Can Cleaner Biomass Compete with Gas?

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Leaching Improves Economics of Fuel Production

Treated secondary biomass can generate energy at a cost comparable to that of natural-gas-fired power production, according to an EPRI study.

When biomass is combusted for energy generation or converted to liquid fuels, its inorganic constituents can result in corrosion, deposition of materials, and other equipment degradation. Treating biomass to remove these substances can reduce or eliminate these problems for a more cost-effective process.

Since 2010, EPRI and Thermorefinery Technologies have evaluated the effects of proprietary leaching and torrefaction processes on secondary biomass. They found that leaching removes all or most sulfur, chlorine, alkali metals, and phosphorus compounds, yielding a much cleaner feedstock for use in processes such as combustion, gasification, and fast pyrolysis. When tested in fast pyrolysis, the treated biomass demonstrated a significantly higher rate of conversion to liquid and gas fuels compared with untreated biomass. Treatment also increased the efficiency of fast pyrolysis, eliminated pollutants such as sulfur oxides, and significantly reduced the need for liquid fuel refining. The three streams produced in fast pyrolysis can be used for energy generation (gas stream), liquid fuels and chemical production (gas and liquid streams), and soil additives to promote crop growth (solid stream).

When factoring these enhancements, EPRI determined that the cost of biomass-based energy generation in an integrated leaching/flash pyrolysis/combustion plant can be competitive with natural-gas generation at a cost of $2.50 per million British thermal units.