Exergetic Analysis and Assessment of Industrial Furnaces

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Hakan Caliskan ◽  
Arif Hepbasli
Keyword(s):  
Maximum Rate ◽  
Exergy Analysis ◽  
Heating Furnace ◽  
The Other ◽  
Flue Gases ◽  
Exergy Destruction ◽  
Furnace Temperature ◽  
Radiant Tube ◽  
Exergetic Analysis ◽  
Exergy Losses

This study presents exergy analysis of a natural gas-fired radiant tube-heating furnace. In the analysis, actual data over a test period of 3 h were used. Exergy efficiencies, destructions, losses, and entropy generation of the furnace were determined. For an average furnace temperature of 666.6°C, average exergy efficiency value was calculated to be 9.6%. The exergy destruction rate was obtained to be 5.34 kW while exergy rates of the flue gases, exergy losses, and exergy steel were 12.53 kW, 44.28 kW, and 6.6 kW, respectively. On the other hand, the exergy rate of the product (steel) was found to be between 4.61 kW and 9.88 kW over the 15 min test periods, and it reached a maximum rate at the end of the second hour.

scholarly journals Exergy Analysis of Adiabatic Liquid Air Energy Storage (A-LAES) System Based on Linde–Hampson Cycle

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 945
Author(s):  
Lukasz Szablowski ◽  
Piotr Krawczyk ◽  
Marcin Wolowicz
Keyword(s):  
Energy Storage ◽  
Research And Development ◽  
Large Scale ◽  
Exergy Analysis ◽  
The Other ◽  
Compressed Air ◽  
Exergy Destruction ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Discharge Pressure

Efficiently storing energy on a large scale poses a major challenge and one that is growing in importance with the increasing share of renewables in the energy mix. The only options at present are either pumped hydro or compressed air storage. One novel alternative is to store energy using liquid air, but this technology is not yet fully mature and requires substantial research and development, including in-depth energy and exergy analysis. This paper presents an exergy analysis of the Adiabatic Liquid Air Energy Storage (A-LAES) system based on the Linde–Hampson cycle. The exergy analysis was carried out for four cases with different parameters, in particular the discharge pressure of the air at the inlet of the turbine (20, 40, 100, 150 bar). The results of the analysis show that the greatest exergy destruction can be observed in the air evaporator and in the Joule–Thompson valve. In the case of air evaporator, the destruction of exergy is greatest for the lowest discharge pressure, i.e., 20 bar, and reaches over 118 MWh/cycle. It decreases with increasing discharge pressure, down to approximately 24 MWh/cycle for 150 bar, which is caused by a decrease in the heat of vaporization of air. In the case of Joule–Thompson valve, the changes are reversed. The highest destruction of exergy is observed for the highest considered discharge pressure (150 bar) and amounts to over 183 MWh/cycle. It decreases as pressure is lowered to 57.5 MWh/cycle for 20 bar. The other components of the system do not show exergy destruction greater than approximately 50 MWh/cycle for all considered pressures. Specific liquefaction work of the system ranged from 0.189 kWh/kgLA to 0.295 kWh/kgLA and the efficiency from 44.61% to 55.18%.

EXERGY ANALYSIS OF GEOTHERMAL POWER PLANT KAMOJANG 68, 3 MW IN CAPACITY

2018 ◽  
Vol 7 (2) ◽  
Author(s):  
Amiral Aziz
Keyword(s):  
Energy Efficiency ◽  
Power Plant ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Preliminary Design ◽  
Exergy Destruction ◽  
Geothermal Power Plant ◽  
Production Wells ◽  
Geothermal Power ◽  
Exergy Losses

The importance of exergy analysis in preliminary design of geothermal power has been proven. An exergy analysis was carried out and the locations and quantities of exergy losses, wastes and destructions in the different processes of the plan were pinpointed. The obtained results show that the total exergy available from production wells KMJ 68 was calculated to be 6967.55 kW. The total exergy received from wells which is connected during the analysis and enter into the separator was found to be 6337.91 kW in which 5808.8 kW is contained in the steam phase. The overall exergy efficiency for the power plant is 43.06% and the overall energy efficiency is 13.05 %, in both cases with respect to the exergy from the connected wells. The parts of the system with largest exergy destruction are the condenser, the turbine, and the disposed waste brinekeywords: exergy, irreversibility, geothermal power plant, KMJ 68

scholarly journals Thermodynamic Limitations and Exergy Analysis of Brackish Water Reverse Osmosis Desalination Process

Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 11
Author(s):  
Alanood A. Alsarayreh ◽  
Mudhar A. Al-Obaidi ◽  
Alejandro Ruiz-García ◽  
Raj Patel ◽  
Iqbal M. Mujtaba
Keyword(s):  
Reverse Osmosis ◽  
Brackish Water ◽  
Exergy Analysis ◽  
Exergy Destruction ◽  
First Pass ◽  
Simulation Results ◽  
Membrane Technologies ◽  
Physical And Chemical ◽  
Exergy Losses ◽  
Reverse Osmosis Desalination

The reverse osmosis (RO) process is one of the most popular membrane technologies for the generation of freshwater from seawater and brackish water resources. An industrial scale RO desalination consumes a considerable amount of energy due to the exergy destruction in several units of the process. To mitigate these limitations, several colleagues focused on delivering feasible options to resolve these issues. Most importantly, the intention was to specify the most units responsible for dissipating energy. However, in the literature, no research has been done on the analysis of exergy losses and thermodynamic limitations of the RO system of the Arab Potash Company (APC). Specifically, the RO system of the APC is designed as a medium-sized, multistage, multi pass spiral wound brackish water RO desalination plant with a capacity of 1200 m3/day. Therefore, this paper intends to fill this gap and critically investigate the distribution of exergy destruction by incorporating both physical and chemical exergies of several units and compartments of the RO system. To carry out this study, a sub-model of exergy analysis was collected from the open literature and embedded into the original RO model developed by the authors of this study. The simulation results explored the most sections that cause the highest energy destruction. Specifically, it is confirmed that the major exergy destruction happens in the product stream with 95.8% of the total exergy input. However, the lowest exergy destruction happens in the mixing location of permeate of the first pass of RO desalination system with 62.28% of the total exergy input.

scholarly journals Exergetic Analysis of Bioethanol Production from Tunisian Waste Dates

2018 ◽  
Vol 11 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Wahada Zeineb ◽  
Khila Zouhour ◽  
Louhichi Boulbaba ◽  
Boukchina Rachid ◽  
Hajjaji Noureddine
Keyword(s):  
Production Process ◽  
Chemical Engineering ◽  
Exergy Analysis ◽  
System Development ◽  
Assessment Tools ◽  
Bioethanol Production ◽  
Exergy Destruction ◽  
Laws Of Thermodynamics ◽  
Energy Exchanges ◽  
Exergetic Analysis

Objective:This study aims at contributing to the area of sustainable bioethanol production system development. The main objective of this study is to thermodynamically evaluate a bioethanol production process from waste dates.Methods & Materials:To this end, several chemical engineering assessment tools have been simultaneously applied. These tools simulate the bioethanol production process using the SuperPro software in order to determine all the materials and energy exchanges. An exergy analysis is also carried out, based on the first and second laws of thermodynamics, in order to locate thermodynamic imperfections in the process.Results:The results obtained show that approximately 60% of the exergy fed to the process is recovered in the useful products (bioethanol and exhausted pulp used as feedstuff). The overall exergy destroyed in the process considered is about 377 kW which represents 7% of the exergy reaching the process. The distillation section, the most energy-intensive stage, constitutes the main contributor of exergy destruction, followed by the fermentation reactor with contributions of 47% and 33%, respectively.

Quantification of Losses and Irreversibilities in a Marine Engine for Gas and Diesel Fuelled Operation Using an Exergy Analysis Approach

2020 ◽  
Author(s):  
Beichuan Hong ◽  
Senthil Krishnan Mahendar ◽  
Jari Hyvönen ◽  
Andreas Cronhjort ◽  
Anders Christiansen Erlandsson
Keyword(s):  
Gas Exchange ◽  
Exergy Analysis ◽  
Transport Sector ◽  
Exergy Destruction ◽  
Two Stage ◽  
Marine Engine ◽  
Turbocharging System ◽  
Engine System ◽  
The Impact ◽  
Exergy Losses

Abstract Large bore marine engines are a major source of fossil fuel consumption in the transport sector. The development of more efficient and cleaner marine engine systems are always required. Exergy analysis is a second-law based approach to indicate the maximum amount of work obtainable from a given system. In this study, an exergy analysis is used to identify losses and improvement potential of a large bore Wärtsilä 31DF four-stroke marine engine system with two-stage turbocharging. An exergy-based framework is implemented on a calibrated 1D engine model to view the evolution of exergy flow over each engine sub-system while operating on different load points fuelled with natural gas and diesel separately. The overall distributions of engine energy and exergy are initially compared at a systematic level regarding the impact of fuel mode and operating load. Furthermore, the engine irreversibilities are characterized as three types: combustion, heat dissipation, and gas exchange losses. The first type, combustion irreversibility, is the largest source of engine exergy losses amounting to at least 25% of fuel exergy. A crank resolved analysis showed that premixed gas combustion produces lower exergy losses compared to diesel diffusion combustion. The second type, thermal exergy transferred and destroyed by heat losses, are summarized for the entire engine system. From the exergy view, the charge coolers present an opportunity to recover about 9% of the brake power at full load. The last type, gas exchange losses, are categorized by accounting the flow losses caused by the valve throttling, fluid friction in pipes and the irreversibility of the two-stage turbocharging system. Most of exergy destruction in gas paths occurs at turbocharging system, where the high pressure turbocharger contributes to around 40% of the total flow exergy destruction.

scholarly journals Exergy Analysis of Fluidized Desiccant Cooling System

Entropy ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. 757 ◽  
Author(s):  
Zbigniew Rogala ◽  
Piotr Kolasiński
Keyword(s):  
Exergy Analysis ◽  
Cooling System ◽  
The Other ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Regenerative Heat ◽  
Design And Implementation ◽  
Air Cooler ◽  
Evaporative Cooler ◽  
Direct Evaporative Cooler

One of the main challenges in the design and implementation of fluidized desiccant cooling (FDC) systems is increasing their low COP (coefficient of performance). Exergy analysis is one of the tools especially suitable for improvement and optimization of FDC systems. The improvement of performance is impossible as long as the main sources of exergy destruction are not identified and evaluated. In this paper, the exergy analysis was applied in order to identify these components and processes of the FDC system that are mainly responsible for exergy destruction. Moreover, the exergy efficiency of a simple fluidized desiccant cooler was determined. The results showed that fluidized beds and regenerative heat exchanger were the main exergy destruction sources with a 32% and 18% share of total exergy destruction, respectively. On the other hand, the direct evaporative cooler and air cooler placed after the desorbing fluidized bed were characterized by the lowest exergy efficiencies. This work contributes to better understanding of FDC operation principles and improvement of the performance of FDC technology.

scholarly journals Exergy analysis of a reversible chiller

2021 ◽  
pp. 105-106
Author(s):  
Volodymyr Voloshchuk ◽  
Olena Nekrashevych ◽  
Volodymyr Voloshchuk ◽  
Pavlo Gikalo
Keyword(s):  
Heat Exchangers ◽  
Exergy Analysis ◽  
System Component ◽  
Space Heating ◽  
Exergy Destruction ◽  
Exergetic Analysis ◽  
Operational Modes

The work presents the results of exergetic analysis of a reversible chiller providing both cooling and space heating in varying operational modes. The year values of avoidable parts of exergy destruction occurring in each system component are used for the analysis. The outcomes obtained showed that the both inside and outside heat exchangers have the highest priority for improvement revealing more than 718 kW-hr avoidable year exergy destruction within the system.

scholarly journals Conventional and Advanced Exergoeconomic Analysis of a Compound Ejector-Heat Pump for Simultaneous Cooling and Heating

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3511
Author(s):  
Ali Khalid Shaker Al-Sayyab ◽  
Joaquín Navarro-Esbrí ◽  
Victor Manuel Soto-Francés ◽  
Adrián Mota-Babiloni
Keyword(s):  
Heat Pump ◽  
Exergy Analysis ◽  
Waste Heat ◽  
District Heating ◽  
Cost Comparison ◽  
Exergy Destruction ◽  
Pump System ◽  
Heat Pump System ◽  
Destruction Rate ◽  
Exergoeconomic Analysis

This work focused on a compound PV/T waste heat driven ejector-heat pump system for simultaneous data centre cooling and waste heat recovery for district heating. The system uses PV/T waste heat as the generator’s heat source, acting with the vapour generated in an evaporative condenser as the ejector drive force. Conventional and advanced exergy and advanced exergoeconomic analyses are used to determine the cause and avoidable degree of the components’ exergy destruction rate and cost rates. Regarding the conventional exergy analysis for the whole system, the compressor represents the largest exergy destruction source of 26%. On the other hand, the generator shows the lowest sources (2%). The advanced exergy analysis indicates that 59.4% of the whole system thermodynamical inefficiencies can be avoided by further design optimisation. The compressor has the highest contribution to the destruction in the avoidable exergy destruction rate (21%), followed by the ejector (18%) and condenser (8%). Moreover, the advanced exergoeconomic results prove that 51% of the system costs are unavoidable. In system components cost comparison, the highest cost comes from the condenser, 30%. In the same context, the ejector has the lowest exergoeconomic factor, and it should be getting more attention to reduce the irreversibility by design improving. On the contrary, the evaporator has the highest exergoeconomic factor (94%).

Research for Swing Heating Furnace Temperature Optimization System of Plate Roller-Hearth Normalizing Furnace

2013 ◽  
Vol 380-384 ◽  
pp. 4232-4236
Author(s):  
Jing Li ◽  
Qiu Shi Wang ◽  
Hua Chen Liao
Keyword(s):  
Heat Treatment ◽  
Continuous Improvement ◽  
Treatment Process ◽  
Heating Furnace ◽  
Matlab Simulation ◽  
Furnace Temperature ◽  
Temperature Prediction ◽  
Temperature Optimization ◽  
Prediction Curve ◽  
Roller Hearth

In recent years, with the continuous improvement of the quality requirements of the plate heat treatment, the swing heated gradually become the focus of attention of many researchers. Based on the above considerations, in this paper, we established the furnace temperature pre-setting system, using the intelligence algorithm of improved PSO, under the premise of swing heating of roller-hearth normalizing furnace; and studied the optimal furnace temperature optimization curve, namely the optimal furnace temperature system, under the heat treatment process of the swing of the whole furnace and steel mixed. Through the Matlab simulation, we obtained the steel Temperature Prediction curve under the optimal furnace temperature system. By comparison, verifying the accuracy of the researched optimal furnace temperature optimization curve.

Filtration by superficial and deep glomeruli of normovolemic and volume-depleted rats

1986 ◽  
Vol 250 (1) ◽  
pp. F86-F91
Author(s):  
R. V. Pinnick ◽  
V. J. Savin
Keyword(s):  
Basement Membrane ◽  
Maximum Rate ◽  
Rate Of Change ◽  
The Other ◽  
Membrane Area ◽  
Morphometric Analyses ◽  
Three Samples ◽  
Glomerular Size ◽  
Glomerular Ultrafiltration

We measured glomerular ultrafiltration coefficient (Kf) of isolated superficial (S) and deep (D) glomeruli of normovolemic and volume-depleted rats. Filtration was induced in vitro, and Kf was calculated from the maximum rate of change in glomerular size. Basement membrane area (A) for each glomerulus was estimated from morphometric analyses, and glomerular capillary hydraulic conductivity (Lp) was calculated by the formula Lp = Kf/A. Kf of S and D glomeruli of normovolemic rats were 2.98 +/- 0.98 and 4.25 +/- 0.07 nl . min-1 . mmHg-1, respectively. In hypovolemic rats, Kf of S glomeruli fell by approximately 50% to 1.52 +/- 0.14 nl . min-1 . mmHg-1 (P less than 0.001), whereas Kf of D glomeruli remained unchanged at 4.28 +/- 0.10 nl . min-1 . mmHg-1. Lp, calculated using the peripheral capillary area, averaged 1.98 +/- 0.09 and 1.98 +/- 0.06 microliter . min-1 . mmHg-1 . cm-2 in S and D glomeruli of normovolemic rats and 1.89 +/- 0.11 microliter . min-1 . mmHg-1 . cm-2 in D glomeruli of hypovolemic rats. Lp of S glomeruli of volume-depleted rats (0.90 +/- 0.03 microliter . min-1 . mmHg-1 . cm-2) was lower than in any of the other three samples. Mild hypovolemia causes the Kf of S glomeruli to decline, whereas Kf of D glomeruli remains constant. The decrease in Kf occurs without an alteration in capillary area and is most likely due to a decrease in Lp.

Sign in / Sign up

Export Citation Format

Share Document