[en] Highlights: • An innovative method of gasification with use of flue gas was investigated. • Gasification temperature ranging from 350 °C was considered. • Discussed gasification unit is connected to a power boiler. • Syngas with combustible components is recirculated to the boiler. • Wide range of biomass and waste fuels can be used as a feedstock. - Abstract: The paper presents results of the investigation of an innovative biomass and alternative fuel low-temperature gasification method before co-firing in industrial or power plant boilers. Before running industrial-size installation, laboratory tests were carried out to determine usability of alternative fuels to low-temperature gasification process. Tests were conducted in a laboratory reactor designed and constructed specifically for this purpose. The experimental stand enables recording of the weight loss of a sample and syngas composition. The process occurs for a fuel sample of a constant weight and known granulation and with a flue gas of known composition used as a gasifying agent. The aim of the laboratory research was to determine the usability of selected biomass fuel for indirect co-firing in power boilers and to build a knowledge base for industrial-size process by defining the process kinetics (time for fuel to remain in the reactor), recommended fuel granulation and process temperature. Presented industrial-size gasification unit has been successfully built in Marcel power plant in Radlin town, Poland. It consist an innovative rotary gasification reactor. Gasification process takes place with use of flue gas from coal and coke-oven fired boiler as a gasifying agent with recirculation of resulting gas (syngas) with combustible components: CO, H_2, CH_4. C_nH_m to the boiler’s combustion chamber. The construction of the reactor allows the use of a wide range of fuels (biomass, industrial waste and municipal waste). This paper presents the results of the reactor tests using coniferous wood pellets as a fuel. Presented tests confirmed a possibility of continuous low-temperature gasification in a rotary gasification reactor with combustion of a process’ products in boiler’s combustion chamber.

[en] Highlights: • Biomass grindability index based solely on mean mass diameters is unreliable. • Standard biomass grindability determination test should utilize volumetric samples. • Biomass grindability index should base on both energy consumption and fines increase. -- Abstract: The main objective of the research was to develop a method of biomass grindability determination (Biomass Grindability Index), which would allow for a clear classification of different types of solid biofuels in terms of their milling properties. The objective of the research included also the assessment of the possibility of adaptation of the existing coal grindability determination methods for evaluation of biomass milling. In the course of research, the biomass grindability determination method was modified to obtain the highest possible reliability of the developed index. The scope of laboratory tests being focused on influence of circumferential speed of test mill beaters, particle size distribution of sample, test time, mass and volume of sample. The results of laboratory and industrial tests have shown that the grindability index based on mean particle sizes of feed and product is unreliable. Grindability of different types of biomass, comminuted in beater mills, can be clearly determined by the index expressed as the ratio of energy consumption during the test to the amount of specified product size fraction. During the study laboratory test results obtained for proposed grindability index were compared to other grindability indices determined for utilized in research types of biomass.

[en] Highlights: • None of the additives show the tendency to As, Ni, Sb and Zn capture in the ash. • Ammonium sulphate captures and immobilises Cr and Cu in the bottom ash. • Halloysite is effective in Cd, Co, V and Mn capture in the bottom ash. • Kaolinite is the most effective in Pb capture. -- Abstract: Up to now, a few studies on the efficiency of heavy metal(-oid)s capture by a sorbent directly mixed with fuel, have been performed. For this reason, the main objective of the study is to determine whether or not such a solution is effective when RDF is incinerated. The paper presents a two-step analysis of the impact of three sorbents (ammonium sulphate, kaolinite and halloysite) in three dosages (2, 4 and 8 wt%) on heavy metal(-oid)s retention in the bottom ash. 12 heavy metal(-oid)s were taken into consideration - As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, V and Zn. Samples were incinerated in a lab-scale tubular reactor at two temperatures - 900 °C and 1100 °C. The first step of investigation constitutes ICP analysis of heavy metal(-oid)s content in the bottom ash, coupled with SEM/EDS analysis. Afterwards, the second step was to determine the stability of formed additive-heavy metal(-oid)s complexes via leachability tests in neutral and acid environments. The performed research has shown that ammonium sulphate is effective in Cr, Cu and Hg capture, halloysite – in Cd, Co, V and Mn capture, whereas kaolinite – in Pb capture.