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Enhanced Temperature difference control of distillation columns based on the averaged absolute variation magnitude

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Chinese Journal of Chemical Engineering 2021年第1期34卷 266-278页

作者： Yang Yuan Kejin Huang Xing Qian Haisheng Chen Lijing Zang Liang Zhang College of Information Science and Technology Beijing University of Chemical TechnologyBeijing 100029China

Temperature difference control(TDC)schemes can clearly suppress the adverse influence of pressure variations on product quality control of various distillation columns(DCs)by employing Temperature differences(TDs)between the sensitive stage temperature(T_(S))and reference stage temperature(T_(R)),i.e.,T_(S)-T_(R),to infer the controlled product qualities.However,because the TDC scheme has failed to specially take the corresponding relationship between the TD employed in each control loop and the controlled product quality into account,it may suffer from relatively large steady-state errors in the controlled product qualities.To address this problem,an enhanced TDC(ETDC)scheme is proposed in the current article,in which an enhanced TD(ETD),i.e.,T_(S)-α×T_(R),is employed to replace the conventional TD for each control loop.While the locations of the sensitive and reference stages of the ETD are respectively determined according to sensitivity analysis and SVD analysis,the adjusted coefficientαis set to be the ratio between the averaged absolute variation magnitudes(AAVMs)of the T_(S)and T_(R)so that the relationship between the T_(S)and T_(R)can be appropriately coordinated.With reference to the operations of three different distillation systems,i.e.,one conventional DC distilling an ethanol(E)/butanol(B)binary mixture,one conventional DC distilling an E/propanol(P)/B ternary mixture,and one dividing-wall distillation column distilling an E/P/B ternary mixture,the performance of the ETDC scheme is assessed by compared with the conventional TDC scheme and the double TD control(DTDC)scheme.The dynamic simulation results show that the ETDC scheme is better than the conventional TDC scheme with reduced steady-state errors in the controlled product qualities and improved dynamic responses,and is comparable with the DTDC scheme despite the less temperature measurements are employed.

关键词： Distillation column Temperature difference AAVM temperature inferential control Process control

Electrode connection optimization for both Temperature difference and purification of lanthanum rod during solid-state electrotransport

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Rare Metals 2023年第2期42卷 713-718页

作者： Jia-Min Zhong Zong-An Li Xiao-Wei Zhang Lin Zhou Zhi-Qiang Wang De-Hong Chen National Engineering Research Center for Rare Earth Materials Grirem Advanced Materials Co.Ltd.General Research Institute for Nonferrous MetalsBeijing100088China

In order to solve the problem of large Temperature difference between the center and ends of the metallic rod in the purification process of solid-state electrotransport(SSE),three types of electrode connections of tantalum and the corresponding rods of metallic lanthanum were designed,the temperature distributions of three kinds of rod were measured,and the influence of Temperature difference on the purification effect of solid-state electrotransport was investigated.The results indicate that the maximum Temperature difference of the rod will be significantly reduced through decreasing the cross section of electrode connection to make its unit length resistance close to that of rod,or increasing the unit length resistance of the section at both ends of the rod.When these two measures are adopted at the same time,the effect of decreasing rod Temperature difference is the best in the present study,and the maximum Temperature difference of the rod can be reduced to 29℃when the maximum temperature of the rod is 820℃.The migration velocity of the impurities at rod ends can be obviously improved after the rod Temperature difference is reduced,which enables the purification effect and efficiency of solid-state electrotransport to be greatly raised;it is also found that the major impurities iron in metallic lanthanum migrates more easily than oxygen and carbon during the purification of metal lanthanum with solid-state electrotransport.

关键词： Solid-state electrotransport Electrode connection Temperature difference Metallic lanthanum Purification effect

Single Neuron PID Control Based on Expert Experiences for Temperature difference Control System of a Digester

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Paper And Biomaterials 2017年第1期2卷 52-58页

作者： YaNan Huang AiJuan Zhang MuYi Hu Jiangsu Provincial Key Laboratory of Pulp and Paper Science and Technology Nanjing Forestry UniversityNanjingJiangsu Province210037China

Considering the Temperature difference of displacement cooking characterized by severe non-linearity, large time delay, and real-time control, a cascade PID adaptive control strategy composed of a single neuron is proposed to ensure cooking temperature uniformity. The control strategy introduces expert experiences to adjust the single neuron gain K, while a single neuron PID self-learning and adaptive ability, as well as cascade advantage can be combined to realize the real-time and fast Temperature difference control. In the Simulink, the s-function of this control strategy is used to carry out a dynamic simulation experiment with Temperature difference characteristics and verify the robustness and response to model mismatch. Compared to conventional Temperature difference-flow PID cascade control and single neuron PID cascade control, this control strategy has better robustness and stronger adaptability. The results of real-time control on the THJSK-1 experiment platform indicate this control strategy is feasible.

关键词： displacement cooking Temperature difference expert experiences single neuron cascade PID

Numerical Simulation of Heat Transfer Performance for Ultra-Thin Flat Heat Pipe

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Journal of Thermal Science 2023年第2期32卷 643-649页

作者： YAN Wentao YANG Xin LIU Tengqing WANG Shuangfeng School of Electric Power South China University of TechnologyGuangzhou 510640China Key Laboratory of Enhanced Heat Transfer and Energy Conservation of the Ministry of Education School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

The heat transfer performance of ultra-thin flat heat pipes with#180 copper mesh wick was studied by numerical simulation for different heating powers.The length,width and height of the ultra-thin flat heat pipe are 80 mm,8.5 mm and 1 mm,respectively.The temperature distribution and flow characteristics of ultra-thin flat heat pipes were simulated by coupling porous media model and user-defined function(UDF)in FLUENT.To validate the accuracy of the numerical model,the simulation results of the ultra-thin flat heat pipe are compared with the experimental data in predicting the evaporation section temperature.The numerical model has good accuracy for the one-dimensional heat transfer method of ultra-thin flat heat pipes.The velocity,pressure drop of the wick and total Temperature difference have the same variation trend.With the increase of heating power,the Temperature difference of ultra-thin flat heat pipes increases,and the pressure drop and the liquid velocity in the wick also increase.

关键词： ultra-thin flat heat pipes evaporation section temperature Temperature difference copper mesh simulation

Hole-growth phenomenon during pyrolysis of a cation-exchange resin particle

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第12期23卷 974-987页

作者： Zheng-liang HUANG Yun-bo YU Qi SONG Yao YANG Jing-yuan SUN Jing-dai WANG Yong-rong YANG Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology College of Chemical and Biological EngineeringZhejiangUniversityHangzhou 310027China State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China

A novel central hole-expansion phenomenon is identified, in which the cation-exchange resin is pyrolyzed in a mixed atmosphere of nitrogen and oxygen at 400–500 ℃. In this reaction, the reaction path is predictable and always starts from the center of the resin particle to form a central hole, then continues and expands around the hole, finally forming a uniformly distributed hole group;the particle surface remains intact. Analysis shows that this formation mode is due to the different reaction paths of sulfonic groups between the surface and interior of the particle, caused by the Temperature difference. On the surface, transformation reactions happen at high temperatures(410–500 ℃) to form stable organic sulfur structures, while decomposition occurs inside the particle at a relatively low temperature(<410 ℃) and promotes complete pyrolysis of the copolymer matrix to form holes.

关键词： Non-catalytic gas-solid reaction Cation-exchange resin Pyrolysis Central-hole expansion Temperature difference Transformation

Organization and evolution of climate responsive strategies,used in Turpan vernacular buildings in arid region of China

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Frontiers of Architectural Research 2023年第3期12卷 556-574页

作者： Wenfang He Zhenying Wu Ran Jin Jiaping Liu School of Architecture Xi’an University of Architecture and TechnologyXi’an 710055China State Key Laboratory of Green Building in Western China Xi’an University of Architecture and TechnologyXi’an 710055China

Under the global crisis of energy shortage and environmental pollution,the climate responsive strategies used in vernacular buildings have attracted much attention for their potential to reduce energy consumption and carbon emissions.However,the relationships between these traditional climatic strategies were not precisely perceived,which may cause the inapplicability of these strategies for contemporary rural houses.In this paper,taking the Turpan vernacular buildings in arid region of China,the climate responsive strategies of buildings in the most significant periods such as the Gaochang period(before 1318),the Khanate and Republican period(1318–1949),the Modern period(1949–2010),and the Contemporary period(2011–present)were summarized.In addition,two different types of climatic strategies organizations,namely multilayer spaces and integrated building envelopes,were identified based on the Temperature difference measurement and comparative analysis.The assessment of thermal performance of the organizations was conducted by the methodology of software simulation.Furthermore,the applicability of the organizations in rural areas was discussed,and a new combined organization was proposed.Consequently,this study can contribute to provide the main approaches for climatically responsive rural houses.

关键词： Climate responsive strategy Vernacular building Organization Temperature difference Multilayer space Arid

Simulation of three-stage operating temperature for supersaturation water-based condensational growth tube

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Journal of Environmental Sciences 2020年第4期32卷 275-285页

作者： Jiejie Bian Huaqiao Gui Zhibo Xie Tongzhu Yu Xiuli Wei Wenyu Wang Jianguo Liu Key Laboratory of Environmental Optics and Technology Anhui Institute of Optics and Fine MechanicsChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China CAS Center for Excellence in Regional Atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

In order to realize accurate dynamic control of supersaturation and to study condensation growth characteristics of nanoparticles through different levels of super saturation,a series of parametric analyses and systematic comparisons between two-stage and three-stage operating temperature designs were simulated with COMSOL Multiphysics.The simulation results showed that the three-stage operating temperature did not change peak supersaturation compared with two operating temperatures,and the three-stage operating temperature was superior in decreasing the amount of water vapor and the temperature,thus lowering particle loss and variation in detection and collection.The peak supersaturation level increased by 0.3 as the flow rate increased from 0.6 to 2.0 L/min,but the supersaturation peak moved from 0.0027 z0 to 0.08 z0(i.e.,the growth time and the final size decreased by 40%).Peak supersaturation increased as the Temperature difference increased or the Temperature difference window was shifting left,and minimum activation size decreased.Shifting the 70℃Temperature difference window from 9℃,79℃-1℃,71℃for the condenser and initiator temperatures resulted in peak supersaturation in the centerline being above 5.8,and the activation size changed as low as 1 nm.Experiments with flow rates varying by a factor of 2.5(from 0.6 to 1.5 L/min)resulted in a final size decrease of 43%(from 3.2 to 1.8μm),and experimental results of outlet particle size distributions were equivalent with theoretical analysis as the operating temperature was changed.

关键词： Operating temperature Supersaturation profile Flow rate Minimum activation size Temperature difference

A Numerical Investigation of the Thermal Performances of an Array of Heat Pipes for Battery Thermal Management

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Fluid Dynamics & Materials Processing 2019年第4期15卷 343-356页

作者： Chaoyi Wan School of Automobile and Traffic Engineering Jiangsu University of TechnologyChangzhou213001China

A comparative numerical study has been conducted on the thermal performance of a heat pipe cooling system considering several influential factors such as the coolant flow rate,the coolant inlet temperature,and the input power.A comparison between numerical data and results available in the literature has demonstrated that our numerical procedure could successfully predict the heat transfer performance of the considered heat pipe cooling system for a battery.Specific indicators such as temperature,heat flux,and pressure loss were extracted to describe the characteristics of such a system.On the basis of the distributions of the temperature ratio of the battery surface,together with the heat flux and the streamlines around the heat pipe condenser,we conclude that the low disturbance of the coolant is the cause of the temperature gradient along the fluid flow direction.

关键词： Battery thermal management heat pipe numerical model Temperature difference

Thermal shock resistance and crack growth behavior of Aurivillius phase Bi4Ti3O12-based ferroelectric ceramics

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Progress in Natural Science:Materials International 2021年第2期31卷 248-254页

作者： Qian Xu Shaoxiong Xie Yu Chen Qingyuan Wang MOE Key Laboratory of Deep Earth Science and Engineering College of Architecture and Environment Sichuan University School of Mechanical Engineering Chengdu University College of Materials Science and Engineering Sichuan University

A type of W/Cr co-doped Bi4Ti3O12(ab. BTWC) ceramics were synthesized utilizing the traditional solid-state reaction process, and its thermal shock resistance(TSR) as well as the crack growth behavior was systematically investigated by water quenching technology. It can be found by the succeeded fractographic analysis that many edge thermal cracks began to appear in the samples subjected to thermal shock with ΔT=400°C. According to an integrated TSR model, the critical thermal-shock Temperature difference ΔTCwas calculated to be 356°C. Moreover, it can be noticed that the indenter induced crack growth behaviors under thermal shock loads presented three stages, i.e. no growth, large growth, and moderate growth, along with ΔT increasing from 0°C to 700°C. Finally, the asymmetry of P-E hysteresis loops was observed and understood by the orientated polarization of defect dipoles after the sample was thermally shocked, while the water-quenching process above the Curie temperature of the ceramics could lead to a random orientation of the defect dipoles. This research can not only evaluate the service conditions of Bi4Ti3O12high-temperature piezoceramics, but also understand the failure mechanism of bismuth layer structured ferroelectric ceramics in the case of thermal shock.

关键词： Bi 4 Ti 3 O 12 ceramics TSR Crack growth Temperature difference