Gasification technology

The advantage of gasification compared to normal biomass combustion is the very compact equipment.

In combustion-based systems, the energy output is limited to production of hot water (e.g. for district heating) or steam for relatively low-efficiency processes (typically below 24% efficient), while in gasi-fication-based systems the efficiency may exceed 30%.

Updraft gasification

Gasification of biomass may be carried out according to several different schemes and we decided (in 1989) to base future work on updraft gasification. The reasons are:

• Updraft gasification is well proven technology (for peat and coal) and some information on design and operation was available from various sources.
• For updraft gasifiers a wide fuel mix and moisture content range is considered possible
• The updraft gasifier features a high carbon conversion and high cold-gas efficiency (a measure for transforming chemical energy from solid fuel into gas).
• High modulation range and fast modulation capability were reported as inherent in the technology.
• Information on “up-scalability” indicated that gasifiers based on this concept might be built in unit sizes up to about 20 MW fuel input.

Advantages of the gasification process

The advantage of the gasification process is that the inhomogeneous biomass waste is converted into a homogenous gas with a considerably higher level of applicability:

• The product gas may, without any cleaning, be used for gas-fired steam boilers combined with steam turbines or for increased steam superheating (and consequently higher power efficiency) at e.g. municipal solid waste energy plants.
• The product gas may, after a modest clean-up, be burned using low NOx gas burner technology in connection with indirectly fired power technologies (such as indirectly fired gas turbines and Stirling engines) with efficiencies exceeding 28%.
• After adequate clean-up the product gas may even be used for direct firing of gas turbines and gas engines (with a potential efficiency exceeding 32%), and in the future also for powering fuel cells (with efficiencies exceeding 40%).

A 1 MWth experimental gasifier was built at Kyndby, Denmark in 1989 in cooperation with Keramische Industrie Bedarfs in Berlin.

Read more about the gasification process

The Harboøre gasifier

On the basis of the experimental gasifier, a commercial plant was built in Harboøre Municipality (Jutland, Denmark) with a full-scale gasifier for the combined heat and power plant.

The development was supported by the Danish Energy Authority and ELKRAFT Power Utilities.

Read more about the Harboøre programme

Contact us for more information about gasification

If you wish to know more about our gasification solutions, please contact Thomas Hopp