Numerical prediction of high efficiency boiler heat exchanger performance

1998 ◽  
Vol 18 (11) ◽  
pp. 1089-1099 ◽  
Author(s):  
L.Y. Huang ◽  
J.X. Wen ◽  
T.G. Karayiannis ◽  
R.D. Matthews
Keyword(s):  
Heat Exchanger ◽  
High Efficiency ◽  
Numerical Prediction

Externally-Fired Combined Cycle Repowering of Existing Steam Plants

1993 ◽  
Author(s):  
Christian L. Vandervort ◽  
Mohammed R. Bary ◽  
Larry E. Stoddard ◽  
Steven T. Higgins
Keyword(s):  
Heat Exchanger ◽  
Steam Turbine ◽  
Gas Turbine ◽  
High Efficiency ◽  
Low Cost ◽  
Operating Experience ◽  
Capital Cost ◽  
Combined Cycle ◽  
Plant Design ◽  
Generating Capacity

The Externally-Fired Combined Cycle (EFCC) is an attractive emerging technology for powering high efficiency combined gas and steam turbine cycles with coal or other ash bearing fuels. The key near-term market for the EFCC is likely to be repowering of existing coal fueled power generation units. Repowering with an EFCC system offers utilities the ability to improve efficiency of existing plants by 25 to 60 percent, while doubling generating capacity. Repowering can be accomplished at a capital cost half that of a new facility of similar capacity. Furthermore, the EFCC concept does not require complex chemical processes, and is therefore very compatible with existing utility operating experience. In the EFCC, the heat input to the gas turbine is supplied indirectly through a ceramic heat exchanger. The heat exchanger, coupled with an atmospheric coal combustor and auxiliary components, replaces the conventional gas turbine combustor. Addition of a steam bottoming plant and exhaust cleanup system completes the combined cycle. A conceptual design has been developed for EFCC repowering of an existing reference plant which operates with a 48 MW steam turbine at a net plant efficiency of 25 percent. The repowered plant design uses a General Electric LM6000 gas turbine package in the EFCC power island. Topping the existing steam plant with the coal fueled EFCC improves efficiency to nearly 40 percent. The capital cost of this upgrade is 1,090/kW. When combined with the high efficiency, the low cost of coal, and low operation and maintenance costs, the resulting cost of electricity is competitive for base load generation.

Effect of Mass Flow Rate of Inlet Gas on Holdup Mass of Solidcyclone Heat Exchanger

2014 ◽  
Vol 592-594 ◽  
pp. 1498-1502 ◽  
Author(s):  
T. Mothilal ◽  
K. Pitchandi
Keyword(s):  
Heat Exchanger ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Efficiency ◽  
Solid Particles ◽  
Operating Parameters ◽  
Water Removal ◽  
Solvent Recovery ◽  
Solid Feed Rate

Effect of mass flow rate of inlet gas on holdup mass in a high efficiency cyclone has been performed. Cyclone as heat transfer equipment may be used for drying, solidification, water removal, solvent recovery, sublimation, chemical reaction and oxidation. In all such cases, performance of cyclone depends on the surface area of the solid particles inside the cyclone. The holdup varies with the variation in operating parameters. This proposed work will present an effect of mass flow rate of inlet gas on cyclone heat exchanger and calculation of holdup mass by varying the mass flow rate of inlet gas, solid feed rate and diameter of the particle.

System Design of a 2.0 MWth Sodium/Molten Salt Pilot System

2020 ◽  
Author(s):  
Kenneth M. Armijo ◽  
Matthew D. Carlson ◽  
Dwight S. Dorsey ◽  
Joshua M. Christian ◽  
Craig S. Turchi
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
System Design ◽  
Molten Salt ◽  
High Efficiency ◽  
Performance Model ◽  
Transfer Coefficients ◽  
Storage Duration ◽  
Pump Speed ◽  
Receiver System

Abstract Nitrate molten salt concentrating solar power (CSP) systems are currently deployed globally and are considered state-of the art heat transfer fluids (HTFs) for present day high-temperature operation. Although slightly higher limits may be possible with molten salt, to fully realize SunShot efficiency goals of $15/kWhth HTFs and an LCOE of 6¢/kWh, HTF technologies working at higher temperatures (e.g., 650 °C to 750 °C) will require an alternative to molten salts, such as with alkali metal systems. This investigation explores the development of a 2.0 MWth sodium receiver system that employs a sodium receiver as the HTF, as well as with a ternary chloride (20%NaCl/40%MgCl/40%KCl by mol wt.%) salt as a thermal energy storage (TES) medium to facilitate a 6-hr. storage duration. A sodium-to-salt heat exchanger model as well as a salt-to-sCO2 primary heat exchanger model are employed and evaluated in this investigation. A thermodynamic system design model was developed using Engineering Equation Solver (EES) where state properties were calculated at inlets and outlets along both hot and cold legs of the pilot-scale plant. This investigation assesses receiver performance as well as system efficiency studies for the pump and system operational ranges. Results found that high efficiency sodium receivers were found to have higher heat transfer coefficients and required far less spreading of incident flux. The system performance model results suggest that for a pump speed of 2400 RPM, respective hot and cold pump TDH values were determined to be 260.1–307 ft. and 260.1–307 ft for pump flow rates of 90–120 GPM.

Experimental Study on Thermal Hydraulic Characteristics of Steam Condensation in Capillary Glass Tubes

2009 ◽  
Author(s):  
Koji Iiyama ◽  
Akiko Kaneko ◽  
Yutaka Abe ◽  
Yutaka Suzuki
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
High Efficiency ◽  
Capillary Tube ◽  
Glass Tube ◽  
Phase Changes ◽  
Vapor Flow ◽  
Hydraulic Characteristics ◽  
Microchannel Heat Exchanger ◽  
Condensation Flow

At present, a microchannel heat exchanger is requested to achieve high efficiency in small size energy equipments. In order to clarify the heat transfer mechanism in a microchannel heat exchanger, knowledge on the thermal hydraulic characteristics of condensation flow in the channels is essential. However, study on the thermal hydraulic characteristics of condensation flow in a microchannel is hardly conducted except visualization of flow patterns. Objectives of the present study are to estimate the heat transfer performance of the present device and to observe the condensation behavior of vapor flow to clarify the thermal hydraulic characteristics of condensation flow in a capillary tube. As the results, it is confirmed that the microchannel heat exchanger realizes heat exchange of 7 kW when phase changes. In a single capillary glass tube as a simulated unit microchannel, the annular flow, the injection flow and the bubbly flow in a capillary tube are observed. According to the comparison of the present device and the glass tube experiment, it is suggested that the flow structure in the microchannel heat exchanger is almost same as that in the glass capillary tube.

Application Study of Newly Developed Turbo Heat Pump for 130 Degrees Celsius Water for an Industrial Process

2011 ◽  
Author(s):  
Shuichi Umezawa ◽  
Haruo Amari ◽  
Hiroyuki Shimada ◽  
Takashi Matsuhisa ◽  
Ryo Fukushima ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Low Temperature ◽  
Heat Source ◽  
Heat Pump ◽  
High Efficiency ◽  
Industrial Process ◽  
Application Study ◽  
Hot Air ◽  
Heat Demand ◽  
Temperature Heat

This paper reports application study of newly developed turbo heat pump for 130 degrees Celsius (°C) water for an industrial process in an actual factory. The heat pump is characterized by high efficiency and large heat output, by using a state-of-the-art turbo compressor. The heat pump requires a low temperature heat source in order to achieve high efficiency. The heat demand is for several drying furnaces in the factory, which requires producing hot air of 120 °C. The heat exchanger was designed to produce the hot air. Experiments were conducted to confirm the performance of the heat exchanger under a reduced size of the heat exchanger. Low temperature heat sources are from both exhaust gas of the drying furnaces and that of an annealing furnace. The heat exchangers were also designed to recover heat of the exhaust gas from the two types of furnace. A thermal storage tank was prepared for the low temperature heat source, and for adjusting the time difference between the heat demand and the low temperature heat source. The size of the tank was determined by considering the schedule of furnaces operations. As a result of the present study, it was confirmed that the heat pump was able to satisfy the present heat demand while retaining high efficiency. Primary energy consumption and CO2 emission of the heat pump were calculated on the basis of the present results in order to compare them with those of the boilers.

Numerical simulation of flow distribution in the header of plate-fin heat exchanger

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040111
Author(s):  
Shu-Ling Tian ◽  
Ying-Ying Shen ◽  
Yao Li ◽  
Hai-Bo Wang ◽  
Sheryar Muhammad ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Optimization Design ◽  
High Efficiency ◽  
Flow Distribution ◽  
Optimal Number ◽  
Compact Structure ◽  
Flow Maldistribution

Plate-fin heat exchangers are widely used in industry at present due to their compact structure and high efficiency. However, there is a problem of flow maldistribution, resulting in poor performance of heat exchangers. The influence of the header configuration on fluid flow distribution is studied by using CFD software FLUENT. The numerical results show that the fluid flow inside the header is seriously uneven. The reliability of the numerical simulation is validated against the published results. They are found to be basically consistent within considerable error. The optimal number of the punch baffle is investigated. Various header configuration with different opening ratios have been studied under the same boundary conditions. The gross flow maldistribution parameter (S) is used to evaluate flow nonuniformity, and the flow maldistribution parameters of different schemes under different Reynolds numbers are listed and compared. The optimal header with minimum flow maldistribution parameter is obtained through the performance analysis of headers. It is found that the flow maldistribution of the improved header is significantly smaller compared with the conventional header. Hence, the efficiency of the heat exchanger is effectively enhanced. The conclusion provides a reference for the optimization design of plate-fin heat exchanger.

scholarly journals PROFOUND HYPOTHERMIA WITH SIMPLIFIED EQUIPMENT: A DISPOSABLE STAINLESS STEEL HEAT EXCHANGER OF HIGH EFFICIENCY

1961 ◽  
Vol 42 (5) ◽  
pp. 563-574 ◽  
Author(s):  
William G. Esmond ◽  
Safuh Altar ◽  
John Stram ◽  
Andreas D. Demetriades ◽  
Amin Jurf ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Heat Exchanger ◽  
High Efficiency ◽  
Profound Hypothermia ◽  
Stainless Steel Heat ◽  
Steel Heat

Experimental Study on Peeling Properties of T Type Brazing Joint

2019 ◽  
Vol 795 ◽  
pp. 116-122
Author(s):  
Peng Yang Duan ◽  
Dong Xing Wang ◽  
Guo Yan Zhou ◽  
Shan Tung Tu
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
High Efficiency ◽  
Base Material ◽  
Peel Test ◽  
Type Specimen ◽  
Peel Strength ◽  
Manufacturing Cost ◽  
Standard Samples ◽  
Compact Structure

As the key component of the high temperature gas cooled reactor (HTGR), the performance of the plate fin heat exchanger determines the working efficiency and life of the HTGR. Although the plate-fin structure has lots of advantages such as high efficiency, compact structure, low manufacturing cost, its application will be affected by the vacuum brazing technology and harsh conditions, like high temperature and high pressure. In the practical application of plate-fin heat exchanger, the process of "splitting" between the fin and the diaphragm is very similar to that of the adhesive joint and the delamination of the composite. In the present study, a T-type specimen was designed for the the peel testing of brazed joints. Five kinds of specimens were designed based on the difference between the weld gap and the thickness of the sample base material. The tests were carried out under 450°C and 650°C at five kinds of loading rates, respectively. The peel force-displacement curves of standard samples were obtained . The maximum peel strength and average peel strength were calculated. In addition, the influence of base metal thickness, brazing gap, loading rate and test temperature on the maximum peel strength were analyzed by controlling variable method. Keywords: brazing joint; T-type peel test

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