Shell and Plate Feedwater Heater Prototype Test

1 Copyright © 2014 by ASME

SPFWH™ is a trademark or registered trademark of Tranter Inc. Other names may be trademarks of their respective owners.

SHELL AND PLATE FEEDWATER HEATER PROTOTYPE TEST

Creed Taylor

Westinghouse Electric Company Chattanooga, Tennessee, U.S.A.

Rhorn John Tranter Inc.

Wichita Falls, Texas, U.S.A.

Jason L. Williams Tranter Inc.

Wichita Falls, Texas, U.S.A.

ABSTRACT

Westinghouse Electric Company and Tranter Inc. are collaborating to develop the modular, low-pressure horizontal shell and plate feedwater heater (SPFWH™) heat exchanger product. This design utilizes easily removable modules of welded heat transfer plates within a pressure vessel instead of traditional tubes as the pressure boundary and heat transfer interface between the steam and feedwater. Design advantages include improved long-term performance, inspection and maintenance access. Each SPFWH™ heat exchanger will be designed to meet all plant-specific requirements and is ASME Section VIII compliant.

A prototype SPFWH™ heat exchanger design (herein called the prototype or test unit) was fabricated and tested to validate the functionality of the design features and benchmark the correlations used to predict the performance. The test was performed in the Tranter Inc. laboratory facility using full temperature and pressure steam conditions over a broad operating range typical of low pressure feedwater heaters.

Heat transfer coefficient characteristics have been evaluated and the prototype test data shows good agreement with established empirical correlations and other industry research. These results indicate that the SPFWH™ heat exchanger design is a viable alternative to a shell-and-tube type heat exchanger due to the performance, compactness, modularity, and robustness of the new design.

INTRODUCTION

This publication provides a product overview of the SPFWH™ heat exchanger design and describes the prototype testing. The background section contains a product overview including a brief history of the shell and welded plate technology, discussion of the design features and advantages. The testing section contains a description of the prototype design, the test loop and the tests conducted including a range of conditions. The results and discussion section contains a description of the data collected during the test, a discussion of

results and comparison with predictions. The conclusion section provides summary comments about the product and prototype test.

BACKGROUND

SPFWH™ Heat Exchanger Design Overview

The SPFWH™ heat exchanger design, as depicted in Figure 1, is designed for full shell side access. The key features shown in this Figure include replaceable heat transfer plates and removable heads.

Figure 1. SPFWH™ heat exchanger design features

The SPFWH™ heat transfer plate core assembly is made up of multiple fully welded plate modules connected to each other with gaskets and connecting hardware. Each module is made up of a number of heat transfer plates that are alternately welded at both the port and circumferential locations, and module end plates for connecting to adjacent modules. The module design is capable of retaining high fluid pressure

Proceedings of the ASME 2014 Power Conference POWER2014

July 28-31, 2014, Baltimore, Maryland, USA

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(≥1000 psia) exceeding “typical” low pressure feedwater heater requirements. This design enables removal of any plate module without breaking any welds.

Existing Shell and Tube Technology

Traditional Shell and Tube feedwater heater designs have experienced a number of challenges:

1. Component degradation; 2. Limited shell side access (difficult boroscopic

inspections); 3. Limited tube access (difficult leak location detection); 4. Difficult and costly maintenance; 5. Difficulty in determining leaks leading to increased

plugging of tubes; 6. System degradation leading to unplanned maintenance

outages; 7. Loss of System thermal performance (i.e. lost heat

transfer area) and hydraulic performance (i.e. loss of pump margin due to higher pressure drop).

In general, customers need a cost competitive solution, with long-term performance, improved reliability and serviceability. The SPFWH™ heat exchanger aims to address the Shell and Tube design challenges and meet customer needs as discussed in the next section.

Shell and Plate Technology Background

In Shell and Plate heat exchangers, plates function as the pressure boundary and heat transfer surface between two fluids. Corrugated heat transfer plates, as shown in Figure 2, are pressed from a single sheet of metal (i.e. 316L SS). Flow channels are created by alternately welding a series of corrugated plates together at both the ports and circumferential joints as shown in Figure 3. This figure also shows the module end plates welded to the first and last heat transfer plate in the module.

Flow between the corrugated heat transfer plates is highly turbulent resulting in high heat transfer coefficients as compared to the same flow within a tube. A counter current flow arrangement, as shown in Figure 4, provides the maximum thermal efficiency. Shell side heat transfer modes are both condensing and sub-cooled liquid forced convection in one pass. Plate side heat transfer is single phase forced convection in one pass.

Thousands of welded Shell and Plate Heat Exchangers are in operation in a variety of applications ranging from Crude Oil Heaters to Ammonia Condensers including steam condensation applications (Reference 1).

Figure 2. Heat transfer plate pressed from single sheet of metal

Figure 3. Plate module section

Figure 4. Counter-current flow configuration


SPFWH™ Heat Exchanger Design Advantages

Long-term performance is improved since the heat transfer plate modules can be easily replaced if needed, thus eliminating tube plugging and associated thermal and hydraulic design margin impacts. A hydraulic design margin example is that feedwater pump margins are maintained since there are no increased pressure drops associated with tube plugging. A thermal design margin example is that 100% of the original designed surface is available over the life of the unit to provide optimal Thermal Performance.

Component potential susceptibility for common degradation mechanisms is improved as a result of the plate geometry and material selection. Potential for flow induced vibration (FIV) is significantly reduced due to a heat transfer plate geometry that features tightly-spaced, corrugated plate-to-plate contact points which are typically less than ~0.5” apart. This configuration is fundamentally different than “long span” supported tubes typical of traditional shell and tube designs. Potential for flow accelerated corrosion (FAC) is minimized by selecting high quality alloy materials such as Stainless steel (316L) for the plates and >0.1% chrome steel for the other areas susceptible to FAC (Reference 2).

Provision for component inspection and maintenance is improved since the bolted removable heads and removable plate cores provide access to 100% of the heat transfer surface and internals. The design eliminates the need for difficult boroscopic inspections, eddy current inspections, tube plugging and staking maintenance activities. Heat transfer modules can be visually inspected, pressure tested, replaced and/or expanded at a planned service outage, if needed. Thus the design provides potential for incremental economic refurbishment.

The SPFWH™ heat exchanger design is compact and low weight compared to traditional Shell and Tube designs due to a high heat transfer area to volumetric ratio. For example, the prototype contained ~70 ft2 of heat transfer area within a cylindrical volume of ~0.9 ft3 (Cylinder and Plate Diameter = 17.3 in, Cylinder Length = 6.4 in, 40 corrugated plates); as a comparison the surface area of a straight tube bundle (Tube outer diameter = 5/8 in, Triangular Pitch 0.833 in, Number of tubes = 364) was calculated to be ~28 ft2 of heat transfer area within the same cylindrical volume. This example indicates that the plate arrangement contains approximately 2.5 times as much surface area per volume for this tube pitch. Additionally, plate heat exchangers typically have narrow channel widths on the order of 0.1 inches (i.e. small hydraulic diameters) and thus relatively high Reynolds numbers and heat transfer coefficients between the corrugated plate channels compared to shell and tube heat exchangers for a given flow rate.

Units will be sized to meet plant-specific requirements and can be designed to accommodate future plant upratings. The design provides for effective condensation, sub-cooling, venting, stable level control and prevention of drain flow

flashing. Units will be designed to comply with all ASME VIII requirements.

TESTING

The SPFWH™ heat exchanger prototype tests were conducted between June 2013 and January 2014 at the Tranter Inc. Test Laboratory in Wichita Falls, Texas. The test program consisted of seven separate tests which examined various aspects of feedwater heater performance. Tests performed included: Hydrostatic, Heat-up / Cool-down, Level, Vent, Nominal Design conditions, Abnormal Design conditions and Fatigue as described in this section.

The objectives of the prototype test program were to: 1. Provide a test demonstration of the major design concepts

in an integrated scale model test. 2. Provide experimental validation of design tools used for

prediction of overall performance. 3. Specifically:

a. Characterize the steady-state operating performance of the prototype over the heat load range;

b. Characterize the performance of the prototype over the water level range;

c. Characterize the response of the prototype to typical plant transients;

d. Demonstrate the adequacy of the module connections and sealing gasket design;

e. Demonstrate the thermal fatigue resistance of the design.

These objectives have been addressed in the series of tests and are summarized herein.

Prototype Design

The prototype design contained the features planned for use in the full size unit; prominent features include: a shell, a removable head, a fully removable heat transfer core made up of heat transfer modules, module connection hardware, gaskets, internal baffles, nozzles and level taps. The prototype design used ethylene propylene diene monomer (EPDM) rubber gaskets due to the low cost, ease of use, chemical compatibility with lab fluid systems and short term test duration. For the full size SPFWH™ product, activities are planned to ensure long term gasket integrity in a plant application including: gasket requirements evaluation, selection and qualification. Basic geometric data for the prototype is provided in Table 1 and a photograph of the prototype installed in the test loop is shown in Figure 5.

Table 1. Prototype basic geometry data Parameter Prototype Plate Model Number SPW-40 Plate Material 316L Stainless Steel Outer diameter of plate, mm (in.) 440 (17.3)Port diameter of plate, mm (in.) 80 (3.1)Plate thickness, mm (in.) 0.6 (0.024)Number of modules 3 Flow configuration Counter-current flow


Figure 5. Photo of prototype installed in the test loop

Test Loop

In order to achieve the desired test conditions, a test loop system was configured as shown schematically in Annex A - Figure 9 of this report. The system contains various equipment including: a boiler, multiple chillers, auxiliary heat exchangers, hot and cold water tanks, multiple pumps, piping, and valves. In order to achieve steady steam pressure for the tests, the boiler controls were fine-tuned and a pressure regulating valve was installed.

Instruments used in this test were selected based on measurement range, accuracy and instrument uncertainty. For example highly accurate instruments such as coriolis flow and density meters were used to measure the plate side flow and a vortex meter was used to measure shell side steam flow. Instrument calibration was performed either by the instrument vendor in the shop or by personnel in the lab to physical standards immediately prior to the test. Instrument accuracy was periodically checked throughout the testing.

The data acquisition system used for the prototype test is based on a National Instruments LabVIEW platform. The system provided for real time monitoring of measured quantities as well as calculated quantities. A customized program was written to display important information for control of the test; for example, steam pressure and heat load information were continuously plotted to ensure steady conditions. In addition, the system was used to control equipment such as the boiler setpoint and automatic valve position during the fatigue test.

Test Conditions

Testing was performed using full temperature and pressure steam conditions over a broad operating range typical of low pressure feedwater heaters (Table 2). Test points were systematically selected to provide trends over a broad range of conditions (heat load, temperatures, pressures and flows) and to

confirm repeatable results. Stringent data acceptance criteria were selected to ensure high quality and repeatable data. For example, the absolute difference between measured shell and plate side heat load was monitored along with the steadiness of fluid flows and pressures. The bulk of the data has measured shell and plate side heat loads within ± 5%. Test data covers a range of forced convection on the plate side and condensing and sub-cooling heat transfer modes on the shell side. Comparison and validation of Tranter’s proprietary thermal design software, Conductor III, was also accomplished using this data. Test points were also chosen to demonstrate close thermal approaches, as well as a range of sub-cooling.

Table 2. Range of experimental conditions, data characteristics Conditions Range Inlet vapor pressure, kPa (psia) 117 – 662

(17 - 96.2) Inlet vapor temperature, °C (°F) 104 – 163

(219 – 325) Drain Cooler Approach (DCA) temperature, ∆°C (∆°F)

0 – 87 (0 -157)

Terminal Temperature Difference (TTD), ∆°C (∆°F)

3.9 – 129 (7 -232)

Outlet condensate sub-cooling, ∆°C (∆°F) 0 – 127 (0 - 229)

Heat duty, kW (MMBTU/hr) based on cold side

52.8 - 721.0 (0.18 - 2.46)

Number of data points 82

Hydrostatic Test

The objective of the hydrostatic test was to confirm the pressure retaining capability of the prototype. All pressure boundary and supporting design features were tested including: plate modules, gaskets, closure hardware, shell, nozzles, internal structures and baffles. The hydrostatic test was completed independently for both the plate and the shell side. The results of this test are described in the following section.

Heat-up and Cool-down Test

The objective of the heat-up and cool-down tests were to confirm the transient performance characteristics such as level behavior, quantify thermal lag times, and identify any design limits, set points or safeguards for the prototype. The heat-up test was conducted by starting the test with the prototype at a cold condition and proceeding to a full power steady state condition. The cool-down test was conducted by starting the test with the unit at a full power steady state condition and proceeding to a cold condition. During both tests the plate side flow rate, plate side inlet temperature, shell side pressure and shell side level were actively controlled. The results of these tests are described in the following section.


Level Test

The objectives of the level test were to confirm the predicted thermal and hydraulic performance, i.e. Terminal Temperature Difference (TTD) and Drain Cooler Approach (DCA), of the prototype as a function of shell side water level, demonstrate the adequacy of the level tap locations, and determine the “design normal” water level set point. The level test was conducted starting from a steady state operating condition with the water level at the lowest measureable level on the sight glass and a data point was taken. The water level was then increased by ~1”, then the test unit reached a new steady operating condition and a data point was taken. This process was repeated until the water level reached the top of the sight glass. Shell side and plate side inlet temperatures and plate side flow were maintained throughout the test. Shell side level was controlled using the drain outlet valve. The results of this test are described in the following section.

Vent Test

The objectives of the vent test were to demonstrate the successful removal of non-condensable gases from the shell during startup and power operation conditions.

The startup vent test was conducted starting from a cold condition with air on the shell side. The startup vents were opened during heat-up to steady state condition and closed a short time after the venting fluid was noted to be steam. The power operation vent test was conducted starting from a full power condition and introducing air on the shell side. Likewise the vents were opened to remove the air and closed after a short time the venting fluid was noted to be steam. The results of these tests are described in the following section.

Normal Design Test

The objective of the nominal design test was to confirm the performance characteristics of the prototype including: TTD, DCA, plate side pressure drop, shell side pressure drop and shell side level stability. The nominal design test was completed and consisted of many steady state points over a range of operating conditions (heat load, temperatures, pressures and flows). During the test the plate side flow rate, plate side inlet temperature, shell side pressure and shell side level were actively controlled. The results of this test are described in the following section.

Abnormal Design Test

The objective of the abnormal design test was to confirm the performance characteristics of the prototype during potential abnormal conditions including high plate side flow and low plate side inlet temperature. Although not held to the desired normal design limits, the performance characteristics of interest include: TTD, DCA, plate side pressure drop, shell side pressure drop and shell side level stability. The abnormal design test was completed and consisted of several steady state points over a range of operating conditions (heat load,

temperatures, pressures and flows) outside of the normal design conditions. During the test the plate side flow rate, plate side inlet temperature, shell side pressure and shell side level were actively controlled. The results of this test are described in the following section.

Fatigue Test

The objective of the fatigue test was to confirm the fatigue endurance of the design features in the prototype by flushing the shell side of the test unit with alternating cycles of hot (steam) and cold (water) fluid. The fill and drain cycle times were calculated based on the test unit fluid volume and available fluid pressures in order to achieve the desired maximum and minimum soak temperatures. The results of this test are described in the following section.

RESULTS AND DISCUSSION

Hydrostatic Test

A plate-side test pressure of 175 psia was maintained for 1.5 hours with no losses and no leaks detected during or after the test. A shell-side test pressure of 195 psia was maintained for 1.5 hours with no losses and no leaks detected during or after the test. In separate pressure testing, the module design successfully maintained a pressure >1000 psia for 2 hours with no leaks detected.

Heat-up and Cool-down Test

The test unit operated as expected during both heat-up and cool-down transient tests. Shell side water level was easy to manually maintain using the drain valve and sight glass. The unit exhibited a rapid thermal response to imposed conditions due to the efficient heat transfer characteristics of the plates and the relatively small hold-up volume.

Level Test

The test unit operated as expected during the level test. Two separate sight glasses were included in the prototype unit to confirm the adequacy of the location and determine if there was any variation in level along the length of the shell. For the prototype, the two sight glass locations were both deemed to be acceptable and both measured the same level indicating that there was no water level variation along the length of the shell. As level increased, DCA decreased similar to the characteristic curve shown in Reference 3 for traditional feedwater heater designs and TTD increased as expected. The prototype DCA and TTD behavior during the level test are described in more detail in the discussion of results section. Based on this testing the “normal level” was chosen for the remainder of the performance tests; this level was low on the sight glass and corresponded to a shallow water volume within the shell.

Vent Test

The test unit operated as expected during the startup vent test. As expected, with non-condensable gas occupying the


shell volume, steam flow was minimal and thus heat load was essentially zero. Upon opening of the vent, steam began to flow into the shell. After the non-condensable gas was vented, the valve was closed and the unit operated consistent with a heat-up to steady condition. More than one vent location was tested and successfully demonstrated the removal of non-condensable gases during startup.

Normal Design Test

A number of operating conditions (i.e. steam inlet pressure and feedwater inlet temperature) representative of low pressure feedwater heaters were tested and the prototype unit performed consistent with predictions as elaborated on in the discussion section.

Abnormal Design Test

A wide range of operating conditions were tested including several that are representative of abnormal conditions experienced by feedwater heaters in operation. For example, increased plate side flow cases were performed to simulate a parallel feedwater heater string out of service; decreased plate side inlet temperature cases were performed to simulate an upstream feedwater heater stage out of service. Other operating conditions were tested to confirm the performance trends and validate the correlations and software used for thermal design; for example a separate “condensation only” test was conducted.

Fatigue Test

A severe alternating thermal cycle was used to demonstrate the capability of the prototype to withstand rapid temperature variations. The steam (hot) temperature was approximately 345 °F, the water (cold) temperature was approximately 60°F and the cycle time was approximately 4 minutes. The unit completed 2,500 fatigue cycles and subsequently successfully re-passed the hydrostatic pressure test.

Discussion of Results

As part of the testing program, the prototype unit was disassembled (modules removed from the shell), inspected and reassembled. This enabled testing with different numbers of active modules which helped to achieve a wide variation of operating conditions. As a result of the disassembly and reassembly of the prototype, minor design features (additional alignment components) will be added to improve the assembly process.

The functionality of the design features were demonstrated as follows. The module design has demonstrated pressure retaining capabilities greater than those required in a typical low pressure feedwater heater application. The level tap locations were shown to be acceptable for measuring and controlling shell side level. The performance impacts were determined for the unit as a function of water level and a “normal level” was selected. The startup vent was demonstrated to be essential and functioned as intended.

For the operational vent test, air was introduced into the shell at a pressure just above the incoming steam pressure. The air volume was not regulated and thus air displaced the steam in the shell removing the driving heat load for steam flow. The vent valve was then opened and steam flow resumed. However, a continuous removal of non-condensable gases was not demonstrated and thus the operational vent test on the prototype was ultimately inconclusive. Given the relatively small volume of the prototype as compared to a full size SPFWH™ design, the vent locations on the prototype were not deemed to be representative for a full size unit. Assessments of where non-condensable gases are likely to collect and provision to remove non-condensable gases will be made from various locations in the SPFWH™ lead application.

The prototype performance was predicted using Tranter’s proprietary thermal design software, Conductor III, which has been benchmarked to available industry research (Reference 4 and other Heat Transfer Research Institute reports) and to Tranter test data. Figure 6 provides a comparison of the predicted thermal duty to the measured thermal duty for all data points; this figure also includes a nominal and ±20% curves for reference. Selected test data is provided in Annex B Table 3. The data shows good agreement between Conductor III software predictions and the test data over a range of conditions. Approximately a dozen atypical data points were encountered that had the largest differences from predictions. These were at low duty with either incomplete shell side condensation or potential plate side channel boiling which may have occurred at the limits of the lab system capability.

Figure 6. Predicted vs. Measured thermal duty

In almost all test cases, heat transfer on the shell side included both condensation and sub-cooling in one pass through the plate channel. The Conductor III software was able


to accurately predict the condensation area, condensation heat transfer coefficient, sub-cooling area and sub-cooling heat transfer coefficient based on the inlet conditions and flows.

DCA values measured in the test varied depending on the inlet conditions and water level; in general the plates easily sub-cooled the exiting shell side fluid to DCA values of 10°F and below. Figure 7 shows the DCA data during the level test, a polynomial line curve fit of the data to show the general trend and the typical DCA curve for a feedwater heater from Reference 3. In general, the DCA prototype data trend follows that of the typical curve with a general downward curve.

Figure 7. DCA vs. Level

TTD values also varied depending on the inlet conditions and water level as shown in Figure 8. Although the magnitude of TTD for the prototype is much larger than typical, the trend is similarly linear and with a similar slope. Most of the data has relatively large TTD values due to test loop limitations. However, TTD values as low as 7°F were shown to be achievable. The boiler and piping in the test loop was challenged to provide a steady flow of steam (shell side fluid) below ~34 psia (~255°F) depending on the plate side conditions pressures; having said that, some limited data was obtained for steam pressures as low ~18 psia (~220°F). At low steam pressures, when steam flow increased the pressure drop quickly exceeded the available pressure thus effectively choking the steam flow (pipe limit). Another challenge is that the hot water supply (plate side fluid) was a 1000 gallon tank open to atmospheric pressure and thus the bulk temperature could not exceed ~ 210 °F without potential for hot spots to boil. The hot water pump increased the pressure of the fluid by a few pounds per square inch but the pressure drop in the heat exchanger could easily exceed this head increase. In such

conditions, plate side boiling could occur. The net result is that due to the system limits there was not a close temperature approach on the terminal feedwater exit for the prototype under most conditions. Data was taken with various TTD values, and despite the limitations discussed above TTD values as low as 7 °F were achieved in the lab. Based on this experience either of the following would be needed in order to achieve closer TTD approaches: a larger steam pipe with lower losses and/or a pressurized hot water tank. In summary, sufficient data was gathered to confirm the overall behavior of the plates.

Figure 8. TTD vs. Level

These results demonstrate that the close thermal approaches required of a high performing feedwater heater are achievable with a properly sized SPFWH™ heat exchanger in an appropriately designed and operated feedwater system.

The fatigue test demonstrated the robust nature of the prototype design to withstand severe thermal cycling. Further design improvements are planned in order to make the design even more resistant to thermal fatigue.

CONCLUSIONS

These test results indicate that the SPFWH™ heat exchanger design is a viable alternative to a shell-and-tube type heat exchanger due to the performance, compactness, modularity, and robustness of the new design.

A lead application, targeted in 2014, will demonstrate the design in a commercial setting which will provide valuable additional data and operational feedback.


ACKNOWLEDGMENTS

The authors would like to thank Pete Mickus, Cesar Romero, Jere Baber, Sven Sjogren, Chuck Harden, Wes Boyd, Jan Ivey and Ted Andersen for their support.

NOMENCLATURE

DCA Drain Cooler Approach Temperature Difference

FAC Flow Accelerated Corrosion FIV Flow Induced Vibration HTRI Heat Transfer Research Institute SPFWH™ Shell and Plate Feedwater Heater TTD Terminal Temperature Difference

REFERENCES

[1] Tranter Welded Products brochure, 2011 http://tranter.com/literature/products/welded-products-brochure.pdf

[2] TR-106611 Revision 1, “Flow-Accelerated Corrosion in Power Plants”, Electric Power Research Institute, 1998.

[3] “Standards for Closed Feedwater Heaters”, Seventh Edition, Heat Exchange Institute, Inc., 2004.

[4] PHE 14 “Condensation in Welded-Plate Heat Exchangers”, Heat Transfer Research Institute, 2010.


ANNEX A

TEST LOOP As discussed in the Testing section, a schematic of the test loop used to test the prototype is shown in Figure 9 below.

Figure 9. Schematic of test loop


ANNEX B

SELECTED TEST DATA As discussed in the Testing section, selected test data is shown in Table 3 below.

Table 3. Selected Test Data Parameter Units Pt. 1 Pt. 2 Pt. 3 Pt. 4 Plate Side Flow (water) lb/hr 52,433 141,144 128,528 3,854 Plate Side Inlet Temperature °F 126 110 80 199 Plate Side Outlet Temperature °F 133 122 99 248 Plate Side Heat Load MMBTU/hr 0.36 1.70 2.39 0.19 Shell Side Flow (steam) lb/hr 345 1544 2,350 213 Shell Side Inlet Temperature °F 249 299 315 255 Shell Side Inlet Pressure psia 30.2 70.2 86.6 33.7 Shell Side Outlet Temperature °F 135 117 185 199 Shell Side Heat Load MMBTU/hr 0.37 1.72 2.46 0.22 Terminal Temperature Difference (TTD)

∆°F 116 177 216 7

Drains Cooler Approach (DCA) Temperature Difference

∆°F 9 7 105 0

Log Mean Temperature Difference (LMTD)

∆°F 42 55 154 1

Sub-cooling ∆°F 113 183 130 55 Overall Heat Transfer Coefficient (U)

BTU/hr °F ft2

122 994 474 2,529*

Conductor III Heat Load MMBTU/hr 0.38 1.72 2.66 0.19 Percent Difference in Heat Load Predicted to Plate Side

% 5.2 0.9 10.1 0.0

Notes: Low DCA, High TTD, Low Duty

Low DCA, High TTD, High Duty

Highest Shell side Duty

Atypical data point. Lowest TTD, and DCA *Plate side boiling possible contributor to highest U

Documents

Shell and Plate Feedwater Heater Prototype Test