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

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.

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

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2378 ◽  
Author(s):  
Guillermo Valencia ◽  
Armando Fontalvo ◽  
Yulineth Cárdenas ◽  
Jorge Duarte ◽  
Cesar Isaza
Keyword(s):  
Natural Gas ◽  
Conversion Efficiency ◽  
Power Output ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Energy And Exergy ◽  
Net Power Output

Waste heat recovery (WHR) from exhaust gases in natural gas engines improves the overall conversion efficiency. The organic Rankine cycle (ORC) has emerged as a promising technology to convert medium and low-grade waste heat into mechanical power and electricity. This paper presents the energy and exergy analyses of three ORC–WHR configurations that use a coupling thermal oil circuit. A simple ORC (SORC), an ORC with a recuperator (RORC), and an ORC with double-pressure (DORC) configuration are considered; cyclohexane, toluene, and acetone are simulated as ORC working fluids. Energy and exergy thermodynamic balances are employed to evaluate each configuration performance, while the available exhaust thermal energy variation under different engine loads is determined through an experimentally validated mathematical model. In addition, the effect of evaporating pressure on the net power output, thermal efficiency increase, specific fuel consumption, overall energy conversion efficiency, and exergy destruction is also investigated. The comparative analysis of natural gas engine performance indicators integrated with ORC configurations present evidence that RORC with toluene improves the operational performance by achieving a net power output of 146.25 kW, an overall conversion efficiency of 11.58%, an ORC thermal efficiency of 28.4%, and a 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 of mechanical engine power.

scholarly journals Thermoeconomic Optimization with PSO Algorithm of Waste Heat Recovery Systems Based on Organic Rankine Cycle System for a Natural Gas Engine

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4165 ◽  
Author(s):  
Guillermo Valencia Ochoa ◽  
Carlos Acevedo Peñaloza ◽  
Jorge Duarte Forero
Keyword(s):  
Natural Gas ◽  
Performance Optimization ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Pso Algorithm ◽  
Gas Engine ◽  
Natural Gas Engine

To contribute to the economic viability of waste heat recovery systems application based on the organic Rankine cycle (ORC) under real operation condition of natural gas engines, this article presents a thermoeconomic optimization results using the particle swarm optimization (PSO) algorithm of a simple ORC (SORC), regenerative ORC (RORC), and double-stage ORC (DORC) integrated to a GE Jenbacher engine type 6, which have not been reported in the literature. Thermoeconomic modeling was proposed for the studied configurations to integrate the exergetic analysis with economic considerations, allowing to reduce the thermoeconomic indicators that most influence the cash flow of the project. The greatest opportunities for improvement were obtained for the DORC, where the results for maximizing net power allowed the maximum value of 99.52 kW, with 85% and 80% efficiencies in the pump and turbine, respectively, while the pinch point temperatures of the evaporator and condenser must be 35 and 16 °C. This study serves as a guide for future research focused on the thermoeconomic performance optimization of an ORC integrated into a natural gas engine.

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