An Immersed Particle Heat Exchanger for Externally Fired and Heat Recovery Gas Turbines

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Luciano Andrea Catalano ◽  
Fabio De Bellis ◽  
Riccardo Amirante ◽  
Matteo Rignanese
Keyword(s):  
Heat Exchanger ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Gas Flow ◽  
High Efficiency ◽  
Small Diameter ◽  
Experimental Tests ◽  
Limiting Factor ◽  
Pipe Length ◽  
Alumina Particles

Designing and manufacturing high-efficiency heat exchangers is usually considered a limiting factor in the development of gas turbines employing either heat recovery Joule–Brayton cycles or external combustion. In this work, an innovative heat exchanger is proposed, modeled, and partially tested to validate the developed numerical model employed for its design. The heat exchanger is based on an intermediate medium (aluminum oxide Al2O3) flowing in countercurrent through an hot stream of gas. In this process, heat can be absorbed from the hot gas, temporarily stored, and then similarly released in a second pipe, where a cold stream is warmed up. A flow of alumina particles with very small diameter (of the order of hundreds of microns) can be employed to enhance the heat transfer. Experimental tests demonstrate that simple one-dimensional steady equations, also neglecting conduction in the particles, can be effectively employed to simulate the flow in the vertical part of the pipe, namely, to compute the pipe length required to achieve a prescribed heat exchange. On the other side, full three-dimensional computational fluid dynamics simulations have been performed to demonstrate that a more thorough gas flow and particle displacement analysis is needed to avoid a bad distribution of alumina particles and, thus, to achieve high thermal efficiency.

A High-Efficiency Heat Exchanger for Closed Cycle and Heat Recovery Gas Turbines

2010 ◽  
Author(s):  
Luciano Andrea Catalano ◽  
Fabio De Bellis ◽  
Riccardo Amirante ◽  
Matteo Rignanese
Keyword(s):  
Heat Exchanger ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Gas Flow ◽  
High Efficiency ◽  
Small Diameter ◽  
Limiting Factor ◽  
Closed Cycle ◽  
Pipe Length ◽  
Alumina Particles

Designing and manufacturing high-efficiency heat exchangers is usually considered a limiting factor in the development of both heat recovery Joule-Brayton cycles and closed-cycle (external combustion) gas turbine plants. In this work, an innovative heat exchanger is proposed, modeled and partially tested to validate the developed numerical model employed for its design. The heat exchanger is based on an intermediate medium (aluminum oxide Al2O3) flowing in counter-current through an hot stream of gas. In this process, heat can be absorbed from the hot gas, temporarily stored and then similarly released in a second pipe, where a cold stream is warmed up. A flow of alumina particles with very small diameter (of the order of hundreds of micron) can be employed to enhance the heat transfer. Experimental tests demonstrate that simple one-dimensional steady equations, also neglecting conduction in the particles, can be effectively employed to simulate the flow in the vertical part of the pipe, namely to compute the pipe length required to achieve a prescribed heat exchange. On the other side, full three-dimensional Computational Fluid Dynamics (CFD) simulations have been performed to demonstrate that a more thorough gas flow and particle displacement analysis is needed to avoid some geometrical details that may cause a bad distribution of alumina particles, and thus to achieve high thermal efficiency.

Prediction and Performance of Compact Latent Heat Recovery Heat Exchanger With Small Diameter Tubes

2007 ◽  
Author(s):  
Masahiro Osakabe
Keyword(s):  
Heat Exchanger ◽  
Power System ◽  
Latent Heat ◽  
Heat Recovery ◽  
Small Diameter ◽  
Cooling Water ◽  
Prediction Method ◽  
Outer Diameter ◽  
Exhaust Gas ◽  
And Performance

The most part of energy losses in power system such as fuel cells is due to the heat released by the exhaust gas to atmosphere. The exhaust gas consists of non-condensable gas and steam with sensible and latent heat. As a lot of latent heat is included in the exhaust gas, its recovery is very important to improve the power system efficiency. Based on the previous basic studies, a thermal hydraulic prediction method for latent heat recovery exchangers was proposed. For the condensation of steam on heat transfer tubes, the modified Sherwood number taking account of the mass absorption effect on the wall was used. Two kinds of compact heat exchanger with staggered banks of bare tubes of 10.5 or 4mm in outer diameter was designed with the prediction method. The more compactness was obtained with the smaller tubes at a designed heat recovery. The thermal hydraulic behavior in the compact heat exchangers was experimentally studied with air-steam mixture gas. In the parametric experiments varying the steam mass concentration, the temperature distributions of cooling water and mixture gas were measured. The experimental results agreed well with the prediction proposed in this study and the more compactness with the smaller tubes was proved.

Fanno Design of Blow-Off Lines in Heavy Duty Gas Turbine

2013 ◽  
Author(s):  
Marco Cioffi ◽  
Enrico Puppo ◽  
Andrea Silingardi
Keyword(s):  
Gas Turbines ◽  
Gas Flow ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Design Procedure ◽  
Flow Equation ◽  
Heavy Duty ◽  
Cross Sectional ◽  
Pipe Length ◽  
Choked Flow

In typical heavy duty gas turbines the multistage axial compressor is provided with anti-surge pipelines equipped with on-off valves (blow-off lines), to avoid dangerous flow instabilities during start-ups and shut-downs. Blow-off lines show some very peculiar phenomena and somewhat challenging fluid dynamics, which require a deeper regard. In this paper the blow-off lines in axial gas turbines are analyzed by adopting an adiabatic quasi-unidimensional model of the gas flow through a pipe with a constant cross-sectional area and involving geometrical singularities (Fanno flow). The determination of the Fanno limit, on the basis of the flow equation and the second principle of thermodynamics, shows the existence of a critical pipe length which is a function of the pipe parameters and the initial conditions: for a length greater than this maximum one, the model requires a mass-flow reduction. In addition, in the presence of a regulating valve, so-called multi-choked flow can arise. The semi-analytical model has been implemented and the results have been compared with a three-dimensional CFD analysis and cross-checked with available field data, showing a good agreement. The Fanno model has been applied for the analysis of some of the actual machines in the Ansaldo Energia fleet under different working conditions. The Fanno tool will be part of the design procedure of new machines. In addition it will define related experimental activities.

Thermodynamic Performance of Wet Compression and Regenerative (WCR) Gas Turbine

2003 ◽  
Author(s):  
Qun Zheng ◽  
Minghong Li ◽  
Yufeng Sun
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Regenerative Process ◽  
Specific Power ◽  
Heat Recovery Steam Generator ◽  
Thermodynamic Performance ◽  
Wet Compression ◽  
Steam Heat

Thermodynamic performance of wet compression and regenerative (WCR) gas turbine are investigated in this paper. The regenerative process can be achieved by a gas/air (and steam) heat exchanger, a regenerator, or by a heat recovery steam generator and then the steam injected into the gas turbine. Several schemes of the above wet compression and regenerative cycles are computed and analyzed. The calculated results indicate that not only a significant specific power can be obtained, but also is the WCR gas turbine an economic competitive option of efficient gas turbines.

NUMERICAL SIMULATION AND PARAMETRIC STUDIES FOR EVALUATION OF BALANCED VENTILATION AND EARTH AIR EXCHANGERS SYSTEM COUPLED TO A DOMESTIC BUILDING

2013 ◽  
Vol 21 (01) ◽  
pp. 1350002 ◽  
Author(s):  
YOUNES KARTACHI ◽  
ABDELLAH MECHAQRANE
Keyword(s):  
Heat Exchanger ◽  
Heat Recovery ◽  
High Efficiency ◽  
Residential Buildings ◽  
Ventilation System ◽  
Primary Energy ◽  
Climatic Conditions ◽  
Design Parameters ◽  
Climate Data ◽  
The Impact

In this study, we analyze the impact of ventilation heat recovery with the heating and cooling potential of earth air heat exchanger in real climatic conditions in domestic buildings in the Middle Atlas region. In our case study, we calculate the primary energy used by a domestic building built as per the conventional house design parameters required by the Moroccan regulation. We use climate data for the city of Fes in Northern Moroccan. Three system configurations were considered. The first was the mechanical extract ventilation system both with and without heat recovery. The second was the mechanical extract ventilation system with earth to air heat exchanger system (EAHEX), and the third system was the mechanical balanced ventilation system coupled with EAHEX system. Primary energy use strongly influences natural resources efficiency and the environmental impacts of energy supply activities. In this study we explore the primary energy implications of the mechanical balanced ventilation system coupled with the EAHEX system in residential buildings. The results of this study shows that the use of a balanced ventilation system, with a high efficiency instead of a mechanical extract ventilation system, decreases the final and primary energy consumption. Moreover, it decreases or increases the CO2 emission depending on the primary energy sources.

Selective Catalytic Reduction Impact on Heat Recovery Steam Generator Design and Operation

1986 ◽  
Author(s):  
James S. Davis ◽  
G. C. Duponteil
Keyword(s):  
Selective Catalytic Reduction ◽  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Gas Flow ◽  
High Efficiency ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Heat Recovery Steam Generator ◽  
The Impact

Selective Catalytic Reduction (SCR) is a post-combustion method to reduce the oxides of nitrogen (NOx), present in flue gases such as gas turbine exhaust streams, to N2 and water. It involves the injection of ammonia and the use of a catalyst module to promote the reaction to obtain high efficiency (60–86+%) NOx reduction. Several operating parameters can influence catalyst performance to include temperature, gas flow distribution, presence of sulfur compounds and catalyst age. This paper examines the impact of a SCR integration in a gas turbine heat recovery steam generator (HRSG) design/operation. Limitations on HRSG load and following capabilities, effect on capital cost and overall performance and current SCR system experience represent a number of areas that are examined.

scholarly journals Simulation of a Heat Recovery Steam Generator Operating in a Combined Cycle Plant

2013 ◽  
Author(s):  
Raphael Duarte ◽  
Sandro Ferreira ◽  
Rafael Barbosa
Keyword(s):  
Heat Exchanger ◽  
Power Plant ◽  
Steam Generator ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Computational Models ◽  
Structural Changes ◽  
Combined Cycle ◽  
Heat Recovery Steam Generator ◽  
Energy Potential

The heavy duty gas turbines evolution led to higher combined cycle efficiencies. Thus, more complex heat recovery steam generators were developed in order to maximize the use of that energy potential. Therefore, computational models capable to predict the operational conditions of the equipment may be needed in order to analyze the system behavior for different situations. This article describes a computational model able to simulate the off-design behavior of a heat recovery steam generator (HRSG) operating in a combined cycle power plant. The model was developed so that it can be used in both model-based diagnostics systems and performance evaluation systems. Each heat exchanger inside the HRSG was designed individually and arranged according to the analyzed equipment. The computer code’s architecture was built in such a way that it can be easily changed, allowing the analysis of other HRSG’s configurations with simple structural changes, given the program’s modularity. In order to deal with the lack of details of the power plant equipment, which means not enough geometrical information of each heat exchanger, a generic algorithm tool was used to calibrate the heat exchangers models using only the measured data of the power plant SCADA. The developed program was validated against operational data from a real plant and showed satisfactory results, confirming the robustness of this model.

Unsteady Conjugate Heat Transfer Analysis of an Air Immersed Solid Particle With Application to an Innovative Heat Exchanger

2011 ◽  
Author(s):  
Leonardo Nettis ◽  
Fabio De Bellis ◽  
Luciano A. Catalano ◽  
Roberto Verzicco
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Solid Particle ◽  
Conjugate Heat Transfer ◽  
Gas Flow ◽  
High Efficiency ◽  
Large Diameter ◽  
Solid Particles ◽  
Heat Transfer Analysis ◽  
1D Model

The improvement of both heat recovery Joule-Brayton cycles and closed cycle (externally fired) gas turbine plants is strongly limited by the availability of high efficiency heat exchangers. In such a scenario, a non conventional heat exchanger was recently proposed; this device employs falling solid particles to perform heat transfer between two separate gas flows and was designed with a 1D model neglecting conduction within the particles. Although experimental reliability of this assumption was already obtained, there is no proof available of the quantitative effect introduced by the above mentioned simplification. In this work, Direct Numerical Simulation (DNS) of a solid particle immersed in a gas flow has been performed in order to further validate the hypothesis of negligible conduction and to enhance the design of the proposed heat exchanger. Unsteady Conjugate Heat Transfer (CHT) has been used to predict the final temperature of the solid sphere for Reynolds numbers ranging from 30 to nearly 300, the computational grid being generated with the Immersed Boundary (IB) technique. A validation of the study is presented, together with grid independence and boundary independence assessment. The results fully confirmed the worthiness of the initial assumption, with a 1.4% maximum error for high Reynolds conditions (large diameter particles) with respect to the 1D model. Additionally, the code has been employed to explore the influence both of several particles disposed in a row and of the distance between successive particles.

Review of Heat Exchanger Studies for High-Efficiency Gas Turbines

2007 ◽  
Author(s):  
Ji Hwan Jeong ◽  
Lae Sung Kim ◽  
Jae Keun Lee ◽  
Man Yeong Ha ◽  
Kui Soon Kim ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Air Transportation ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Materials Selection ◽  
Air Cooler ◽  
Cooling Air

Air transportation has been being expanded remarkably, and its growth is expected to continue in the coming decades. Environmental issues and airlines require gas turbine manufacturers to produce environmentally friendly gas-turbine engines with lower emissions and improved specific fuel consumption. These requirements can be met by incorporating heat exchangers into gas turbines for intercooling and recuperation. Relevant research in such areas as the design of a heat exchanger matrix, materials selection, and manufacturing technology and optimization has been carried out by a variety of researchers. These works are reviewed in this paper. The recent advance in technologies appears to herald the development of intercoolers and recuperators for civil aeroplane gas turbines. Based on results reported in previous studies, potential heat exchanger designs for an aero gas turbine recuperator, intercooler, and cooling-air cooler are suggested.

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