Mercury is a highly toxic metal which naturally occurs in the Earth’s crust and has adverse effects on both humans and the environment. The use of fossil fuels for electricity generation and specific industries sources of mercury emissions. These emissions depend on the mercury content in fuels of different types, the process gas temperature and composition, the implementation of air pollutant control devices (APCDs), etc. The APCDs partially capture and/or oxidize mercury in flue gas as a side benefit. In some cases, the emissions are reduced by mercury-dedicated or mixed methods. Mercury transformation in process gases is generally based on a chain of homogeneous and/or heterogeneous reactions. The theory of gaseous mercury/solid phase reactions and its mechanisms is widely studied in the literature. In this review, we focused on the theoretical and practical studies of these mechanisms, including mercury oxidization and capture from specified laboratory simulated or process gases and industries. We summarized research on various reactions – mostly of a chemical type – between different forms of mercury derived from process gases, and solids, including particles of different kinds (fly ash, adsorbents or catalysts). We additionally reviewed the literature on the interactions between mercury and sulfur compounds in the simulated and process gases.

The mathematical approach to SOFC modelling helps to reduce dependence on the experimental approach. In the current study, six different diffusion mass transfer models were compared to more accurately predict the process behavior of fuel and product diffusion for SOFC anode. The prediction accuracy of the models was extensively studied over a range of parameters. New models were included as compared to previous studies. The Knudsen diffusion phenomenon was considered in all the models. The stoichiometric flux ratio approach was used. All the models were validated against experimental data for a binary (CO-CO2) and a ternary fuel system (H2-15 H2O-Ar). For ternary system, the pressure gradient is important for pore radius below 0.6 μm and current density above 0.5 A/cm2. For binary system, the pressure gradient may be ignored. The analysis indicates that the MBFM is identified to be the best performing and versatile model under critical SOFC operating conditions such as fuel composition and cell temperature. The diffusive slip phenomenon included in MBFM is useful in SOFC operating conditions when fuel contains heavy molecules. The DGMFM is a good approximation of DGM for the binary system.

This study presents the results of tests on the mixing power and distribution of three velocity components in the mixing tank for an FBT impeller during tank emptying with an operating impeller. A laser PIV system was used to determine speed distributions. It was found that for the relative liquid height in the tank H* = H/H0 ≈ 0.65 and H* ≈ 0.45, the liquid circulation in the impeller zone changed from radial to axial and vice versa. These changes were accompanied by changes in the mixing power which even reached 40%. In the theoretical part, a method of calculating the mixing power using the classical model of the central vortex and distribution of the tangential speed in the impeller zone was proposed. Although the method turned out to be inaccurate, it was useful for determining the relative power.