Exergy Analysis of a Turbo Expander: Modeling and Simulation

Natural gas is a mixture that is widely used in the industries. Knowledge of its thermodynamic properties is essential for evaluating the process and equipment performance. This paper quantifies the energy that can be extracted from natural gas using a turbo expander. Natural gases of wide-ranging compositions collected from 6 different gas fields in Egypt were investigated based on energy and exergy analysis. The study was conducted using MATLAB. Numerous simulation runs were made by taking various typical feed compositions classified as lean and rich. The effects of increasing the amount of C1, C5 in the feed stream on the efficiency of energy utilization are presented. A validation analysis was performed. The results show similar trends and good agreements. It was concluded from the results that when the concentration of methane in the gas mixture increase, the exergetic efficiency decreases. The results also show that the values of thermodynamic properties depend on the relative amount of heavy components in the feed stream.

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ANALISA ENERGI DAN EKSERGI PADA PENGERINGAN TEPUNG TAPIOKA MENGGUNAKAN PENGERING KONTINYU UNGGUN FLUIDISASI GETAR

REAKTOR ◽

10.14710/reaktor.16.1.24-31 ◽

2016 ◽

Vol 16 (1) ◽

pp. 24 ◽

Cited By ~ 2

Author(s):

Suherman Suherman ◽

Rona Trisnaningtyas

Keyword(s):

Energy Efficiency ◽

Fluidized Bed ◽

Exergy Analysis ◽

Cassava Starch ◽

Energy Utilization ◽

Exergetic Efficiency ◽

Energy And Exergy ◽

Vibrated Fluidized Bed ◽

Energy And Exergy Analysis ◽

Utilization Ratio

Energy and exergy analysis of cassava starch drying in continuous vibrated fluidized bed dryer were carried out to assess the performance of the system in terms of energy utilization ratio, energy efficiency, exergy inflow and outflow, exergy loss, and exergetic efficiency. The results showed cassava starch has starch content 87%, degree of whiteness 95%, negative fiber content, sperichal granula with average diameter12.32 μm, orthorhombic crystal structure and crystal size 47.467 nm . Energy utilization and energy utilization ratio increased from 0.08 to 0.20 J/s and 0.35 to 0.4 as the drying temperature increased from 50 to 70 oC. Energy efficiency increased from 13.80 % to 23.31 %, while exergy inflow, outflow, and losses increased from 4.701 to 14.678, 2.277 to 6.344, and 2.424 to 8.334 J/s respectively in the above temperature range. Exergetic efficiency decreased with increase in drying air temperature, while exergetic improvement potential increased with increased drying air temperature. Keywords: Cassava starch, continuous drying, energy and exergy analysis, vibrated fluidized bed Abstrak Analisis energi dan eksergi pengeringan pati tapioka menggunakan pengering kontinu unggun fluidisasi getar, telah dilakukan untuk menilai kinerja sistem dalam bentuk utilisasi energi, efisiensi energi, eksergi masuk dan keluar, eksergi hilang dan efisiensi eksergi. Hasil analisis pati memiliki kandungan starch 87%, tingkat keputihan 95%, kandungan serat negatif, bentuk partikel granular spherical dengan diameter 12,32 μm, struktur kristal orthorhombic dan ukuran kristal sebesar 47,467 nm. Peningkatan suhu pengering dari 50 menjadi 70 0C akan meningkatkan utilisasi energi dan rasio utilisasi energi dari 0,08 menjadi 0,20 J/s dan 0,35 menjadi 0,4. Efisiensi energi meningkat dari 13,80% hingga 23,31%, sedangkan eksergi masuk dan keluar, eksergi hilang meningkat dari 4,701 menjadi 14,678, 2,277 menjadi 6,344, dan 2,424 menjadi 8,334 J/s. Efisiensi eksergi menurun dengan naiknya suhu sedangkan potensi pengembangan eksergi meningkat dengan naiknya suhu. Kata kunci:. Analisis energi dan eksergi, pati tapioka, pengeringan kontinu, unggun fluidisasi getar

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Energy and Exergy Analysis of Different Exhaust Waste Heat Recovery Systems for Natural Gas Engine Based on ORC

10.20944/preprints201905.0247.v1 ◽

2019 ◽

Author(s):

Guillermo Valencia ◽

Armando Fontalvo ◽

Yulineth Cardenas ◽

Jorge Duarte ◽

Cesar Isaza

Keyword(s):

Natural Gas ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Exergy Analysis ◽

Waste Heat ◽

Natural Gas Engine ◽

Exhaust Waste Heat ◽

Energy And Exergy ◽

Energy And Exergy Analysis ◽

Net Power Output

One way to increase overall natural gas engine efficiency is to transform exhaust waste heat into useful energy by means of a bottoming cycle. Organic Rankine cycle (ORC) is a promising technology to convert medium and low grade waste heat into mechanical power and electricity. This paper presents an energy and exergy analysis of three ORC-Waste heat recovery configurations by using an intermediate thermal oil circuit: Simple ORC (SORC), ORC with Recuperator (RORC) and ORC with Double Pressure (DORC), and Cyclohexane, Toluene and Acetone have been proposed as working fluids. An energy and exergy thermodynamic model is proposed to evaluate each configuration performance, while available exhaust thermal energy variation under different engine loads was determined through an experimentally validated mathematical model. Additionally, the effect of evaportating pressure on net power output , absolute thermal efficiency increase, absolute specific fuel consumption decrease, overall energy conversion efficiency, and component exergy destruction is also investigated. Results evidence an improvement in operational performance for heat recovery through RORC with Toluene at an evaporation pressure of 3.4 MPa, achieving 146.25 kW of net power output, 11.58% of overall conversion efficiency, 28.4% of ORC thermal efficiency, and an specific fuel consumption reduction of 7.67% at a 1482 rpm engine speed, a 120.2 L/min natural gas Flow, 1.784 lambda, and 1758.77 kW mechanical engine power.

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The Energy and Exergy Efficiencies of Renewable Energy Utilization in a Building Stock

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.361-363.335 ◽

2013 ◽

Vol 361-363 ◽

pp. 335-338

Author(s):

Xiao Chen

Keyword(s):

Renewable Energy ◽

Exergy Analysis ◽

Hot Water ◽

Energy Utilization ◽

Efficiency Improvement ◽

Building Stock ◽

Domestic Hot Water ◽

Energy And Exergy ◽

Energy And Exergy Analysis ◽

Heating Mode

An surface water heat pump (SWHP) system and some solar domestic hot water (SDHW) systems were constructed in a building stock located in Xiangtan for the purpose of energy saving and environmental improvement. This study aims to evaluate the energy and exergy efficiencies of renewable energy utilization based on energy and exergy analysis. We found the energy and exergy efficiencies of the SWHP system in heating mode to be 395% and 17.78%, respectively. The energy and exergy efficiencies for the SDHW systems were found to be 34.96% and 17.5%, respectively. Some measures for the exergy efficiency improvement are discussed in this paper.

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