Project objectives
  • Project objectives

Project objectives

The aims of the AshMelT project are:

I Development of a test method for the assessment of the ash melting characteristics of solid biofuels
II Specification of ash melting classes for solid biofuels
III Providing a draft for a European standard for the developed test method
IV Development of a proposal for the implementation of the procedure as testing reference in the ENplus® wood pellets label

To meet the above specified objectives laboratory experiments and combustion experiments are conducted by RTD institutions from all over Europe. Results are validated by external laboratories in a Round Robin test and by combustion tests conducted by RTD performers and boiler manufacturers. To achieve the mentioned aims the following objectives have to be fulfilled successively.

Specification of relevant parameters for an assessment of ash melting behaviour
All measureable parameters or allocable properties of biomass or biomass ashes that potentially provide information with regard to ash melting behaviour or slag formation will be summarised. For this purpose fuel properties like ash content, melting temperatures, elementary composition of biomass fuels and related indices or factors will be considered. Moreover, some qualitative information such as type o biomass can be taken into account too. Furthermore, the relevance of each particular parameter for evaluating the ash melting behaviour is to be estimated. A desktop study will be conducted summarising the state of the art. Also, results from previous and ongoing initiatives of the project partners will be taken into account in order to reach this objective.

Overview about state of the art of test methods, fuel classification and combustion tests regarding ash melting behaviour
In order to provide a sound basis for the scientific and technological work within the project, information about state of the art is to be gathered, compiled and summed up in a report.
State of the art of test methods: Information about available test methods, their measurement principles and – if available – their relevance regarding the assessment of ash melting behaviour will be compiled. Moreover, results from previous investigations of these methods and main conclusions will be summarised.
Fuel classification: Results and conclusions concerning the characterisation and classification of solid biomass fuels will be summarised, in particular with regard to ash melting behaviour.
Combustion tests: Available information about practical combustion tests evaluating the ash melting behaviour of solid biomass fuels will be gathered. Therefore, attention will be paid to experimental setup and procedure as well as methods for a quantitative evaluation of the formed slag.

Specification of ash melting classes for solid biofuels
Therefore, fuel classes are to be specified based on measurable and determinable parameters, describing at least two groups differing in their ash melting and/or slag formation properties. An initial classification system will be developed based on the state of the art summary. In the course of the project, information from experimental work is gathered and evaluated in order to improve the initial concept. The resulting fuel classification system will be validated by the results from round robin test and combustion experiments, respectively. An adequate classification system allows for a basic evaluation of the melting properties of solid biomass fuels.

Selection of three to four test methods for further detailed evaluation
A two step procedure is foreseen for the selection of the analysis method that will be developed. At first the most promising principles are chosen for practical evaluation based on the summary of state of the art of test methods. Moreover, the experiences of the participating research institutes will be considered. Secondly, one method will be selected based on the results of experimental work from laboratory tests and combustion tests, considering predefined evaluation criteria.

Optimisation of the selected test method for the characterisation of the ash melting properties of solid biomass
The selected method will be optimised based on the requirements identified during the laboratory experiments aiming at a maximum practical relevance (considering the results from the combustion tests and some benchmarking criteria like repeatability, reproducibility, time consumption, required operating materials. The optimisation procedure is based on a repeated cycle of optimisation measures and experimental validation within that work package.

Determination of the applicability of the defined fuel classes to different combustion technologies
Different combustion technologies in terms of grate systems and design of the combustion zone show considerable differences regarding their sensitivity towards slag forming fuels. Representatives of the most important technologies will be used for combustion experiments in order to evaluate and validate both an ash melting method and a fuel classification system. Thus, the applicability of the fuel classes to particular technologies will be determined.

Specifications of the range of application of fuel classes to the burner concept of SMEpartner Ligno
Ligno has developed a highly slag resistant novel auger burner that can be adapted to different fuel qualities. Combustion tests will be conducted in order to specify the range of application of fuel classes to the auger burner concept. Moreover, measures for an adequate adaption of the combustion system to the respective fuel classes will be identified.

Providing a description of a suitable test method for an assessment of the ash melting behaviour as a draft for an European standard
The whole method in terms of equipment, procedure and evaluation is to be described in an adequate quality, in order to fulfil the requirements of a testing standard. Basic requirements according to the testing standard will be defined in an early phase of the project and already be considered during method evaluation and development. Moreover, quality of the description and documentation of the method are validated in a round robin test. The practical relevance will be verified by combustion tests. The development of the draft standard will be done involving representatives from SMEs, SMEAssociations and in particular members of standardisation bodies.