Exergy analysis of the diesel pre-reforming solid oxide fuel cell system with anode off-gas recycling in the SchIBZ project. Part I: Modeling and validation

Solid oxide fuel cell (SOFC) systems with anode off-gas recirculation (AGR) and diesel pre-reforming are advantageous because they can operate with the current fuel infrastructure. In the SchIBZ-project, the prototype of such a SOFC system for maritime applications has already been commissioned. In this first paper, we model the system devices to conduct an exergy analysis of this real SOFC plant and validate them with experimental values from experiments in laboratory scale. The results of our simulation agree well with the experimental values. The calculations with the validated results may be closer to the real thermodynamic behavior of such system components than previous literature.     

Thermodynamics of CO2 solubility in mixtures monoethanolamine with organic solvents and water and commercial experience of energy saving gas purification technology

The gas–liquid equilibrium in systems containing CO₂, monoethanolamine (MEA), water and many organic solvents, for example alcohols, glycols, esters of glycols and so on, has been investigated. Some regularities of solubility as the function of dielectric constant of solvent and other properties have been found. Thermodynamic analysis has shown some peculiarities of stripping process which allows a reduction of energy consumption. Pilot plant tests of some absorbents, for example mixtures of MEA with N-methylpyrrolidone, tetrahydrofurfuril alcohol, benzyl alcohol, ethylene glycol and other mixtures, have confirmed the calculation results. The experience of industrial usage of energy saving technology of CO₂ removing from synthesis gas at several commercial plants by substitution of part of water by organic solvent has been accumulated.     

UV, Raman and XRD study of polymorphism of poly(methyl-n-propylsilane)

Raman, UV and XRD studies have been performed to characterize the structures of differently prepared samples of poly(methyl-n-propylsilane). The results demonstrate polymorphism of this polymer between T_c and T_g. At room temperature the polymer can exist in up to four modifications which comprise one amorphous disordered phase and three more ordered modifications, differing in the interchain organization and in the silicon backbone conformations. The latter are considered to be deviant, transoid and all-anti, respectively. The number of the modifications present and relative amount of each strongly depends on the preparation method and thermal history of the sample as well as on the molecular weight.     

Types of Continuous Casters and the Quality of Continuous-Cast Slabs for Obtaining Rolled Products for Crucial Applications

This article examines the production of continuous-cast slabs for the production of thick (thicker than 20 mm) plates used in critical applications. It is shown that the melt needs to be carefully prepared for casting on a continuous caster. When the steel is made in a converter, the pig iron must be desulfurized beforehand and the steel tapped from the furnace must subsequently be treated on ladle-furnace and vacuum-degassing units. It was established that production of high-quality slabs suitable for obtaining critical rolled products can be consistently achieved only through the use of a vertical continuous caster. The bending and unbending which slabs undergo on curvilinear casters and the curved axis of such casters make it very difficult or even impossible to obtain slabs and thick plates that do not have asymmetrically distributed nonmetallic inclusions, axial segregation, and internal and external cracks. The article analyzes the success that the company Severstal' had in rebuilding its vertical slab caster. The project, carried out by TsNIIchermet and the companies ORMET-YuUMZ and Korad, shows that Russian metallurgical science, the metallurgical industry, and the machine-building sector have competitive engineering solutions to offer.     

Fast-switching-speed,low-forward-voltage-drop static induction (SI) thyristor

A static induction (SI) thyristor using a normally-off planar-gate structure in a low power class has been developed to be used as a power switching device in a three-phase inverter circuit. A 600 V-15 A class SI thyristor with very fast switching time (tgt, tgq) and low forward voltage drop (V_TM) was designed and created. This design was performed with a reasonable wafer structure (n^?/n/p⁺), an n^? base carrier concentration and thickness, and a gate structure (gate diffusion length and gate-gate pitch). Microscopic processing was used to obtain this SI thyristor. The performance trade-off between turn-off time and forward voltage drop is controlled by a lifetime control process using proton irradiation that results in a very fast switching time with tgt of 500 ns and tgq of 500 ns with V_TM of 1.5 V (at I_T= 18 A). At a current level of I_T = 18 A, the current density in the active area becomes 200 A/cm², which indicates that the performance of the SI thyristor is superior to that of conventional IGBTs and MOSFETs.