Low manganese and sulfur gray irons were produced by adding inoculant base Fe-Si with small amounts of Al and Ca in the ladle. The effect of the cast thickness, inoculant amount and shakeout time of the green sand molds were studied on the graphite flake formation by microscopically techniques. A thermodynamic analysis was carried out for the cast iron produced with the FactSage 7.2 software. Stability phase diagrams were obtained for both gray cast irons to different manganese (0.1 to 0.9 wt.%) and sulfur (0.01 to 0.12 wt.%) amounts to 1150°C. It was shown that lower amounts of manganese and sulfur allow forming the 3Al2O3·2SiO2, Al2O3, and ZrO2 solid compounds. The thermodynamic results match with those obtained by SEM-EDS. It is possible to form MnS particles in the liquid phase when the solubility product (%Mn) × (%S) equals 0.042 and 0.039 for heats A and B, respectively.

This paper presents the results of thermodynamic analysis of the crude distillation units of two refineries in Nigeria. The analysis was intended to assess the thermodynamic efficiencies of the refineries and proffer methods of improving the efficiencies. Presented results show the atmospheric distillation units of the refineries have 33.3% and 31.6% exergetic efficiencies and 86.5% and 74.6% energetic efficiencies, respectively. Modifications of the operating and feed conditions of the refineries resulted in increased exergetic efficiencies for as much as 62.3% and 38.7% for the refineries. Thermodynamic analysis of the refineries can bring about efficiency improvement and effectiveness of the refineries.

Most satellites stationed in space use catalytic propulsion systems for attitude control and orbit adjustment. Hydrazine is consumed extensively as liquid monopropellant, in the thrusters. Catalytic reactor is the most important section in the catalytic thruster. Ammonia and nitrogen gases are produced as a result of complete catalytic decomposition of hydrazine in the reactor, causing an increase in temperature and a rise in specific impulse. Ammonia is subsequently decomposed, leading to nitrogen and hydrogen gases. Decomposition of ammonia leads to a decrease in temperature, molecular weight and specific impulse. The latter phenomenon is unavoidable. The effect of ammonia decomposition on the reactor temperature, molecular weight of gaseous products and conclusively on specific impulse was studied in this article. At adiabatic state, thermodynamic analysis revealed that the maximum and minimum temperatures were 1655 K and 773 K, respectively. The highest molecular weight was obtained at ammonia conversion of zero and the lowest when ammonia conversion was 100%. The maximum specific impulse (305.4 S) was obtained at ammonia conversion of zero and completely conversion of ammonia, the minimum specific impulse (about 213.7 s) was obtained. For specific impulse, the result of thermodynamic calculation in this work was validated by the empirical results.

One of the problems in Russia Power Sector strategy until 2035 is the technologies development for mitigation of harmful emissions by the heat and power production industry. This goal may be reached by the transition to environmentally friendly generation units such as oxy-fuel combustion power cycles that burn organic fuels in pure oxygen. This paper provides the results of research on one of the most efficient oxy-fuel combustion power cycle, which was modified by the usage of nitrogen for turbine cooling. The computer simulation and parametric optimization approaches are described in detail. The net efficiency of the oxy-fuel combustion power cycle in relationship to the carbon dioxide turbine exhaust pressure is shown. Moreover, the influence of the regenerator scheme and modeling parameters on heat performance is obtained. Particularly, it was found that the transition to a scheme with five two-threaded heat exchangers decrease cycle efficiency by 4.2% compare to a scheme with a multi-stream regenerator.