查看更多>>摘要：Gas explosion is a common serious accident in underground coal mines and industrial production processes. Porous media, due to its special cellular structure, has a significant effect on stopping the propagation of pressure and flame, which can effectively reduce the explosion hazard. In this study, the explosion suppression effect of Fe-Ni and Cu foams with different pore sizes (20 and 40 holes pores per inch (ppi)) was experimentally investigated and comparatively analyzed at opening blockage ratios (OBR) equal to 0.36, 0.64 and 0.84, respectively. The results demonstrate that Fe-Ni foam with 20ppi quenches the flame only under the OBR of 0.84, which indicates that the larger the OBR is, the better the explosion suppression effect is. However, under the OBR of 0.64, the porous media achieve an enhanced quenching efficiency and the shortest quenching time. In addition, when the vent area is relatively large, the obstacle effect of porous media is stronger than its pressure absorption capacity, thus leading to an increased pressure in the explosion area. The lowest peak overpressure attenuation rate, - 25.9%, is observed for 40ppi Fe-Ni foam under the OBR of 0.36. In general, the OBR is positively correlated with the depressurization capacity. Among all the cases used in this study, the 20ppi Cu foam boasts the highest upstream and downstream peak overpressure attenuation rates under three OBRs, 0.86%, and 6.33%, respectively.
查看更多>>摘要：Industrial waste disposal is conducted by coprocessing in the cement kiln. This process can save resources and dispose of industrial waste in a way that is beneficial to the environment by using renewable energy and being a viable alternative to the cement industry in several countries. Nowadays, there is competition among industrial waste processors due to their increasing numbers. Therefore, this study aimed to investigate the significant factors related to forecasting the selection of industrial waste disposal services in cement kilns by developing random parameters with heterogeneity in means and variances. To our knowledge, there are no studies analyzing the selection of industrial waste disposal in coprocessing. Thus, this analysis is a novel approach, able to reduce the least bias and incorrect inference that may lead to operation on effective dealing measures to explain individual relationships based on the differences of several customers. The questionnaires were completed by the customers. According to our findings, a statistically significant factor that customers considered was the image of industrial waste disposal processors by coprocessing in cement kiln, and factors of distances from the waste processors had a significant role in customer decision, whereas the logistics job position may choose the service due to the E-license convenience. The limitation of the study is findings in Thailand. Coprocessing in other countries can use the research results and incorporate them into their strategic business plan in the future to ensure the sustainability of their service by coprocessing cement kilns.
查看更多>>摘要：Heavy metals such as zinc and nickel can be found in wastewater from steel electroplating trace concentrations. These heavy metals harm the ecosystem and human health, which must be addressed. This study aimed to use fluidized bed homogeneous crystallization process (FBHCP) to recover nickel-zinc crystal from simulated electroplating wastewater. The best-operating conditions include a 10.2 initial pH of the crystallization reagent, variable nickel ion concentrations of 200 - 500 mg·L~(-1), and variable zinc ion concentrations of 100 - 400 mg·L~(-1). The nickel-zinc solution has a starting concentration of 300 mg L~(-1) of both nickel ions and zinc ions and a 1.75 molar ratio (MR) of [CO3~(2-)]/[Ni~(2+)+Zn~(2+)]. The highest removal rate for zinc was 99.6 %, and for nickel was 88.7 %. According to SEM morphology, the crystals generated have a high-density smooth crystal with pores. According to XRD analysis, the crystals generated were layered hydroxide salts (LHS) of nickel-zinc with the structural formula. FBHCP was employed to successfully recover NiZn - LHS crystals from simulated wastewaters, which can now be utilized for future adsorption applications.
查看更多>>摘要：Integration of biomass gasification with Solid Oxide Fuel Cell (SOFC) is a promising technology, particularly for small scale decentralized power systems. In this paper, to reduce the CO2 emission and biomass consumption of this system, it is incorporated with solar-based hydrogen production. The produced hydrogen is injected into the biomass gasification-SOFC system, proposing two different configurations. In the first configuration, the hydrogen is injected into the anode inlet (to provide a hydrogen rich fuel), while in the second proposed configuration it is injected into the afterburner of the SOFC (to increase the gas turbine inlet temperature). The two proposed configurations are comprehensively assessed and compared from thermodynamic, environmental and economic standpoints. In thermoeconomic analysis, the negative environmental damage costs of CO2 emission, as the primary greenhouse gas, is taken into account. Also, a parametric study is conducted to ascertain the major design variables after which tri-objective optimization is performed based on CO2 emission, levelized cost of electricity and exergy efficiency. The results indicated superior performance for the system with hydrogen injection into the anode compared to the injection into the afterburner. The former configuration has 20.6% higher exergy efficiency with 23.2% lower emission and 14.0% lower levelized electricity cost. For this configuration under the optimum operation, the exergy efficiency, CO2 emission and electricity cost are found to be 24.85%, 0.257 kgAWh and 0.0911 $/kWh, respectively.
查看更多>>摘要：In this work, high removal of contaminants in hospital wastewater has been achieved using an integration of electrocoagulation (EC) with ultrafiltration (UF) and reverse osmosis (RO). In EC system, Al electrodes were arranged in a monopolar-parallel and bipolar configuration. There are two parameters studied in the EC system, i.e., the configuration of electrodes (2A-2C-2B and 4A-2C-2B) and current densities. The EC-UF system with a configuration of 4A-2 C-2B and a current density of 88.5 A.m~(-2) resulted in high removal of TSS, TDS, BOD, and COD by 95.12 %, 97.53 %, 95.18 %, and 97.88 %, respectively. The effluent quality of the EC-UF was improved by substituting UF with RO membrane. The TSS, TDS, BOD, and COD removal were enhanced to 97.64 %, 99.85 %, 97.88 %, and 98.38 %, respectively. The permeate flux decline in UF membrane system was 47.83 % during 60 min of filtration time due to cake layer fouling on the membrane surface, while in the RO membrane system was 29.49 %. Since the EC-UF and EC-RO showed high efficiency in contaminants removal, these configurations could be used as clean technology to produce clean water for water reuse purposes. At a wastewater capacity of 5 m~3.day~(-1), the operating cost for the EC-UF system was 3.92 US$.m~(-3), while the EC-RO system was 4.02 US$. m~(-3). The increase of wastewater capacity to 50 m~3.day~(-1) reduced the operating cost to 0.89 US$.m~(-3) for the EC-UF system and 0.93 US$.m~(-3) for the EC-RO system.
查看更多>>摘要：Lead dioxide (PbO2) is a common anode for wastewater treatment in electrochemical oxidation studies thanks to its high oxygen evolution potential, great hydroxyl radical productivity, and low cost. There has been much research focusing on PbO2 preparation and application from different perspectives in recent years. In this paper, with "PbO2 degradation performance optimization" as the clue, electrode modification strategy and operation condition are systematically reviewed, together with the standard evaluation indexes of electrical and electrochemical properties for PbO2. The electrodeposition processes can be divided into substrate and interlayer selection, electrodeposition bath adjustment, energy input modulation and new configuration introduction, impacting the catalytic activity and stability. Organic pollutants degradation is a significant application aspect of PbO2. Four major influence factors in the electrochemical degradation process are discussed, including external circuit control, co-existing ions, solution physicochemical properties and reactor configuration. Other couplings and combination technologies are introduced based on electrochemical oxidation with PbO2 anode. Further, the future research directions of PbO2 anode in wastewater treatment are forecasted.
查看更多>>摘要：Polycyclic aromatic hydrocarbons (PAHs) pose versatile risks to the environment and human health. However, studies on their occurrences, spatial distributions, seasonal variations, possible sources and potential risks of the Han River are still not clear. In this study, 16 PAHs were investigated in the surface water and sediments from 15 sampling sites of the Middle and Lower Reaches of the Han River during the dry, normal, and flood seasons. It was found that the sum concentration of PAHs (SPAHs) determined by GC-MS ranged from 18.3 to 146.8 ng/L (mean 77.4 ng/L) in surface water, while it was 137.1-1478.4 ng/g (mean 679.6 ng/g) in sediments. The two to three rings PAHs in surfer water and four-five-ring in sediments PAHs comprised the majority of the detected compounds. The level of PAHs in dry season was higher than that in the flood and normal seasons, and the distributions of PAHs varied substantially along the river without clear trend in surface water and sediments. The sources of PAHs in surface water and sediments were mainly from biomass and coal combustion, followed by petroleum combustion. The human health risk of PAHs were evaluated using the risk entropy method of Kalf in surface water, and the mean effects range-median quotient method in sediments, respectively. Overall, the potential health risks caused by PAHs are still acceptable with special concerns about certain specific issues.
查看更多>>摘要：As a part of self-diagnosis functions, the instrumentation signal quality bit (SQB) is widely introduced in engineering applications, especially in nuclear power plant (NPP) distributed control systems (DCSs). However, the introduction of SQB significantly increases the DCS software complexity and may potentially be unsafe against its design intention. To reduce unscheduled shutdown accidents caused by potential unsafety, it is necessary to conduct a systematic safety analysis on the SQB. Therefore, this paper selects a CPR1000 NPP unscheduled shutdown accident as the research object to abstractly model and reproduce. The system-theoretic process analysis method is applied to analyze the SQBs involved in the unscheduled shutdown accident, which provides a way to identify the behavior of the system components, the interactions between them, and the safety constraints from the perspective of the whole NPP. Therefore, the weaknesses and potential factors affecting safe NPP operation are located, and countermeasures can be proposed. The safety analysis process can inform the identification of potentially unsafe scenarios and complement the verification and validation of the DCS software. Finally, the NPP economy should be improved while maintaining its reliable and safe operation.
查看更多>>摘要：Novel integration of a hydrogen liquefaction process and cryogenic rectification of air is presented. The thermodynamics analysis including the 2nd Law and sensitivity analysis regarding this process are conducted. The proposed cryogenic process can produce 111.3 kg/s of nitrogen and 42 kg/s of oxygen with argon. In addition, this process produces more than 132 × 10~3 tons of liquid hydrogen and 751 tons of crude neon per year. Moreover, as the number of the used compressor is very fewer than of the conventional process, the required power consumption of the proposed cryogenic plant is almost low. Based on the exergy analysis, using expanders, providing the requested refrigeration condition by solar heat exchangers and proper streams, and integrating two processes with the similar operating condition, the exergetic efficiency of the cycle is more than 70 %. The sensitivity analysis of operating parameters such as pressure, temperature, reflux ratio, and the number of stages of column presents their the importance of them on the recovered neon, oxygen, and nitrogen. Moreover, the production of cryogenic liquids is more sensitive to operating pressure and temperature than the reflux ratio and the number of stages.
查看更多>>摘要：The evolution of energy systems has always been a major contributing factor to improve quality of life. Emerging energy sources, such as hydrogen and battery, seem to be promising to provide reliable and clean energy in the near future. Hydrogen is clean energy with only water as the combustion product. The unprecedented political and business momentum has driven a rapid development of hydrogen as secure and affordable energy (Yue et al., 2021). Nowadays, hydrogen is primarily used by industry for oil refining and the production of ammonia, methanol and steel. Other uses of hydrogen include the transport empowered by the fuel cell, power generation for electricity, and residential use when blended into the existing natural gas networks. Lithium batteries have the merits of low weight, high energy density and relatively long lifetimes; therefore, it is widely used for the portable electronic devices, and the recent applications include electric vehicles, grid and utility (Chen et al., 2021).
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