INVESTIGATION OF SLAGGING IN PULVERIZED FUEL COCOMBUSTION OF BIOMASS AND COAL AT A PILOT-SCALE TEST FACILITY

One option to reduce the CO2 emissions is biomass used for energy prod uction. Co-combustion of biomass in existing coal-fired power stations offers a great potential. In pulverized coal combustion facilities, o ne implementation problem is the tendency of slagging and fouling of b iomass. At the IVD, experiments were carried out to obtain information about biomass deposit characteristics in pulverized fuel (pf) co-comb ustion. This paper presents results from the IVD 0.5 MW pf combustion experimental facility obtained from different tests with coal-biomass mixtures ranging from small biomass shares up to a pure biomass firing . Samples of fuels, the fly ash path, deposition and slagging probes, and slags on furnace walls were taken. The amounts of deposits found o n probes inserted into the combustion chamber, their macroscopic chara cteristics, elemental composition and fusion temperatures were analyze d and compared. Generally, the deposits from the co-combustion experim ents softened in ash fusion tests like the main component (coal ash) r ather than like a mixture. When co-firing biomass with 25% of thermal input, no slagging was detected on cooled probes with 650 degrees C in the flue gas with 1050 degrees C. Most deposit samples from the probe s softened at higher temperatures compared to the laboratory-made ash and as expected for a mixture, but melted as mixtures are expected to. Slagging occurred on uncooled refractory samples, at higher biomass s hares, and when the biomass particles were not completely burnt out an d sticky when reaching the probes. Published by Elsevier Science B.V.