Lagrangian simulation and exergy analysis for waste heat recovery from high-temperature particles using countercurrent moving beds

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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Analysis and Verification of High Temperature Heat Pump Dryer using Waste Heat Recovery Type for R245fa Refrigerant

Journal of the Korea Society For Power System Engineering ◽

10.9726/kspse.2016.20.2.073 ◽

2016 ◽

Vol 20 (2) ◽

pp. 73-78

Author(s):

Kyung-Jin Bae ◽

Dong-An Cha ◽

Oh-Kyung Kwon

Keyword(s):

High Temperature ◽

Heat Pump ◽

Heat Recovery ◽

Waste Heat Recovery ◽

Waste Heat ◽

Temperature Heat ◽

High Temperature Heat Pump

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Exergy analysis of the Szewalski cycle with a waste heat recovery system

Archives of Thermodynamics ◽

10.1515/aoter-2015-0020 ◽

2015 ◽

Vol 36 (3) ◽

pp. 25-48 ◽

Cited By ~ 2

Author(s):

Tomasz Kowalczyk ◽

Paweł Ziółkowski ◽

Janusz Badur

Keyword(s):

Heat Recovery ◽

Waste Heat Recovery ◽

Power Plants ◽

Exergy Analysis ◽

Waste Heat ◽

Reference Conditions ◽

Heat Rate ◽

Working Fluid ◽

Regeneration System ◽

Waste Heat Recovery System

Abstract The conversion of a waste heat energy to electricity is now becoming one of the key points to improve the energy efficiency in a process engineering. However, large losses of a low-temperature thermal energy are also present in power engineering. One of such sources of waste heat in power plants are exhaust gases at the outlet of boilers. Through usage of a waste heat regeneration system it is possible to attain a heat rate of approximately 200 MWth, under about 90 °C, for a supercritical power block of 900 MWel fuelled by a lignite. In the article, we propose to use the waste heat to improve thermal efficiency of the Szewalski binary vapour cycle. The Szewalski binary vapour cycle provides steam as the working fluid in a high temperature part of the cycle, while another fluid – organic working fluid – as the working substance substituting conventional steam over the temperature range represented by the low pressure steam expansion. In order to define in detail the efficiency of energy conversion at various stages of the proposed cycle the exergy analysis was performed. The steam cycle for reference conditions, the Szewalski binary vapour cycle as well as the Szewalski hierarchic vapour cycle cooperating with a system of waste heat recovery have been comprised.

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