The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimiz...The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimization and reactor design can be established by analyzing the solubility of hydrogen in liquefaction solvents.Experimental studies of hydrogen solubility in liquefaction solvents are challenging due to harsh reaction conditions and complex solvent compositions.In this study,the composition and content of liquefied solvents were analyzed.As model compounds,hexadecane,toluene,naphthalene,tetrahydronaphthalene,and phenanthrene were chosen to represent the liquefied solvents in chain alkanes and monocyclic,bicyclic,and tricyclic aromatic hydrocarbons.The solubility of hydrogen X(mol/mol)in pure solvent components and mixed solvents(alkanes and aromatics mixed in proportion to the chain alkanes+bicyclic aromatic hydrocarbons,bicyclic saturated aromatic hydrocarbons+bicyclic aromatic hydrocarbons,and bicyclic aromatic hydrocarbons+compounds containing het-eroatoms composed of mixed components)are determined using Aspen simulation at temperature and pressure conditions of 373–523 K and 2–10 MPa.The results demonstrated that at high temperatures and pressures,the solubility of hydrogen in the solvent increases with the increase in temperature and pressure,with the pressure having a greater impact.Further-more,the results revealed that hydrogen is more soluble in straight-chain alkanes than in other solvents,and the solubility of eicosanoids reaches a maximum of 0.296.The hydrogen solubility in aromatic ring compounds decreased gradually with an increase in the aromatic ring number.The influence of chain alkanes on the solubility of hydrogen predominates in a mixture of solvents with different mixing ratios of chain alkanes and aromatic hydrocarbons.The solubility of hydrogen in mixed aromatic solvents is less than that in the corresponding single solvents.Hydrogen is less soluble in solvent compounds containing heteroatoms than in compounds without heteroatoms.展开更多
Light olefins is the incredibly important materials in chemical industry.Methanol to olefins(MTO),which provides a non-oil route for light olefins production,received considerable attention in the past decades.However...Light olefins is the incredibly important materials in chemical industry.Methanol to olefins(MTO),which provides a non-oil route for light olefins production,received considerable attention in the past decades.However,the catalyst deactivation is an inevitable feature in MTO processes,and regeneration,therefore,is one of the key steps in industrial MTO processes.Traditionally the MTO catalyst is regenerated by removing the deposited coke via air combustion,which unavoidably transforms coke into carbon dioxide and reduces the carbon utilization efficiency.Recent study shows that the coke species over MTO catalyst can be regenerated via steam,which can promote the light olefins yield as the deactivated coke species can be essentially transferred to industrially useful synthesis gas,is a promising pathway for further MTO processes development.In this work,we modelled and analyzed these two MTO regeneration methods in terms of carbon utilization efficiency and technology economics.As shown,the steam regeneration could achieve a carbon utilization efficiency of 84.31%,compared to 74.74%for air combustion regeneration.The MTO processes using steam regeneration can essentially achieve the near-zero carbon emission.In addition,light olefins production of the MTO processes using steam regeneration is 12.81%higher than that using air combustion regeneration.In this regard,steam regeneration could be considered as a potential yet promising regeneration method for further MTO processes,showing not only great environmental benefits but also competitive economic performance.展开更多
In response to the lack of reliable physical parameters in the process simulation of the butadiene extraction,a large amount of phase equilibrium data were collected in the context of the actual process of butadiene p...In response to the lack of reliable physical parameters in the process simulation of the butadiene extraction,a large amount of phase equilibrium data were collected in the context of the actual process of butadiene production by acetonitrile.The accuracy of five prediction methods,UNIFAC(UNIQUAC Functional-group Activity Coefficients),UNIFAC-LL,UNIFAC-LBY,UNIFAC-DMD and COSMO-RS,applied to the butadiene extraction process was verified using partial phase equilibrium data.The results showed that the UNIFAC-DMD method had the highest accuracy in predicting phase equilibrium data for the missing system.COSMO-RS-predicted multiple systems showed good accuracy,and a large number of missing phase equilibrium data were estimated using the UNIFAC-DMD method and COSMO-RS method.The predicted phase equilibrium data were checked for consistency.The NRTL-RK(non-Random Two Liquid-Redlich-Kwong Equation of State)and UNIQUAC thermodynamic models were used to correlate the phase equilibrium data.Industrial device simulations were used to verify the accuracy of the thermodynamic model applied to the butadiene extraction process.The simulation results showed that the average deviations of the simulated results using the correlated thermodynamic model from the actual values were less than 2%compared to that using the commercial simulation software,Aspen Plus and its database.The average deviation was much smaller than that of the simulations using the Aspen Plus database(>10%),indicating that the obtained phase equilibrium data are highly accurate and reliable.The best phase equilibrium data and thermodynamic model parameters for butadiene extraction are provided.This improves the accuracy and reliability of the design,optimization and control of the process,and provides a basis and guarantee for developing a more environmentally friendly and economical butadiene extraction process.展开更多
This paper describes a simple, easy process for screening microorganisms, and introduces a laboratory simulation device and process of microbial enhanced oil recovery (MEOR) , which is a necessary research step for t...This paper describes a simple, easy process for screening microorganisms, and introduces a laboratory simulation device and process of microbial enhanced oil recovery (MEOR) , which is a necessary research step for trial in oilfields. The MEOR mechanism and the influence of adsorption, diffusion, metabolism, nutrition, porosity, and permeability are analyzed. The research indicates that different microbes have different efficiencies in EOR and that different culture types play different roles in EOR. The effect of syrup is better than that of glucose, and larger porosity is favorable to the reproduction and growth of microbes, thereby improving the oil recovery. Using crude oil as a single carbon source is more appreciable because of the decrease in cost of oil recovery. At the end of this paper, the development of polymerase chain reaction (PCR) for the future is discussed.展开更多
Simulations of photoresist etching,aerial image,exposure,and post-bake processes are integrated to obtain a photolithography process simulation for microelectromechanical system(MEMS) and integrated circuit(IC) fa...Simulations of photoresist etching,aerial image,exposure,and post-bake processes are integrated to obtain a photolithography process simulation for microelectromechanical system(MEMS) and integrated circuit(IC) fabrication based on three-dimensional (3D) cellular automata(CA). The simulation results agree well with available experimental results. This indicates that the 3D dynamic CA model for the photoresist etching simulation and the 3D CA model for the post-bake simulation could be useful for the monolithic simulation of various lithography processes. This is determined to be useful for the device-sized fabrication process simulation of IC and MEMS.展开更多
Considering the deficiency in milling process parameters selection, based on the modelling of dynamic milling force and the deduction of chatter stability limits, the chatter stability lobes simulation program for mil...Considering the deficiency in milling process parameters selection, based on the modelling of dynamic milling force and the deduction of chatter stability limits, the chatter stability lobes simulation program for milling is developed with MAT- LAB. The simulation optimization application software of dynamics was designed using engineering simulation software Visio Basic. The chatter stability lobes for milling, which can be used as an instruction guide for the selection of process parameters, are simulated with frequency response functions (FRFs) gained by hammer test. The validation and accuracy of the simulation algorithm are verified by experiments. The simulation method has been used in a factory with an excellent application effect.展开更多
The process and mechanism of the ligand volume controlled Pd(PR3)2 (PR3=PH3, PMe3, and PtBu3) oxidative addition with aryl bromide were investigated, using density functional theory method with the conductor-like ...The process and mechanism of the ligand volume controlled Pd(PR3)2 (PR3=PH3, PMe3, and PtBu3) oxidative addition with aryl bromide were investigated, using density functional theory method with the conductor-like screening model. Association pathway and dissocia-tion pathway were investigated by the comparison of several energies. The cleavage energy of Pd(PR3)2 complex was calculated, as well as the oxidative addition reaction barrier energy of Pd(PR3)n (n=1,2) with aryl bromide in N,N-dimethylformamide solvent. This study proved that the ligands volume possessed a great impact on the mechanism of oxidative addition: less bulky ligand palladium associated with aryl bromide via two donor ligands,but larger bulky ligand palladium coordinated via monoligand.展开更多
Hydrogenated microcrystalline silicon (~c-Si:H) films with a high deposition rate of 1.2nm/s were prepared by hot-wire chemical vapor deposition (HWCVD). The growth-front roughening processes of the μc-Si..H fil...Hydrogenated microcrystalline silicon (~c-Si:H) films with a high deposition rate of 1.2nm/s were prepared by hot-wire chemical vapor deposition (HWCVD). The growth-front roughening processes of the μc-Si..H films were investi- gated by atomic force microscopy. According to the scaling theory, the growth exponent β≈0.67, the roughness exponent α≈0.80,and the dynamic exponent 1/z = 0.40 are obtained. These scaling exponents cannot be explained well by the known growth models. An attempt at Monte Carlo simulation has been made to describe the growth process of μc-Si: H film using a particle reemission model where the incident flux distribution,the type and concentration of growth radical, and sticking,reemission,shadowing mechanisms all contributed to the growing morphology.展开更多
This paper presented a comparative study of monoethanolamine (MEA) and diethanolamine (DEA) for post- combustion CO2 capture (PCC) process with different process configurations to study the interaction effect be...This paper presented a comparative study of monoethanolamine (MEA) and diethanolamine (DEA) for post- combustion CO2 capture (PCC) process with different process configurations to study the interaction effect between solvent and process. The steady state process model of the conventional MEA-based PCC process was developed in Pro/II and was validated with the experimental data. Then ten different process configurations were simulated for both MEA and DEA. Their performances in energy consumption were compared in terms of reboiler duty and total equivalent work. The results show that DEA generally has better thermal performances than MEA for all these ten process configurations. Seven process configurations provide 0.38%-4.61% total energy saving compared with the conventional PCC process for MEA, and other two configurations are not favourable. For DEA, except one configuration, other process configurations have 0.27%-4.50% total energy saving. This work also analyzed the sensitivities of three key parameters (amine concentration, stripper pressure and lean solvent loading) in conventional process and five process modifications to show optimization strategy.展开更多
The recent works on the development of computational mass transfer (CMT) method and its applications in chemical process simulation are reviewed. Some development strategies and challenges in future research are als...The recent works on the development of computational mass transfer (CMT) method and its applications in chemical process simulation are reviewed. Some development strategies and challenges in future research are also discussed.展开更多
Against the realistic background of excess production capacity, product structure imbalance, and high material and energy consumption in steel enterprises, the implementation of operation optimization for the steel ma...Against the realistic background of excess production capacity, product structure imbalance, and high material and energy consumption in steel enterprises, the implementation of operation optimization for the steel manufacturing process is essential to reduce the production cost, increase the production or energy efficiency, and improve production management. In this study, the operation optimization problem of the steel manufacturing process, which needed to go through a complex production organization from customers' orders to workshop production, was analyzed. The existing research on the operation optimization techniques, including process simulation, production planning, production scheduling, interface scheduling, and scheduling of auxiliary equipment, was reviewed. The literature review reveals that, although considerable research has been conducted to optimize the operation of steel production, these techniques are usually independent and unsystematic.Therefore, the future work related to operation optimization of the steel manufacturing process based on the integration of multi technologies and the intersection of multi disciplines were summarized.展开更多
To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collec...To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collection plates were determined firstly. Then the model parameters for the resistance of perforated and collection plates, obtained by small-scale flow simulation, were validated by medium-scale experiments. Through the comparison of the resistance and velocity distribution between simulation results and experimental data, the simplified model is proved to present the resistance characteristics of perforated and collection plates accurately. Numerical results show that after optimization, both the flow rate and the pressure drop in the upper room of electric field regions are basically equivalent to those of the lower room, and the velocity distribution in flue inlet of WESP becomes more uniform. Through the application in practice, the effectiveness and reliability of the optimization scheme are proved, which can provide valuable reference for further optimization of WESP.展开更多
Coal bed methane has been considered as an important energy resource.One major difficulty of purifying coal bed methane comes from the similar physical properties of CH_4 and N_2.The ZIF-8/water-glycol slurry was used...Coal bed methane has been considered as an important energy resource.One major difficulty of purifying coal bed methane comes from the similar physical properties of CH_4 and N_2.The ZIF-8/water-glycol slurry was used as a medium to separate coal bed methane by fluidifying the solid adsorbent material.The sorption equilibrium experiment of binary mixture(CH_4/N_2)and slurry was conducted.The selectivity of CH_4 to N_2 is within the range of 2-6,which proved the feasibility of the slurry separation method.The modified Langmuir equation was used to describe the gas-slurry phase equilibrium behavior,and the calculated results were in good agreement with the experimental data.A continuous absorption-adsorption and desorption process on the separation of CH_4/N_2 in slurry is proposed and its mathematical model is also developed.Sensitivity analysis is conducted to determine the operation conditions and the energy performance of the proposed process was also evaluated.Feed gas contains 30 mol%of methane and the methane concentration in product gas is 95.46 mol%with the methane recovery ratio of 90.74%.The total energy consumption for per unit volume of product gas is determined as 1.846 kWh Nm^(-3).Experimental results and process simulation provide basic data for the design and operation of pilot and industrial plant.展开更多
The success of catalytic schemes for the large-scale valorization of CO_(2) does not only depend on the development of active,selective and stable catalytic materials but also on the overall process design.Here we pre...The success of catalytic schemes for the large-scale valorization of CO_(2) does not only depend on the development of active,selective and stable catalytic materials but also on the overall process design.Here we present a multidisciplinary study(from catalyst to plant and techno-economic/lifecycle analysis)for the production of green methanol from renewable H2 and CO_(2).We combine an in-depth kinetic analysis of one of the most promising recently reported methanol-synthesis catalysts(InCo)with a thorough process simulation and techno-economic assessment.We then perform a life cycle assessment of the simulated process to gauge the real environmental impact of green methanol production from CO_(2).Our results indicate that up to 1.75 ton of CO_(2) can be abated per ton of produced methanol only if renewable energy is used to run the process,while the sensitivity analysis suggest that either rock-bottom H2 prices(1.5$kg1)or severe CO_(2) taxation(300$per ton)are needed for a profitable methanol plant.Besides,we herein highlight and analyze some critical bottlenecks of the process.Especial attention has been paid to the contribution of H2 to the overall plant costs,CH4 trace formation,and purity and costs of raw gases.In addition to providing important information for policy makers and industrialists,directions for catalyst(and therefore process)improvements are outlined.展开更多
To optimize industrial Fischer-Tropsch (IT) synthesis with the slurry bubble column reactor (SBCR) and iron- based catalyst, a comprehensive process model for IT synthesis that includes a detailed SBCR model, gas ...To optimize industrial Fischer-Tropsch (IT) synthesis with the slurry bubble column reactor (SBCR) and iron- based catalyst, a comprehensive process model for IT synthesis that includes a detailed SBCR model, gas liquid separation model, simplified CO2 removal model and tail gas cycle model was developed. An effective iteration algorithm was proposed to solve this process model, and the model was validated by industrial demonstration experiments data (SBCR with 5.8 m diameter and 30 m height), with a maximum relative error 〈 10% for predicting the SBCR performances. Subsequently, the proposed model was adopted to optimize the industrial SBCR performances simultaneously considering process and reactor parameters variations. The results show that C5+yield increases as catalyst loading increases within 10-70 ton and syngas H2/CO value decreases within 1.3-1.6, but it doesn't increase obviously when the catalyst loading exceeds 45 ton (about 15 wt% concentration). Higher catalyst loading will result in higher difficulty for wax/catalyst separation and higher catalyst cost. There- fore, the catalyst loading (45 ton) is recommended for the industrial demonstration SBCR operation at syngas H2/ CO = 1.3, and the C5 + yield is about 402 ton" per day, which has an about 16% increase than the industrial dem- onstration run result.展开更多
Carbon dioxide(CO_(2))capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency,relatively low cost,and environmental impact.Polyvinylamine(PVAm)-based facilitated transp...Carbon dioxide(CO_(2))capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency,relatively low cost,and environmental impact.Polyvinylamine(PVAm)-based facilitated transport(FT)membranes were developed in the last decade for CO_(2) capture.This work discusses the challenges of applying PVAm-based FT membranes from materials to processes for postcombustion CO_(2) capture in power plants and cement factories.Experiences learned from a pilot demonstration system can be used to guide the design of other membranes for CO_(2) capture.The importance of module and process design is emphasized in the achievement of a high-performance membrane system.Moreover,the results from process simulation and cost estimation indicate that a three-stage membrane system is feasible for achieving a high CO_(2) purity of 95 vol%.The specific CO_(2) capture cost was found to significantly depend on the required CO_(2) capture ratio,and a moderate CO_(2) capture ratio of 50%presented a cost of 63.7USD per tonne CO_(2) captured.Thus,FT membrane systems were found to be more competitive for partial CO_(2) capture.展开更多
High strength compacted graphite iron (CGI) or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications.The mechanical engineering industry has recogniz...High strength compacted graphite iron (CGI) or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications.The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings.New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components.During the last 20 years,casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings.The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation.Depending on the alloy poured,different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting.Therefore,it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields.To be able to quantitatively predict these defects,solidification simulation had to be combined with density and mass transport calculations,in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges.For cast iron foundries,the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes,especially since the influence of alloying elements,melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron.This allows the prediction of local structures,phases and ultimately the local mechanical properties of cast irons,to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting.Casting quality issues related to thermally driven stresses in castings are also gaining increasing attention.State-of-the-art tools allow the prediction of residual stresses and iron casting distortion quantitatively.Cracks in castings can be assessed,as well as the reduction of casting stresses during heat treatment.As the property requirements for cast iron as a material in design strongly increase,new alloys and materials such as ADI might become more attractive,where latest software developments allow the modeling of the required heat treatment.Phases can be predicted and parametric studies can be performed to optimize the alloy dependent heat treatment conditions during austenitization,quenching and ausferritization.All this quantitative information about the material's performance is most valuable if it can be used during casting design.The transfer of local properties into the designer's world,to predict fatigue and durability as a function of the entire manufacturing route,will increase the trust in this old but highly innovative material and will open new opportunities for cast iron in the future.The paper will give an overview on current capabilities to quantitatively predict cast iron specific defects and casting performance and will highlight latest developments in modeling the manufacture of cast iron and ADI as well as the prediction of iron casting stresses.展开更多
The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO c...The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO content is usually stacked in residue field,easily draining away with the rain and corroding the soil.In this work,we coupled the treatment of flue gas and carbide slag to propose a facile CO_(2)mineralization route to prepare light calcium carbonate.And the route feasibility was comprehensively evaluated via experiments and simulation.Through experimental investigation,the Ca^(2+) leaching and mineralization reaction parameters were determined.Based on the experiment,a process was built and optimized through Aspen Plus,and the energy was integrated to obtain the overall process energy and material consumption.Finally,the net CO_(2)emission reduction rate of the entire process through the life-cycle assessment method was analyzed.Moreover,the relationship between the parameters and the CO_(2)emission life-cycle assessment was established.The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO_(2))^(-1) of energy(including heat energy of 979.32 kW·h·(t CO_(2))^(-1) and electrical energy of 175.37 kW·h·(t CO_(2))^(-1)),and the net CO_(2)emission reduction rate was 35.8%.The light CaCO_(3)product can be sold as a high value-added product.According to preliminary economic analysis,the profit of mineralizing can reach more than 2,100 CNY·(t CO_(2))^(-1).展开更多
基金the financial support from the National Key Research and Development Program of China(2022YFB4101302-01)the National Natural Science Foundation of China(22178243)the science and technology innovation project of China Shenhua Coal to Liquid and Chemical Company Limited(MZYHG-22–02).
文摘The cyclic hydrogenation technology in a direct coal liquefaction process relies on the dissolved hydrogen of the solvent or oil participating in the hydrogenation reaction.Thus,a theoretical basis for process optimization and reactor design can be established by analyzing the solubility of hydrogen in liquefaction solvents.Experimental studies of hydrogen solubility in liquefaction solvents are challenging due to harsh reaction conditions and complex solvent compositions.In this study,the composition and content of liquefied solvents were analyzed.As model compounds,hexadecane,toluene,naphthalene,tetrahydronaphthalene,and phenanthrene were chosen to represent the liquefied solvents in chain alkanes and monocyclic,bicyclic,and tricyclic aromatic hydrocarbons.The solubility of hydrogen X(mol/mol)in pure solvent components and mixed solvents(alkanes and aromatics mixed in proportion to the chain alkanes+bicyclic aromatic hydrocarbons,bicyclic saturated aromatic hydrocarbons+bicyclic aromatic hydrocarbons,and bicyclic aromatic hydrocarbons+compounds containing het-eroatoms composed of mixed components)are determined using Aspen simulation at temperature and pressure conditions of 373–523 K and 2–10 MPa.The results demonstrated that at high temperatures and pressures,the solubility of hydrogen in the solvent increases with the increase in temperature and pressure,with the pressure having a greater impact.Further-more,the results revealed that hydrogen is more soluble in straight-chain alkanes than in other solvents,and the solubility of eicosanoids reaches a maximum of 0.296.The hydrogen solubility in aromatic ring compounds decreased gradually with an increase in the aromatic ring number.The influence of chain alkanes on the solubility of hydrogen predominates in a mixture of solvents with different mixing ratios of chain alkanes and aromatic hydrocarbons.The solubility of hydrogen in mixed aromatic solvents is less than that in the corresponding single solvents.Hydrogen is less soluble in solvent compounds containing heteroatoms than in compounds without heteroatoms.
基金the financial support from the Strategic Priority Research Program of Chinese Academy of Sciences(XDA21010100)。
文摘Light olefins is the incredibly important materials in chemical industry.Methanol to olefins(MTO),which provides a non-oil route for light olefins production,received considerable attention in the past decades.However,the catalyst deactivation is an inevitable feature in MTO processes,and regeneration,therefore,is one of the key steps in industrial MTO processes.Traditionally the MTO catalyst is regenerated by removing the deposited coke via air combustion,which unavoidably transforms coke into carbon dioxide and reduces the carbon utilization efficiency.Recent study shows that the coke species over MTO catalyst can be regenerated via steam,which can promote the light olefins yield as the deactivated coke species can be essentially transferred to industrially useful synthesis gas,is a promising pathway for further MTO processes development.In this work,we modelled and analyzed these two MTO regeneration methods in terms of carbon utilization efficiency and technology economics.As shown,the steam regeneration could achieve a carbon utilization efficiency of 84.31%,compared to 74.74%for air combustion regeneration.The MTO processes using steam regeneration can essentially achieve the near-zero carbon emission.In addition,light olefins production of the MTO processes using steam regeneration is 12.81%higher than that using air combustion regeneration.In this regard,steam regeneration could be considered as a potential yet promising regeneration method for further MTO processes,showing not only great environmental benefits but also competitive economic performance.
基金supported by the National Natural Science Foundation of China(22178190)。
文摘In response to the lack of reliable physical parameters in the process simulation of the butadiene extraction,a large amount of phase equilibrium data were collected in the context of the actual process of butadiene production by acetonitrile.The accuracy of five prediction methods,UNIFAC(UNIQUAC Functional-group Activity Coefficients),UNIFAC-LL,UNIFAC-LBY,UNIFAC-DMD and COSMO-RS,applied to the butadiene extraction process was verified using partial phase equilibrium data.The results showed that the UNIFAC-DMD method had the highest accuracy in predicting phase equilibrium data for the missing system.COSMO-RS-predicted multiple systems showed good accuracy,and a large number of missing phase equilibrium data were estimated using the UNIFAC-DMD method and COSMO-RS method.The predicted phase equilibrium data were checked for consistency.The NRTL-RK(non-Random Two Liquid-Redlich-Kwong Equation of State)and UNIQUAC thermodynamic models were used to correlate the phase equilibrium data.Industrial device simulations were used to verify the accuracy of the thermodynamic model applied to the butadiene extraction process.The simulation results showed that the average deviations of the simulated results using the correlated thermodynamic model from the actual values were less than 2%compared to that using the commercial simulation software,Aspen Plus and its database.The average deviation was much smaller than that of the simulations using the Aspen Plus database(>10%),indicating that the obtained phase equilibrium data are highly accurate and reliable.The best phase equilibrium data and thermodynamic model parameters for butadiene extraction are provided.This improves the accuracy and reliability of the design,optimization and control of the process,and provides a basis and guarantee for developing a more environmentally friendly and economical butadiene extraction process.
文摘This paper describes a simple, easy process for screening microorganisms, and introduces a laboratory simulation device and process of microbial enhanced oil recovery (MEOR) , which is a necessary research step for trial in oilfields. The MEOR mechanism and the influence of adsorption, diffusion, metabolism, nutrition, porosity, and permeability are analyzed. The research indicates that different microbes have different efficiencies in EOR and that different culture types play different roles in EOR. The effect of syrup is better than that of glucose, and larger porosity is favorable to the reproduction and growth of microbes, thereby improving the oil recovery. Using crude oil as a single carbon source is more appreciable because of the decrease in cost of oil recovery. At the end of this paper, the development of polymerase chain reaction (PCR) for the future is discussed.
文摘Simulations of photoresist etching,aerial image,exposure,and post-bake processes are integrated to obtain a photolithography process simulation for microelectromechanical system(MEMS) and integrated circuit(IC) fabrication based on three-dimensional (3D) cellular automata(CA). The simulation results agree well with available experimental results. This indicates that the 3D dynamic CA model for the photoresist etching simulation and the 3D CA model for the post-bake simulation could be useful for the monolithic simulation of various lithography processes. This is determined to be useful for the device-sized fabrication process simulation of IC and MEMS.
基金Tianjin Municipal Association of Higher Vocational&Technical Education Projects(No.XIV412)
文摘Considering the deficiency in milling process parameters selection, based on the modelling of dynamic milling force and the deduction of chatter stability limits, the chatter stability lobes simulation program for milling is developed with MAT- LAB. The simulation optimization application software of dynamics was designed using engineering simulation software Visio Basic. The chatter stability lobes for milling, which can be used as an instruction guide for the selection of process parameters, are simulated with frequency response functions (FRFs) gained by hammer test. The validation and accuracy of the simulation algorithm are verified by experiments. The simulation method has been used in a factory with an excellent application effect.
基金This work was supported by the National Natural Science Foundation of China (No.20776089) and the New Century Excellent Talents Program of Ministry of Education (No.NCET-05-0783). The State Key Laboratory of Polymer Materials Engineering in Sichuan University was acknowledged for providing dmol3 modules and Prof. Ying Xue, Xiang-yuan Li, and Quan Zhu were grateful for the useful discussions.
文摘The process and mechanism of the ligand volume controlled Pd(PR3)2 (PR3=PH3, PMe3, and PtBu3) oxidative addition with aryl bromide were investigated, using density functional theory method with the conductor-like screening model. Association pathway and dissocia-tion pathway were investigated by the comparison of several energies. The cleavage energy of Pd(PR3)2 complex was calculated, as well as the oxidative addition reaction barrier energy of Pd(PR3)n (n=1,2) with aryl bromide in N,N-dimethylformamide solvent. This study proved that the ligands volume possessed a great impact on the mechanism of oxidative addition: less bulky ligand palladium associated with aryl bromide via two donor ligands,but larger bulky ligand palladium coordinated via monoligand.
文摘Hydrogenated microcrystalline silicon (~c-Si:H) films with a high deposition rate of 1.2nm/s were prepared by hot-wire chemical vapor deposition (HWCVD). The growth-front roughening processes of the μc-Si..H films were investi- gated by atomic force microscopy. According to the scaling theory, the growth exponent β≈0.67, the roughness exponent α≈0.80,and the dynamic exponent 1/z = 0.40 are obtained. These scaling exponents cannot be explained well by the known growth models. An attempt at Monte Carlo simulation has been made to describe the growth process of μc-Si: H film using a particle reemission model where the incident flux distribution,the type and concentration of growth radical, and sticking,reemission,shadowing mechanisms all contributed to the growing morphology.
文摘This paper presented a comparative study of monoethanolamine (MEA) and diethanolamine (DEA) for post- combustion CO2 capture (PCC) process with different process configurations to study the interaction effect between solvent and process. The steady state process model of the conventional MEA-based PCC process was developed in Pro/II and was validated with the experimental data. Then ten different process configurations were simulated for both MEA and DEA. Their performances in energy consumption were compared in terms of reboiler duty and total equivalent work. The results show that DEA generally has better thermal performances than MEA for all these ten process configurations. Seven process configurations provide 0.38%-4.61% total energy saving compared with the conventional PCC process for MEA, and other two configurations are not favourable. For DEA, except one configuration, other process configurations have 0.27%-4.50% total energy saving. This work also analyzed the sensitivities of three key parameters (amine concentration, stripper pressure and lean solvent loading) in conventional process and five process modifications to show optimization strategy.
基金Supported by the National Science Foundation of China(20736005).ACKNOWLEDGEMENTSThe authors acknowledge the assistance from thestaff in the State Key Laboratories of Chemical Engineering (Tianjin University).
文摘The recent works on the development of computational mass transfer (CMT) method and its applications in chemical process simulation are reviewed. Some development strategies and challenges in future research are also discussed.
基金financially supported by the National Natural Science Foundation of China (No.51734004)the National Key Research and Development Program of China (No.2017YFB0304005)the National Natural Science Foundation of China (No.51474044)。
文摘Against the realistic background of excess production capacity, product structure imbalance, and high material and energy consumption in steel enterprises, the implementation of operation optimization for the steel manufacturing process is essential to reduce the production cost, increase the production or energy efficiency, and improve production management. In this study, the operation optimization problem of the steel manufacturing process, which needed to go through a complex production organization from customers' orders to workshop production, was analyzed. The existing research on the operation optimization techniques, including process simulation, production planning, production scheduling, interface scheduling, and scheduling of auxiliary equipment, was reviewed. The literature review reveals that, although considerable research has been conducted to optimize the operation of steel production, these techniques are usually independent and unsystematic.Therefore, the future work related to operation optimization of the steel manufacturing process based on the integration of multi technologies and the intersection of multi disciplines were summarized.
文摘To improve the dust removal performance of the wet electrostatic precipitator(WESP), a flow field optimization scheme was proposed via CFD simulation in different scales. The simplified models of perforated and collection plates were determined firstly. Then the model parameters for the resistance of perforated and collection plates, obtained by small-scale flow simulation, were validated by medium-scale experiments. Through the comparison of the resistance and velocity distribution between simulation results and experimental data, the simplified model is proved to present the resistance characteristics of perforated and collection plates accurately. Numerical results show that after optimization, both the flow rate and the pressure drop in the upper room of electric field regions are basically equivalent to those of the lower room, and the velocity distribution in flue inlet of WESP becomes more uniform. Through the application in practice, the effectiveness and reliability of the optimization scheme are proved, which can provide valuable reference for further optimization of WESP.
基金The financial supports received from the National Natural Science Foundation of China(21522609,21636009 and 21878328)the National Key Research and Development Program of China(Nos.2017YFC0307302,2016YFC0304003)+1 种基金the Science Foundation of China University of Petroleum,Beijing(No.2462018BJC004)Beijing Science and Technology Program,China(No.Z181100005118010)。
文摘Coal bed methane has been considered as an important energy resource.One major difficulty of purifying coal bed methane comes from the similar physical properties of CH_4 and N_2.The ZIF-8/water-glycol slurry was used as a medium to separate coal bed methane by fluidifying the solid adsorbent material.The sorption equilibrium experiment of binary mixture(CH_4/N_2)and slurry was conducted.The selectivity of CH_4 to N_2 is within the range of 2-6,which proved the feasibility of the slurry separation method.The modified Langmuir equation was used to describe the gas-slurry phase equilibrium behavior,and the calculated results were in good agreement with the experimental data.A continuous absorption-adsorption and desorption process on the separation of CH_4/N_2 in slurry is proposed and its mathematical model is also developed.Sensitivity analysis is conducted to determine the operation conditions and the energy performance of the proposed process was also evaluated.Feed gas contains 30 mol%of methane and the methane concentration in product gas is 95.46 mol%with the methane recovery ratio of 90.74%.The total energy consumption for per unit volume of product gas is determined as 1.846 kWh Nm^(-3).Experimental results and process simulation provide basic data for the design and operation of pilot and industrial plant.
基金support from the King Abdullah University of Science and Technology(KAUST).T.Cordero-Lanzac and A.T.Aguayo acknowledge the financial support received from the Spanish Ministry of Science and Innovation with some ERDF funds(CTQ2016-77812-R)the Basque Government(IT1218-19)+2 种基金T.Cordero-Lanzac also acknowledges the Spanish Ministry of Education,Culture and Sport for the award of his FPU grant(FPU15-01666)A.Navajas and L.M.Gandía gratefully acknowledge the financial support from Spanish Ministerio de Ciencia,Innovación y Universidades,and the European Regional Development Fund(ERDF/FEDER)(grant RTI2018-096294-B-C31)L.M.Gandía also thanks Banco de Santander and Universidad Pública de Navarra for their financial support under“Programa de Intensificación de la Investigación 2018”initiative.
文摘The success of catalytic schemes for the large-scale valorization of CO_(2) does not only depend on the development of active,selective and stable catalytic materials but also on the overall process design.Here we present a multidisciplinary study(from catalyst to plant and techno-economic/lifecycle analysis)for the production of green methanol from renewable H2 and CO_(2).We combine an in-depth kinetic analysis of one of the most promising recently reported methanol-synthesis catalysts(InCo)with a thorough process simulation and techno-economic assessment.We then perform a life cycle assessment of the simulated process to gauge the real environmental impact of green methanol production from CO_(2).Our results indicate that up to 1.75 ton of CO_(2) can be abated per ton of produced methanol only if renewable energy is used to run the process,while the sensitivity analysis suggest that either rock-bottom H2 prices(1.5$kg1)or severe CO_(2) taxation(300$per ton)are needed for a profitable methanol plant.Besides,we herein highlight and analyze some critical bottlenecks of the process.Especial attention has been paid to the contribution of H2 to the overall plant costs,CH4 trace formation,and purity and costs of raw gases.In addition to providing important information for policy makers and industrialists,directions for catalyst(and therefore process)improvements are outlined.
基金Supported by the National Key R&D Program of China(2017YFB0602500)
文摘To optimize industrial Fischer-Tropsch (IT) synthesis with the slurry bubble column reactor (SBCR) and iron- based catalyst, a comprehensive process model for IT synthesis that includes a detailed SBCR model, gas liquid separation model, simplified CO2 removal model and tail gas cycle model was developed. An effective iteration algorithm was proposed to solve this process model, and the model was validated by industrial demonstration experiments data (SBCR with 5.8 m diameter and 30 m height), with a maximum relative error 〈 10% for predicting the SBCR performances. Subsequently, the proposed model was adopted to optimize the industrial SBCR performances simultaneously considering process and reactor parameters variations. The results show that C5+yield increases as catalyst loading increases within 10-70 ton and syngas H2/CO value decreases within 1.3-1.6, but it doesn't increase obviously when the catalyst loading exceeds 45 ton (about 15 wt% concentration). Higher catalyst loading will result in higher difficulty for wax/catalyst separation and higher catalyst cost. There- fore, the catalyst loading (45 ton) is recommended for the industrial demonstration SBCR operation at syngas H2/ CO = 1.3, and the C5 + yield is about 402 ton" per day, which has an about 16% increase than the industrial dem- onstration run result.
文摘Carbon dioxide(CO_(2))capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency,relatively low cost,and environmental impact.Polyvinylamine(PVAm)-based facilitated transport(FT)membranes were developed in the last decade for CO_(2) capture.This work discusses the challenges of applying PVAm-based FT membranes from materials to processes for postcombustion CO_(2) capture in power plants and cement factories.Experiences learned from a pilot demonstration system can be used to guide the design of other membranes for CO_(2) capture.The importance of module and process design is emphasized in the achievement of a high-performance membrane system.Moreover,the results from process simulation and cost estimation indicate that a three-stage membrane system is feasible for achieving a high CO_(2) purity of 95 vol%.The specific CO_(2) capture cost was found to significantly depend on the required CO_(2) capture ratio,and a moderate CO_(2) capture ratio of 50%presented a cost of 63.7USD per tonne CO_(2) captured.Thus,FT membrane systems were found to be more competitive for partial CO_(2) capture.
文摘High strength compacted graphite iron (CGI) or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications.The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings.New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components.During the last 20 years,casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings.The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation.Depending on the alloy poured,different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting.Therefore,it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields.To be able to quantitatively predict these defects,solidification simulation had to be combined with density and mass transport calculations,in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges.For cast iron foundries,the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes,especially since the influence of alloying elements,melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron.This allows the prediction of local structures,phases and ultimately the local mechanical properties of cast irons,to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting.Casting quality issues related to thermally driven stresses in castings are also gaining increasing attention.State-of-the-art tools allow the prediction of residual stresses and iron casting distortion quantitatively.Cracks in castings can be assessed,as well as the reduction of casting stresses during heat treatment.As the property requirements for cast iron as a material in design strongly increase,new alloys and materials such as ADI might become more attractive,where latest software developments allow the modeling of the required heat treatment.Phases can be predicted and parametric studies can be performed to optimize the alloy dependent heat treatment conditions during austenitization,quenching and ausferritization.All this quantitative information about the material's performance is most valuable if it can be used during casting design.The transfer of local properties into the designer's world,to predict fatigue and durability as a function of the entire manufacturing route,will increase the trust in this old but highly innovative material and will open new opportunities for cast iron in the future.The paper will give an overview on current capabilities to quantitatively predict cast iron specific defects and casting performance and will highlight latest developments in modeling the manufacture of cast iron and ADI as well as the prediction of iron casting stresses.
基金the support from National Natural Science Foundation of China(22078208)the Major Science and Technology Projects of Inner Mongolia Autonomous Region(2020ZD0025)China Chengda Engineering Co.,Ltd.for its software support。
文摘The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO content is usually stacked in residue field,easily draining away with the rain and corroding the soil.In this work,we coupled the treatment of flue gas and carbide slag to propose a facile CO_(2)mineralization route to prepare light calcium carbonate.And the route feasibility was comprehensively evaluated via experiments and simulation.Through experimental investigation,the Ca^(2+) leaching and mineralization reaction parameters were determined.Based on the experiment,a process was built and optimized through Aspen Plus,and the energy was integrated to obtain the overall process energy and material consumption.Finally,the net CO_(2)emission reduction rate of the entire process through the life-cycle assessment method was analyzed.Moreover,the relationship between the parameters and the CO_(2)emission life-cycle assessment was established.The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO_(2))^(-1) of energy(including heat energy of 979.32 kW·h·(t CO_(2))^(-1) and electrical energy of 175.37 kW·h·(t CO_(2))^(-1)),and the net CO_(2)emission reduction rate was 35.8%.The light CaCO_(3)product can be sold as a high value-added product.According to preliminary economic analysis,the profit of mineralizing can reach more than 2,100 CNY·(t CO_(2))^(-1).