Objectives

A promising route to achieve CO2 reduction is the use of short cycle carbon containing fuels, which can be classified as secondary fuels. These fuels have the potential to replace fossil fuels but operational and environmental problems may dramatically affect the combustion system. To focus on the problem of secondary fuel application one requires detailed in advance knowledge of the typical combustion behaviour of these fuels. The objective of this project is to provide simple, capable test methods, which give more insight in the fate of secondary fuel combustion in power plants. The achievement this knowledge on the preparation and combustion characteristics of secondary fuels is pre-competitive and can be used by any power plant operator or manufacturer in Europe.

Description of work

The BIOFLAM project consists of 4 Work Packages, which concentrate on Fuel Preparation (WP1), Fuel Conversion (WP2), Full Scale Experiments (WP3) and Evaluation and Dissemination of results (WP4). In WP1 the assessment of the grinding behaviour of blends of secondary and primary fuel in conventional coal pulverising systems is the primary task. WP2 concerns the development of characterisation methods for secondary fuels. Power generators and boiler manufacturers co-operate on a European level in WP3 to gather full-scale power plant experience. The critical assessment of the results and the possible application in industry is the major item of WP4. With 16 partners from 8 European countries this program covers a wide range of fossil fuel application in utilities throughout Europe and can be used as an input to other EU projects on alternative fuels.

Expected results

The aim of the project is to provide reliable methods to characterise the preparation and combustion performance of blends of coal and secondary fuels. This includes a detailed understanding of the fundamental processes, which are to be considered when using non-standard fuels together with coal. Besides the direct implications, which can be obtained from the numerous experimental investigations, the collected data are used for the further development of mathematical models, which can be used to predict the behaviour of an unknown fuel before application on industrial scale.

Achieved results after 1 year

The first step of the project was the determination of the secondary fuels, which were used by the partners. Every partner was involved in this selection process to cover the whole range of secondary fuels of interest to be used within the project on a European basis. It was agreed to use Wood pellets, Cacao shells, Paper sludge, Mushroom substrate, Waste wood, Sewage sludge, and Olive residue as secondary fuels. As primary fuels one lignite and two hard coals, which represent typical coals used in Europe for power production were selected. After the fuel selection process the technical facilities used in WP2, to execute the lab scale test were modified in order to fit with the requirements when using these variety of secondary fuels. This work is almost finished and preliminary investigations with the various secondary fuels have started. Simultaneously detailed mathematical modelling work has been started in order to be able to predict combustion behaviour of blends of secondary fuels with coal. In that respect the mathematical models for devolatilization and tar yield were adopted for the use with various secondary fuels since the chemical and physical structure of these fuels can differ substantially from that of coal. The validation of the modified mathematical models is still ongoing and at the moment it looks very promising.