Upload
khokha-madih
View
213
Download
1
Embed Size (px)
DESCRIPTION
MIT22_033F11_lec02
Citation preview
Process Heat GroupMajor Challenges
Lecture 222.033/22.33 Nuclear Engineering Design Project
September 14, 2011
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 1
The Three Challenge Problems
Heat exchanger (Hx) design Heat transport Heat storage (if necessary)
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 2
http:22.033/22.33First, Some Nomenclature
Sensible heating temperature change .
Q = m c p T Latent heating phase change
. Q = m h fg
Bond energy storage enthalpy of chemical reactions
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 3
http:22.033/22.33Where Do We Find Them?
Courtesy of the Generation IV International Forum. Used with permission.
Source: http://www.gen-4.org/Technology/systems/gfr.htm
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 4
http://www.gen-4.org/Technology/systems/gfr.htmhttp:22.033/22.33Heat Exchangers Fundamental Parameters
Hx effectiveness () Measures how
much heat is transferred compared to how much is possible
=1 is ideal, but American Institute of Physics. All rights reserved. This content is excluded from ourCreative Commons license. For more information, see http://ocw.mit.edu/fairuse. practically
Source: Dean Bartlett. The Fundamentals of Heat Exchangers The Industrial Physicist, AIP, p. 20 (1996) impossible (big Hx)
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 5
http:22.033/22.33http://ocw.mit.edu/fairuseHeat Exchangers Fundamental Parameters
Diagram of heat exchanger removed due to copyright restrictions. See lecture video for details.
***Source: Ramesh K. Shah, Dusan P. Sekulic. Fundamentals of Heat Exchanger Design. John Wiley & Sons, Inc. p. 102 (2003).
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 6
http:22.033/22.33Heat Exchangers Fundamental Parameters
Q = UAFTlm Q = Heat transfer rate (W)U = Thermal conductance (W/m2K)A = Heat transfer area (m2)Tlm = Log mean temperature difference (K)
F = Factor (for flow configuration)
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 7
http:22.033/22.33Heat Exchangers Log Mean Temperature Difference (LMTD)
( TH TC ) T = lm ln
TH TC
LMTD is a good measure of the effectiveness of simlar heatexchangers of different designs
Often, LMTD (counter flow) > LMTD (parallel flow)
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 8
http:22.033/22.33Heat Exchangers Finding Key Parameters
Figure 1 A big, complicated heatexchanger chart
Source: Wolverine Tube Heat Transfer Data Book, p. 93 (2001), accessed at
http://www.wlv.com/products/databook /ch2_5.pdf
Courtesy of Wolverine Tube, Inc. Used with permission.
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 9
http://www.wlv.com/products/databook/ch2_5.pdfhttp://www.wlv.com/products/databook/ch2_5.pdfhttp:22.033/22.33Heat Exchangers Fundamental Parameters
For all flow configurations
Hx is balanced when C* = 1
NTU = Number of Transfer Units John Wiley & Sons, Inc. All rights reserved. This content is excluded from our CreativeCommons license. For more information, see http://ocw.mit.edu/fairuse.
***Source: Ramesh K. Shah, Dusan P. Sekulic. Fundamentals of Heat Exchanger Design. John Wiley & Sons, Inc. p. 116, 118-119 (2003).
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 10
http://ocw.mit.edu/fairusehttp:22.033/22.33Hx Flow Types
***After Ramesh K. Shah & Dusan P. Sekulic. Fundamentals of Heat Exchanger Design. John Wiley & Sons, Inc. (2003).
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 11
Heat Exchanger Classification by Flow Arrangement
Parallel counter-flow
m-shell passesn-tube passes
Fluid 1 m passesFluid 2 n passesSplit-flow Divided-flowCross-
counter-flowCross-
parallel-flowCompound
flow
Extended surface Shell-and-tube Plate
Counter-flow Parallel-flow Cross-flow Split-flow Divided-flow
Single-pass Multi-pass
Image by MIT OpenCourseWare.
http:22.033/22.33Parallel Flow vs. Counterflow
See http://www.engineeringtoolbox.com/arithmetic-logarithmic-mean-temperature-d_436.html
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 12
tpi
tsi
tpo
tso
Parallel-flow
tpi
tsi
tpotso
Counter-flow
tito
ti
to
Tem
per
ature
Tem
per
ature
Image by MIT OpenCourseWare.
http://www.engineeringtoolbox.com/arithmetic-logarithmic-mean-temperature-d_436.htmlhttp:22.033/22.33Hx Flow Configurations
After Ramesh K. Shah, Dusan P. Sekulic. Fundamentals of Heat Exchanger Design. John Wiley & Sons, Inc. (2003).
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 13
Tubular Extended surface Regenerative
Heat Exchanger Classification by Construction
Double-pipe Pipe coilsShell-and-tube Spiral tube
Plate-type
PHE Plate coilSpiral Printed circuit
Gasketed Welded Brazed
Plate-fin Tube-fin
Cross flow to tubes
Parallel flow to tubes
Ordinaryseparating
wall
Heat-pipewall
Rotary
Fixed-matrix
Rotating hoods
Image by MIT OpenCourseWare.
http:22.033/22.33Hx Flow Configurations - Tubular
Source: Wikimedia Commons
Courtesy of Wikipedia User:H Padleckas. Used with permission. Courtesy of Harlan Bengtson. Used with permission.
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 14
http:22.033/22.33Hx Flow Configurations Plate Plate (brazed) type Spiral type
Alfa Biz Limited. All rights reserved. This content is excluded from our CreativeCommons license. For more information, see http://ocw.mit.edu/fairuse.
Source: http://www.alfa-biz.com/Gasketed-Plate-Heat-Exchanger.asp Source: http://www.hiwtc.com/photo/products/16/02/14/21470.jpg
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 15
Jooshgostar Equipments Manufacturing Company (JEMCO). All rightsreserved. This content is excluded from our Creative Commons license.For more information, see http://ocw.mit.edu/fairuse.
http://www.alfa-biz.com/Gasketed-Plate-Heat-Exchanger.asphttp://www.hiwtc.com/photo/products/16/02/14/21470.jpghttp://ocw.mit.edu/fairusehttp://ocw.mit.edu/fairuseHx Heat Transfer Mechanisms
Other design parameters should largely determine this choice
After Ramesh K. Shah, Dusan P. Sekulic. Fundamentals of Heat Exchanger Design. John Wiley & Sons, Inc. (2003).
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 16
Heat Exchanger Classification by Heat Transfer Mechanism
Single-phase convectionon both sides
Single-phase convectionon one side, two-phaseconvection on other side
Combined convection andradiative heat transfer
Two-phase convection on both sides
Image by MIT OpenCourseWare.
http:22.033/22.33Heat Exchangers - Questions
What type to use?What working fluids?What geometry? Flow considerations? Laminar or
turbulent? Where is the tradeoff between cost & performance? Materials concerns? See also: T. Kuppan. Heat exchanger design handbook.
and Som, Introduction To Heat Transfer.
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 17
http:22.033/22.33Heat Transport
Main problem: Get process heat from the reactor to the hydrogen & biofuels plants
How? Must consider: Temperatures Losses Flow rates Flow transients
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 18
http:22.033/22.33Heat Transport Long Distance
How to model it? Thermal resistances FEM Loop analysis
How to pump it? Forced? Gravity? Distance from Rx to H2, biofuel plant is one
of the most important parameters
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 19
http:22.033/22.33Heat Transport - Questions
What are the constraints? (TH-Rx ) , TC-H2, TC-bioHow far does the heat have to go? Where to take the heat from? How to transport it? How to model it? What/where are losses? Should some of it be stored...
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 20
http:22.033/22.33Heat Storage
Heat storage is a way to balance out load instabilities (capacitive effect)
Store some heat to run turbines and/or product factories during transients
Can help avoid or delay plants load-dumping or load-following
Must balance benefits gained vs. heat lost by storage
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 21
http:22.033/22.33I
Heat Storage Electrical AnalogySource Load, losses switch (transport,
dissipative, hydraulic)
Reactor Heat storage system Power (current)
Courtesy of Prof. Eric C. Toolson. Used with permission.
Image source: http://www.unm.edu/~toolson/rc_circuit.html
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 22
http://www.unm.edu/~toolson/rc_circuit.htmlhttp:22.033/22.33Heat Storage Technologies
Sensible heat storage Simply apply hot fluid to a material, reverse
flow when required Latent heat storage
Uses phase change materials (PCMs) Dependent on melting point, heat of fusion
Bond energy storage Dependent on reaction temperature, enthalpy
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 23
http:22.033/22.33Heat Storage Sensible Heat
Example: Hot gas on alumina fluidized bed
Source: R. Shinnar et al. A novel storage method for concentrating solar power plants allowing operation at high temperature. DoE Presentation, Boulder, CO (2011).
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 24
Prof. Reuel Shinnar. All rights reserved. This content is excluded from our CreativeCommons license. For more information, see http://ocw.mit.edu/fairuse.
http:22.033/22.33http://ocw.mit.edu/fairuseHeat Storage Sensible Heat
Other proposed & demonstrated storagemedia: Molten salt, concrete
NREL. All rights reserved. This content is excluded from our CreativeCommons license. For more information, see http://ocw.mit.edu/fairuse.
Thermocline test at Sandia National Laboratories
Concrete TES at U. Stuttgart See http://www.nrel.gov/csp/troughnet/thermal_energy_storage.html
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 25
Sandia National Labs. All rights reserved. This content is excluded from ourCreative Commons license. For more information, see http://ocw.mit.edu/fairuse.
http://www.nrel.gov/csp/troughnet/thermal_energy_storage.htmlhttp://ocw.mit.edu/fairusehttp:22.033/22.33http://ocw.mit.edu/fairuseHeat Storage Phase Change Materials
More compact Layout can be more
Source: M. Demirbas. complicated Thermal Energy Storage
.
and Phase Change Materials: An Overview
Salts can be corrosive Energy Sources, Part B,1:8595, 2006. Graphite foils have
been used to improve heat spreading
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 26
Taylor and Francis Group, LLC. All rights reserved. This content is excluded from ourCreative Commons license. For more information, see http://ocw.mit.edu/fairuse.
http://ocw.mit.edu/fairuseHeat Storage Bond Energy
Absorb/Release chemical energy by shifting chemical equilibrium reactions
Change temperature, pressure Examples: hydration, hydriding,
ammonia/salt reactions Chemical reaction should be reversible
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 27
Heat Storage Questions
What temperature(s) is/are required?What materials to use?What capacity to use? (kWh, MWh, Gwh)How does cost scale with size?What are loss rates & pathways?When would it be used, if at all?Where would it be located?
MIT Dept. of Nuclear Science and Engineering Dr. Michael P. Short, 2011 22.033/22.33 Nuclear Design Course Page 28
MIT OpenCourseWarehttp://ocw.mit.edu
22.033 / 22.33 Nuclear Systems Design ProjectFall 2011
For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.
http://ocw.mit.edu/termshttp://ocw.mit.eduSlide 1Slide 2Slide 3Slide 4Slide 6Slide 7Slide 8Slide 9Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 25Slide 27Slide 28