ADM1 and experimental data from the literature. Lactate and ethanol are included in the model as intermediates to simulate the bio-hydrogen production processes more closely. Simulated effects of carbohydrate to protein ratio in the feed on pH, H2, biomass and fatty acid production using standard model parameters compare quite well with experimental results. The overall hydrogen and biomass production corresponds well with measurements for some feeds and less for others. The maximum theoretical yield is significantly higher than the simulated and measured values and is highest when the feed consists of only carbohydrates. The analysis suggests that the modified ADM1 is capable of simulating the main mechanisms involved in biological hydrogen production processes, implying that the model can be used to identify, and find strategies to influence limiting factors in bio-hydrogen production processes. Model weaknesses regarding the acidogenesis processes are observed and areas for further improvements discussed.