High-Temperature, Coal-Fired Combustor With Ceramic Heat Exchangers for CCGT Systems

1980 ◽  
Author(s):  
H. W. Carpenter ◽  
J. Campbell ◽  
L. H. Russell ◽  
D. E. Wright
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Heat Exchangers ◽  
Working Fluid

High-temperature, coal-fired combustors with ceramic heat exchangers were designed for CCGT systems. The objective in evaluating CCGT systems is to convert U.S. coal to electricity with higher efficiency. Higher temperatures are required to accomplish this goal and ceramic heat exchanger surfaces allow the use of working fluid temperatures to 2500 F and higher. The results of a comprehensive government study are described in which an atmospheric fluidized bed and cyclone fired combustor/heat exchanger were designed for operation at 1750 and 2250 F.

Investigation of Supercritical CO2 Thermal Hydraulic Characteristics in a Printed Circuit Heat Exchanger

2018 ◽  
Author(s):  
Wen Fu ◽  
Xizhen Ma ◽  
Peiyue Li ◽  
Minghui Zhang ◽  
Sheng Li
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Supercritical Co2 ◽  
Three Dimensional ◽  
Working Fluid ◽  
Printed Circuit ◽  
Carbon Dioxide Co2

Printed circuit heat exchangers are considered for use as the intermediate heat exchangers (IHXs) in high temperature gas-cooled reactors (HTGRs), molten salts reactors (MSRs) and other advanced reactors. A printed circuit heat exchanger (PCHE) is a highly integrated plate-type compact heat exchanger with high-temperature, high-pressure applications and high compactness. A PCHE is built based on the technology of chemical etching and diffusion bonding. A PCHE with supercritical carbon dioxide (CO2) as the working fluid was designed in this study based on the theory correlations. Three-dimensional numerical analysis was then conducted to investigate the heat transfer and pressure drop characteristics of supercritical CO2 in the designed printed circuit heat exchanger using commercial CFD code, FLUENT. The distributions of temperature and velocity through the channel were modeled. The influences of Reynolds number on heat transfer and pressure drop were analyzed. The numerical results agree well with the theory calculations.

THE EFFECT OF LIQUID SUCTION HEAT EXCHANGER SUB-COOLER ON PERFORMANCE OF A FREEZER USING R404A AS WORKING FLUID

2015 ◽  
Vol 76 (11) ◽  
Author(s):  
Muhammad Nuriyadi ◽  
Sumeru Sumeru ◽  
Henry Nasution
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cooling Capacity ◽  
Experimental Results ◽  
Working Fluid ◽  
Liquid Line ◽  
Cabin Temperature

This study presents the effect of liquid-suction heat exchangers (LSHX) sub-cooler in a freezer. The LSHX sub-cooler is a method to increase the cooling capacity of the evaporator by lowering temperature at the condenser outlet. The decrease in temperature of the condenser outlet will cause a decrease in the quality refrigerant entering the evaporator. The lower the quality of the refrigerant entering the evaporator, the higher the cooling capacity produced by the evaporator. The LSHX sub-cooler utilizes a heat exchanger to transfer heat from the outlet of the condenser (liquid line) to the suction of the compressor. In the present study, three different LSHX sub-coolers in the freezer with cabin temperature settings of 0, -10 and -20oC were investigated. The results showed that the lowest and the highest of effectiveness of the heat exchanger were 0.28 and 0.58, respectively. The experimental results also showed that EER reduction is occurred at the cabin temperature setting of 0oC and -10oC, whereas the EER improvements were always occurred at the cabin temperature settings of -20oC.

scholarly journals Evaluation of Alternative Designs for a High Temperature Particle-to-sCO2 Heat Exchanger

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Clifford K. Ho ◽  
Matthew Carlson ◽  
Kevin J. Albrecht ◽  
Zhiwen Ma ◽  
Sheldon Jeter ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
High Temperature ◽  
Heat Exchanger ◽  
Transfer Coefficient ◽  
Fluidized Bed ◽  
Structural Reliability ◽  
Packed Bed ◽  
Heat Losses ◽  
Transient Operation

This paper presents an evaluation of alternative particle heat-exchanger designs, including moving packed-bed and fluidized-bed designs, for high-temperature heating of a solar-driven supercritical CO2 (sCO2) Brayton power cycle. The design requirements for high pressure (≥20 MPa) and high temperature (≥700 °C) operation associated with sCO2 posed several challenges requiring high-strength materials for piping and/or diffusion bonding for plates. Designs from several vendors for a 100 kW-thermal particle-to-sCO2 heat exchanger were evaluated as part of this project. Cost, heat-transfer coefficient, structural reliability, manufacturability, parasitics and heat losses, scalability, compatibility, erosion and corrosion, transient operation, and inspection ease were considered in the evaluation. An analytic hierarchy process was used to weight and compare the criteria for the different design options. The fluidized-bed design fared the best on heat transfer coefficient, structural reliability, scalability, and inspection ease, while the moving packed-bed designs fared the best on cost, parasitics and heat losses, manufacturability, compatibility, erosion and corrosion, and transient operation. A 100 kWt shell-and-plate design was ultimately selected for construction and integration with Sandia's falling particle receiver system.

Fluidized-Bed Heat Transfer Modeling for the Development of Particle/Supercritical-CO2 Heat Exchanger

2017 ◽  
Author(s):  
Zhiwen Ma ◽  
Janna Martinek
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Solid Particles ◽  
Heat Transfer Modeling ◽  
Power Cycle ◽  
Heat Exchanger Design ◽  
Temperature Heat ◽  
The Cost

Concentrating solar power (CSP) technology is moving toward high-temperature and high-performance design. One technology approach is to explore high-temperature heat-transfer fluids and storage, integrated with a high-efficiency power cycle such as the supercritical carbon dioxide (s-CO2) Brayton power cycle. The s-CO2 Brayton power system has great potential to enable the future CSP system to achieve high solar-to-electricity conversion efficiency and to reduce the cost of power generation. Solid particles have been proposed as a possible high-temperature heat-transfer medium that is inexpensive and stable at high temperatures above 1,000°C. The particle/heat exchanger provides a connection between the particles and s-CO2 fluid in the emerging s-CO2 power cycles in order to meet CSP power-cycle performance targets of 50% thermal-to-electric efficiency, and dry cooling at an ambient temperature of 40°C. The development goals for a particle/s-CO2 heat exchanger are to heat s-CO2 to ≥720°C and to use direct thermal storage with low-cost, stable solid particles. This paper presents heat-transfer modeling to inform the particle/s-CO2 heat-exchanger design and assess design tradeoffs. The heat-transfer process was modeled based on a particle/s-CO2 counterflow configuration. Empirical heat-transfer correlations for the fluidized bed and s-CO2 were used in calculating the heat-transfer area and optimizing the tube layout. A 2-D computational fluid-dynamics simulation was applied for particle distribution and fluidization characterization. The operating conditions were studied from the heat-transfer analysis, and cost was estimated from the sizing of the heat exchanger. The paper shows the path in achieving the cost and performance objectives for a heat-exchanger design.

Performance Optimization of Compact Ceramic High Temperature Heat Exchangers

2007 ◽  
Author(s):  
Q. Y. Chen ◽  
M. Zeng ◽  
D. H. Zhang ◽  
Q. W. Wang
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Performance Optimization ◽  
Heat Exchangers ◽  
Radiation Heat Transfer ◽  
Surface Radiation ◽  
Radiation Heat ◽  
High Temperature Side ◽  
Temperature Heat

In the present paper, the compact ceramic high temperature heat exchangers with parallel offset strip fins and inclined strip fins (inclined angle β = 0∼70°) are investigated with CFD method. The numerical simulations are carried out for high temperature (1500°C), without and with radiation heat transfer, and the periodic boundary is used in transverse direction. The fluid of high temperature side is the standard flue gas. The material of heat exchanger is SiC. NuS-G.R(with surface and gaseous radiation heat transfer) is averagely higher than NuNo.R (without radiation heat transfer) by 7% and fS-G.R is averagely higher than fNo.R by 5%. NuS-G.R(with surface and gaseous radiation heat transfer) is averagely higher than NuS.R (with only surface radiation heat transfer) by 0.8% and fS-G.R is averagely higher than fS.R by 3%. The thermal properties have significantly influence on the heat transfer and pressure drop characteristics, respectively. The heat transfer performance of the ceramic heat exchanger with inclined fins (β = 30°) is the best.

scholarly journals The Optimization of Heat Exchanger Solidity for Coal-Fired Fluidized Bed Combustors

1979 ◽  
Author(s):  
G. Miller ◽  
V. Zakkay ◽  
S. Rosen
Keyword(s):  
New York ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Working Fluid ◽  
Special Importance ◽  
Fluidized Bed Combustion ◽  
New York University ◽  
Efficient Extraction ◽  
Mass Flows ◽  
Fluidized Bed Combustor

The efficient extraction of a high-temperature working fluid from a coal-fired fluidized bed combustor depends, to a great extent, on the design of the immersed heat exchanger. Of special importance is the solidity of the cooling tubes immersed in the bed. The interaction between increasing solidity and the consequent degradation of proper fluidization and circulation is being studied at the New York University fluidized bed combustion facility. It is found that under certain conditions, the solidity of heat exchanger in the bed can be significantly increased and thus one can extract increased mass flows of clean working fluid. In addition, a variation in local solidity may be another mechanism for improving performance.

scholarly journals Investigation of heat transfer enhancement in an annular conduit with angled fins using functionalized GNP colloidal suspension

2021 ◽  
Vol 945 (1) ◽  
pp. 012058
Author(s):  
Sayshar Ram Nair ◽  
Cheen Sean Oon ◽  
Ming Kwang Tan ◽  
S.N. Kazi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Power Plants ◽  
Colloidal Suspension ◽  
Industrial Applications ◽  
Point Of View ◽  
Solid Particles ◽  
Working Fluid

Abstract Heat exchangers are important equipment with various industrial applications such as power plants, HVAC industry and chemical industries. Various fluids that are used as working fluid in the heat exchangers such as water, oil, and ethylene glycol. Researchers have conducted various studies and investigations to improve the heat exchanger be it from material or heat transfer point of view. There have been attempts to create mixtures with solid particles suspended. This invention had some drawbacks since the pressure drop was compromised, on top of the occurrence of sedimentation or even erosion, which incurs higher maintenance costs. A new class of colloidal suspension fluid that met the demands and characteristics of a heat exchanger was then created. This novel colloidal suspension mixture was then and now addressed as “nanofluid”. In this study, the usage of functionalized graphene nanoplatelet (GNP) nanofluids will be studied for its thermal conductivity within an annular conduit with angled fins, which encourage swirling flows. The simulation results for the chosen GNP nanofluid concentrations have shown an enhancement in thermal conductivity and heat transfer coefficient compared to the corresponding base fluid thermal properties. The data from this research is useful in industrial applications which involve heat exchangers with finned tubes.

scholarly journals Study on Shell-and-Tube Heat Exchanger Models with Different Degree of Complexity for Process Simulation and Control Design

2018 ◽  
Author(s):  
Javier Bonilla
Keyword(s):  
Heat Exchanger ◽  
Molten Salt ◽  
Heat Exchangers ◽  
Control Strategies ◽  
Thermal Storage ◽  
Working Fluid ◽  
Tube Heat Exchanger ◽  
Test Loop ◽  
Shell And Tube ◽  
Thermal Oil

Many commercial solar thermal power plants rely on indirect thermal storage systems in order to provide a stable and reliable power supply, where the working fluid is commonly thermal oil and the storage fluid is molten salt. The thermal oil - molten salt heat exchanger control strategies, to charge and discharge the thermal storage system, strongly affect the performance of the whole plant. Shell-and-tube heat exchangers are the most common type of heat exchangers used in these facilities. With the aim of developing advanced control strategies accurate and fast dynamic models of shell-and-tube heat exchangers are essential. For this reason, several shell-and-tube heat exchanger models with different degrees of complexity have been studied, analyzed and validated against experimental data from the CIEMAT-PSA molten salt test loop for thermal energy systems facility. Simulation results are compared in steady-state as well as transient predictions in order to determine the required complexity of the model to yield accurate results.

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