Biomass Combustion and Co-firing

Database of Biomass Cofiring initiatives

Database of Biomass Cofiring initiatives

Introduction

Over the past 5-10 years there has been remarkably rapid progress over in the development of cofiring. Several plants have been retrofitted for demonstration purposes, while another number of new plants are already being designed for involving biomass co-utilization with fossil fuels. IEA Bioenergy Task 32 has compiled a database to provide an overview of this experience. 

Typical power stations where co-firing is applied are in the range from approximately 50 MWe (a few units are between 5 and 50 MWe) to 700 MWe. The majority are equipped with pulverised coal boilers (tangentially fired, front-wall fired, back-wall fired, dual-wall fired and cyclone). Furthermore, bubbling and circulating fluidized bed boilers, cyclone boilers, and stoker boilers are used. Tests have been performed with every commercially significant (lignite, sub-bituminous coal, bituminous coal, and opportunity fuels such as petroleum coke) fueltype, and with every major category of biomass (herbaceous and woody fueltypes generated as residues and energy crops).

Basically one can distinguish three different concepts for cofiring biomass in pulverised coal boilers, all of which have already been implemented either on a demonstration or a fully commercial basis, and each with its own particular merits and disadvantages: 

  • Direct cofiring is the most straightforward applied, most commonly applied and low-cost of all. Biomass fuel and coal are burned together n the same furnace, using the same or separate mills and burners depending on the biomass fuel characteristics. 
  • In the concept of indirect cofiring, a biomass gasifier can be used to convert solid biomass raw materials into a clean fuel gas form, which can be burned in the same furnace as coal. This offers the advantages that a wider range of biomass fuels can be used (e.g. difficult to grind) and that the fuel gas can eventuall be cleaned and filtered to remove impurities before it is burned. Experiences with this option are rather limited. Examples are the Zeltweg plant in Austria and the AMERGAS project in the Netherlands.
  • Finally it is also possible to install a completely separate biomass boiler and increase the steam parameters in the coal power plant steam system.

More detailed information about the possibilities and limitations of cofiring are described can be found in a background paper, available here.


Wallarawang Power Station, Delta Electricity, Australia


Global database

IEA Bioenergy Task 32 has prepared a global overview of around 150 initiatives where biomass is cofired in boilers that use different types of coal as the main fuel. The dataset is available as a searchable database on this website.

This internet site contains a database that describes cofiring initiatives world-wide. Here, the following definition of cofiring has been used: 

Partial
substitution of coal as a main fuel
in a utility boiler with biomass or waste

This definition implies that the partial substitution of biomass with relatively small amounts of coal (also referred to as ‘reverse cofiring’), which is increasingly done in several fluidized bed installations in Scandinavia to decrease ash related problems in boilers, is not included in this overview.

 

Disclaimer:

The information in this database has been extracted from many different information sources and compiled in a structured way so that it can be easily evaluated. Task 32 of the IEA Bioenergy Agreement does not accept any liability related to incorrect representation or interpretation of the used data. 


Development of the database has been done in close collaboration with the other organsations represented in Task 32. In case you wish to see any additions or modifications, please contact Jaap Koppejan.

Version 2.0, © IEA Bioenergy Task 32, last updated in 2017

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