Traditional data-driven fault diagnosis methods depend on expert experience to manually extract effective fault features of signals,which has certain limitations.Conversely,deep learning techniques have gained promine...Traditional data-driven fault diagnosis methods depend on expert experience to manually extract effective fault features of signals,which has certain limitations.Conversely,deep learning techniques have gained prominence as a central focus of research in the field of fault diagnosis by strong fault feature extraction ability and end-to-end fault diagnosis efficiency.Recently,utilizing the respective advantages of convolution neural network(CNN)and Transformer in local and global feature extraction,research on cooperating the two have demonstrated promise in the field of fault diagnosis.However,the cross-channel convolution mechanism in CNN and the self-attention calculations in Transformer contribute to excessive complexity in the cooperative model.This complexity results in high computational costs and limited industrial applicability.To tackle the above challenges,this paper proposes a lightweight CNN-Transformer named as SEFormer for rotating machinery fault diagnosis.First,a separable multiscale depthwise convolution block is designed to extract and integrate multiscale feature information from different channel dimensions of vibration signals.Then,an efficient self-attention block is developed to capture critical fine-grained features of the signal from a global perspective.Finally,experimental results on the planetary gearbox dataset and themotor roller bearing dataset prove that the proposed framework can balance the advantages of robustness,generalization and lightweight compared to recent state-of-the-art fault diagnosis models based on CNN and Transformer.This study presents a feasible strategy for developing a lightweight rotating machinery fault diagnosis framework aimed at economical deployment.展开更多
Phosphorylated sugars,recognized as central intermediates in carbohydrate metabolism and critical precursors for enzymatic synthesis of rare sugars,face significant technical barriers in their industrialscale producti...Phosphorylated sugars,recognized as central intermediates in carbohydrate metabolism and critical precursors for enzymatic synthesis of rare sugars,face significant technical barriers in their industrialscale production.The multi-enzymatic preparation systems for these compounds inherently accumulate complex impurities,including protein-based catalysts,residual substrates,and oligosaccharide byproducts,posing persistent challenges in product separation and biocatalyst recycling.To address this limitation,we conducted a systematic investigation of ultrafiltration-based separation strategies during the multi-enzyme-catalyzed synthesis of fructose-1,6-bisphosphate(FDP),with particular emphasis on membrane fouling mechanisms.By screening the ultrafiltration membranes,UE020 showed the best performance in the model system,achieving significant separation targets:99.97% retention of bovine serum albumin,FDP/maltodextrin separation coefficient of 7.41,and FDP recovery of 93.63%.An analysis of the components of resistance revealed that concentration polarization induced by maltodextrin was the main factor constituting the resistance,irreversible resistance due to bovine serum albumin was a secondary effect,and the resistance constituted by FDP was negligible.A mitigation strategy employing powdered activated carbon for dynamic membrane formation significantly improved system performance,reducing irreversible resistance by 59.14% and enhancing flux recovery by 20.85%.In this study,ultrafiltration was strategically employed to achieve efficient separation of FDP and enzyme recovery.Significantly,we deciphered the synergistic fouling mechanisms arising from interactions within the multicomponent system containing phosphorylated sugars,oligosaccharides,and proteins.These findings provide a mechanistic framework for scaling up multi-enzymatic systems dedicated to phosphorylated sugar biosynthesis,effectively bridging the gap between laboratory-scale synthesis and industrial implementation.展开更多
Secondary aluminum dross(SAD),a by-product of aluminum extraction from primary aluminum dross,contains metallic aluminum particles coated with dense oxidized films,complicating the recovery of metallic aluminum using ...Secondary aluminum dross(SAD),a by-product of aluminum extraction from primary aluminum dross,contains metallic aluminum particles coated with dense oxidized films,complicating the recovery of metallic aluminum using traditional methods.Ball-milling was employed to break and alter the structure of these oxidized films.The results indicated that the films became thinner and stripped away,exposing the aluminum surface.Based on the in-situ observation of the structure evolution of milled SAD particles with temperature,the metallic aluminum liquid was efficiently recovered from SAD at 680℃via supergravity-enhanced separation,where the recovery ratio and mass fraction of Al in the separated aluminum phase were up to 95.72%and 99.10 wt.%,respectively.Moreover,the tailings can be harmlessly utilized in refractory,cement and ceramic fields with subsequent treatment,such as denitrification,dechlorination,and fluoride fixation.展开更多
In this study,the Stokes formula is used to analyze the separation effect of three-phase separators used in a Oilfield Central Processing Facility.The considered main influencing factors include(but are not limited to...In this study,the Stokes formula is used to analyze the separation effect of three-phase separators used in a Oilfield Central Processing Facility.The considered main influencing factors include(but are not limited to)the typical size of oil and water droplets,the residence time and temperature of fluid and the dosage of demulsifier.Using the“Specification for Oil and Gas Separators”as a basis,the control loops and operating parameters of each separator are optimized Considering the Halfaya Oilfield as a testbed,it is shown that the proposed approach can lead to good results in the production stage.展开更多
The basic flow model of laminar flow field and the trajectory model of dispersed phase drops are derived. Based on the comparable volumetric flow rate, the dispersed flow rate can be linearly discretized. Consequently...The basic flow model of laminar flow field and the trajectory model of dispersed phase drops are derived. Based on the comparable volumetric flow rate, the dispersed flow rate can be linearly discretized. Consequently, the trajectory of a droplet in the channel can be tracked, and the trajectories of all drops are observed in order to statistically analyse the drops for capture or entrainment. Therefore, in terms of theoretical model of motion, the stratified two phase flow systems are studied in the mixture of nitrobenzene and concentrated sulfuric acid. The analytical results indicate that the trajectories of droplets of different diameters are different at the same location. The larger droplets can help to promote the efficiency of plate separators. The thickness of trickling film has a significant influence on the efficiency of numerical simulation when the concentration of the dispersed phase is greater than 10%. So the modification of thickness of trickling film can help to get the real flow field efficiency. The low flow rate lowers the average Renolds number so that the lighter phase droplets have sufficient time to interact with the trickling film. It is an indispensable factor for predicting efficiency that coalesced drops flow off inclined plates together with trickling films. A comparison confirms that the simulation results are in good agreement with the experiment results.展开更多
Three-phase centrifuge was used to process oily sludge,and the requirement of mud,oil and water three-phase separation was satisfied through the optimization of parameters. The results showed that when the input quant...Three-phase centrifuge was used to process oily sludge,and the requirement of mud,oil and water three-phase separation was satisfied through the optimization of parameters. The results showed that when the input quantity was lower than 5 m^3/h,the optimal operation parameters of the three-phase centrifuge are shown as follows: the frequency of the main motor and vice motor was 33 and 30 Hz respectively,and the flocculant flow was 0. 7 m^3/h,while the oily sludge temperature was 55 ℃. Water content in the separated sludge decreased from 98% to lower than 70%,and the goal of reduction and harmless treatment of oily sludge could be achieved,which could provide essential conditions for subsequent resource utilization and could be used to guide industrial production.展开更多
The CO2 separation from natural gas, syngas or flue gas represents an important industrial field of applications. An economic and energy-efficient CO2 separation from these gas streams is a prerequisite for sustainabl...The CO2 separation from natural gas, syngas or flue gas represents an important industrial field of applications. An economic and energy-efficient CO2 separation from these gas streams is a prerequisite for sustainable industry contributions to the megatrends resource efficiency and globalization of technologies. One way of reducing operational expenditure for these separation processes is the development of better performing CO2 absorbents. Although a number of absorbents for the separation of CO2 from process gas streams exist, the need for the development of CO2 absorbents with an improved absorption performance, less corrosion and foaming, no nitrosamine formation, lower energy requirement and therefore less operational expenditure remains. Recent industrial activities have led to the development of novel high-performance CO2 scrubbing agents that can be employed in numerous industrial processes such as natural gas treatment, purification of syngas and the scrubbing of flue gas. The objective of this paper is to introduce these new high-performance scrubbing agents and to compare their performance with other state-of-the-art absorbents. It turned out, that the evaluated absorbents offer high cyclic capacities in the range of 2.4 to 2.6 mol CO2/kg absorbent and low absorption enthalpies (–30 kJ/mol) allowing for distinctive savings in the regeneration energy of the absorbent. Calculations with the modified Kremser model resulted in a reduction of the specific reboiler heat duty of 55%. Furthermore, the absorbents are less corrosive than standard amines as indicated by the measured corrosion rates of 0.21 mm/y versus 1.18 mm/y for a piperazine/methyldiethanolamine mixture. Based on new experimental results it is shown how substantial savings in operational and capital expenditure can be realized due to favorable absorbent properties. The novel high-performance CO2 system solutions meet recent industrial absorbent requirements and allow for more efficient or new CO2 separation processes.展开更多
In this paper, we combined magnetostatics and laminar flow in microfluidics and studied a particle separation scheme employing magnetophoretic force in inhomogeneous magnetic field. A detailed model and analysis is sh...In this paper, we combined magnetostatics and laminar flow in microfluidics and studied a particle separation scheme employing magnetophoretic force in inhomogeneous magnetic field. A detailed model and analysis is shown and the proposed scheme is capable of efficiently separating magnetic particles with different permeability and sizes. The method shows a way to separate efficient particles and could potentially be implemented in biological and chemical systems.展开更多
As the core component of circulating fluidized bed boiler, the efficiency of separator directly affects the safe and economic operation of the unit. Two 300MW circulating fluidized bed boilers in Diaobingshan Gangue P...As the core component of circulating fluidized bed boiler, the efficiency of separator directly affects the safe and economic operation of the unit. Two 300MW circulating fluidized bed boilers in Diaobingshan Gangue Power Plant have been put into operation since 2009 and 2010. Because the separator is in a high temperature and high circulating ash operating environment, the inner cylinder of the separator is worn and deformed rapidly, and the efficiency of the separator is greatly reduced, resulting in excessively high bed temperature and separator temperature, an increase in the original amount of environmental protection, and an increase in the cost of environmental protection materials, which affects the safe and economic operation of the unit. In view of this phenomenon, Diaobingshan Coal Gangue Power Plant has improved the efficiency of two furnace separators. After the transformation and operation, the bed temperature and the outlet temperature of the separator have dropped significantly during the operation of the unit, and the original amount of environmental protection has dropped significantly, and the consumption of environmental protection materials has dropped significantly, and the energy-saving effect is remarkable.展开更多
The gas/liquid spiral separator, a key component in the compressed air system, was used to remove liquid and oil from gas stream by centrifugal and gravitational forces. To optimize the design of the separator,the rel...The gas/liquid spiral separator, a key component in the compressed air system, was used to remove liquid and oil from gas stream by centrifugal and gravitational forces. To optimize the design of the separator,the relationship between the performance and structural parameters of separators is studied. Computational fluid dynamics (CFD) method is employed to simulate the flow fields and calculate the pressure drop and separation efficiency of air-liquid spiral separators with different structural parameters. The RSM (Reynolds stress model)turbulence model is used to analyze the highly swirling flow fields while the stochastic trajectory model is used to simulate the traces of liquid droplets in the flow field. A simplified calculation formula of pressure drop in spiral structures is obtained by modifying Darcy's equation and verified by experiment.展开更多
A desulphurization experimental study under the effects of compounding physical force fields has been described for 〈 0.5 mm fine particles of high sulfur coal. A statistical test using the Box-Behnken Design of expe...A desulphurization experimental study under the effects of compounding physical force fields has been described for 〈 0.5 mm fine particles of high sulfur coal. A statistical test using the Box-Behnken Design of experiments was conducted to evaluate the effects of individual operating variables and their interactions on desulfurization of fine coal using an enhanced centrifugal gravity separator. A model describing the relation between desulphurization efficiency of pyrite sulfur and different operating variables has been designed. The interactions between different factors on the pyrite sulfur desulphurization efficiency have been analysed. The optimal test conditions for desulfarization are extracted from the Design-Expert 6.0 software. Finally, the pointed out. advantage of centrifugal gravity separation for fine coal is pointed out.展开更多
Diffractive optical elements（DOEs） with spectrum separation and beam concentration（SSBC） functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into seve...Diffractive optical elements（DOEs） with spectrum separation and beam concentration（SSBC） functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.展开更多
The herringbone water-sediment separation structure(HWSSS) was developed to prevent debris flows. This paper mainly focuses on evaluating the sediment separation efficiency of HWSSS in debris flow prevention and deter...The herringbone water-sediment separation structure(HWSSS) was developed to prevent debris flows. This paper mainly focuses on evaluating the sediment separation efficiency of HWSSS in debris flow prevention and determining the grid opening width D, a crucial structure parameter for HWSSS design. Theoretical analysis on the total sediment separation rate Pt reveals that the efficiency of sediment separation is much related with sediment grain size distribution(GSD) and grid opening width. The lower limit of Pt is deduced from the perspective of safety consideration by transforming debris flow into sediment-laden flow. Hydraulic model tests were carried out. Based on the regression analysis of the experimental data, the quantitative relationships between Pt and D and GSD characteristic values were finally established. A procedure for determining optimal grid opening width is proposed based on these analyses. These results are of significance in evaluating sediment separation effect by HWSSS in debris flow prevention and contribute to a more explicit methodology for design of HWSSS.展开更多
The cyclone separator is an important separation device.This paper presents a new type of embedded two-stage cyclone,which includes a 2 nd-stage cyclone(internal traditional cyclone)with multiple inlets and a 1 st-sta...The cyclone separator is an important separation device.This paper presents a new type of embedded two-stage cyclone,which includes a 2 nd-stage cyclone(internal traditional cyclone)with multiple inlets and a 1 st-stage cyclone(outer cylinder)that unifies the 2 nd-stage cyclone inlets into one inlet.The Taguchi experimental method was used to study the two-stage cyclone separator’s inlet area on its performance.Studies have shown that the increase of the 1 st-stage cyclone inlet area and the increase in the number of 2 nd-stage cyclone inlets(N)positively affect reducing the pressure drop and a negative effect on efficiency.It is recommended to use 2 S(the original 1 st-stage cyclone inlet area)of the 1 st-stage cyclone inlet area and 2 N of the 2 nd-stage cyclone inlets when separating fine particles.Compared with a traditional cyclone,the pressure drop is reduced by 1303 Pa,the mass separation efficiency(Eq)is increased by 0.56%,and the number separation efficiency(En)is increased by 2.05%.When separating larger particles,it is recommended to use 2 S of the 1 st-stage cyclone inlet area and 4 N of the 2 nd-stage cyclone inlets.Compared with a traditional cyclone,although Endecreases slightly,the pressure drop is reduced by 3055 Pa,and the Eqis increased by 0.56%.The research results provide new insight into the design of the cyclone.展开更多
Vortices motion in the anisotropic turbulent flow of cyclones makes a vital impact on flow stability and collection performance.Nevertheless,there remains a lack of clarity in the overall feature of vortices motion.In...Vortices motion in the anisotropic turbulent flow of cyclones makes a vital impact on flow stability and collection performance.Nevertheless,there remains a lack of clarity in the overall feature of vortices motion.In this work,a numerical analysis was conducted to clarify the complex motion of the vortex core in a cyclone separator.The validity of the numerical model was demonstrated by comparing the computational results with experimental data in the literature.As revealed by the results,the vortex core not only has a precession motion about the geometrical center axis but also does a nutation motion in the axial direction.The frequencies of the precession motions show two main peaks.And the magnitudes of the precession and nutation motions have non-uniform distributions in the cyclone.Moreover,the precession-nutation motions of the vortex cores exhibit a similar fluctuant pattern to the dust ring on the separator wall.The inlet gas velocity and the inlet solid loading show vital effects on the magnitudes and frequencies of precession and nutation motion.展开更多
Sand production often leads to the failure of production equipment on offshore platform.Therefore,a new idea has been put forward,which is installing cyclone or baffle in the internal of the slug catcher for better sa...Sand production often leads to the failure of production equipment on offshore platform.Therefore,a new idea has been put forward,which is installing cyclone or baffle in the internal of the slug catcher for better sand control.In this paper,an experimental study is presented,which mainly includes sand particles accumulation shape,migration law and separation performance.The results suggest that the accumulation area is mainly divided into two zones:the crowded settlement zone and the free settlement zone.The crowded settlement zone has a special shape,which can be characterized by two parameters:accumulation length and accumulation angle.Axial sampling analysis shows obvious particle classification.Median particle size decreases with the increase of the axial distance,and the range of particle size distribution narrows gradually.The separation experiment shows that the gas velocity has the greatest influence on the separation efficiency.When the gas velocity is 14 m·s^ 1,the separation efficiency drops sharply,which can be abated by installing cyclone separator.In addition,the separation efficiency tends to be a constant under different gas velocities by installing baffle with appropriate height.Then the effectiveness and rationality of installing internal components can be strongly proved.All these provide important guidance for maximizing the sand control function of the slug catcher.展开更多
As primary separators in pressurized water reactors (PWRs), cyclone separators separate most of the water from vapor-water two-phase mixture, which is important to the safety and economics of nuclear power plants. To ...As primary separators in pressurized water reactors (PWRs), cyclone separators separate most of the water from vapor-water two-phase mixture, which is important to the safety and economics of nuclear power plants. To improve the performance of cyclone separators, we tested new structures in this study, e.g. porosity and inclined angle of the separator wall. Under different structures, separation efficiency and pressure drop were studied theoretically and experimentally. Results show that each of the structural parameters has an effect on separator performance, but none of the trends is monotonically in experimental ranges. Besides separator structures, the comprehensive performance is also determined by flow patterns. From segregated to homogeneous flow, the separation ability decreases. The separation efficiency is about 5% higher at 20° inclined angle when the superficial velocities are 0.012 and 16 m·s-1 for the liquid and gas, respectively. The separation efficiency is only 91% without an impeller, while it is up to 100% at the same superficial velocities of air and water, 16 and 0.015 m·s-1 , respectively. Based on the study, it is promising to understand deeply the separation mechanism and further to provide data for designing large-scaled separators for advanced pressurized water reactors.展开更多
Coal is primarily beneficiated by wet gravity methods. The wet processing of coal is an efficient practice. However, it introduces the moisture in the range of 6%-15%, depending upon the size of coal which is as detri...Coal is primarily beneficiated by wet gravity methods. The wet processing of coal is an efficient practice. However, it introduces the moisture in the range of 6%-15%, depending upon the size of coal which is as detrimental as ash content to the heating value of coal. Dry beneficiation of coal fines was carried out using an air fluidized vibrating table in which the coal particles get separated from the heavier mineral particles as a result of horizontal and vertical stratification. Two level factorial design matrix was used to optimize and assess the interactive effects of the operational parameters of a pneumatic table viz. deck eccentric, side tilt and air flow rate on the clean coal yield and its ash content. Double stage processing was found to be more effective for reducing the ash content of the clean coal. Initial stage of processing at a higher ash level generates a reject of high ash with low combustibles. Cleaning of the rougher concentrate at 34%-35% ash level shows significant improvement in the organic efficiency （88.6%） and useful heat value of clean coal （15690 kJ/kg）. The performance of air fluidized vibrating deck was measured by Ep value which is 0.18.展开更多
The effects of separation time and magnetic induction intensity on the separation efficiency of alumina particles with diameters varying from 30 to 200 μm in aluminum melt were investigated. The experimental results ...The effects of separation time and magnetic induction intensity on the separation efficiency of alumina particles with diameters varying from 30 to 200 μm in aluminum melt were investigated. The experimental results show that the particle-accumulated layer is formed in the periphery of the solidified specimen when the diameter of the separated molten metal, the magnetic induction intensity and the separation time are 10 mm, 0.04 T and 1 s, respectively. When the separation time is 2 s, the particle-accumulated layer can be observed obviously and the separation efficiency is about 80%. There are few alumina particles in the inner of the solidified specimen when the separation time is 3 s. The separation efficiency higher than 85% can be achieved when the separation time is longer than 3 s. When the magnetic induction intensity is 0.06 T, the visible particle-accumulated layer can be formed in 1 s and the separation efficiency is higher than 95%. The experimental results were compared with the calculated results at last.展开更多
基金supported by the National Natural Science Foundation of China(No.52277055).
文摘Traditional data-driven fault diagnosis methods depend on expert experience to manually extract effective fault features of signals,which has certain limitations.Conversely,deep learning techniques have gained prominence as a central focus of research in the field of fault diagnosis by strong fault feature extraction ability and end-to-end fault diagnosis efficiency.Recently,utilizing the respective advantages of convolution neural network(CNN)and Transformer in local and global feature extraction,research on cooperating the two have demonstrated promise in the field of fault diagnosis.However,the cross-channel convolution mechanism in CNN and the self-attention calculations in Transformer contribute to excessive complexity in the cooperative model.This complexity results in high computational costs and limited industrial applicability.To tackle the above challenges,this paper proposes a lightweight CNN-Transformer named as SEFormer for rotating machinery fault diagnosis.First,a separable multiscale depthwise convolution block is designed to extract and integrate multiscale feature information from different channel dimensions of vibration signals.Then,an efficient self-attention block is developed to capture critical fine-grained features of the signal from a global perspective.Finally,experimental results on the planetary gearbox dataset and themotor roller bearing dataset prove that the proposed framework can balance the advantages of robustness,generalization and lightweight compared to recent state-of-the-art fault diagnosis models based on CNN and Transformer.This study presents a feasible strategy for developing a lightweight rotating machinery fault diagnosis framework aimed at economical deployment.
基金the funding support provided by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDC0120402)the National Key Research&Development Program of China (2022YFC2105103)。
文摘Phosphorylated sugars,recognized as central intermediates in carbohydrate metabolism and critical precursors for enzymatic synthesis of rare sugars,face significant technical barriers in their industrialscale production.The multi-enzymatic preparation systems for these compounds inherently accumulate complex impurities,including protein-based catalysts,residual substrates,and oligosaccharide byproducts,posing persistent challenges in product separation and biocatalyst recycling.To address this limitation,we conducted a systematic investigation of ultrafiltration-based separation strategies during the multi-enzyme-catalyzed synthesis of fructose-1,6-bisphosphate(FDP),with particular emphasis on membrane fouling mechanisms.By screening the ultrafiltration membranes,UE020 showed the best performance in the model system,achieving significant separation targets:99.97% retention of bovine serum albumin,FDP/maltodextrin separation coefficient of 7.41,and FDP recovery of 93.63%.An analysis of the components of resistance revealed that concentration polarization induced by maltodextrin was the main factor constituting the resistance,irreversible resistance due to bovine serum albumin was a secondary effect,and the resistance constituted by FDP was negligible.A mitigation strategy employing powdered activated carbon for dynamic membrane formation significantly improved system performance,reducing irreversible resistance by 59.14% and enhancing flux recovery by 20.85%.In this study,ultrafiltration was strategically employed to achieve efficient separation of FDP and enzyme recovery.Significantly,we deciphered the synergistic fouling mechanisms arising from interactions within the multicomponent system containing phosphorylated sugars,oligosaccharides,and proteins.These findings provide a mechanistic framework for scaling up multi-enzymatic systems dedicated to phosphorylated sugar biosynthesis,effectively bridging the gap between laboratory-scale synthesis and industrial implementation.
基金supported by the National Natural Science Foundation of China(Nos.52304342,52174275,51774037)the China Postdoctoral Science Foundation(No.2021M700393)。
文摘Secondary aluminum dross(SAD),a by-product of aluminum extraction from primary aluminum dross,contains metallic aluminum particles coated with dense oxidized films,complicating the recovery of metallic aluminum using traditional methods.Ball-milling was employed to break and alter the structure of these oxidized films.The results indicated that the films became thinner and stripped away,exposing the aluminum surface.Based on the in-situ observation of the structure evolution of milled SAD particles with temperature,the metallic aluminum liquid was efficiently recovered from SAD at 680℃via supergravity-enhanced separation,where the recovery ratio and mass fraction of Al in the separated aluminum phase were up to 95.72%and 99.10 wt.%,respectively.Moreover,the tailings can be harmlessly utilized in refractory,cement and ceramic fields with subsequent treatment,such as denitrification,dechlorination,and fluoride fixation.
基金This study was supported by the Natural Science Foundation of Shandong Province(Grant No.ZR2021QE030).
文摘In this study,the Stokes formula is used to analyze the separation effect of three-phase separators used in a Oilfield Central Processing Facility.The considered main influencing factors include(but are not limited to)the typical size of oil and water droplets,the residence time and temperature of fluid and the dosage of demulsifier.Using the“Specification for Oil and Gas Separators”as a basis,the control loops and operating parameters of each separator are optimized Considering the Halfaya Oilfield as a testbed,it is shown that the proposed approach can lead to good results in the production stage.
文摘The basic flow model of laminar flow field and the trajectory model of dispersed phase drops are derived. Based on the comparable volumetric flow rate, the dispersed flow rate can be linearly discretized. Consequently, the trajectory of a droplet in the channel can be tracked, and the trajectories of all drops are observed in order to statistically analyse the drops for capture or entrainment. Therefore, in terms of theoretical model of motion, the stratified two phase flow systems are studied in the mixture of nitrobenzene and concentrated sulfuric acid. The analytical results indicate that the trajectories of droplets of different diameters are different at the same location. The larger droplets can help to promote the efficiency of plate separators. The thickness of trickling film has a significant influence on the efficiency of numerical simulation when the concentration of the dispersed phase is greater than 10%. So the modification of thickness of trickling film can help to get the real flow field efficiency. The low flow rate lowers the average Renolds number so that the lighter phase droplets have sufficient time to interact with the trickling film. It is an indispensable factor for predicting efficiency that coalesced drops flow off inclined plates together with trickling films. A comparison confirms that the simulation results are in good agreement with the experiment results.
文摘Three-phase centrifuge was used to process oily sludge,and the requirement of mud,oil and water three-phase separation was satisfied through the optimization of parameters. The results showed that when the input quantity was lower than 5 m^3/h,the optimal operation parameters of the three-phase centrifuge are shown as follows: the frequency of the main motor and vice motor was 33 and 30 Hz respectively,and the flocculant flow was 0. 7 m^3/h,while the oily sludge temperature was 55 ℃. Water content in the separated sludge decreased from 98% to lower than 70%,and the goal of reduction and harmless treatment of oily sludge could be achieved,which could provide essential conditions for subsequent resource utilization and could be used to guide industrial production.
文摘The CO2 separation from natural gas, syngas or flue gas represents an important industrial field of applications. An economic and energy-efficient CO2 separation from these gas streams is a prerequisite for sustainable industry contributions to the megatrends resource efficiency and globalization of technologies. One way of reducing operational expenditure for these separation processes is the development of better performing CO2 absorbents. Although a number of absorbents for the separation of CO2 from process gas streams exist, the need for the development of CO2 absorbents with an improved absorption performance, less corrosion and foaming, no nitrosamine formation, lower energy requirement and therefore less operational expenditure remains. Recent industrial activities have led to the development of novel high-performance CO2 scrubbing agents that can be employed in numerous industrial processes such as natural gas treatment, purification of syngas and the scrubbing of flue gas. The objective of this paper is to introduce these new high-performance scrubbing agents and to compare their performance with other state-of-the-art absorbents. It turned out, that the evaluated absorbents offer high cyclic capacities in the range of 2.4 to 2.6 mol CO2/kg absorbent and low absorption enthalpies (–30 kJ/mol) allowing for distinctive savings in the regeneration energy of the absorbent. Calculations with the modified Kremser model resulted in a reduction of the specific reboiler heat duty of 55%. Furthermore, the absorbents are less corrosive than standard amines as indicated by the measured corrosion rates of 0.21 mm/y versus 1.18 mm/y for a piperazine/methyldiethanolamine mixture. Based on new experimental results it is shown how substantial savings in operational and capital expenditure can be realized due to favorable absorbent properties. The novel high-performance CO2 system solutions meet recent industrial absorbent requirements and allow for more efficient or new CO2 separation processes.
文摘In this paper, we combined magnetostatics and laminar flow in microfluidics and studied a particle separation scheme employing magnetophoretic force in inhomogeneous magnetic field. A detailed model and analysis is shown and the proposed scheme is capable of efficiently separating magnetic particles with different permeability and sizes. The method shows a way to separate efficient particles and could potentially be implemented in biological and chemical systems.
文摘As the core component of circulating fluidized bed boiler, the efficiency of separator directly affects the safe and economic operation of the unit. Two 300MW circulating fluidized bed boilers in Diaobingshan Gangue Power Plant have been put into operation since 2009 and 2010. Because the separator is in a high temperature and high circulating ash operating environment, the inner cylinder of the separator is worn and deformed rapidly, and the efficiency of the separator is greatly reduced, resulting in excessively high bed temperature and separator temperature, an increase in the original amount of environmental protection, and an increase in the cost of environmental protection materials, which affects the safe and economic operation of the unit. In view of this phenomenon, Diaobingshan Coal Gangue Power Plant has improved the efficiency of two furnace separators. After the transformation and operation, the bed temperature and the outlet temperature of the separator have dropped significantly during the operation of the unit, and the original amount of environmental protection has dropped significantly, and the consumption of environmental protection materials has dropped significantly, and the energy-saving effect is remarkable.
文摘The gas/liquid spiral separator, a key component in the compressed air system, was used to remove liquid and oil from gas stream by centrifugal and gravitational forces. To optimize the design of the separator,the relationship between the performance and structural parameters of separators is studied. Computational fluid dynamics (CFD) method is employed to simulate the flow fields and calculate the pressure drop and separation efficiency of air-liquid spiral separators with different structural parameters. The RSM (Reynolds stress model)turbulence model is used to analyze the highly swirling flow fields while the stochastic trajectory model is used to simulate the traces of liquid droplets in the flow field. A simplified calculation formula of pressure drop in spiral structures is obtained by modifying Darcy's equation and verified by experiment.
文摘A desulphurization experimental study under the effects of compounding physical force fields has been described for 〈 0.5 mm fine particles of high sulfur coal. A statistical test using the Box-Behnken Design of experiments was conducted to evaluate the effects of individual operating variables and their interactions on desulfurization of fine coal using an enhanced centrifugal gravity separator. A model describing the relation between desulphurization efficiency of pyrite sulfur and different operating variables has been designed. The interactions between different factors on the pyrite sulfur desulphurization efficiency have been analysed. The optimal test conditions for desulfarization are extracted from the Design-Expert 6.0 software. Finally, the pointed out. advantage of centrifugal gravity separation for fine coal is pointed out.
基金Project supported by the National Basic Research Program of China(Grant No.2013CBA01702)the National Natural Science Foundation of China(Grant Nos.11474206,91233202,11374216,and 11404224)+1 种基金the Scientific Research Project of Beijing Education Commission,China(Grant No.KM201310028005)the Scientific Research Base Development Program of the Beijing Municipal Commission of Education and the Beijing Youth Top-Notch Talent Training Plan,China(Grant No.CIT&TCD201504080)
文摘Diffractive optical elements（DOEs） with spectrum separation and beam concentration（SSBC） functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.
基金supported by the National Science and Technology Support Program (2011BAK12B00)
文摘The herringbone water-sediment separation structure(HWSSS) was developed to prevent debris flows. This paper mainly focuses on evaluating the sediment separation efficiency of HWSSS in debris flow prevention and determining the grid opening width D, a crucial structure parameter for HWSSS design. Theoretical analysis on the total sediment separation rate Pt reveals that the efficiency of sediment separation is much related with sediment grain size distribution(GSD) and grid opening width. The lower limit of Pt is deduced from the perspective of safety consideration by transforming debris flow into sediment-laden flow. Hydraulic model tests were carried out. Based on the regression analysis of the experimental data, the quantitative relationships between Pt and D and GSD characteristic values were finally established. A procedure for determining optimal grid opening width is proposed based on these analyses. These results are of significance in evaluating sediment separation effect by HWSSS in debris flow prevention and contribute to a more explicit methodology for design of HWSSS.
基金financially supported by the National Key Research and Development Program of China(2016YFC0801700)the Project of the National Natural Science Foundation of China(51604018)the Basic Research Funding of the China Academy of Safety Science and Technology(2019JBKY11 and 2019JBKY04)。
文摘The cyclone separator is an important separation device.This paper presents a new type of embedded two-stage cyclone,which includes a 2 nd-stage cyclone(internal traditional cyclone)with multiple inlets and a 1 st-stage cyclone(outer cylinder)that unifies the 2 nd-stage cyclone inlets into one inlet.The Taguchi experimental method was used to study the two-stage cyclone separator’s inlet area on its performance.Studies have shown that the increase of the 1 st-stage cyclone inlet area and the increase in the number of 2 nd-stage cyclone inlets(N)positively affect reducing the pressure drop and a negative effect on efficiency.It is recommended to use 2 S(the original 1 st-stage cyclone inlet area)of the 1 st-stage cyclone inlet area and 2 N of the 2 nd-stage cyclone inlets when separating fine particles.Compared with a traditional cyclone,the pressure drop is reduced by 1303 Pa,the mass separation efficiency(Eq)is increased by 0.56%,and the number separation efficiency(En)is increased by 2.05%.When separating larger particles,it is recommended to use 2 S of the 1 st-stage cyclone inlet area and 4 N of the 2 nd-stage cyclone inlets.Compared with a traditional cyclone,although Endecreases slightly,the pressure drop is reduced by 3055 Pa,and the Eqis increased by 0.56%.The research results provide new insight into the design of the cyclone.
基金Authors thank for the joint funding of a Key Research and Development Plan of Shandong Province(Public Science and Technology)(2019GSF109038)the Key Laboratory of Multiphase Flow Reaction and Separation Engineering of Shandong Province(2019MFRSE-A01)the National Natural Science Foundation of China(51809236).
文摘Vortices motion in the anisotropic turbulent flow of cyclones makes a vital impact on flow stability and collection performance.Nevertheless,there remains a lack of clarity in the overall feature of vortices motion.In this work,a numerical analysis was conducted to clarify the complex motion of the vortex core in a cyclone separator.The validity of the numerical model was demonstrated by comparing the computational results with experimental data in the literature.As revealed by the results,the vortex core not only has a precession motion about the geometrical center axis but also does a nutation motion in the axial direction.The frequencies of the precession motions show two main peaks.And the magnitudes of the precession and nutation motions have non-uniform distributions in the cyclone.Moreover,the precession-nutation motions of the vortex cores exhibit a similar fluctuant pattern to the dust ring on the separator wall.The inlet gas velocity and the inlet solid loading show vital effects on the magnitudes and frequencies of precession and nutation motion.
文摘Sand production often leads to the failure of production equipment on offshore platform.Therefore,a new idea has been put forward,which is installing cyclone or baffle in the internal of the slug catcher for better sand control.In this paper,an experimental study is presented,which mainly includes sand particles accumulation shape,migration law and separation performance.The results suggest that the accumulation area is mainly divided into two zones:the crowded settlement zone and the free settlement zone.The crowded settlement zone has a special shape,which can be characterized by two parameters:accumulation length and accumulation angle.Axial sampling analysis shows obvious particle classification.Median particle size decreases with the increase of the axial distance,and the range of particle size distribution narrows gradually.The separation experiment shows that the gas velocity has the greatest influence on the separation efficiency.When the gas velocity is 14 m·s^ 1,the separation efficiency drops sharply,which can be abated by installing cyclone separator.In addition,the separation efficiency tends to be a constant under different gas velocities by installing baffle with appropriate height.Then the effectiveness and rationality of installing internal components can be strongly proved.All these provide important guidance for maximizing the sand control function of the slug catcher.
基金Supported by National Natural Science Foundation of China (No. 51006068)Science and Technology on Reactor System Design Technology Laboratory,Nuclear Power Institute of China
文摘As primary separators in pressurized water reactors (PWRs), cyclone separators separate most of the water from vapor-water two-phase mixture, which is important to the safety and economics of nuclear power plants. To improve the performance of cyclone separators, we tested new structures in this study, e.g. porosity and inclined angle of the separator wall. Under different structures, separation efficiency and pressure drop were studied theoretically and experimentally. Results show that each of the structural parameters has an effect on separator performance, but none of the trends is monotonically in experimental ranges. Besides separator structures, the comprehensive performance is also determined by flow patterns. From segregated to homogeneous flow, the separation ability decreases. The separation efficiency is about 5% higher at 20° inclined angle when the superficial velocities are 0.012 and 16 m·s-1 for the liquid and gas, respectively. The separation efficiency is only 91% without an impeller, while it is up to 100% at the same superficial velocities of air and water, 16 and 0.015 m·s-1 , respectively. Based on the study, it is promising to understand deeply the separation mechanism and further to provide data for designing large-scaled separators for advanced pressurized water reactors.
文摘Coal is primarily beneficiated by wet gravity methods. The wet processing of coal is an efficient practice. However, it introduces the moisture in the range of 6%-15%, depending upon the size of coal which is as detrimental as ash content to the heating value of coal. Dry beneficiation of coal fines was carried out using an air fluidized vibrating table in which the coal particles get separated from the heavier mineral particles as a result of horizontal and vertical stratification. Two level factorial design matrix was used to optimize and assess the interactive effects of the operational parameters of a pneumatic table viz. deck eccentric, side tilt and air flow rate on the clean coal yield and its ash content. Double stage processing was found to be more effective for reducing the ash content of the clean coal. Initial stage of processing at a higher ash level generates a reject of high ash with low combustibles. Cleaning of the rougher concentrate at 34%-35% ash level shows significant improvement in the organic efficiency （88.6%） and useful heat value of clean coal （15690 kJ/kg）. The performance of air fluidized vibrating deck was measured by Ep value which is 0.18.
基金Projects(50474055, 50274018) supported by the National Natural Science Foundation of ChinaProject (20052176) supported by the Natural Science Foundation of Liaoning Province, China
文摘The effects of separation time and magnetic induction intensity on the separation efficiency of alumina particles with diameters varying from 30 to 200 μm in aluminum melt were investigated. The experimental results show that the particle-accumulated layer is formed in the periphery of the solidified specimen when the diameter of the separated molten metal, the magnetic induction intensity and the separation time are 10 mm, 0.04 T and 1 s, respectively. When the separation time is 2 s, the particle-accumulated layer can be observed obviously and the separation efficiency is about 80%. There are few alumina particles in the inner of the solidified specimen when the separation time is 3 s. The separation efficiency higher than 85% can be achieved when the separation time is longer than 3 s. When the magnetic induction intensity is 0.06 T, the visible particle-accumulated layer can be formed in 1 s and the separation efficiency is higher than 95%. The experimental results were compared with the calculated results at last.
