Combustion tests at pilot-scale combustion plants
Based on co-operations with Austrian furnace and boiler manufacturers pilot-scale combustion plants for combustion tests with various types of biomass fuels are available for BIOS. These combustion plants, which have especially been designed for the performance of such test runs, are based on moving grate combustion technologies and hot water boilers (180 and 350 kWth). Especially for the development of combustion technologies for “new” and regarding their combustion behaviour not well known biomass fuels, tests runs at these plants are of outstanding relevance with respect to fuel characterisation and the subsequent conception and design of real-scale plants.
Within dedicated test runs with the respective biomass fuel, which usually last for several days, plant operation data are collected by the process control system and additionally, samples from all relevant in-going and out-going streams are taken. Usually the following parameters are determined and samples are taken:
- flue gas composition,
- temperatures and volume flows of the flue gas in different plant sections,
- furnace and boiler temperatures,
- deposit formation in furnaces and boilers (applying deposit probes),
- particle size distributions, concentrations and chemical compositions of fly ashes and aerosols (fine particulates) in different sections of the plant,
- fuel and ash sampling and subsequent chemical analyses of the samples taken.
As a first step during the evaluation of the test runs, mass, energy and element balances over the respective plant are calculated. Based on these balances on the one hand a plausibility check of the measurement results is performed, and on the other hand, the behaviour of certain elements of interest is studied. In the following the results of the test runs are evaluated with special respect to the:
- combustion behaviour of the fuel investigated,
- formation of gaseous emissions (NOx, HCl, SOx, heavy metals),
- aerosol and fly ash formation,
- formation and chemical characterisation of ash deposits as well as evaluation of their potential for corrosion
- slagging behaviour of the ashes formed.
The data gained from these evaluations form an important basis for the characterisation of a new biomass fuel and also represent a starting point for the subsequent development, conception and design of an appropriate combustion plant including flue gas cleaning system which is tailored to the demands of the respective fuel.