Biomass Gasification and Syngas

Biomass-based gasifiers, such as the BioMax units, produce electricity and thermal energy from woody waste including wood chips from hard and soft wood, sawdust pellets, coconut shells, nut shells or corncobs.

The units heat these fuels with about one-third of the oxygen necessary for complete combustion to produce a mixture of carbon dioxide and hydrogen, known as syngas. Biomass energy accounts for about 11% of the global primary energy supply, and it is estimated that about 2 billion people worldwide depend on biomass for their energy needs.

Wood gasification seems to be catching on as a viable technology for avoidance of greenhouse gas emissions. It has many great uses. Some years ago wood gas was seen as cheaper by all means, but charcoal gasifiers had the edge were so much easier to handle. There are many gasifiers that produce gas from wood and then burn the gas, leaving ash and charcoal.

Wood chips can be fed into gasification plant gasifiers and the gas produced is used to light the furnace in the chamber. Woody biomass plants can show economics which are very local and can provide a secure return on investment in many circumstances. Technologies range from boilers, to gasifiers, to pyrolyzers, to just plain wood stoves. Wood gas can be used to power cars with ordinary internal combustion engines if a wood gasifier is attached. This was quite popular during World War II in several European countries because the armies active in the war did not always have access to oil.

Performance parameters such as air factor, feeding point position and bed height are determined by running trials and looking for a maximum gasifier efficiency and gas heating value and a minimum tar content in the gas. Other parameters which can be optimized by using CSFB software are the pressure drop, the bubble diameter and the gas velocities in the bed

Syngas, produced in gasification process plants, can be used as a fuel to generate electricity or steam, or as a basic chemical building block for a multitude of uses. When mixed with air, sit can be used in gasoline or diesel engines with few modifications to the engine.

Syngas is a mixture of hydrogen and carbon monoxide and it can be converted into fuels such as hydrogen, natural gas or ethanol. Syngas (which leaves the converter at a temperature of around 2,200 degrees Fahrenheit) is fed into a cooling system which generates steam. The gasification process converts feedstock such as coal, crude oil, petroleum-based materials or gases into marketable fuels and products.

Models range in size from 5-kW units for home use to 15-kW machines, enough to power a small business. The company is currently demonstrating six gasifiers in off-grid field applications. Modeling results are compared with the experimental results published in the literature. Predicted effects of bed temperature, equivalence ratio and fuel moisture content on main gaseous composition, tar and NH3 emissions generally agree with the literature data.

Syngas can be used for a multitude of uses. When mixed with air, it can be used in gasoline or diesel engines with few modifications to the engine.

The gasification process converts feedstock such as coal, crude oil, petroleum-based materials or gases into marketable fuels and products.

Steve Last