The present study deals with modelling and validation of a planar Solid Oxide Fuel Cell (SOFC) design fuelled by gas mixture of partially pre-reformed methane. A 3D model was developed using the ANSYS Fluent Computational Fluid Dynamics (CFD) tool that was supported by an additional Fuel Cell Tools module. The governing equations for momentum, heat, gas species, ion and electron transport were implemented and coupled to kinetics describing the electrochemical and reforming reactions. In the model, the Water Gas Shift reaction in a porous anode layer was included. Electrochemical oxidation of hydrogen and carbon monoxide fuels were both considered. The developed model enabled to predict the distributions of temperature, current density and gas flow in the fuel cell.

The paper presents a thermodynamic analysis of the integration of a cryogenic air separation unit into a negative CO ₂ emission gas power plant. The power cycle utilizes sewage sludge as fuel so this system fits into the innovative idea of bioenergy with carbon capture and storage. A cryogenic air separation unit integrated with the power plant was simulated in professional plant engineering and thermodynamic process analysis software. Two cases of the thermodynamic cycle have been studied, namely with the exhaust bleed for fuel treatment and without it. The results of calculations indicate that the net efficiencies of the negative CO ₂ emission gas power plant reach 27.05% (combustion in 95.0% pure oxygen) and 24.57% (combustion in 99.5% pure oxygen) with the bleed. The efficiencies of the cycle without the bleed are 29.26% and 27.0% for combustion in 95.0% pure oxygen and 99.5% pure oxygen, respectively. For the mentioned cycle, the calculated energy penalty of oxygen production was 0.235 MWh/kgO ₂ for the lower purity value. However, for higher purity namely 99.5%, the energy penalty of oxygen production for the thermodynamic cycle including the bleed and excluding the bleed was indicated 0.346 and 0.347 MWh/kgO ₂, respectively. Additionally, the analysis of the oxygen purity impact on the carbon dioxide purity at the end of the carbon capture and storage installation shows that for the case with the bleed, CO ₂ purities are 93.8% and 97.6%, and excluding the bleed they are 93.8% and 97.8%, for the mentioned oxygen purities respectively. Insertion of the cryogenic oxygen production installation is required as the considered gas power plant uses oxy-combustion to facilitate carbon capture and storage method.

The paper aims to confirm the syngas application as a reburning fuel to reduce e.g. NO emission during natural gas combustion. The main aim of this modelling work was to predict pollutants generated in the exhaust gases and to indicate the influence of the syngas on the natural gas combustion process. The effect of residence time of fuel-air mixture was also been performed. Calculations were made with CHEMIKN-PRO for reburning process using syngas. The boundary conditions of the reburning process were based on experimental investigations. The addition of 5, 10, 15 and 19% of reburning fuel into natural gas combustion was studied. The effects of 0.001 to 10 s of residence time and the addition of 5, 10, and 15% of syngas on combustion products were determined. The performed numerical tests confirmed that co-combustion of the natural gas with syngas (obtained from sewage sludge gasification) in the reburning process is an efficient method of NOx reduction by c.a. 50%. Syngas produced from sewage sludge can be utilised as a reburning fuel.

In the paper the results of analysis of an integrated gasification combined cycle IGCC polygeneration system, of which the task is to produce both electricity and synthesis gas, are shown. Assuming the structure of the system and the power rating of a combined cycle, the consumption of the synthesis gas for chemical production makes it necessary to supplement the lack of synthesis gas used for electricity production with the natural gas. As a result a change of the composition of the fuel gas supplied to the gas turbine occurs. In the paper the influence of the change of gas composition on the gas turbine characteristics is shown. In the calculations of the gas turbine the own computational algorithm was used. During the study the influence of the change of composition of gaseous fuel on the characteristic quantities was examined. The calculations were realized for different cases of cooling of the gas turbine expander’s blades (constant cooling air mass flow, constant cooling air index, constant temperature of blade material). Subsequently, the influence of the degree of integration of the gas turbine with the air separation unit on the main characteristics was analyzed.