查看更多>>摘要： Recently, the consequences caused by frequent large-scale power grid accidents are more significant with arousing great attention of power grid enterprises. Scientific safety investments are essential to improve the overall safety level of the power grid enterprises and promote safe production. This study, proposed a dynamic and integrated approach for safety investment decision-making of power grid enterprises based on the entropy weight method (EWM) and the system dynamics (SD) theory. By applying the accident loss assessment and the safety performance evaluation, the SD-based model for the safety investment decisionmaking for power grid enterprises was developed. The results show that risk assessment is the critical factor for power grid safety, followed by safety training, organizational investment, and technological investment. Moreover, the proposed safety investment decision-making model can be continuously updated and optimized with future emerging data to support the dynamic prediction of power grid safety investment.
查看更多>>摘要： To improve inorganic carbon capture utilization (CCU) technology, practical solution for global warming technology, we studied the formation and transformation trends of mineral carbonation using simulated brine, we converted CO2 into inorganic compounds, metal carbonate, using CO2 saturated aqueous monoethanolamine (MEA) solution. The produced metal carbonate varied according to the simulated brine's cation component, resulting from ion interactions in the system. It turns out that the common ion effect, which occurred due to the system's ion interactions involving changes of ionic atmosphere and salinity of the system, was the main reason for the various carbonation trends. Salting- out effect dom-inantly occurred in the single precipitation system whereas salting-in effect occurs in multi precipitation system (system CM and system CMN). However, salting-out effect also occurred in system CMN because of Na~+. Moreover, we also found that Na~+, which was overlooked in prior studies regarding polymorph transformation, also affects polymorph transformation. The interactions between the abovementioned effects involved the variation in the results. This variation interrupted the wide usage of the technology. However, through the study, we suggest ambient estimation of the final product with cation component. It would help future studies and demonstration of the inorganic CCU technology using brine.
查看更多>>摘要： Potential pool fire hazards due to the leakage of combustible liquid chemical materials during storage and transportation pose a threat to process safety in the process industry. A pool fire may occur on the inclined surface of broken pipelines or facilities. The influence of an inclined surface on pool fire behavior was experimentally and theoretically studied. The results showed that the flame tilt angle and flame length increased with inclination angle, while the flame height exhibited an opposite trend. These phenomena were mainly caused by the restriction of air entrainment due to the inclined surface. The flame pulsation frequency generally decreased with the increase of inclination angle and was weakly dependent on the heat release rate. Dimensionless models were developed to predict the flame tilt angle, flame length, flame height, and flame pulsation frequency. The predictive values were in good agreement with experimental data.
查看更多>>摘要： This study presents an integrated hybrid framework of data-driven (cascade forward neural network (CFNN)), metaheuristic (artificial bee colony (ABC)), and a mechanistic modeling (Aspen simulation) approach for the biomass pyrolysis process for bio-oil production. We applied CFNN and an ABC to predict and optimize bio-oil yield. The CFNN model achieved high prediction performance with a correlation coefficient value of 0.95 and a root mean squared error value of 0.39. Furthermore, the CFNN-ABC derived optimum parameters were then validated using a mechanistic model of the pyrolysis process. The CFNN and Aspen simulation results were following the experimental results, with an average deviation of 5%. The feature importance showed that the internal information about biomass was more relevant than external factors for bio-oil yield. The partial dependence plots were developed to know the insights into the biomass pyrolysis process. This study presents a modeling and simulation platform for bio-oil production that can increase the waste-to-energy process and can be helpful for academia.
查看更多>>摘要： Incineration is a harmless way to treat municipal sludge. However, it is difficult to fix heavy metals in the sludge-incinerated ash (SIA). To fix the heavy metals and recycle the SIA effectively, this work innovatively proposed the SIA as skeleton material, and five shape-stable phase change composites (SSPCCs) with different mass ratios of SIA to NaNO3 (phase change material, PCM) were fabricated via the cold-compression & hot-sintering (CCHS) method. Then, key thermal performance, mechanical strength, and micro-morphology were investigated while the chemical compatibility between the SIA components and NaNO3 was analyzed. Results showed that the SSPCCs could fix the heavy metals properly, and the SIA was suitable for skeleton material; The SSPCC with the mass ratio 5:5 of SIA to NaNO3 reached a maximal thermal energy storage (TES) density of 409.25 kJ/kg in the range of 100-400 °C, which had high mechanical strength of 139.65 MPa and good thermal stability; The SIA components demonstrated excellent chemical compatibility with NaNO3.
查看更多>>摘要： Risk performance reasoning strategy for LNG ships navigating in Arctic waters is proposed in this paper. Many uncertainties exist in the reasoning of ship navigation risk in Arctic waters, which are influenced by multi-source risk causing events. As a result of the aforementioned concerns, the dynamic Bayesian network (DBN) structure is offered as a solution for an uncertain risk assessment model. The DBN network can benefit from a strategy for solving ambiguous data information based on Dempster-Shafer (D-S) evidence theory and a cloud model. Additionally, a risk performance reasoning technique for LNG tanker collision accidents in Arctic waters is developed. Besides, the marine meteorological reanalysis data, data from ship-borne sensor monitoring, and expert knowledge in the suggested risk performance reasoning method are incorporated. A case study confirmed that the risk performance reasoning of accidents was needed revealed that the main risk in Arctic summer waters is posed by obstacles in the channel that are difficult to detect, such as icebergs and reefs.
查看更多>>摘要： In the present work, in a batch quartz tube reactor, supercritical water gasification and supercritical water oxidation were used to treat tetracycline hydrochloride (TC). The results show that the increase in temperature, the extension of reaction time, and the decrease in initial concentration all had a positive impact on the removal of TC. After adding 0.108 mol/L H2O2 (n = 1), the removal rate reached 100% at 1000 mg/L, 400 °C and 100 s. First-order degradation kinetics was used to fit the degradation of TC. In the absence of H2O2, its pre-exponential factor and activation energy were found to be 0.03 s~(-1) and 6.14 kj/mol, respectively. After adding H2O2, its pre-exponential factor and activation energy were found to be 6.70 s~(-1) and 25.66 kJ/mol, respectively. The degradation process of TC was explored and the results show that TC can be degraded into smaller molecular substances in supercritical water. After adding H2O2, the degradation efficiency of TC was significantly improved the degradation process was also more thorough. There were two main degradation processes, namely the ring-opening reaction and the central carbon cracking.
查看更多>>摘要： In the real scenarios, explosions generally occur under turbulent environments. In this study, the turbulence is generated by introducing inert gas jets, and the interaction between jet turbulence and inert gas dilution is extremely complicated under different conditions. Therefore, the aim of this study is to investigate the influence of gas jets on explosion behavior of hydrogen-air mixtures with various hydrogen concentrations (from 10% to 70%) at different initial pressures (i.e., 50 kPa, 100 kPa, 150 kPa, 200 kPa), and a series of experiments are conducted in a standard 20 L spherical explosion chamber at environmental temperature 300 K. The effect of gas jets on explosions of hydrogen-air mixtures with various hydrogen concentrations at initial pressure of 100 kPa is first studied, the experimental results illustrate that jet has minor impact on the explosion behavior when hydrogen concentration ranges from 20% to 70%. However, the enhancement effect of gas jets on the reaction process is significant as hydrogen concentration is 10%. Therefore, the impact of various gas jets (i.e., CO2, and N2) on explosion behavior at different initial pressure is mainly examined as hydrogen-air mixtures are near the lower explosive limits. It is found that the enhancing effect of gas jets on explosion behavior is profound for hydrogen-air mixtures at higher initial pressure, however, the suppression effect caused by the higher concentration of inert gas could balance the promoting effect by turbulence at lower initial pressure. Moreover, the encouraging effect of CO2 jet is more apparent than that of N2 jet when jet duration time is relatively short, because the turbulence intensity induced by CO2 is greater due to its larger molecular weight.
查看更多>>摘要： The efficient extraction of rare earth elements from spent phosphor was achieved by microwave alkali fusion -leaching. Effect of temperature on the dielectric properties was studied. The addition of alkali greatly enhanced the microwave heating ability of the phosphor with loss tangent value increasing from 0.031 to 0.084 at 800 °C, which was ascribed to the strong susceptibility of molten sodium hydroxide and roasted products to microwave interaction. Effects of process parameters of roasting and acid leaching were investigated. When the phosphor was treated at 800 °C for 30 min with mass ratio of NaOH/phosphor of 2:1 followed by acid leaching of 4 mol/L HCl with the liquid-solid ratio of 10:1 at 60 °C for 120 min, the leaching efficiencies of Ce and Tb were 97.86% and 95.75%, respectively. Microwave roasting showed the advantages of lower temperature, shorter time and higher leaching ratio of rare earths compared with conventional roasting. Enhanced thermal motion of sodium hydroxide, improved kinetic conditions and changes of crystal structures resulting from microwave selective heating may be responsible for microwave-enhanced rare earths extraction. Kinetic studies showed that both the alkali roasting and leaching process of rare earths were controlled by product layer diffusion.
查看更多>>摘要： Wastewater from olive oil mills (OMW) represents a major environmental problem that requires effective treatment to decrease pollution. In the present work, the treatment of olive oil mill wastewater by coagulation was studied using Moringa Oliefera as a natural coagulant. The processing is optimized using both Design of Experiments (DOE) methodology and a central composite design (CCD) combined with the response surface methodology (RSM). The optimization describes the relationship between 3 responses (turbidity, COD, and polyphenols) and 4 independent variables (Moringa Oliefera concentration, pH, agitation speed, and time). Analysis of variance ANOVA using Fisher's test indicated that the established models were significant. The study showed that the model was characterized by a good fit, justified by the very high adjusted coefficient of determination (R~2Adj = 86.73%, R~2Adj = 90.39% and R~2Adj = 93.33% for the turbidity, COD, and polyphenols, respectively). Furthermore, the optimum conditions for a good purification performance of OMW using Moringa Oliefera are as follows [Mo] = Moringa Oliefera = 65 g/L, pH = 6, Agitation speed (Ss) = 35 rpm and Agitation time (St) = 25 min. Under these conditions, the turbidity, COD and polyphenol removal efficiencies are 96%, 88%, and 86% respectively. Finally, the proposed treatment process is a critical development in sustainable environmental technologies.
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