The relation between fuel and elemental composition of coal combustion by-products (CCB’s) has been developed with a new model: the KEMA TRACE MODEL®. This is an empirical and statistical model. This model is supported by roughly twenty mass balance studies conducted for 100% coal firing in the eighties and with the same amount from co-firing in the nineties. The results in the model give a good impression of the average composition of residues in the ash, as well as emissions into the air. These results of the KEMA model are used in official documents for discussions with governmental authorities, for Environmental Impact Statements (EIS) and in license applications.

Besides modeling, we are active in:

• quality control of CCB’s: sampling, fast  characterization tests, handling 
• thermo-dynamic calculations.   

Mineralogical, chemical and physical characterization is the first step toward assessing the opportunities of utilization of CCB's. Characterization has become of major importance to assess the influences of co-combustion on the properties and quality of CCB’s. For over 10 years KEMA has been involved in the characterization of CCB’s from co-combustion, using a wide range of methods like Scanning Electron Microscopy, X-ray-diffraction, and elemental analyses. 

Recently KEMA carried out co-combustion experiments in its 1 MWth KEMA test rig, to produce representative fly-ashes from high-percentage co-firing (more than 10% on a mass basis) of demolition wood, RDF and poultry litter. The fly-ashes produced were tested for their performance as a filler in concrete.

Read more about CCB's from co-combustion in the paper below: "Influence of co-combustion on the quality of coal fly ash".

In the Netherlands KEMA supports the Vliegasunie (Dutch Fly Ash Corporation) with research and consultancy on the implementation and utilization of coal combustion byproducts (CCB’s). The CCB’s are utilized in the Netherlands in the following applications:

Fly ash

• pozzolanic filler in cement and concrete
• raw material for the production of Portland clinker
• filler in asphalt
• raw material for ceramics.    

Bottom ash

• fine aggregate in concrete
• road construction.    

Gypsum

• raw material for the production of self-leveling floors and other building materials (gypsum).    

KEMA is also actively involved in studies to develop PFA as a raw material for zeolites, road construction, artificial lightweight aggregates and agricultural applications.

Implementation of demonstration projects

• setup of demonstration projects
• management and supervision
• monitoring of environmental and technical aspects.  

Implementation for regular utilization

• development and implementation of quality control systems, tests, standards etc. all specific to upgrading the process of CCB’s and its utilization
• troubleshooting
• development of standards. The Dutch recommendations for fly ash from co-combustion for use as a filler in concrete are mainly based on research by KEMA.  

For more information please contact us.