Comparing Exergy Analysis and Physical Optimum Method Regarding an Induction Furnace

In order to achieve energy and climate goals, energy and resource efficiency are considered a key measure. Limit-value-oriented methods such as the exergy analysis and the physical optimum method are used to show the limits of efficiency improvement. In this context, the physical optimum represents the theoretical ideal reference process. Despite their similarities, no comprehensive comparison to the exergy analysis has been carried out yet. Thus, the purpose of this study is to close this gap by examining differences and intersections using the example of an induction furnace. The minimum energy input according to the physical optimum method is 1327 MJ/t whereas the exergy of the melting product is 1393 MJ/t, depending on transit flows taken into account. The exergy analysis extends considerably beyond the physical optimum method in terms of the complexity and accuracy of the assessment of material flows by using exergy units. The exergy analysis makes clear which exergy is linked to the losses and thus reveals the potential for coupling processes. This results in different areas of application for the two methods.

Geochemistry and tectonic significance of late Paleoproterozoic A-type granites along the southern margin of the North China Craton

The Longwangzhuang pluton is a typical example of Paleoproterozoic A-type granite intrusions at the southern margin of the North China Craton. This pluton is composed of arfvedsonite granite and minor aegirine–augite granites. Samples from both granite types display similar zircon U-Pb ages with 207U-206Pb ages of 1612 ± 19 Ma [mean square weighted deviation (MSWD) = 0.66] and 1609 ± 24 Ma (MSWD = 0.5), respectively. The granites exhibit similar high silica (SiO2 = 71.1–73.4 wt.%), high alkaline (Na2O + K2O = 8.10–9.26 wt.%, K2O/Na2O > 1), and low Al2O3 (11.8–12.8 wt. %) contents and metaluminous to weakly peraluminous bulk chemistry. The chemical variations of the Longwangzhuang pluton suggest the effects of mineral fractionation. In addition, all samples show typical characteristics of A-type granites, such as high 10000Ga/Al ratios (4.10–7.28), high FeOtot/(FeOtot + MgO) ratios (0.88–0.99), and high Zr (484–1082 ppm), Ce (201–560 ppm), and Y (78–156 ppm) contents. The εNd(t) values and the (206Pb/204Pb)t, (207Pb/204Pb)t, and (208Pb/204Pb)t ratios of the arfvedsonite granite samples vary from −4.6 to –5.3, 15.021 to 17.349, 15.241 to 15.472, and 33.206 to 36.905, respectively, and those for the aegirine–augite granite sample amount at −0.2, 14.421, 15.175, and 33.706. The distinct and variable Nd and Pb isotope values indicate the presence of heterogeneous protoliths. Based on its geochemistry, its low initial Pb isotope ratios, and its enrichment in Nd isotopes, we infer that the Longwangzhuang A-type granite is the partial melting product of basement rocks such as the Taihua Group gneisses accompanied by some involvement of juvenile material from the mantle. Together with published data from other Paleoproterozoic A-type granite plutons exposed at the southern margin of the craton, our findings suggest that these granites had a similar origin. Furthermore, geochemically, they can be divided into two groups: A2-type, which formed earlier (~1.8–1.6 Ga), and A1-type, which formed later (~1.6–1.5 Ga). Combining this information with the variations in whole-rock Nd and zircon Hf isotopic composition at ca. 1.6 Ga, we propose that tectonic transformation from post-orogenic to anorogenic magmatism occurred at the southern margin of the North China Craton at that time.

Preparation and properties of melted zircon

The data on the melting of zircon with the addition of glassforming oxides are given. The structure of the synthesized materials is represented by baddeleite and glass phase, which determine the operational characteristics of the refractory. Corrosion tests of samples of melted zircon in molten aluminum alloys showed their zero wettability and minimal corrosion. The material with an less than 2 % SiO2 was obtained when melted zircon was treated with a solution of 10 % HF. The threefold decrease in the silica content in the melting product was observed in electric arc furnace with carbothermic melting of zircon.

INVESTIGATION OF OIL SHALE COMBUSTION BYPRODUCTS OBTAINED BY PLASMA TREATMENT

This paper presents research into a possibility of synthesizing a silicate melt based on oil shale combustion byproducts obtained in Dalian Province (China). The energy of thermal plasma is used for this in the mineral fiber production. An experimental electroplasma unit is developed to provide melting of refractory nonmetallic materials, the stationary power of which is 30 kW. During the melting process of the mixture, the formation of the gaseous phase is observed. Using scanning electron microscope, maps of the qualitative distribution of the elemental composition on the surface of the melting product were obtained. Using the scanning electron microscope, the elemental composition maps are obtained for the melting product surface.

Towards biolubricant compatible vegetable oils by pore mouth hydrogenation with shape-selective Pt/ZSM-5 catalysts

Pore mouth hydrogenation of vegetable oil with Pt/ZSM-5 is confirmed by the similar intermediately melting product selectivity for various crystal sizes.