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.

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 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.

Processes and Responses

2017 ◽  
Author(s):  
Jochen Rau
Keyword(s):  
Heat Engine ◽  
Cyclic Process ◽  
Free Enthalpy ◽  
Initial State ◽  
Thermodynamic Potentials ◽  
Grand Potential ◽  
Laws Of Thermodynamics ◽  
Cyclic Processes ◽  
Energy Exchanges ◽  
Thermodynamic Processes

Thermodynamic processes involve energy exchanges in the forms of work, heat, or particles. Such exchanges might be reversible or irreversible, and they might be controlled by barriers or reservoirs. A cyclic process takes a system through several states and eventually back to its initial state; it may convert heat into work (engine) or vice versa (heat pump). This chapter defines work and heat mathematically and investigates their respective properties, in particular their impact on entropy. It discusses the roles of barriers and reservoirs and introduces cyclic processes. Basic constraints imposed by the laws of thermodynamics are considered, in particular on the efficiency of a heat engine. The chapter also introduces the thermodynamic potentials: free energy, enthalpy, free enthalpy, and grand potential. These are used to describe energy exchanges and equilibrium in the presence of reservoirs. Finally, this chapter considers thermodynamic coefficients which characterize the response of a system to heating, compression, and other external actions.

Optimization of Hydrothermal Pretreatment of Lignocellulosic Biomass in the Bioethanol Production Process

ChemSusChem ◽  
2012 ◽  
Vol 6 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Christos K. Nitsos ◽  
Konstantinos A. Matis ◽  
Kostas S. Triantafyllidis
Keyword(s):  
Production Process ◽  
Lignocellulosic Biomass ◽  
Hydrothermal Pretreatment ◽  
Bioethanol Production

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%).

Bioethanol production process rheology

2017 ◽  
Vol 106 ◽  
pp. 59-64 ◽  
Author(s):  
E. Oropeza-De la Rosa ◽  
L.G. López-Ávila ◽  
G. Luna-Solano ◽  
D. Cantú-Lozano
Keyword(s):  
Production Process ◽  
Bioethanol Production
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