Pilot-Scale Comparison of Steam Gasification with Herbaceous and Woody Feed stocks, Research proposal

Background

Production of renewable transportation fuels from biomass has become an important priority to reduce the nation's dependence upon imported oil and minimize the impact upon the environment. However, a sustainable biofuels economy will require conversion processes that utilize the lignocellulosic components of plants so as not to compete with food production. [2] This research focuses on developing processes that use a variety of feed stocks, such as agricultural residues, waste from forest thinning, and energy crops. Biomass gasification combined with catalytic synthesis has the potential to meet these criteria. This approach can potentially produce alcohols or Fischer-Tropsch fuels from a variety of biomass sources. [3]

Key to the economic viability of gasification/catalytic synthesis processes is the production of a syngas with low concentrations of products which interfere with the catalytic step, such as methane, tars and sulfur compounds. [4] Catalysts play a role in producing clean gas. For instance, dolomite is a suitable catalyst for the removal of hydrocarbons while Alkali catalysts reduce tars significantly. Commercially available Nickel catalysts are effective at removal of hydrocarbons and adjustment of syngas quality. [1] Developing an understanding of the formation of these species as a function of feedstock is critical for evaluating and optimizing gasification.

Methodology

In this study, steam gasification will be conducted on pilot scale of mixed hardwoods, corn Stover, switch grass and wheat straw. Process conditions such as steam-to-biomass ratio and temperature are investigated and their effects upon product formation. Real-time measurements of gaseous products will be gathered, including sulfur compounds. The chemical composition of the tars formed will be monitored in real time using a Molecular Beam Mass Spectrometer (MBMS). The process and unit operations, operational lessons-learned, and results from the experiments as they relate to the formation of undesirable products will be discussed.

Benefits

The research helps generate knowledge on processes for gasification wide variety of agricultural lignocellulosic feed stocks and hence helping in design of successful gasification units. This intern contributes a lot to advancement and competitiveness of the gasification.

The results of the study have also potential benefit in large scale development of gasification reactors that produce better quality gas and hence contributing a lot to increased use of gasification and biomass energy at national level.

The research also generates knowledge on optimum values of steam to biomass ratio and temperature to produce more and quality syngas. This helps determine the economical variability of the technology and gives insights into the cost reduction ways.

References

1. David Sutto et.al, 2001, Review of literature on catalyst for biomass gasification, Fuel processing technology, Elsevier publications

2. Biomass research and development board, 2008, National biofuels action plan, http://www1.eere.energy.gov/biomass/ as accessed Nov 2, 2009

3. Rapagna S et.al, 1998, Catalytic gasification of biomass to produce hydrogen rich gas, Volume 23, No.7, Elsevier