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Establishment of a Static Model Based on Measured heat loss for COREX Process

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Journal of Iron and Steel Research(International) 2015年第3期22卷 200-206页

作者： Wei SHEN Sheng-li WU Ming-yin KOU Kai-ping DU Ying SUN School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The heat loss and its,distribution are of great importance for the calculation and simulation of COREX process. Based on Baosteel COREX process, a method was applied to measure the heat loss of the furnace shell, the accessory equipments and the cooling water system. Then, a static model was established based on the measured heat loss of COREX process. The results showed that the main heat loss of furnace shells took place at the dome of the COREX melter-gasifier and the reducing gas entrance position of the shaft furnace while the main heat loss caused by cooling water occurred at the tap hole area. And the heat loss caused by cooling water accounts for about 85% of the total heat loss in COREX process. The measured total heat loss for producing every 1 t hot metal was 542. 164 MJ, which accounted for about 92 % of the theoretical total heat loss.

关键词： COREX process heat loss heat loss distribution static model measurement method

Performance analyses of a novel finned parabolic trough receiver with inner tube for solar cascade heat collection

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Science China(Technological Sciences) 2023年第5期66卷 1417-1434页

作者： LIU Peng REN TingTing GE YanLin LIU Wei CHEN LinGen Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan430205China School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan430074China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan430205China

Designing highly-efficient parabolic trough receiver(PTR)contributes to promoting solar thermal utilization and alleviating energy crisis and environmental problems.A novel finned PTR with inner tube(FPTR-IT),which can provide different grades of thermal energy with two heat transfer fluids(oil and water),is designed to improve thermal efficiency.In this FPTR-IT,an inner tube and straight fins are employed to respectively lessen heat loss at upper and lower parts of the absorber.Based on the design,a numerical model is developed to investigate its performance.Comparisons with other PTRs indicate that the FPTR-IT can combine the advantages of PTR with inner tube and finned PTR and obtain the best performance.Moreover,performance evaluation under broad ranges of direct normal irradiances(300–1000 W/m^(2)),flow rates(50–250 L/min)and inlet temperatures(400–600 K)of oil as well as flow rates(3.6–10 L/min)and inlet temperatures(298.15–318.15 K)of water is investigated.Compared with conventional PTR,heat loss is reduced by 20.7%–63.2%and total efficiency is improved by 0.03%–4.27%.Furthermore,the proportions of heat gains for water and oil are located in 8.3%–73.9%and-12.0%–64.3%,while their temperature gains are located in 11.6–37.9 K and-1.2–19.6 K,respectively.Thus,the proposed FPTR-IT may have a promising application prospect in remote arid areas or islands to provide different grades of heat for electricity and freshwater production.

关键词： finned parabolic trough receiver inner tube heat loss total efficiency solar cascade heat collection performance analyses

Solar thermoelectric generator and thermoelectric cooler performance:analysis and comparison using a different shape geometry

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Clean Energy 2023年第6期7卷 1233-1246页

作者： ALkhadher Khalil Smail Sahnoun Ahmed Elhassnaoui Said Yadir Abdellatif Obbadi Youssef Errami Laboratory:Electronics Instrumentation and EnergyFaculty of SciencesChouaib Doukkali UniversityEl JadidaMorocco National School of Applied Sciences—ENSABM Sultan Moulay Slimane University—Beni MallalMorocco Laboratory of Materials ProcessesEnvironment and QualityENSACadi Ayyad UniversitySafiMorocco

Thermoelectric devices are one of the technologies used either to generate electricity by applying a temperature difference using thermal energy or as a heating/cooling system by applying an electrical voltage.The number of materials required to produce a product is an important factor in determining its price.Production costs associated with these materials,as well as their availability and quality,play a crucial role in price determination by manufacturers.In this context,a method that employs a uniform volume distribution was implemented.This approach enabled the analysis to focus on other variables,thereby promoting a more precise and relevant evaluation of overall performance.Based on the finite element method,this study investigated the influence of geometric shape,including Rect-leg,Y-leg,Pin-leg and X-leg designs,on the performance of solar thermoelectric generators and thermoelectric coolers.The study was conducted considering the same hot alumina junction surface that receives solar radiation;however,the ef-fective surface,which corresponded to the heat flow area and had a similar area near the exposed surface,varied depending on the chosen leg geometry,thus impacting the heat flux due to the variation in thermal resistance.In the case of a solar thermoelectric generator,the Rect-leg model,having the same effective surface area,presented the lowest heat loss value resulting from convection and radiation in the heat spreader and the hot alumina plate.Under the same conditions,the Y-leg showed the highest value.The Rect-leg design generated,by using thermal and optical concentration,the highest output power of 0.028 and 0.054 W,and efficiency of 3.47%and 4.7%,respectively,whereas the Y-leg generated lower values of 0.006523 and 0.018744 W for power,and 2.83%and 2.71%for efficiency,respectively.In the case of the thermoelectric coolers,the Y-leg generated the highest temperature difference between the hot and cold sides of 67.28 K at an electric current value of 1.8 A,whereas the Rect-leg,Pin-leg and X-leg

关键词： solar thermoelectric generators heat loss thermoelectric coolers coefficient of performance leg geometry same leg volume performance

Numerical study of conduction and radiation heat losses from vacuum annulus in parabolic trough receivers

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Frontiers in Energy 2022年第6期16卷 1048-1059页

作者： Dongqiang LEI Yucong REN Zhifeng WANG Key Laboratory of Solar Thermal Energy and Photovoltaic System Chinese Academy of SciencesBeijing 100190China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Beijing Engineering Research Center of Solar Thermal Power Beijing 100190China

Parabolic trough receiver is a key component to convert solar energy into thermal energy in the parabolic trough solar system.The heat loss of the receiver has an important influence on the thermal efficiency and the operating cost of the power station.In this paper,conduction and radiation heat losses are analyzed respectively to identify the heat loss mechanism of the receiver.A 2-D heat transfer model is established by using the direct simulation Monte Carlo method for rarefied gas flow and heat transfer within the annulus of the receiver to predict the conduction heat loss caused by residual gases.The numerical results conform to the experimental results,and show the temperature of the glass envelope and heat loss for various conditions in detail.The effects of annulus pressure,gas species,temperature of heat transfer fluid,and annulus size on the conduction and radiation heat losses are systematically analyzed.Besides,the main factors that cause heat loss are analyzed,providing a theoretical basis for guiding the improvement of receiver,as well as the operation and maintenance strategy to reduce heat loss.

关键词： parabolic trough receiver vacuum annulus rarefied gas DSMC(direct simulation Monte Carlo) heat loss

General heat balance for oxygen steelmaking

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Journal of Iron and Steel Research(International) 2021年第5期28卷 538-551页

作者： N.Madhavan G.A. Brooks M.A. Rhamdhani B.K. Rout A. Overbosch Department of Mechanical and Product Design Engineering Swinburne University of TechnologyHawthorn 3122VICAustralia Tata Steel Ijmuiden 1951 JZThe Netherlands

Energy balances are a general fundamental approach for analyzing the heat requirements for metallurgical processes.The formulation of heat balance equations was involved by computing the various components of heat going in and coming out of the oxygen steelmaking furnace.The developed model was validated against the calculations of Healy and McBride.The overall heat losses that have not been analyzed in previous studies were quantified by back-calculating heat loss from 35 industrial data provided by Tata Steel.The results from the model infer that the heat losses range from 1.3%to 5.9%of the total heat input and it can be controlled by optimizing the silicon in hot metal,the amount of scrap added and the postcombustion ratio.The model prediction shows that sensible heat available from the hot metal accounts for around 66%of total heat input and the rest from the exothermic oxidation reactions.Out of 34%of the heat from exothermic reactions,between 20%and 25%of heat is evolved from the oxidation of carbon to carbon monoxide and carbon dioxide.This model can be applied to predict the heat balance of any top blown oxygen steelmaking technology but needs further validation for a range of oxygen steelmaking operations and conditions.

关键词： heat balance Static model Process control Optimization Basic oxygen steelmaking heat loss

Potential of performance improvement of concentrated solar power plants by optimizing the parabolic trough receiver

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Frontiers in Energy 2020年第4期14卷 867-881页

作者： Honglun YANG Qiliang WANG Jingyu CAO Gang PEI Jing LI Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230026China

This paper proposes a comprehensive thermodynamic and economic model to predict and compare the performance of concentrated solar power plants with traditional and novel receivers with different configurations involving operating temperatures and locations.The simulation results reveal that power plants with novel receivers exhibit a superior thermodynamic and economic performance compared with traditional receivers.The annual electricity productions of power plants with novel receivers in Phoenix,Sevilla,and Tuotuohe are 8.5%,10.5%,and 14.4%higher than those with traditional receivers at the outlet temperature of 550℃.The levelized cost of electricity of power plants with double-selectivecoated receivers can be decreased by 6.9%,8.5%,and 11.6%.In Phoenix,the optimal operating temperature of the power plants is improved from 500℃to 560℃by employing a novel receiver.Furthermore,the sensitivity analysis of the receiver heat loss,solar absorption,and freeze protection temperature is also conducted to analyze the general rule of influence of the receiver performance on power plants performance.Solar absorption has a positive contribution to annual electricity productions,whereas heat loss and freeze protection temperature have a negative effect on electricity outputs.The results indicate that the novel receiver coupled with low melting temperature molten salt is the best configuration for improving the overall performance of the power plants.

关键词： concentrated solar power parabolic trough receiver heat loss solar energy annual performance

Conceptual Design of 25-Barrel Pellet Injector with Cycle Refrigerator for HL-2A Tokamak

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Plasma Science and Technology 2006年第4期8卷 473-476页

作者：肖正贵朱根良刘德权 Southwestern Institute of Physics Chengdu 610041China

The preliminary design of a multi-barrels pellet injector with cycle refrigerator as an advanced plasma-fuelling tool for HL-2A tokamak has been proposed. The design aims at precise temperature control, easy operation with high reliability and high flexibility. GM-cycle refrigerator and pipe-gun structure have been employed to produce 25 pellets in 25 gun barrels simultaneously and the design aims. have been accomplished. Prime design principle, engineering parameters, structure and layout of the cryostat components as well as calculation of heat load for the cryostat are presented.

关键词： pellet injector cycle refrigerator heat loss heat sink

Structure and stability of non-adiabatic reverse smolder waves

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Applied Mathematics and Mechanics(English Edition) 2013年第6期34卷 657-668页

作者：袁枋平卢占斌 Institute of Applied Mathematics and Mechanics Shanghai University

The structure and stability of non-adiabatic reverse smolder waves are investigated numerically. First, the 1D steady-state responses of reverse smolder waves in the presence of convective heat losses are studied with the rate of incoming air flow as the control parameter. Based on the 1D steady solutions, the linear stability and the Lewis number effects on the stability are examined by a numerical normal mode analysis. Finally, the dynamical evolution processes of unstable reverse smolder waves are studied by direct numerical simulations. It is shown that, in comparison with the adiabatic case, the presence of heat losses leads to a backward shift of the extinction limit. For varying Lewis numbers, the extinction limit shifts forward with the increase of the Lewis number while the smolder temperature remains unchanged. Furthermore, results of a linear stability analysis show that the maximum growth rate decreases with the increasing Lewis number, implying that increasing the Lewis number tends to weaken the thermal-diffusive instability of non-adiabatic reverse smolder waves. Direct numerical simulation results show that, on the fuel-rich branch, the unstable plane reverse smolder wave gradually develops to a regular steady fingering pattern, whereas on the fuel-lean branch, similar to the adiabatic case, vigorous fragmentation instability occurs, and is accompanied by a substantial local temperature rise, which may be sufficiently high to trigger the transition to flaming combustion.

关键词： reverse smolder wave heat loss stability Lewis number

Modeling of Rotary Kiln in Cement Industry

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Energy and Power Engineering 2016年第1期8卷 23-33页

作者： Hamid Reza Goshayeshi Fariba Kerdar Poor Department of Mechanical Engineering Mashhad Branch Islamic Azad University Mashhad Iran

Cement production is a highly energy-intensive process, and the rotary kiln is the most important part of the process. Having a comprehensive model of the kiln in order to reduce manufacturing costs, better performance can be created. In this paper, the influence processes in a simulated cement rotary kiln and operating parameters on the output of the study were to develop and validate the systems using the same batch. The followings were examined: solid phase, gas and coating temperature change in a rotary kiln.

关键词： Rotary Kiln Cement heat loss Energy