Attainable and Operating Regions for Production of Hydrogen from Biomass

The depletion of fossil fuels and the emission of greenhouse gases have led to a high demand for renewable and sustainable energy sources. Biomass is one such source, and its thermal conversion has the potential to produce hydrogen-rich syngas through gasification. This process involves the use of oxygen and steam as oxidising agents at high temperatures. The products obtained from biomass gasification are subjected to the Water Gas Shift (WGS) process, which helps in improving the quality of hydrogen. The objective of this study is to develop synthetic tools to optimize the reactor design of biomass gasification. This will be achieved by analysing the attainable and operating regions of the gasifier. These tools use mass and energy balances, partial pressures, and reaction equilibria to optimize outputs based on feed compositions and oxidising agent ratios in a gasification unit. The gas yield and hydrogen concentration both show a significant increase and then a decline as the reaction temperature rises. The maximum hydrogen concentration observed is 44.8 vol% at 950°C. Increasing the reaction temperature further results in high energy consumption and it suppresses the exothermic water gas shift reaction. It has been observed that hydrogen levels increase as steam is added to the gasifier. However, there is a decrease in hydrogen levels as the steam-to-biomass ratio increases beyond a certain point. An optimal ratio to maintain gasifier efficiency has been identified between 1.2 and 1.3. Before investing time and resources into pilot plants and experiments, it's beneficial to explore attainable and operating region techniques for viable hydrogen production from biomass gasification.