Investigation of the co-firing of natural gas and RDF in a model combustion chamber**

The production and utilization of fuel derived from municipal solid waste (RDF/SFR) is an effective method for saving organic fuel and decreasing emissions of harmful substances and greenhouse gases at landfill and refuse dumps. Ukraine has a potential for the production of 1.5–2 million tons of RDF/SFR with a calorific value of 10–25 MJ/kg annually. In the case of involving these fuels to power sector, about 2500 GW-h of electricity and 4500 GW-h of heat can be produced annually. One of the promising variants to involve RDF/SFR to power sector is their combustion, including co-firing with natural gas, aimed at the production of heat and electricity, in particular, using the existing boilers of small and middle steam capacity in compliance with stringent ecological requirements (Directive 2010/75/EU etc.). For performing this investigation, we chose a GMP-16 gas-and-oil-fired burner, mounted into a cylindrical combustion chamber. The gas-and-oil-fired hot-water boilers of KVGM grade, designed for heating and hot water supply, are equipped with burners of this type. In computer modeling, we determined the influence of RDF additions on the co-firing with natural gas for a given geometry of the combustion chamber components (with a burner of 18.6 MW heat output). We obtained calculated dependences of temperatures, velocities, distributions of gas component concentrations, carbon remained in the solid phase, as well as the concentrations of nitrogen oxides and carbon monoxide over the combustion chamber. According to preliminary assessments, we established that additions of up to 20% RDF/SFR (by heat at input) in their co-firing with natural gas will not change substantially the technical and ecological parameters in operation of the combustion chamber.