Xiang Gao,Ying Chen,Pengcheng Xu,Dan Zheng,Xinxin Li
The selective detection of propane gas molecules using semiconductor gas sensors has always been a challenge within research. In this study, we successfully synthesized a γ-Fe2O3nanomaterial with a selective catalytic effect on propane and loaded it onto a ZnO sensing material to construct a double-layer microsensor, which showed good sensing response characteristics in the detection of the refrigerant R290 (which is mainly propane). In addition, we also prepared a series of iron oxides, including nanomaterials such as α-Fe2O3, Fe3O4, and FeO, as well as γ-Fe2O3materials with different specific surface areas obtained at various processing temperatures, and we carried out gas sensing research on R290. The results show that the γ-Fe2O3material has a better sensitivity to R290, and the γ-Fe2O3material calcined at 200 °C shows the best performance. Our results can provide a theoretical basis for the design and optimization of semiconductor gas sensors for alkane detection.
Propane (R290) as a natural refrigerant has attracted much interest in the refrigeration and air conditioning fields. To increase the solubility-database for R290 in oils and better understand the oil presence effect on evaporator performance, solubilities of R290 in two polyol ester oils (RL 32H and RL 68H) were measured from 253.15 to 343.15 K. The nonrandom two-liquid model was used to correlate the measured data. R290 is more soluble in RL 68H than in RL 32H. New pressure–enthalpy–vapor quality diagrams were plotted for pure R290 and R290/oil blends at different circulating oil mass fractions. A demarcation point was found along the isotherms of the R290 and R290/oil blend, that is mainly dependent on the solubility and circulating oil mass fraction. The lower is the demarcation point, the greater is the contribution of the sensible heat, which is unfavorable to the heat transfer. The enthalpy changes through an evaporator with and without the presence of oil were analyzed, indicating that the enthalpy change ratio increases as the superheat rises and the mass fraction of the circulating oil decreases.
危险品化学品经营许可证（带存储）