The photochemical system,which utilizes only solar energy and H_(2)O/CO_(2) to produce hydrogen/carbon-based fuels,is considered a promising approach to reduce CO_(2) emissions and achieve the goal of carbon *** date,...
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The photochemical system,which utilizes only solar energy and H_(2)O/CO_(2) to produce hydrogen/carbon-based fuels,is considered a promising approach to reduce CO_(2) emissions and achieve the goal of carbon *** date,numerous photochemical systems have been developed to obtain a viable solar-to-fuel production system with sufficient energy ***,more effort is still needed to meet the requirements of industrial *** this review,we systematically discuss a typical photochemical system for solar-to-fuel production,from classical theories and fundamental mechanisms to raw material selection,reaction condition optimization,and unit device/system advancement,from the viewpoint of ordered energy ***-of-the-art photochemical systems,including photocatalytic,photovoltaic-electrochemical,photoelectrochemical,solar thermochemical,and other emerging systems,are *** highlight the existing bottlenecks and discuss the developing trend of this ***,optimization strategies and new opportunities are proposed to enhance photochemical systems with higher energy efficiency.
China is the largest producer and consumer of calcium carbide in the *** calcium carbide industry is an indispensable industry to support the basic life of *** huge production capacity of calcium carbide is accompanie...
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China is the largest producer and consumer of calcium carbide in the *** calcium carbide industry is an indispensable industry to support the basic life of *** huge production capacity of calcium carbide is accompanied by a large number of solid waste carbide *** to the immature treatment technology of carbide slag,a large number of carbide slag are stacked on-site,resulting in land occupation,air-drying,easy take-off ash,and pollution of the environment and water *** China,calcium carbide is mainly used to produce acetylene and further utilized,80%of which is used to produce polyvinyl chloride(PVC).A large amount of carbide slag is not used,while only a small part is used in the traditional building materials industry,flue gas desulfurization,sewage treatment,etc.,however,the economic benefits are ***,converting the solid waste carbide slag produced by the calcium carbide industry into high value-added CaCO3,CaCl2,CaSO4 whiskers,*** become a potential way to expand the development field of the calcium carbide industry and is environmentally *** paper focuses on summarizing the traditional and emerging high value-added utiliza-tion technologies of carbide slag,and then introduces the application research of carbide slag in carbon emission ***,the defects of these technologies are summarized and further research directions are *** study provides basic guidance for the diversified development of efficient resource utilization of carbide *** abstract Diversified development of calcium carbide industry,resource utilization of solid waste carbide slag and its application of carbon emission reduction have been fully reviewed.
The accurate short-term load prediction is an essential prerequisite for ensuring the reliable and economic operation of combined heat and power stations. In this study, the heat load and power load prediction models ...
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Induced-charge electro-osmosis(ICEO)is a research hotspot in bioengineering and analytical ***-outflow asymmetry of ICEO was reported in the existing literatures,but systematic study on this phenomenon is *** this exp...
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Induced-charge electro-osmosis(ICEO)is a research hotspot in bioengineering and analytical ***-outflow asymmetry of ICEO was reported in the existing literatures,but systematic study on this phenomenon is *** this experimental study,we found that in strong electric fields,not only the velocity magnitude but also the vortex positions of ICEO are asymmetrical along the inflow and outflow directions because of the pronounced non-uniform surface electrokinetic *** the inflow and outflow directions,the amplitudes of velocities are unequal,ICEO maximum velocity positions change depending on the electric field intensity and sodium chloride(NaCl)***,the distances between vortex centers are *** NaCl solution concentration of 0.001 mol⋅L^(-1),the outflow velocity almost *** asymmetry rises with the increasing electric field *** new discoveries can direct the application of microscale devices.
A double reheat ultra-supercritical boiler is an important development direction for high-parameter and large-capacity coal-fired power plants due to its high thermal efficiency and environmental *** has developed a 1...
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A double reheat ultra-supercritical boiler is an important development direction for high-parameter and large-capacity coal-fired power plants due to its high thermal efficiency and environmental *** has developed a 1000 MW double reheat ultra-supercritical boiler with steam parameters of 35 MPa at 605℃/613℃/613℃.Reasonable water wall design is one of the keys to safe and reliable operation of the *** order to examine the thermal-hydraulic characteristics of the double reheat ultra-supercritical boiler,the water wall system was equivalent to a flow network comprising series-parallel circuits,linking circuits and pressure nodes,and a calculation model was built on account of the conservation equations of energy,momentum and *** the iterative solving of nonlinear equations,the prediction parameters of the water wall at boiler maximum continue rate(BMCR),75%turbine heat-acceptance rate(THA)and 30%THA loads,including total pressure drops,flow distribution,outlet steam temperatures,fluid and metal temperatures were *** results of calculation exhibit excellent thermal-hydraulic characteristics and substantiate the feasibility of the water wall design of the double reheat ultra-supercritical boiler.
In the process of pyrolysis and combustion of coal particles, coal structure evolution will be affected by the ash behavior, which will further affect the char reactivity, especially in the ash melting temperature zon...
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In the process of pyrolysis and combustion of coal particles, coal structure evolution will be affected by the ash behavior, which will further affect the char reactivity, especially in the ash melting temperature zone. Lu’an bituminous char and ash samples were prepared at the N_(2) and air atmospheres respectively across ash melting temperature. A scanning electron microscope (SEM) was used to observe the morphology of char and ash. The specific surface area (SSA) analyzer and thermogravimetric analyzer were respectively adopted to obtain the pore structure characteristics of the coal chars and combustion parameters. Besides, an X-ray diffractometer (XRD) was applied to investigate the graphitization degree of coal chars prepared at different pyrolysis temperatures. The SEM results indicated that the number density and physical dimension of ash spheres exuded from the char particles both gradually increased with the increasing temperature, thus the coalescence of ash spheres could be observed obviously above 1100℃. Some flocculent materials appeared on the surface of the char particles at 1300℃, and it could be speculated that β-Si_(3)N_(4) was generated in the pyrolysis process under N_(2). The SSA of the chars decreased with the increasing pyrolysis temperature. Inside the char particles, the micropore area and its proportion in the SSA also declined as the pyrolysis temperature increased. Furthermore, the constantly increasing pyrolysis temperature also caused the reactivity of char decrease, which is consistent with the results obtained by XRD. The higher combustion temperature resulted in the lower porosity and more fragments of the ash.
Although having been increasingly studied, there is still controversy as to when the addition of nanoparticles could improve the drag reduction performance of polymer drag reducer and particularly what is the underlyi...
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Although having been increasingly studied, there is still controversy as to when the addition of nanoparticles could improve the drag reduction performance of polymer drag reducer and particularly what is the underlying mechanism from the fluid dynamics viewpoint. The drag reduction effects of adding SiO_(2) nanoparticles to various polymer polyacrylamide(PAM) solutions were examined in this *** optimal combination of SiO_(2) nanoparticles with cationic polyacrylamide was ***,the addition of SiO_(2) nanoparticles to cationic polyacrylamide solution was shown to be quite efficient for reducing drag, but only at higher flow rates with Reynolds numbers more than 6000, below which the nanoparticle addition is even negative. The addition of SiO_(2) nanoparticles to the PAM solution is supposed to play a dual role. The first is an increase in flow resistance caused by the Brownian motion of nanoparticles, while the second is a decrease in flow resistance caused by acting as nodes to protect the polymer chain from shear-induced breaking under high shear action. At optimal nanoparticle concentration and under higher Reynolds numbers, the later effect is dominant, which could improve the drag reduction performance of polymer drag reducers. Our work should serve as a guide for the application of natural gas fracturing, where the flow rate is frequently very high.
Liquid Droplet Radiator (LDR) system is regarded as a quite promising waste heat rejection system for aerospace engineering.A comprehensive review on the state-of-the-art of LDR system was carried *** thermal design c...
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Liquid Droplet Radiator (LDR) system is regarded as a quite promising waste heat rejection system for aerospace engineering.A comprehensive review on the state-of-the-art of LDR system was carried *** thermal design considerations of crucial components such as working fluid,droplet generator and collector,intermediate heat exchanger,circulating pump and return pipe were *** state-of-the-art of existing mathematical models of radiation and evaporation characteristics of droplet layer from literatures were ***,thermal designs of three LDR systems were *** weight and required planform area between the rectangular and triangular LDR systems were respectively compared and the evaporation models for calculating the mass loss were *** on the review,some prospective studies of LDR system were put forward in this paper.
The supercritical water fluidized bed(SCWFB)is a recently introduced reactor for biomass gasification that does not release *** groups of Geldart B-type quartz sands with different particle sizes were fluidized at a s...
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The supercritical water fluidized bed(SCWFB)is a recently introduced reactor for biomass gasification that does not release *** groups of Geldart B-type quartz sands with different particle sizes were fluidized at a system pressure of 20-27 MPa and system temperature of 410-570℃.A series of experiments were performed for determining the drag coefficient and volume fraction of *** effects of the particles’size,superficial velocity,system pressure,and temperature on the drag coefficient and volume fraction are *** addition,a correlation between experimental and computed values is demonstrated for both the drag coefficient and volume fraction in *** relative error of the correlation is within±30%.The results of this study provide significant guidance for the scaling-up design of SCWFBs and for the development of supercritical water gasification technology.
Porous particle flow is universal in nature and ***,in previous numerical simulations,porous particles have usually been assumed to be *** is necessary to study the flow and heat-transfer characteristics around porous...
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Porous particle flow is universal in nature and ***,in previous numerical simulations,porous particles have usually been assumed to be *** is necessary to study the flow and heat-transfer characteristics around porous particles because they are greatly different from those of impermeable *** this study,two-dimensional steady flow and heat transfer around and through a porous particle with a constant temperature placed in a cold fluid were numerically *** effects of the Reynolds number(Re)and Darcy number(Da)on the flow and heat-transfer characteristics were investigated in *** investigated ranges of the parameters were 10≤Re≤40 and 10^(−6)≤Da≤10^(−2).It is sophisticated to simulate porous particles with traditional simulation methods because of their complicated ***,the lattice Boltzmann method was used to solve the generalized macroscopic governing equations because of its *** drag coefficient decreased with increasing Re or Da,but the decrease was not prominent in the range 10^(−6)≤Da≤10^(−4).The heat-transfer efficiency of the front surface was much stronger than that of the rear *** heat-transfer efficiency between the particle and the fluid increased with increasing Re or ***,for 10^(−6)≤Da≤10^(−4),the increase was not prominent and the heat-transfer enhancement ratio was slightly larger than ***,the effect of Da became more prominent at larger *** addition,new correlations for the drag coefficient and surface-averaged Nusselt number were obtained based on the simulated results.
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