Materials Selection for Metallic Heat Exchangers in Advanced Coal-Fired Heaters

1983 ◽  
Vol 105 (3) ◽  
pp. 446-451 ◽  
Author(s):  
I. G. Wright ◽  
A. J. Minchener
Keyword(s):  
Heat Exchanger ◽  
Fluidized Bed ◽  
Plant Size ◽  
Working Fluid ◽  
High Temperature Strength ◽  
Fluid Temperature ◽  
Alloy 800 ◽  
Nickel Base ◽  
Fluidized Bed Combustor

The application of advanced coal-fired heaters to heat the working fluid for a closed-cycle gas turbine provides some challenging problems for the selection of metallic heat exchanger materials. The requirements of a working fluid temperature of 1550°F (1116 K) at a pressure of 300–600 psig (2.07–4.14 MPa/m2) necessitate that the alloys used for the hottest part of the heat exchanger possess high-temperature strength in excess of that available in widely used alloys like alloy 800. The maximum-duty alloys must therefore be selected from a group of essentially nickel-base alloys for which there is scant information on long-term strength or corrosion resistance properties. The susceptibility to corrosion of a series of candidate heat exchanger alloys has been examined in a pilot plant size fluidized-bed combustor. The observed corrosion behavior confirmed that at certain locations in a fluidized-bed combustor nickel-base alloys are susceptible in varying degrees to rapid sulfidation attack, and must be protected by coating or cladding.

Materials Selection for Metallic Heat Exchangers in Advanced Coal-Fired Heaters

1982 ◽  
Author(s):  
I. G. Wright ◽  
A. J. Minchener
Keyword(s):  
Heat Exchanger ◽  
Fluidized Bed ◽  
Plant Size ◽  
Working Fluid ◽  
High Temperature Strength ◽  
Fluid Temperature ◽  
Alloy 800 ◽  
Nickel Base ◽  
Fluidized Bed Combustor

The application of advanced coal-fired heaters to heat the working fluid for a closed-cycle gas turbine provides some challenging problems for the selection of metallic heat-exchanger materials. The requirements of a working fluid temperature bf 1550 F (1116 K) at a pressure of 300–600 psig (2.07–4.14 MPa/m2) necessitate the alloys used for the hottest part of the heat exchanger must possess high-temperature strength in excess of that available in widely used alloys like alloy 800. The maximum-duty alloys must therefore be selected from a group of essentially nickel-base alloys for which there is scant information on long term strength or corrosion resistance properties. The susceptibility to corrosion of a series of candidate heat exchanger alloys has been examined in a pilot plant size fluidized-bed combustor. The observed corrosion behavior confirmed that at certain locations in a fluidized-bed combustor nickel-base alloys are susceptible in varying degrees to rapid sulfidation attack, and must be protected by coating or cladding.

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.

Experiments on Heat Exchanger Solidity for Coal-Fired Fluidized Bed Applications

1980 ◽  
Vol 102 (4) ◽  
pp. 731-735 ◽  
Author(s):  
G. Miller ◽  
V. Zakkay
Keyword(s):  
New York ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Variable Parameter ◽  
Working Fluid ◽  
Special Importance ◽  
Fluidized Bed Combustion ◽  
New York University ◽  
Efficient Extraction ◽  
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. In a preliminary set of experiments it was found that under certain conditions, the solidity of heat exchanger in the bed may be significantly increased, giving designers an additional variable parameter.

Experimental Study on Compact External Heat Exchanger for a 4 MWth Circulating Fluidized Bed Combustor

2013 ◽  
Vol 448-453 ◽  
pp. 3259-3269
Author(s):  
Zhi Wei Li ◽  
Hong Zhou He ◽  
Huang Huang Zhuang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cooling Water ◽  
External Heat ◽  
Circulating Ash ◽  
Fluidized Bed Combustor ◽  
External Heat Exchanger

The characteristics of the external heat exchanger (EHE) for a 4 MWth circulation fluidized bed combustor were studied in the present paper. The length, width and height of EHE were 1.5 m, 0.8 m and 9 m, respectively. The circulating ash flow passing the heating surface bed could be controlled by adjusting the fluidizing air flow and the heating transferred from the circulating ash to the cooling water. The ash flow rate passing through the heat transfer bed was from 0.4 to 2.2 kg/s. The ash average temperature was from 500 to 750 °C. And the heat transfer rate between the ash and the cooling water was between 150 and 300 W/(m2·°C). The relationships among the circulating ash temperature, the heat transfer, heat transfer rate, the heat transfer coefficient and the circulating ash flow passing through the heating exchange cell were also presented and could be used for further commercial EHE design.

scholarly journals Utilization Waste Brine Water Separator for Binary Electric Energy Conversion in Geothermal Wells

2021 ◽  
Vol 16 (4) ◽  
pp. 411-420
Author(s):  
Herianto
Keyword(s):  
Heat Exchanger ◽  
Electric Energy ◽  
Thermodynamic Cycle ◽  
Geothermal Field ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Binary Cycle ◽  
Water Separator ◽  
Geothermal Wells

Nowadays, geothermal is one of the most environmentally friendly energy that can replace the role of fossils energy by converting steam to electricity. Brine is one of the by-products of the production of geothermal wells that are generally not used or simply re-injected. In fact, brine can be converted into electricity using the binary cycle process. In binary cycle, brine from separator is used as a heater of working fluid and transform it into a vapor phase. The vapor will be used to turn turbines and generators to produce electricity. The working fluid selection in accordance with the heating fluid temperature becomes important because it results in optimization of the thermodynamic cycle. The temperature of the wellhead in the geothermal field will decrease 3% per year and reducing the heating fluid temperature in heat exchanger. So, in this paper intends to utilizes brine to heat the heat exchanger by using iso-butane, n-pentane, and iso-pentane because its critical temperature can be stable at 193℃ wellhead temperatures. From the results of predictions from brain 2 production well for 17 years with iso-butane in this binary cycle planning, can utilize waste brine water separator to converse electric energy to produce 4 MWh electricity.

scholarly journals The Gas Turbine Heat Exchanger in the Fluidized Bed Combustor

1982 ◽  
Author(s):  
C. F. Holt ◽  
A. A. Boiarski ◽  
H. E. Carlton
Keyword(s):  
Heat Exchanger ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Gas Turbine ◽  
Fluidized Bed ◽  
Development Program ◽  
Low Oxygen ◽  
Bed Temperature ◽  
Technical Effort ◽  
Fluidized Bed Combustor

In a current research and development program a coal fired atmospheric fluidized bed combustor is being designed to supply the heat to a closed cycle gas turbine cogeneration system. The major technical effort is directed towards the design of the in-bed heat exchanger, which is required to operate near bed temperature. This high temperature (850 C) exposes the heat exchanger tubes to potentially severe sulfidation. The corrosion behavior depends upon the intimate details of the bed environment and may be related to the occurrence of localized areas of low oxygen partial pressure and high sulfur partial pressure. This paper describes a series of measurements of oxygen partial pressure at various locations within a fluidized bed. The bed, containing densely packed heat exchanger tubes, was operated under various conditions to observe the effect of coal mixing and devolatilization on local oxygen activity. Substantial variations of oxygen partial pressure (below 10−14 atmospheres) were observed. It was noted that these locally severe variations could be substantially modified by changes in coal mixing (as through coal port design). The experiments with varying coal size suggest that rapid devolatilization is desirable and would reduce the extent of locally corrosive environments.

scholarly journals Use of the Low-Potential Heat for Heating Helium in Rocket-Carrier Tank Pressurisation Systems

2021 ◽  
Vol 24 (7) ◽  
pp. 9-19
Author(s):  
Igor Kravchenko ◽  
Yurii Mitikov ◽  
Yurii Torba ◽  
Mykhailo Vasin ◽  
Oleksandr Zhyrkov
Keyword(s):  
Heat Exchanger ◽  
Combustion Chamber ◽  
Heat Exchangers ◽  
Fuel Tank ◽  
Industrial Wastes ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Propulsion Systems ◽  
Rocket Carrier ◽  
First Time

The energy efficiency of new technical developments is a critical issue. It should be noted that today the focus in this issue has seen a major shift to the maximum use of renewable energy sources. The purpose of this research is to reduce the weight of helium heat exchangers of the fuel tank pressurisation systems in modern rocket propulsion systems that use fuel components like liquid oxygen and kerosene-type fuel. This is the first time that the question has been raised about the possibility and advisability of increasing the temperature of helium at the heat exchanger inlet without the use of additional resources. The paper addresses the use of the waste (“low-potential”) heat and ”industrial wastes” present in propulsion systems. Basic laws of complex heat exchange and the retrospective review of applicable heat exchanger structures are applied as a research methodology. Two sources of low-potential heat are identified that have been previously used in the rocket engine building in an inconsistent and piecemeal manner to obtain and heat the pressurisation working fluid. These are the rammedair pressurisation during the motion of the rocket carrier in the atmosphere, and the tank pressurisation as a result of boiling of the top layer of oxidiser which is on the saturation line. This is the first time that the advisability has been substantiated of increasing the temperature of the working fluid at the heat exchanger inlet, first of all due to the use of the low-potential heat. This is also the first time that unemployed sources of low-potential heat and “industrial wastes” are found in modern deep throttling propulsion systems. These are the high-boiling-point fuel in the tank, behind the highpressure pump, at the exit of the combustion chamber cooling duct, and also the fuel tank structures, and the engine plume. A possibility is proved, and an advisability demonstrated of their implementation to increase the efficiency of pressurisation system heat exchangers. This is the first time that the methodology of combustion chamber cooling analysis has been proposed to be adopted for the heating of heat exchanger by the engine plume. This is the first time that a classification of waste heat sources has been developed which can be used to increase the pressurisation working fluid temperature. The identified reserves help to increase the efficiency of the helium heat exchangers of the tank pressurisation systems in the propulsion systems

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