Mixed Fuel Biomass

Anyone operating a biomass power plant recognizes the importance of achieving a stable power output in spite of fluctuations in the fuel supply. Power plants that can handle multiple fuels simultaneously, or indeed sequentially, for example both woody and straw biomass, offer greater flexibility and lower dependence on a single fuel source. However, when mixing fuels the variations in properties such as moisture content, ash content and fusion temperatures pose specific challenges to the plant performance and require modifications to the boiler design.

DP CleanTech has focused significant resources on optimizing the ‘mixed fuel’ or ‘multifuel’power plant solution which is typical for many requirements in emerging markets.

Type of Mixed Fuel Biomass

Mixed fuels, are by nature a combination of different types of biomass, in differing proportions and of different qualities, beyond this there are slight ambiguities related to how mixed fuel is process. Mixed fuels can be simultaneously combusted, or different fuel types can be combusted at different times.

Typical characteristics

The only typical characteristic is the non-homogeneous nature of the fuels and, most likely the variation in fuels over time. Mixed fuel usage is typically found in regions where fuel supply logistics are poor or poorly regulated, as well as in regions with harsh climatic conditions requiring alternative fuel sources in different seasons.

Implications

The design of the power plant must be able to handle the different feedstocks - from the storage barn to the feeding system, even before the combustion takes place. The specific boiler design must take account of the likely fuels, but may be referred to as a mixed fuel or a multifuel boiler design. DP will engineer dual feeding systems and make boiler modifications specific to the fuel mix. Today, DP CleanTech has over 40 mixed fuel power plants in operation around the world.