scholarly journals Evaluation of Two-Column Air Separation Processes Based on Exergy Analysis

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6361
Author(s):  
Muhammad Haris Hamayun ◽  
Naveed Ramzan ◽  
Murid Hussain ◽  
Muhammad Faheem
Keyword(s):  
Large Scale ◽  
Exergy Analysis ◽  
Separation Process ◽  
Air Separation ◽  
Scale Production ◽  
Exergy Destruction ◽  
Separation Processes ◽  
Distillation Columns ◽  
Operational Conditions ◽  
Destruction Rate

Cryogenic air separation processes are widely used for the large-scale production of nitrogen and oxygen. The most widely used design for this process involves two distillation columns operating at different pressures. This work focuses on the selection of suitable cryogenic air separation process by evaluating seven alternative designs of the two-column air separation process based on detailed exergy analysis. The feed conditions (500 tons/h, and 50% relative humidity of air), product purities (99 mole% for both nitrogen and oxygen), and operational conditions (pressures of both distillation columns) are kept same in all designs. The two cryogenic distillation columns in each configuration are heat-integrated to eliminate the need for external utilities. Steady-state simulation results are used to calculate the exergy efficiency (%) of each equipment as well as its contribution toward the overall exergy destruction rate (kW) of the process. The results show that the compression section is a major source of exergy destruction, followed by the low-pressure column, and the multi-stream heat exchanger. A Petlyuk-like configuration, labeled as C1, provides the lowest exergy destruction rate.

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%).

Exergy Analysis of a Novel Cryogenic Concept for the Liquefaction of Natural Gas Integrated Into an Air Separation Process

2016 ◽  
Author(s):  
S. Tesch ◽  
T. Morosuk ◽  
G. Tsatsaronis
Keyword(s):  
Natural Gas ◽  
Power Consumption ◽  
Exergy Analysis ◽  
Primary Energy ◽  
Separation Process ◽  
Air Separation ◽  
Total Power ◽  
Separation Unit ◽  
Total Power Consumption ◽  
Liquefaction Temperature

The increasing demand for primary energy leads to a growing market of natural gas and the associated market for liquefied natural gas (LNG) increases, too. The liquefaction of natural gas is an energy- and cost-intensive process. After exploration, natural gas, is pretreated and cooled to the liquefaction temperature of around −160°C. In this paper, a novel concept for the integration of the liquefaction of natural gas into an air separation process is introduced. The system is evaluated from the energetic and exergetic points of view. Additionally, an advanced exergy analysis is conducted. The analysis of the concepts shows the effect of important parameters regarding the maximum amount of liquefiable of natural gas and the total power consumption. Comparing the different cases, the amount of LNG production could be increased by two thirds, while the power consumption is doubled. The results of the exergy analysis show, that the introduction of the liquefaction of natural gas has a positive effect on the exergetic efficiency of a convetional air separation unit, which increases from 38% to 49%.

scholarly journals Evaluation of Large-Scale Production of Chitosan Microbeads Modified with Nanoparticles Based on Exergy Analysis

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1200 ◽  
Author(s):  
Samir Meramo-Hurtado ◽  
Adriana Herrera-Barros ◽  
Ángel González-Delgado
Keyword(s):  
Large Scale ◽  
Exergy Analysis ◽  
Chemical Species ◽  
Industrial Process ◽  
Simulation Software ◽  
Operating Conditions ◽  
Scale Production ◽  
Water Recovery ◽  
Novel Technologies ◽  
Large Scale Production

Novel technologies for bio-adsorbent production are being evaluated on the lab-scale in order to find the most adequate processing alternative under technical parameters. However, the poor energy efficiency of promising technologies can be a drawback for large-scale production of these bio-adsorbents. In this work, exergy analysis was used as a computer-aided tool to evaluate from the energy point of view, the behavior of three bio-adsorbent production topologies at large scale for obtaining chitosan microbeads modified with magnetic and photocatalytic nanoparticles. The routes were modeled using an industrial process simulation software, based on experimental results and information reported in literature. Mass, energy and exergy balances were performed for each alternative, physical and chemical exergies of streams and chemical species were calculated according to the thermodynamic properties of biomass components and operating conditions of stages. Exergy efficiencies, total process irreversibilities, energy consumption, and exergy destruction were calculated for all routes. Route 2 presents the highest process irreversibilities and route 3 has the highest exergy of utilities. Exergy efficiencies were similar for all simulated cases, which did not allow to choose the best alternative under energy viewpoint. Exergy sinks for each topology were detected. As values of exergy efficiency were under 3%, it was shown that there are process improvement opportunities in product drying stages and washing water recovery for the three routes.

Exergy Analysis of Integration Between Air Separation Process and IGCC

2000 ◽  
Author(s):  
Zelong Liu ◽  
Hongguang Jin ◽  
Rumou Lin
Keyword(s):  
Gas Turbine ◽  
Exergy Analysis ◽  
Combined Cycle ◽  
Air Separation ◽  
Exergy Destruction ◽  
Steam Generation ◽  
Separation Unit ◽  
Air Compressor ◽  
Nitrogen Injection ◽  
Air Separation Unit

Abstract Integrated Gasification Combined Cycle (IGCC) is considered as one of the advanced clean coal power technologies. Here, we have investigated an IGCC with air separation unit (ASU) on the basis of exergy analysis, and clarified the distribution of exergy destruction in sub-systems including air separation unit, coal gasifier, coal gas clean-up unit, air compressor, combustor of gas turbine, gas turbine, heat recovery steam generation and steam turbine. Particularly, we have focused on the interaction between the ASU and the gas turbine (GT). The results obtained disclosed the significant role of the integration between air separation unit and air compressor in the GT, and the effect of nitrogen injection to the combustor on IGCC overall performance. The study also points out that larger exergy destruction take place in the processes of gasification, combustion in GT, and air separation, and so does the change of exergy destruction distribution with the air integration degree and the nitrogen injection ratio. We have demonstrated the potential for improving the IGCC system. This investigation will be valuable for the synthesis of next-generation IGCC.

scholarly journals Rigorous modelling and optimization of hybrid separation processes based on pervaporation

2007 ◽  
Vol 5 (4) ◽  
pp. 1124-1147 ◽  
Author(s):  
Katalin Koczka ◽  
Peter Mizsey ◽  
Zsolt Fonyo
Keyword(s):  
Optimization Method ◽  
Systematic Investigation ◽  
Separation Process ◽  
Total Annual Cost ◽  
Water Mixture ◽  
Separation Processes ◽  
Distillation Columns ◽  
Membrane Technologies ◽  
Hybrid Separation Processes ◽  
Heteroazeotropic Distillation

AbstractHybrid separation processes are becoming more and more important in the practice if membrane technologies are also involved. In this work, a systematic investigation is completed for three sequence alternatives of distillation and pervaporation. These are the following: pervaporation followed with distillation (PV+D), distillation followed with pervaporation (D+PV), two distillation columns and a pervaporation unit between them (D+PV+D). The hybrid separation process alternatives are evaluated with rigorous modelling tools, but first, a rigorous simulation algorithm is determined for the pervaporation. The three hybrid separation processes are rigorously modelled with CHEMCAD, and optimized with the dynamic programming optimization method for the case of the separation of ethanol-water mixture. The objective function is the total annual cost (TAC). The energy consumption is also investigated. The selection of the ethanol-water mixture has two motivations: (i) it is quite often studied and well known, and (ii) to make biofuel (ethanol) production more economical, membrane technologies might also be applied. The results are compared with each other and with the classical separation completed with heteroazeotropic distillation. The optimized TAC shows that the distillation column followed with pervaporation is the most economical hybrid separation process alternative. Its TAC is about 66% of that of the classical separation.

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%.

scholarly journals Reply to Variny et al. Comment on “Hamayun et al. Evaluation of Two-Column Air Separation Processes Based on Exergy Analysis. Energies 2020, 13, 6361”

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6445
Author(s):  
Muhammad Haris Hamayun ◽  
Naveed Ramzan ◽  
Murid Hussain ◽  
Muhammad Faheem
Keyword(s):  
Exergy Analysis ◽  
Air Separation ◽  
Separation Processes

This is a reply to the paper by Variny et al. [...]

Exergy analysis of two cryogenic air separation processes

Energy ◽  
2010 ◽  
Vol 35 (12) ◽  
pp. 4731-4739 ◽  
Author(s):  
L.V. van der Ham ◽  
S. Kjelstrup
Keyword(s):  
Exergy Analysis ◽  
Air Separation ◽  
Separation Processes

scholarly journals Oxygen Production Technologies for Oxy

2009 ◽  
Vol 32 (1) ◽  
pp. 127-138
Author(s):  
H. Katalambula
Keyword(s):  
Large Scale ◽  
Gas Adsorption ◽  
Membrane Separation ◽  
New Technology ◽  
Combustion Process ◽  
High Energy ◽  
Fuel Combustion ◽  
Air Separation ◽  
Scale Production ◽  
Oxygen Production

Carbon dioxide, a dominating contributor to global warming is emitted to the atmosphere from power plantsduring combustion of coal. Oxy-fuel combustion is a new technology leading to a simplified sequestrationof CO2. In this technology, fossil fuel is combusted with oxygen (instead of air) in such a way that the fluegas primarily consists of CO2, which can then be sequestered without significant processing. Part of the fluegas is used to dilute the oxygen in order to maintain the temperatures in the combustion process. The mainenergy penalty in oxy-fuel combustion is the cost of oxygen production. There are three major processes forair separation to produce oxygen, these are: cryogenic distillation, membrane separation and gas adsorption.Cryogenic distillation is well established process for large scale production but high energy consumption isthe main disadvantage of this process. Membrane and adsorption processes are common for small and mediumscale production. In gas adsorption, there are air separation techniques such as pressure and temperatureswing methods. The production of oxygen with 90-95% purity and 5000+tpd production is the main challengefor this technology. At present the technology that can supply oxygen in large quantity is the cryogenicseparation of oxygen from air. The papers aims at presenting a comprehensive review of the air separationtechnologies and identify areas that need attention so that oxy-firing can be achieved. The paper thereforelooks at different technologies used for oxygen production, economic concepts as well as integration issues inthe existing plants.

Sign in / Sign up

Export Citation Format

Share Document