High-methane gasification of fuels from waste – Experimental identification

The paper presents experimental research on innovative technology of RDF fuel produced from combustible waste (other than hazardous) gasification. The gasification process was performed in the compact bed, in the laboratory tubular gas generator with a power of 5 kW. In the first place RDF fuel, not enriched with methane, was gasified with addition of Bio-CONOx. Next, cogasification was performed with 10, 15 and 20% addition of methane-forming formulation. The results indicated that the addition of Bio-CONOx to the fuel resulted in an increase in the content of CH₄ in the syngas (8% - without addition of Bio-CONOx to 18% CH₄ with 20% addition of Bio-CONOx). At the same time there was an increase in shares of other combustible components of syngas (CO and H₂). Enriching fuel with the additive Bio-CONOx increased the calorific value of the syngas LHV from 4 MJ/Nm³ (RDF) to 9 MJ/Nm³ (RDF fuel with 20% addition of Bio-CONOx). Studies have shown that the increase in efficiency of the gasification process has been obtained by setting the process conditions in a tubular reactor, i.e. temperature decomposition: 400–450 °C in the layer of fuel and 800–850 °C in the gas zone above the layer of fuel. Such temperature distribution in the layer of fuel favors exothermic process of hydrogenation of CO and CO₂ to CH₄ form and evaporation and decomposition of fat fraction contained in methane forming supplement. At high temperatures over a layer of fuel (in the atmosphere of unreacted oxygen), some organic vapours (greases and tars) were burnt, and some underwent cracking.