Volatile Organic Compounds (VOCs) are significant contributors to air pollution and play a crucial role as precursors for secondary pollutants such as O3, thereby posing severe health risks and attracting global attention. ZIF-67, a metal-organic framework (MOFs), possesses a porous microstructure and high specific surface area, offering exceptional adsorption performance, catalytic activity, and structural stability. In this investigation, a solvent-thermal method was employed to synthesize a series of Fe-modified ZIF-67 denoted as FCMx. The impact of Fe doping and temperature on the dynamic adsorption performance of toluene was examined. The results revealed satisfactory adsorption performance of FCMx when the Fe doping was 14 mol%. FCM14 achieved saturation adsorption of toluene in approximately 5000 s, exhibiting a saturated adsorption capacity of 1769.80 mg/g at 25 °C. This represented a 25% improvement in adsorption time and a 30% increase in saturated adsorption capacity compared to undoped ZIF-67. Furthermore, at a reaction temperature of 150 °C, FCM14 exhibited saturation time of approximately 4300 s and a saturated adsorption amount of 1471.43 mg/g, indicating a combined effect of chemical and physical adsorption. The findings of this research provide valuable experimental data and theoretical support for the potential industrial application of MOFs in VOC adsorption.

Improving steam parameters in a coal-fired power unit boosts cycle efficiency, lowers coal consumption, and reduces emissions. The backpressure extraction steam turbine (BEST) cycle addresses the problem of excessive superheating of extraction steam. This study analyzed a 1000 MW double reheating unit, finding that heat rate in the conventional and BEST cycle systems is heavily influenced by load under THA conditions. At 100% and 75% loads, the BEST cycle’s heat rate decreases but increases at 50% load. For safe operation during flow interruption and high load rates, a pairwise grouping method is recommended for high-pressure heater interruption. When multiple low-pressure heaters are simultaneously cut off, the unit load needs to be limited based on the number of heaters being removed. when multiple low-pressure heaters are simultaneously cut off, the unit load needs to be limited based on the number of heaters being removed. Removing two low-pressure heaters lowers the load to 90%, and three lowers it to 80%. These findings optimize the thermal system’s parameters and enhance overall efficiency.

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Aiming at the air-conditioning system of underground space engineering, it is proposed to use ground source heat exchanger and hot water exchange tanks in parallel as a composite cold and heat source, which can simultaneously achieve energy-saving requirements. In order to explore the operating heat transfer characteristics of the composite cold and heat source system, a mathematical model of buried pipes and hot water exchange tanks was established. The simulation analysis of the influencing factors such as inlet temperature and fluid flow rate shows that under the condition of small flow rate, increasing the fluid flow rate can significantly improve the buried pipe and the hot water tank and the heat exchange effect; the greater the temperature difference between the inside and outside of the pipe, the better the heat exchange effect of the heat exchanger, under the same flow rate, the heat transfer coefficient of the spiral coil is KDN15>KDN20>KDN25. According to three different load conditions, the flow ratio of the composite cold and heat source is optimized and analyzed. The results show that as long as the flow ratio is properly controlled, the composite cold and heat source can meet the cooling requirements of the air-conditioning system under different working conditions. There is an optimal flow ratio between the heat sources. The greater the ratio R of the extreme working condition load change value to the standard working condition load value, the smaller the value of the optimal flow ratio, and it is not affected by the loop flow rate and the inlet water temperature change.