Page 50 - Energize April 2022

TECHNICAL

Syngas cogeneration, combined

heat and power

INFORMATION FROM CLARKE ENERGY

yngas, also known as synthesis gas, synthetic gas or producer gas, can be produced Synthesis gas composition
from a variety of different materials that contain carbon. These can include biomass challenges
S(wood gas), plastics, coal, municipal waste or similar materials. Historically town gas The composition of syngas is highly
was used to provide a gas supply to many residences in Europe and other industrialised dependent upon the inputs to the gasifier.
countries. Gas engines utilising syngas as a fuel can be configured in a combined heat and A number of the components of syngas
power configuration in order to maximise the efficiency of the system. cause challenges which must be addressed
Syngas is created by the gasification or pyrolysis of carbonaceous materials. Gasification at the outset, including tars, hydrogen
involves subjecting these materials to high temperatures, in the controlled presence of levels and moisture. Hydrogen gas is
oxygen, with only limited combustion to provide thermal energy to sustain the reaction. much quicker to burn than methane,
Gasification can occur in man-made vessels, or alternatively could be conducted in-situ as which is the normal energy source for gas
in underground coal gasification (UCG). Where the fuel to the gasifier is of recent biological engines. Under normal circumstances,
origin, such as wood or organic waste, the gas produced by the gasifier is considered to be faster combustion in the engine cylinders
a renewable fuel and the power produced by its combustion is renewable. When the fuel would lead to the potential of pre-ignition,
to the gasifier is a waste stream, its conversion to power in this manner has the combined knocking and engine backfiring. To counter
benefit of the conversion of this waste into useful products. this challenge, the engine has a number
of technical modifications and the output
Benefits of syngas utilisation in gas engines of the engine is reduced to between 50 to
• Generation of renewable power 70% of its typically natural gas output (i.e.,
• Conversion of problematic wastes to useful fuels a 1063 kW engine running on natural gas is
• Economical onsite power production and reduced transmission losses comparable to a maximum 730 kW engine
• Reduction in carbon emissions on synthetic gas).

Figure 1: The gasification process

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