This article discusses international practice to date in the operation of combined-cycle power plants (CCP) on blast-furnace gas (BG). It describes the most common schemes of BG use from the European list of the best available technologies for the metallurgical industry. Combined-cycle power plants in Japan and China are used as examples to demonstrate the technical-economic effectiveness of employing heatrecovery CCPs. The properties of blast-furnace gas are compared to the properties of other industrial gases. The energy potential of blast-furnace gas is calculated and compared to the potential of natural gas. The principles behind the upgrade of a standard gas-turbine power plant to burn blast-furnace gas are examined. The article also presents theoretical results obtained by the authors in the software package Thermofl ow to illustrate the effi ciency of burning blast-furnace gas in CCPs at Russian plants.

A gas turbine cycle working fluids group based on their production technology and application is presented. The energy parameters analysis procedure of unclosed and closed gas turbine cycles is described. The comparison of the effect of the working fluids thermophysical and thermodynamic properties variations on the useful work l0 of both unclosed and closed gas turbine cycles is presented. The effect of the fuel gas composition variation on the useful cycle work l0 is revealed. The effect of the working fluid thermophysical properties variation on the gas turbine cycle optimal combination of thermodynamic properties (T3 and P3 ) is presented.

Abstract. The impact of gases nonideality in the compression and expansion processes on the specific heat ratio and the heat capacity is analyzed. The specific heat ratio variation leads to temperature variation during compression in the compressor and expansion in the turbine and, consequently, the gas turbine cycle efficiency factor variation. It is also essential to consider the gases nonideality in the compression and expansion processes in the compression processes in compressor. Generally it is assumed during calculations that the heat capacities depend only on temperature, in this case the reference data presented by various authors differs markedly. In the real processes the heat capacity and the specific heat ratio depend on temperature and within the particular temperatures and pressures range depend on pressure. Consequently, the operating fluid nonideality in the gas turbine cycle should be considered. 1.Introduction The processes of gases compression in the noncooled compressor and expansion in the turbine can be assumed as adiabatic to a good approximation. Usually during the thermodynamic analysis of the processes mentioned above it is assumed that the operating fluid is an ideal gas with the thermophysical properties depending only on temperature.In real processes the heat capacity and, consequently, the specific heat ratio depend heavily on temperature and within the particular temperatures and pressures range depend on pressure, it means that the operating fluid nonideality in the gas turbine cycle should be considered.The thermodynamic efficiency improvement in the modern gas turbine units is achieved by means of the increase in the compression pressure ratio in the compressor and the combustion products' temperature rise before the turbine, which can result in the necessity of the gas nonideality consideration. For instance, the change of 2% in the specific heat ratio as compared to the k value being equal to 1.4 at the compression pressure ratio results in the change of 35 K and 30 K in temperature at the end of the compression process in the compressor and at the end of the expansion process in the turbine respectively, in this case the gas turbine cycle efficiency factor changes in 2%. Therefore the accurate determination of the specific heat ratio values is of high importance. 2.The pressure dependence of the specific heat ratio for the nonideal gas Usually during the calculations the heat capacity is taken to be not depending on pressure and the temperature dependences at the pressure of 0.1 MPa, presented in the guidelines [1][2][3] are used. It should be mentioned that sometimes the reference data presented by various authors differ markedly, as it is seen in Fig.1, where the dependences mentioned above are given for air.

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A description of the experimental rig is presented. The effect of combustion air high-temperature (up to 800°C) heating on the model artificial gas combustion process is described. The model artificial gas is a CO-N2 mixture. A comparison of the premixed and diffusion flame lower explosive limits is carried out. Experimental data are compared with open access published data of production of artificial gas-fired CCPP.