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Reduced volatile sulfur compounds emitted from e.g. livestock production and biogas production facilities contribute to general air pollution and local odour nuisance. Improved technologies are required to mitigate the emissions of both hydrogen sulfide and organic sulfur compounds. The present study examines the oxidative absorption of reduced sulfur compounds, i.e. hydrogen sulfide, methanethiol and dimethyl sulfide in a wet oxidation process with cupric chloride. It was found that this process efficiently removes both hydrogen sulfide and methanethiol with removal efficiencies >94% under all process conditions tested, while the removal of dimethyl sulfide was in the range 20–40%. The main products determined were dimethyl disulfide, dimethyl trisulfide and elemental sulfur. It was shown that the process was more efficient than the similar process with ferric ions and higher removal could be obtained with lower residence times. Furthermore, though employing cupric ion as metal catalysts results in the production of gaseous sulfur compounds, it is estimated that this process is efficient for deodorization due to the higher odour threshold values of the product compounds and the pH range is optimal for gas streams containing CO 2.

The dissolution of CuS particles with Fe3+ in acidic sulfate solutions was investigated in an oxygen-free environment. CuS particles, used in this study, were obtained from H2S removal operations from biogas with an acidic CuSO4 solution in a Vitrisol pilot absorber. The CuS particles were porous with an average diameter of 5.8 X 10(-6) m. Zero orders of reaction for both Fe3+ and H2SO4 were determined. Full conversion of CuS could be obtained independent of temperature. The activation energy was determined to be E-A = 22.0 kJ/mol. It seems plausible that the CuS dissolution reaction was affected by diffusion.

This paper deals with characterization of the oxyfuel combustion in a bubbling fluidized bed. The paper proposes a calculation procedure to evaluate gas flow streams, adiabatic flame temperature and concentrations of species in the flue gas. The second part describes a laboratory scale 30 kW oxyfuel BFB and presents results of experiments with various semi-oxyfuel and full oxyfuel modes. The results are compared with experimental results, the agreement is satisfactory with less than 10% relative difference. Sustaining of similar fluidization regime along all different cases resulted in decrease of the adiabatic flame temperature that had to be compensated by thermal volumetric load increase from 3.3 to 4.1 MW/m 3 .

Gas-dynamic perfection and intensity of heat exchange of intake systems determine the efficiency of the piston engine. The results of numerical simulation and experimental study of the heat transfer of gas streams in the intake system of engines having different configurations are presented in the article. Methods of modeling, experimental setup, geometric configuration of pipelines and measuring base are described in the paper. The investigations were carried out under steady-state air flow in the system. The results of mathematical modeling were verified using experimental studies. It is established that the use of profiled sections in the intake system leads to a decrease in the heat transfer rate up to 20 % at low air flow rates (up to 40 m/s) and an increase in the heat transfer rate up to 9 % at high speeds. © Published under licence by IOP Publishing Ltd. The work has been supported by the Russian Science Foundation (grant No. 18-79-10003).