This study reports a high-performance modified oxygen carrier (OC) in a three-cycle chemical looping process in which coal is used as the raw feedstock to produce hydrogen. A series of experiments of coal-direct chemical looping hydrogen generation (CLHG) were conducted in a batch fluidized bed reactor, in the absence or presence of the NaAlO 2. The experimental results indicated that the carbon conversion and hydrogen yield reached 87.0% and 1.30 L Á g −1 , respectively, when the coal/oxygen carrier (Fe4Al6) mass ratio was 1:20. However, FeO was the main product of the reduction process with Fe4Al6, which limits the production of hydrogen during steam oxidation. Therefore, NaAlO 2 was used to improve the reaction performance of the OC. The carbon conversion and hydrogen production of NaAlO 2-loaded oxygen carriers were 10.7% and 9.6% higher than Fe4Al6, respectively. X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and temperatureprogrammed reduction (TPR) techniques were used to characterize the oxygen carriers. According to the XRD analysis results, the addition of 5 wt% NaAlO 2 can generate NaFeO 2. The unique layer structure of NaFeO 2 can loosen the structure between Fe 2 O 3 and Al 2 O 3. Thus, the surface morphology and pore structure of the oxygen carrier were improved, which are responsible for the enhancement in reactivity rather than the catalytic effects of the alkali metal. The cycle performance of the Na0.5Fe4Al6 remained stable after multi-redox cycles, and no serious sintering phenomena were observed; in addition, the carbon conversion and hydrogen yield remained above 86% and 1.40 L Á g −1 , respectively. K E Y W O R D S chemical looping, crystal structure, Fe 2 O 3 /Al 2 O 3 , H 2 production, sodium modification 1 | INTRODUCTION Currently there is growing interest in using hydrogen as a clean energy carrier since it can provide a high Jinshuai Li and Xiuli Zhang contributed equally to this work.
Non-growing season irrigation and farmland subsurface drainage play a crucial role in salt leaching and salinization control in arid irrigation areas. This study aimed to investigate the reduction of autumn irrigation quotas and drainage discharge while maintaining soil moisture retention and reducing soil salinization. Field experiments were conducted with different autumn irrigation quotas (160 mm for SD1, 180 mm for SD2, and 200 mm for SD3) combined with subsurface drainage (1.5 m drain depth and 45 m spacing). A control treatment (referred to as CK) without subsurface drainage received 200 mm of irrigation. The results showed that, after 31 days of autumn irrigation, the groundwater depth in all three subsurface drainage plots stabilized to 1.5 m, with the CK being 0.2–0.3 m shallower compared to the SD plots. The mean soil water content in the 0–150 cm soil layer of the SD1, SD2, SD3, and CK after autumn irrigation was 0.36, 0.39, 0.41, and 0.42 cm3cm−3, respectively. The combination of autumn irrigation and subsurface drainage significantly reduced the soil salt content. The mean desalination rates in the root zone (0–60 cm) soil layer were 57.5%, 53.7%, 51.9%, and 45.1% for the SD3, SD2, CK, and SD1, respectively. The mean desalination rate of 60–150 cm was not significantly different between the SD2 and SD3 (p > 0.05), and both were significantly higher than that of the SD1 and CK (p < 0.05). The drainage discharge was 31, 36, and 40 mm in the SD1, SD2 and SD3, respectively. The amount of salt discharge through the drain pipe increased with increasing irrigation quota, which was 1.22 t/ha, 1.41 t/ha, and 1.50 t/ha for the SD1, SD2, and SD3, respectively. Subsurface drainage is an effective way to prevent salt accumulation in the soil, and an autumn irrigation quota of 180 mm is recommended for leaching of salinity in the Hetao Irrigation District. These findings provide valuable insights into optimizing irrigation practices and managing soil salinization in arid regions.
With dry climate and scarce rainfall, the annual precipitation of desert areas is below 250 mm. The daily temperature difference of desert climate is very significant, the near surface temperature can reach 60 °C to 80 °C in summer and autumn noon, but it can be reduced to below 10 °C at night. If the climate characteristics of the desert can be reasonably used for low-cost water intake, it will provide great convenience to the aborigines and migrants in the desert. Some existing air water intake devices cannot produce good water intake effect due to the low air humidity in the desert. The device uses semiconductor refrigeration to improve the relative humidity of air, so that the adsorption efficiency is significantly improved. Using the low specific heat characteristics of sand to optimize the convection and condensation device, greatly reducing the energy consumption and mechanical failure rate. By using the P, N type semiconductor’s Palp effect, STM32 controls the switching circuit and then controls the voltage direction of the two ends of the semiconductor to realize the switching of refrigeration and heating modes. In this way, low-cost and high-efficiency water intake can be realized in the desert.
There are some problems in the thermal system of Huabei Oilfield, such as high energy consumption, high operation cost and poor production safety. With more stringent requirements for energy conservation and emission reduction, it is particularly important to replace fuel oil projects and improve the efficiency of heating system.The utilization of waste heat and waste heat resources in Huabei Oilfield and the application conditions of various heat pump technologies were investigated, according to the characteristics of large amount of sewage and high temperature produced by crude oil dehydration in Huabei Oilfield. Aiming at the characteristics of large amount of sewage and high temperature produced by crude oil dehydration in Huabei Oilfield, Pilot Application of Optimized Extracted Water Source Heat Pump Technology, the research results are applied to the the He Yi Station in the third oil production plant, estimating the scale and benefit of saving, finally, the purpose of reducing cost and increasing efficiency is achieved, and the data basis and technical guidance for energy saving renovation of thermal system in the future are improved.
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