Technical requirements for bio-methane production from woody biomass and added value of hydrogen input in the process

Details

Supervisors

Jeanmart, Hervé

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil mécanicien, à finalité spécialisée

Abstract

This master thesis is rooted in the global challenge of renewable energy integration into energy mix. More precisely, it takes part in answering the question "How to overcome the intermittency of renewable energies". To this end, it studies the production of methanation by thermal process and its potential coupling with the production of hydrogen that can be produced thanks to renewable energies. To do this, a literature review was first carried out in order to collect data and to synthesise the theories of biomass gasification and syngas methanation processes. It was also concluded that the first is already well developed while the second is still in the research stage. Secondly, a model was developed to model the gasification process and the methanation process separately. These models are based on the equilibrium model. The first model is solved using the stoichiometric method, while the second model is solved using the non-stoichiometric method. These two models were coupled and used to model the whole process of bio-methane production from biomass, through gasification, methanation and finally to obtain bio-methane. Two cases were analysed. A first case where the gasification is done with oxygen as gasification agent and where a hydrogen supply has to be provided. A second case where the gasification is done with steam as gasification agent. The addition of hydrogen in the process of bio-methane production with oxygen gasification is well cost effective. The energy input contained in the hydrogen is well used and is largely recovered in the bio-methane. There is little loss of hydrogen and carbon in this case. The model predicts a CO2 methanation in the pre-methanation reactor for the vapor gasification leading to a large consummation of hydrogen and a small consummation of carbon monoxide. However, an observation of the gas composition before and after the pre-methanation reactor in GoBiGas lets think that in reality, the reactor does not behave like this. A CO methanation take place in the reactor. There are some limits of the model.