In the process of offshore chemical drive, water drive well network and polydrive well network coexist after well network densification, which exerts a deep influence on oil development. To quantitatively characterize the perturbation degree of injected water and polymer, a water-polymer perturbation coefficient considering the dynamic changes of displacement volume of injected water and polymer is proposed. The production characteristics and laws under different displacement modes are analyzed based on the water-polymer perturbation coefficient, and the control strategies are discussed.The results show that the injected water would compress the polymer displacement area and exert an interference on the polymer front edge. Water-polymer perturbation coefficient has a good correlation with stage net oil increase curve, and water-polymer co-flooding process can be divided into five stages according to the water-polymer perturbation coefficient. In addition, water-polymer co-flooding has a better oil production than pure polymer flooding at the initial stage, but for a long period, development effect of pure polymer flooding is much better, and water-polymer alternating injection can balance the displacement front and improve the development effect. The result has a great significance to quantitatively characterize water-polymer perturbation degree and make adjustment measurements.
As the global energy system accelerates its transition toward renewable energy,electrochemical energy storage devices play an increasingly vital role in ensuring power supply stability and promoting efficient energy utilization.However,low-temperature environments pose a significant challenge to the performance of electrochemical energy storage devices.Especially for widely used lithium-ion batteries,the problems such as significant decrease of charge and discharge capacity,increase of internal resistance and shortening of cycle life are particularly prominent,which seriously limits the commercialization development of lithium-ion batteries in cold regions and other scenarios.To address this challenge,this paper provides a systematic review of current research progress on the performance of electrochemical energy storage devices in low-temperature environments.First of all,focusing on the core research topic of modification and optimization of battery cathode materials and electrolyte systems.This study systematically elucidates the mechanism contributing to battery performance under low-temperature conditions,including changes in material resistivity,reduced reactivity of active materials,and increased viscosity of electrolyte materials.Then,the modification strategies of electrolyte to improve the performance of batteries under low temperature are reviewed and analyzed.In addition,other effective ways to optimize the low-temperature performance of energy storage devices and their mechanisms for improving the electrochemical performance are also expounded.
The carboxyl nitrile hard glue wastewater contains raw materials, by-products and some auxiliary materials that are not fully involved in the reaction, and has the characteristics of high chemical oxygen demand (COD), high mass concentration of Pull apart powder(BX), high viscosity and toxicity, resulting in the poor operation of the water treatment process. The pretreatment process with "air flotation, membrane separation and ozone oxidation" as the core was adopted to remove COD and decoking powder from carboxyl nitrile hard adhesive wastewater, so as to improve the biodegradability of wastewater. This pretreatment process had problems such as rubber caking and blocking, filter device blocking and so on, and the overall operation effect was poor. The pretreatment process was improved by increasing the influent flow rate to 105 m3/h, increasing the chemical backwash time and backwash frequency, adjusting the ozone quality concentration to 35 mg/L, and decreasing the height of the packing layer of the ozone catalyst layer to 650 mm. The results show that when the effluent COD is stable at about 1 100 mg/L, the mass concentration of BX is maintained at about 40 mg/L, and BOD/COD (BOD is the ratio of biological oxygen demand) is about 0.30, the influent conditions of the subsequent process can be met, and the stable operation of the system can be ensured.
NiMo/γ?Al2O3 catalyst was prepared by using γ?Al2O3 as the carrier and Ni as the active component,and Mo was introduced to improve the metal dispersion of Ni?based catalysts.The physical properties of the catalysts were characterized by means of BET,XRD,H2?TPD,H2?TPR,and transmission electron microscopy.The performance of the catalysts was evaluated by hydrogenation units,and the effect of metal dispersion of the catalysts on the catalytic activity was investigated.The results show that the introduction of Mo can effectively weaken the interaction between Ni and the carrier.The low?temperature reduction peak of the H2?TPR profile significantly moves forward,and the peak intensity is enhanced.The specific surface area of the catalyst activity increases from 0.7 m2/g to 15.3~16.1 m2/g,and the metal dispersion increases from 0.80% to 18.59%,which indicates that the number of metal active centers on catalyst surfaces increases,and the metal dispersion on the catalyst surfaces improves. Under the same process condition,heavy petrol with catalytic cracking is processed,and the desulfurization rate of NiMo?based catalysts is increased by 15.7% compared with that of Ni?based catalysts.The saturation rate of olefin is increased by 4.9%,and the desulfurization selectivity is decreased by 3.4%.Therefore,the NiMo?based catalysts have positive desulfurization selectivity while ensuring a high desulfurization rate.