Biomass steam gasification for production of SNG – Process design and sensitivity analysis

A process design for small-scale production of Substitute Natural Gas (SNG) by steam gasification of woody biomass is performed. In the course of this work, thermodynamic models for the novel process steps are developed and implemented into an already existing model library of commercial process simulation software IPSEpro. Mathematical models for allothermal steam gasification of biomass as well as for cleaning and methanation of product gas are provided by applying mass balances, energy balances and thermodynamic equilibrium equations. Using these models the whole process is integrated into the simulation software, a flowsheet for an optimum thermal integration of the single process steps is determined and energy savings are identified. Additionally, a sensitivity study is carried out in order to analyze the influence of various operation parameters. Their effects on amount and composition of the product gas and process efficiency are evaluated and discussed within this article.

► A model for the SNG-production process from biomass to raw-SNG is prepared.
► A thermodynamic equilibrium model of the Biomass-Heatpipe-Reformer is developed.
► A sensitivity analysis on the most important operation parameters is carried out.
► Adopting the steam excess ratio a syngas ideally suitable for SNG production is generated.
► Thermodynamic equilibrium models are a useful tool for process design.