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exergy analysis of operation process of district heating systems

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Journal of Central South University 2017年第7期24卷 1663-1670页

作者： JIE Peng-fei KONG Xiang-fei LI Jing School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing 102617China School of Energy and Environmental Engineering Hebei University of TechnologyTianjin 300401China China Environmental Resources Technology Co. LtdBeijing 100012China

The nature of the exergy consumption of district heating(DH) systems can not be explained clearly using the first law of *** analysis method was used.A case study based on a DH system in Inner Mongolia,China,was carried *** impact of operating parameters and design parameters on the energy quality of circulating water and exergy losses of DH systems during heat distribution was *** show that the energy quality of circulating water and exergy losses of DH systems during heat distribution could be reduced by decreasing the indoor temperature or increasing radiator *** with other factors,the outdoor temperature and indoor temperature have a greater impact on the energy quality of circulating water,exergy losses of circulating water,and total exergy losses during heat *** the outdoor temperature varied by 10.00%,the average variation rates of such parameters were 85.12%,90.02%,and 64.60%,*** the outdoor temperature was 273.00 K and indoor temperature varied by 50.00%,the average variation rates of such parameters were 83.88%,99.34% and 32.87%,*** can be observed that the energy quality and exergy losses of DH systems can be reduced in the operation process.

关键词： energy quality coefficient exergy loss rate design parameters operating parameters energy conservation measures

Energy,exergy,economic and environmental comprehensive analysis and multi-objective optimization of a sustainable zero liquid discharge integrated process for fixed-bed coal gasification wastewater

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Chinese Journal of Chemical Engineering 2023年第6期58卷 341-354页

作者： Yanli Zhang Zhengkun Hou Dong Yao Xiaomin Qiu Hongru Zhang Peizhe Cui Yinglong Wang Jun Gao Zhaoyou Zhu Limei Zhong College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042China College of Chemical and Environmental Engineering Shandong University of Science and TechnologyQingdao 266590China

For a long time,China's regional water resource imbalance has restricted the development of coal chemical industry,and it is imperative to achieve zero liquid discharge(ZLD).Therefore,the game relationship between technical indicators,costs and emissions in ZLD process of fixed-bed coal gasification wastewater treatment process should be explored in *** to the accurate model,the simulation for ZLD of fixed-bed coal gasification wastewater treatment process is established,and this process is assessed from the perspective of thermodynamics,economy,and *** total energy consumption of ZLD process before optimization is 4.032×10^(8)*** results of exergy analysis show exergy destruction of ZLD process is 94.55%.For economic and environmental results,the total annual cost is 1.892×10^(7)USD·a^(-1)and the total environmental impact is 4.782×10^(-8).The total energy consumption of the optimal six-step ZLD process based on multi-objective optimization is 4.028×10^(8)*** CO_(2)content in the treated wastewater is 0.1%.This study will have an important role in promoting the establishment of the ZLD process for coal chemistry industry.

关键词： Waste water Case study Energy exergy Economy Environment

Parameter study of sinter waste heat recovery in vertical tank based on energy and exergy analysis

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Journal of Iron and Steel Research International 2020年第1期27卷 22-32页

作者： Jun-sheng Feng Sheng Zhang Hui Dong Gang Pei School of Environment and Energy Engineering Anhui Jianzhu UniversityHefei 230026AnhuiChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina Department of Thermal Science and Energy Engineering University of Science and Technology of ChinaHefei 230026AnhuiChina

The parameter study of sinter waste heat recovery in vertical tank was conducted numerically by using energy and exergy analysis,and the experimental data obtained from a homemade experimental apparatus was applied to verify the reliability of numerical *** on the first and second laws of thermodynamics,the effects of flow rate of cooling air(FRCA)and inlet temperature of cooling air(ITCA),as well as the inner diameter of cooling section(IDCS)and height of cooling section(HCS),on the sinter cooling process were analyzed in *** results show that the average deviation between the experimental data and calculation values is 4.93%,and the model reliability is *** enthalpy exergy of outlet air tends to increase first and then decrease with increasing the FRCA and ITCA,while increasing the IDCS only leads to the increase in enthalpy exergy of outlet *** a given operational condition,the enthalpy exergy of outlet air can reach a maximum value with increasing the *** vertical tank could obtain the maximum enthalpy exergy of outlet air through the adjustments of FRCA and ITCA,as well as the HCS.

关键词： Sinter Waste heat recovery Porous medium-Energy analysis exergy analysis Vertical bank

Entransy and exergy Analyses for Optimizations of Heat-Work Conversion with Carnot Cycle

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Journal of Thermal Science 2016年第3期25卷 242-249页

作者： Chul Ho Han Kyoung Hoon Kim Department of Mechanical System Engineering Kumoh National Institute of Technology Department of Mechanical Engineering Kumoh National Institute of Technology

The concept of entransy has been newly proposed in terms of the analogy between heat and electrical conduction and could bc useful in analyzing and optimizing the heat-work conversion systems. This work presents comparative analyses of entransy and exergy for optimizations of heat-work conversion. The work production and heat transfer processes in Carnot cycle system are investigated with the formulations of exergy destruction, entransy loss, work entransy, entransy dissipation, and cfficiencics for both cases of dumping and non-dumping of used source fluid. The effects of source and condensation temperatures on the system performance arc systematically investigated for optimal condition of producing maximum work or work cntransy.

关键词： entransy exergy heat-work conversion Carnot cycle efficiency

Energy and exergy Analysis of a Cooling/Power Cogeneration Ejector Refrigeration System

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Journal of Thermal Science 2022年第2期31卷 448-462页

作者： YANG Mengke LI Xiuzhen WANG Lin YUAN Junfei WANG Zhanwei LIANG Kunfeng Institute of Refrigeration and Air conditioning Henan University of Science and TechnologyLuoyang 471023China

The organic Rankine cycle is introduced into the conventional ejector refrigeration(CER)system to establish the low-grade heat-driven cooling/power cogeneration ejector refrigeration(CPC-ER)system using the isobutane as the *** comparison with the CER system where external power is consumed by the circulating pump,the power output from the CPC-ER system is more than the power consumption of its circulating pump so that a portion of net power is derived from the CPC-ER *** on the mathematical model of thermodynamics,energy and exergy analysis of the CPC-ER system is carried out and compared with the CER *** results reveal that the equivalent coefficient of performance(COP)of the CPC-ER system is 41.14%to 71.30%higher than that of the CER system,and the exergy efficiency of the CPC-ER system is 1.32 to 1.49 times higher than that of the CER *** the power produced by the turbine and the total exergy output from the CPC-ER system approach the maximum,as the generating temperature in the generator is up to 80°*** CPC-ER system has the higher energy utilization efficiency than the CER system,and it is suitable for the cooling and power-required places with low-grade thermal sources.

关键词： ejector refrigeration exergy power consumption equivalent COP

Enhanced exergy cost optimization of operating conditions in FCCU main fractionator

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Chinese Journal of Chemical Engineering 2018年第8期26卷 1750-1757页

作者： Chonglin Zhong Yi Zheng Shenghu Xu Shaoyuan Li Department of Automation Shanghai Jiao Tong UniversityKey Laboratory of System Control and Information ProcessingMinistry of EducationShanghai 200240China SinopecJiujiang Branch Corporation Jiufiang 332004China

exergy indicates the maximal energy that can do work effectively. Different from optimization of product quality or calculation of generic energy conservation in most previous studies, the application of exergy analysis and exergy cost optimization in petrochemical industry is of great economic and environmental significance. Based on the main fractionator in Jiujiang Petrochemical Complex No. 2 FCCU, an enhanced exergy cost optimization under different operating conditions by adjusting set points of temperature and valves opening degree for flow control is studied in this paper in order to reduce exergy cost and improve the quality of energy. A steadystate optimization algorithm to enhance exergy availability and an objective function comprehensively considering exergy loss are proposed. On the basis of ensuring the quality of petroleum products, the economic benefits can be improved by optimizing the controllable variables due to the fact that exergy cost is decreased.

关键词： exergy Optimization of operating conditions Fractionator FCCU exergy Cost

Energy and exergy analysis of syngas production from different biomasses through air-steam gasification

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Frontiers in Energy 2020年第3期14卷 607-619页

作者： S.Rupesh C.Muraleedharan P.Arun Department of Mechanical Engineering National Institute of Technology CalicutCalicut 673601India

Gasification is a thermo-chemical reaction which converts biomass into fuel gases in a *** efficiency of conversion depends on the effective working of the *** first step in the conversion process is the selection of a suitable feedstock capable of generating more gaseous *** paper analyses the performance of different biomasses during gasification through energy and exergy analysis.A quasi-equilibrium model is developed to simulate and compare the feasibility of different biomass materials as gasifier ***-metric studies are conducted to analyze the effect of temperature,steam to biomass ratio and equivalence ratio on energy and exergy *** the biomasses considered,sawdust has the highest energy and exergy efficiencies and lowest *** a gasification temperature of 1000 K,the steam to biomass ratio of unity and the equivalence ratio of 0.25,the energy efficiency,exergy efficiency and irreversibility of sawdust are 35.62%,36.98%and 10.62 MJ/kg,*** is also inferred that the biomass with lower ash content and higher carbon content contributes to maximum energy and exergy efficiencies.

关键词： gasification modeling energy exergy syngas

exergy as an ecological application used in the recovery process of benthic communities

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Integrative Zoology 2007年第1期2卷 1-9页

作者： Feijun ZHANG Chunfu TONG Zhifa XIE Jianjian LU State Key Laboratory of Estuarine and Coastal Research East China Normal UniversityShanghaiChina

exergy,the thermodynamic function that represents the distance of an open system from equilibrium,is proposed as an ecological indicator for summarizing the complex dynamics occurring in a disturbed community during its recovery *** complex dynamics can be difficult to capture by using classical *** this study,we sampled macrobenthos using the BACI scheme(before versus after;control versus impact)in tidal wetlands of west Chongming Island,China,an area that has been disturbed by ecological engineering *** storage is estimated for benthic *** control area is proposed as dynamic reference for estimating local exergy storage of the benthic *** different methods were used for estimating exergy on the basis of coefficients:(a)taken for taxa groups;(b)estimated from coding genes given for broad taxonomic groups;and(c)estimated from genome size taken as close as possible to the taxonomic level of the species,providing a basis for inferring *** found a decrease of local exergy content in the disturbed area 9 days after the ***,the reference exergy of the benthic community increased(*** the surrounding control area)in accordance with the proposed hypothesis regarding the dynamics of exergy storage during a system’s *** of local exergy arrived at using the three methods provided comparable *** on this,we then discuss the feasibility of using the more readily available genome size data for estimating *** result may have important implications for broader application of this indicator to biological ***,the adjacent control samples seem to represent an appropriate dynamic reference for estimating the local exergy of disturbed *** found that exergy was a useful indicator that integrates the processes underlying the recovery of the benthic community after disturbance.

关键词： application benthic community ecosystem indicator exergy recovery process.

Recent progress in thermodynamics of radiation——exergy of radiation, effective temperature of photon and entropy constant of photon

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Science China(Technological Sciences) 2008年第8期51卷 1096-1109页

作者： CHEN ZeShao MO SongPing HU Peng Department of Thermal Science&Energy Engineering University of Science and Technology of ChinaHefei 230027China

The recent progress on thermodynamic properties of spectral radiant energy in the field of thermodynamics of radiation is reviewed. The effective temperature of photon Tλ representing the energy quality of photon is introduced. The relation between Tλ and the wavelength λ is given as λTλ =c3=5.33016×10?3 m·K. The en- tropy constant of photon is given as sλ=3.72680×10?23 J/K. The exergy, entropy and enthalpy of the spectral blackbody radiation, the equilibrium cavity radiation, the radiation flux in open system are discussed by using Tλ and sλ, as well as the en- tropy change in the process of the state transformation of photon gas. By analyzing the exergy of spectral radiation, the exergy efficiency of spectral radiant energy available for photosynthesis is proved to be higher than that of light energy. The method for the irreversible loss of exergy calculation in radiant energy converters is also discussed.

关键词： thermodynamics of radiation photon gas exergy photon entropy non-equilibrium thermodynamics