This document discusses the advantages of considering compact heat exchangers like plate-and-frame exchangers early in the process design stage. Plate-and-frame exchangers can be significantly smaller than traditional shell-and-tube exchangers while meeting the same heat transfer needs. Specifying design requirements without considering the characteristics of different exchanger types can lead to oversized and more expensive designs. Charts are provided to help estimate the required area of plate-and-frame exchangers for preliminary sizing.
This design project aims to propose a plate type heat exchanger that can meet given heat duty and find the number of plates required. Plate type heat exchanger uses metal plates to transfer heat between two fluids. Starting point of this design is to define given properties
Design Considerations for Plate Type Heat ExchangerArun Sarasan
A plate heat exchanger is a type of heat exchanger that uses metal plates to transfer heat between two fluids. This has a major advantage over a conventional heat exchanger in that the fluids are exposed to a much larger surface area because the fluids spread out over the plates. This facilitates the transfer of heat, and greatly increases the speed of the temperature change. Plate heat exchangers are now common and very small brazed versions are used in the hot-water sections of millions of combination boilers. The high heat transfer efficiency for such a small physical size has increased the domestic hot water (DHW) flowrate of combination boilers. The small plate heat exchanger has made a great impact in domestic heating and hot-water. Larger commercial versions use gaskets between the plates, whereas smaller versions tend to be brazed.
Selection of Heat Exchanger Types
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 BACKGROUND
5 FACTORS INFLUENCING SELECTION
5.1 Type of Duty
5.2 Temperatures and Pressures
5.3 Materials of Construction 5.4 Fouling
5.5 Safety and Reliability
5.6 Repairs
5.7 Design Methods
5.8 Dimensions and Weight
5.9 Cost
5.10 GBHE Experience
6 TYPES OF EXCHANGER
6.1 Shell and Tube Exchangers
6.2 Cylindrical Graphite Block Heat Exchangers
6.3 Cubic Graphite Block Heat Exchangers
6.4 Air Cooled Heat Exchangers
6.5 Gasketed Plate and Frame
6.6 Spiral Plate
6.7 Tube in Duct
6.8 Plate-fin
6.9 Printed Circuit Heat Exchanger (PCHE)
6.10 Scraped Surface/Wiped Film Exchangers
6.11 Welded or Brazed Plate
6.12 Double Pipe
6.13 Electric Heaters
6.14 Fired Process Heaters
TABLE
(1) ADVANTAGES AND DISADVANTAGES OF DIFFERENT SHELL AND TUBE DESIGNS
FIGURES
1 ESTIMATED MAIN PLANT ITEM COSTS
2 ESTIMATED INSTALLED COSTS
3 TEMA HEAT EXCHANGER NOMENCLATURE
4 F ‘CORRECTION FACTORS' : TEMA E SHELL WITH EVEN NUMBER OF PASSE
5 SHELL AND TUBE HEAT EXCHANGER HEAD TYPES
6 GENERAL ARRANGEMENT OF A CYLINDRICAL GRAPHITE BLOCK HEAT EXCHANGER
7 EXPLODED VIEW OF A CUBIC GRAPHITE BLOCK
HEAT EXCHANGER
8 TYPICAL AIR COOLED HEAT EXCHANGER
9 GENERAL VIEW OF ONE END OF A 3-STREAM
PLATE-FIN HEAT EXCHANGER
10 TYPICAL PCHE PLATE
11 VICARB ‘COMPABLOC' EXCHANGER
12 ‘BROWN FINTUBE' MULTITUBE HEAT EXCHANGER
13 FIRED HEATER : SCHEMATICS AND NOMENCLATURE
This design project aims to propose a plate type heat exchanger that can meet given heat duty and find the number of plates required. Plate type heat exchanger uses metal plates to transfer heat between two fluids. Starting point of this design is to define given properties
Design Considerations for Plate Type Heat ExchangerArun Sarasan
A plate heat exchanger is a type of heat exchanger that uses metal plates to transfer heat between two fluids. This has a major advantage over a conventional heat exchanger in that the fluids are exposed to a much larger surface area because the fluids spread out over the plates. This facilitates the transfer of heat, and greatly increases the speed of the temperature change. Plate heat exchangers are now common and very small brazed versions are used in the hot-water sections of millions of combination boilers. The high heat transfer efficiency for such a small physical size has increased the domestic hot water (DHW) flowrate of combination boilers. The small plate heat exchanger has made a great impact in domestic heating and hot-water. Larger commercial versions use gaskets between the plates, whereas smaller versions tend to be brazed.
Selection of Heat Exchanger Types
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 BACKGROUND
5 FACTORS INFLUENCING SELECTION
5.1 Type of Duty
5.2 Temperatures and Pressures
5.3 Materials of Construction 5.4 Fouling
5.5 Safety and Reliability
5.6 Repairs
5.7 Design Methods
5.8 Dimensions and Weight
5.9 Cost
5.10 GBHE Experience
6 TYPES OF EXCHANGER
6.1 Shell and Tube Exchangers
6.2 Cylindrical Graphite Block Heat Exchangers
6.3 Cubic Graphite Block Heat Exchangers
6.4 Air Cooled Heat Exchangers
6.5 Gasketed Plate and Frame
6.6 Spiral Plate
6.7 Tube in Duct
6.8 Plate-fin
6.9 Printed Circuit Heat Exchanger (PCHE)
6.10 Scraped Surface/Wiped Film Exchangers
6.11 Welded or Brazed Plate
6.12 Double Pipe
6.13 Electric Heaters
6.14 Fired Process Heaters
TABLE
(1) ADVANTAGES AND DISADVANTAGES OF DIFFERENT SHELL AND TUBE DESIGNS
FIGURES
1 ESTIMATED MAIN PLANT ITEM COSTS
2 ESTIMATED INSTALLED COSTS
3 TEMA HEAT EXCHANGER NOMENCLATURE
4 F ‘CORRECTION FACTORS' : TEMA E SHELL WITH EVEN NUMBER OF PASSE
5 SHELL AND TUBE HEAT EXCHANGER HEAD TYPES
6 GENERAL ARRANGEMENT OF A CYLINDRICAL GRAPHITE BLOCK HEAT EXCHANGER
7 EXPLODED VIEW OF A CUBIC GRAPHITE BLOCK
HEAT EXCHANGER
8 TYPICAL AIR COOLED HEAT EXCHANGER
9 GENERAL VIEW OF ONE END OF A 3-STREAM
PLATE-FIN HEAT EXCHANGER
10 TYPICAL PCHE PLATE
11 VICARB ‘COMPABLOC' EXCHANGER
12 ‘BROWN FINTUBE' MULTITUBE HEAT EXCHANGER
13 FIRED HEATER : SCHEMATICS AND NOMENCLATURE
Design and Rating of Packed Distillation Columns
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 DESIGN PHILOSOPHY
5 PERFORMANCE GUARANTEES
6 DESCRIPTION OF PACKED COLUMN INTERNALS
7. DESIGN CALCULATIONS
7.1 Selection of Packing Size
7.2 Rough Design
7.3 Detailed Design and Rating
8 LIQUID DISTRIBUTION AND REDISTRIBUTION
8.1 Basic Concepts
8.2 Pour Point Density
8.3 Peripheral Irrigation - the Wall Zone
8.4 Distributor Levelness
8.5 Maximum Bed Height and Liquid Redistribution
9 PRACTICAL ASPECTS OF PACKED COLUMN DESIGN
9.1 Packing
9.2 Support Grid
9.3 Liquid Collector
9.4 Liquid Distributor or Redistributor
9.5 Packing Hold-down Grid
9.6 Reflux or Feed Pipe
9.7 Reboil Return Pipe
9.8 Liquid Draw-offs
9.9 Vapor Draw-offs
10 BIBLIOGRAPHY
APPENDICES
A DEFINITIONS
A.1 INTRODUCTION
A.2 MECHANICAL DEFINITIONS
A.3 PERFORMANCE DEFINITIONS
B PACKING HYDRAULICS - THE NORTON METHOD
TABLES
1 PACKING FACTORS FOR THE MORE COMMON
RANDOM PACKINGS
This presentation contains basic principles of heat exchangers, Flow pattern, types of heat exchangers, selection criteria for heat exchangers, TEMA standars for heat exchangers design
Heat/light/electrical energy is out today’s necessity and has scarcity also. Energy conservation is key requirement of any industry at all times.
In general, industries use heat energy for conservation of raw material to finished product. The source of heat energy is generally saturated or super heated steam. The steam generation is common use one boiler with carity of fuels. Whatever may be the fuel the generation should be as economy as possible which adds to the product cost. Further the usage of steam and recycling steam condensate back to boiler is an art depending on plant layouts.
In this project the steam generator is water tube boiler fired with rice husk. The steam is transferred to the tyre/tube moulds where tyres/tubes are cured while the heat is rejected to the tyres the condensate forms and this condensate is put back to the boiler. While doing so the steam is also stopped back to boiler without rejecting complete heat to the product. This gets flashed into atmosphere at feed water tank. The science of separation of condensate from steam saves energy. Better the separation more the fuel conservation.
In the steam generator the fuel is burnt to heat the water and form steam. This fuel burnt flue gas carries lot of energy, out through chimney. Prior to exhausting through the heat left in flue need to be recovered, through heat recovery mechanisms’. In this project an air-preheater condensate heat recovery unit is the major energy consuming station.
The aim of this experiment is to measurement linear thermal along z direction conductivity and to investigate and verify Fourier’s Law for linear heat conduction along z direction and we proved that K is inversely proportional with ΔT, and we have many errors in our experiment that made the result not clear.
applications of the principles of heat transfer to design of heat exchangersKathiresan Nadar
This file contain a very good description for the processes design of heat ex changer. the file courtesy is Prof. Anand Patwardhan ICT Mumbai (Deemed University)
Design and Rating of Packed Distillation Columns
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 DESIGN PHILOSOPHY
5 PERFORMANCE GUARANTEES
6 DESCRIPTION OF PACKED COLUMN INTERNALS
7. DESIGN CALCULATIONS
7.1 Selection of Packing Size
7.2 Rough Design
7.3 Detailed Design and Rating
8 LIQUID DISTRIBUTION AND REDISTRIBUTION
8.1 Basic Concepts
8.2 Pour Point Density
8.3 Peripheral Irrigation - the Wall Zone
8.4 Distributor Levelness
8.5 Maximum Bed Height and Liquid Redistribution
9 PRACTICAL ASPECTS OF PACKED COLUMN DESIGN
9.1 Packing
9.2 Support Grid
9.3 Liquid Collector
9.4 Liquid Distributor or Redistributor
9.5 Packing Hold-down Grid
9.6 Reflux or Feed Pipe
9.7 Reboil Return Pipe
9.8 Liquid Draw-offs
9.9 Vapor Draw-offs
10 BIBLIOGRAPHY
APPENDICES
A DEFINITIONS
A.1 INTRODUCTION
A.2 MECHANICAL DEFINITIONS
A.3 PERFORMANCE DEFINITIONS
B PACKING HYDRAULICS - THE NORTON METHOD
TABLES
1 PACKING FACTORS FOR THE MORE COMMON
RANDOM PACKINGS
This presentation contains basic principles of heat exchangers, Flow pattern, types of heat exchangers, selection criteria for heat exchangers, TEMA standars for heat exchangers design
Heat/light/electrical energy is out today’s necessity and has scarcity also. Energy conservation is key requirement of any industry at all times.
In general, industries use heat energy for conservation of raw material to finished product. The source of heat energy is generally saturated or super heated steam. The steam generation is common use one boiler with carity of fuels. Whatever may be the fuel the generation should be as economy as possible which adds to the product cost. Further the usage of steam and recycling steam condensate back to boiler is an art depending on plant layouts.
In this project the steam generator is water tube boiler fired with rice husk. The steam is transferred to the tyre/tube moulds where tyres/tubes are cured while the heat is rejected to the tyres the condensate forms and this condensate is put back to the boiler. While doing so the steam is also stopped back to boiler without rejecting complete heat to the product. This gets flashed into atmosphere at feed water tank. The science of separation of condensate from steam saves energy. Better the separation more the fuel conservation.
In the steam generator the fuel is burnt to heat the water and form steam. This fuel burnt flue gas carries lot of energy, out through chimney. Prior to exhausting through the heat left in flue need to be recovered, through heat recovery mechanisms’. In this project an air-preheater condensate heat recovery unit is the major energy consuming station.
The aim of this experiment is to measurement linear thermal along z direction conductivity and to investigate and verify Fourier’s Law for linear heat conduction along z direction and we proved that K is inversely proportional with ΔT, and we have many errors in our experiment that made the result not clear.
applications of the principles of heat transfer to design of heat exchangersKathiresan Nadar
This file contain a very good description for the processes design of heat ex changer. the file courtesy is Prof. Anand Patwardhan ICT Mumbai (Deemed University)
HEAT TRANSFER STUDIES IN WAVY CORRUGATED PLATE HEAT EXCHANGERSIAEME Publication
In the present investigations heat transfer studies are made in three different types of corrugated plate heat exchangers having corrugation angles 300, 400 and 500. Water and Glycerol (40%, 50% and 60%) are taken as test fluid and water as the heating medium. The wall temperatures are measured along the length of the heat exchanger at seven different locations by means of thermocouples. The inlet and outlet temperatures of the test fluid and hot fluid are measured by means of four more thermocouples. Nusselt number is calculated from the experimental observations by calculating film heat transfer coefficient. These values are compared with different Reynolds numbers as well as corrugation angles. It is found from the experimental investigations that increase in corrugation angle has resulted in higher Nusselt’s number for a given Reynolds number and hence higher heat transfer rates. It is also found that 60% glycerol has higher heat transfer compared to 50%, 40% and water.
this ppt is made with the reference of heat exchangers that have been used in NHFI, it almost covers their every aspect that is their working, maintenance, and safety !!
so please suit yourself!!!
Optimization of Air Preheater for compactness of shell by evaluating performa...Nemish Kanwar
Designing of an Air Preheater with increased performance from an existing design through alteration in baffle placement. Analysis of 4 Baffle designs for segmented Baffle case was done using Ansys Fluent. The net heat recovery rate was computed by subtracting pump work from heat recovered. Based on the result, Air Preheater design was recommended.
EVALUATING MATHEMATICAL HEAT TRANSFER EFFECTIVENESS EQUATIONS USING CFD TECHN...AEIJjournal2
this analysis has shown that although mathematical equations are effective and simple tools in producing results, the results may not reflect the actual physical conditions. The analysis showed that theexhaust gas temperature outlet of a double pipe heat exchanger is actually higher than what were calculated using mathematical equations, and therefore, more heat energy is available for recapturing. k-epsilon RNG turbulence model was found to be the most suitable method in analyzing heat transfer in a finned double pipe heat exchanger.
EVALUATING MATHEMATICAL HEAT TRANSFER EFFECTIVENESS EQUATIONS USING CFD TECHN...AEIJjournal2
Mathematical heat transfer equations for finned double pipe heat exchangers based on experimental work
carried out in the 1970s can be programmed in a spreadsheet for repetitive use. Thus avoiding CFD
analysis which can be time consuming and costly. However, it is important that such mathematical
equations be evaluated for their accuracy. This paper uses CFD methods in evaluating the accuracy of
mathematical equations. Several models were created with varying; geometry, flue gas entry temperature,
and flow rates. The analysis should provide designers and manufacturers a judgment on the expected level
of accuracy when using mathematical modelling methodology. This paper simultaneously identifies best
practices in carrying out such CFD analysis.
Evaluating mathematical heat transfer effectiveness equations using cfd techn...aeijjournal
Mathematical heat transfer equations for finned double pipe heat exchangers based on experimental work carried out in the 1970s can be programmed in a spreadsheet for repetitive use. Thus avoiding CFD analysis which can be time consuming and costly. However, it is important that such mathematical equations be evaluated for their accuracy. This paper uses CFD methods in evaluating the accuracy of mathematical equations. Several models were created with varying; geometry, flue gas entry temperature,
and flow rates. The analysis should provide designers and manufacturers a judgment on the expected level
of accuracy when using mathematical modelling methodology. This paper simultaneously identifies best
practices in carrying out such CFD analysis
Shell & tube heat exchanger single fluid flow heat transferVikram Sharma
This article was produced to highlight the fundamentals of single-phase heat exchanger rating using Kern's method. The content is strictly academic with no reference to industrial best practices.
Analysis of Heat Transfer in Spiral Plate Heat Exchanger Using Experimental a...ijsrd.com
Heat transfer is the key to several processes in industrial application. In a present days maximum efficient heat transfer equipment are in demand due to increasing energy cost. For achieving maximum heat transfer, the engineers are continuously upgrading their knowledge and skills by their past experience. Present work is a skip in the direction of demonstrating the use of the computational technique as a tool to substitute experimental techniques. For this purpose an experimental set up has been designed and developed. Analysis of heat transfer in spiral plate heat exchanger is performed and same Analysis of heat transfer in spiral plate heat exchanger can be done by commercially procurable computational fluid dynamic (CFD) using ANSYS CFX and validated based on this forecasting. Analysis has been carried out in parallel and counter flow with inward and outward direction for achieving maximum possible heat transfer. In this problem of heat transfer involved the condition where Reynolds number again and again varies as the fluid traverses inside the section of flow from inlet to exit, mass flow rate of working fluid is been modified with time. By more and more analysis and experimentation and systematic data degradation leads to the conclusion that the maximum heat transfer rates is obtained in case of the inward parallel flow configuration compared to all other counterparts, which observed to vary with small difference in each section. Furthermore, for the increase heat transfer rate in spiral plate heat exchanger is obtain by cascading system.
5 heat exchanger thermal design of oil system for turbo centrifugal compresso...IJCMESJOURNAL
A thermal management is vital issues of all energy equipment such as compressor, gas turbine, and boilers etc. The compressor is generally used in power, oil & gas, air separation, and chemical plant. It is consist of air or gas compression part, gear, bearing, cooling, sealing, lube oil, and control system. In this study focused on heat exchanger for oil supply systems. Lube oil is very important to supply oil and protect bearing. Lube oil’s temperature control is vital issue to prevent system broken. Shell and tube heat exchanger is used as a cooler. In this study, HTRI Xist used to thermal design of oil cooler, with water and nanofluid. The thermal conductivity is ~9.3% higher than water. The tube side overall heat transfer coefficient of nanofluid is increased by ~9% compared to that of water.
Paper Statistics:
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Book Formatting: Quality Control Checks for DesignersConfidence Ago
This presentation was made to help designers who work in publishing houses or format books for printing ensure quality.
Quality control is vital to every industry. This is why every department in a company need create a method they use in ensuring quality. This, perhaps, will not only improve the quality of products and bring errors to the barest minimum, but take it to a near perfect finish.
It is beyond a moot point that a good book will somewhat be judged by its cover, but the content of the book remains king. No matter how beautiful the cover, if the quality of writing or presentation is off, that will be a reason for readers not to come back to the book or recommend it.
So, this presentation points designers to some important things that may be missed by an editor that they could eventually discover and call the attention of the editor.
7 Alternatives to Bullet Points in PowerPointAlvis Oh
So you tried all the ways to beautify your bullet points on your pitch deck but it just got way uglier. These points are supposed to be memorable and leave a lasting impression on your audience. With these tips, you'll no longer have to spend so much time thinking how you should present your pointers.
You could be a professional graphic designer and still make mistakes. There is always the possibility of human error. On the other hand if you’re not a designer, the chances of making some common graphic design mistakes are even higher. Because you don’t know what you don’t know. That’s where this blog comes in. To make your job easier and help you create better designs, we have put together a list of common graphic design mistakes that you need to avoid.
White wonder, Work developed by Eva TschoppMansi Shah
White Wonder by Eva Tschopp
A tale about our culture around the use of fertilizers and pesticides visiting small farms around Ahmedabad in Matar and Shilaj.
Dive into the innovative world of smart garages with our insightful presentation, "Exploring the Future of Smart Garages." This comprehensive guide covers the latest advancements in garage technology, including automated systems, smart security features, energy efficiency solutions, and seamless integration with smart home ecosystems. Learn how these technologies are transforming traditional garages into high-tech, efficient spaces that enhance convenience, safety, and sustainability.
Ideal for homeowners, tech enthusiasts, and industry professionals, this presentation provides valuable insights into the trends, benefits, and future developments in smart garage technology. Stay ahead of the curve with our expert analysis and practical tips on implementing smart garage solutions.
1. 32 www.cepmagazine.org September 2002 CEP
Heat Exchangers
onsidering available heat exchanger technolo-
gies at the outset of process design (at the
process synthesis stage) is not general prac-
tice. In fact, procedures established in some
companies preclude it. For instance, some purchasing de-
partments’ “nightmare” is having to deal with a single sup-
plier — instead they want a general specification that can
be sent to all equipment vendors, in the mistaken belief
that they are then operating on a “level playing field.”
This omission is both unfortunate
and costly. It results in unnecessary cap-
ital expenditure and in reduced energy
efficiency. It also hinders the develop-
ment of energy saving technology.
Pinch analysis is the key tool used by
engineers to develop flowsheets of ener-
gy-intensive processes, where heat ex-
changer selection is particularly impor-
tant. Yet, this tool is hindering the adop-
tion of a more-progressive approach be-
cause of the way it is restricted to tradi-
tional heat exchangers.
Numerous articles have been pub-
lished regarding the advantages of com-
pact heat exchangers. Briefly, their
higher heat-transfer coefficients, com-
pact size, cost effectiveness, and unique
ability to handle fouling fluids make
them a good choice for many services.
A plate-and-frame heat exchanger
(Figure 1) consists of pressed, corrugat-
ed metal plates fitted between a thick, carbon-steel frame.
Each plate flow channel is sealed with a gasket, a weld or
an alternating combination of the two. It is not uncommon
for plate-and-frame heat exchangers to have overall heat-
transfer coefficients that are three to four times those found
in shell-and-tube heat exchangers.
This three-part series outlines the lost opportunities and
the importance of proper heat exchanger selection. This arti-
cle discusses some general aspects of plate-and-frame heat
Use these design charts for preliminary sizing.
Plate-and-Frame
Heat Exchangers
DDeessiiggnniinngg
COMPACT HEAT EXCHANGERS — PART 1:
C
Christopher Haslego,
Alfa Laval
Graham Polley,
www.pinchtechnology.com
s Figure 1. Cutaway drawing of a plate-and-frame heat exchanger.
2. CEP September 2002 www.cepmagazine.org 33
exchangers, outlines a procedure for accurately estimating
the required area, and shows how these units can be used to
simplify processes. Part 2 (which will appear next month)
covers integrating plate-and-frame exchangers (and other
compact technologies) into pinch analysis for new plants,
while Part 3 (which also will appear next month) deals with
the application of plate-and-frame exchangers and pinch
technology to retrofits.
Specifying plate-and-frame heat exchangers
Engineers often fail to realize the differences between
heat transfer technologies when preparing a specification to
be sent to vendors of different types of heat exchangers.
Consider the following example.
A process stream needs to be cooled with cooling water
before being sent to storage. The stream requires C276, an
expensive high-nickel alloy, to guard against corrosion; this
metallurgy makes the stream a candidate for the tubeside of
a shell-and-tube heat exchanger. The cooling water is avail-
able at 80°F and must be returned at a temperature no high-
er than 115°F. The process engineer realizes that with the
water flow being placed on the shellside, larger flowrates
will enhance the heat-transfer coefficient. The basis for the
heat exchanger quotation was specified as shown in the
table. According to the engineer’s calculations, these basic
parameters should result in a good shell-and-tube design
that uses a minimum amount of C276 material.
A typical plate-and-frame exchanger designed to meet the
specification would have about 650 ft2 of area, compared to
about 420 ft2 for a shell-and-tube exchanger. A plate-and-
frame unit designed to the above specification is limited by
the allowable pressure drop on the cooling water. If the cool-
ing water flow is reduced to 655 gal/min and the outlet water
temperature allowed to rise to 115°F, the plate-and-frame
heat exchanger would contain about 185 ft2 of area. The unit
is smaller and less expensive, and it uses less water. The
load being transferred to the cooling tower is the same.
With shell-and-tube heat exchangers, increasing water
flow will minimize heat-transfer area. However, with com-
pact technologies, the effect is exactly the opposite. The
larger water flow actually drives up the cost of the unit.
Rather than supplying a rigid specification to all heat
exchanger manufacturers, the engineer should have ex-
plained the goal for the process stream. This could have
been in the form of the following statement: “The process
stream is to be cooled with cooling water. Up to 2,000
gal/min of water is available at 80°F. The maximum return
temperature is 115°F.” This simple statement could result
in vastly different configurations compared with the de-
signs that would result from the original specification.
Design charts for plate-and-frame exchangers
When it comes to compact heat-transfer technology,
engineers often find themselves at the mercy of the
equipment manufacturers. For example, limited litera-
ture correlations are available to help in the preliminary
design of plate-and-frame heat exchangers.
This article introduces a series of charts (Figures 2–7)
that can be used for performing preliminary sizing of plate-
and-frame exchangers. Examples will help clarify their use.
The following important points should be noted regard-
ing the charts and their use:
1. The heat-transfer correlations apply to single-phase,
liquid-liquid designs.
2. These charts are valid for single-pass units with 0.50-
mm-thick plates. The accuracy of the charts will not be
compromised for most materials of construction.
3. Wetted-material thermal conductivity is taken as
8.67 Btu/h-ft-°F (which is the value for stainless steel).
4. The following physical properties for hydrocarbon-
based fluids were used for the basis: thermal conductivity
(k) = 0.06 Btu/h-ft-°F, density (ρ) = 55.0 lb/ft3, heat capac-
ity (Cp) = 0.85 Btu/lb-°F. The following physical properties
for water-based fluids were used for the basis: thermal con-
ductivity = 0.33 Btu/h-ft-°F, density = 62.0 lb/ft3, heat ca-
pacity = 0.85 Btu/lb-°F.
5. Accuracy should be within ±15% of the service value
for the overall heat-transfer coefficient, assuming a nomi-
nal 10% excess heat-transfer area.
6. For fluids with viscosities between 100 and 500 cP,
use the 100 cP line on the graphs. For fluids in excess of
500 cP, consult equipment manufacturers.
Equations 1–3 are used to calculate the log-mean tem-
perature difference (LMTD) and number of transfer units
(NTU) for the hot and cold streams. After the local heat-
transfer coefficients (h) are read from the charts, the over-
all heat-transfer coefficient (U) is calculated by Eq. 4.
1 1 1
4
U h
x
k hhot cold
= + + ( )
∆
NTU
T T
LMTD
cold
cold out cold in
=
−
( ), ,
3
NTU
T T
LMTD
hot
hot in hot out
=
−
( ), ,
2
LMTD
T T T T
T T
T T
hot in cold out hot out cold in
hot in cold out
hot out cold in
=
−( )− −( )
−
−
( ), , , ,
, ,
, ,
ln
1
Table. Basis for heat exchanger quotation.
Tubeside Shellside
Flowrate, gal/min 500 1,800
Temperature In, °F 280 80
Temperature Out, °F 150 92
Allowable Pressure Drop, psi 15 15
3. Using the charts
Consider the following example.
150,000 lb/h of water is being cooled
from 200°F to 175°F by 75,000 lb/h
of SAE 30 oil. The oil enters the ex-
changer at 60°F and leaves at 168°F.
The average viscosity of the water
passing through the unit is 0.33 cP
and the average viscosity of the oil in
the unit is 215 cP. The maximum-
allowable pressure drop through the
plate heat exchanger is 15 psi on the
hot and cold sides.
Step 1: Calculate the LMTD.
From Eq. 1, LMTD = [(200 – 168)
– (175 – 60)]/ln[(200 – 168)/(175 –
60)] = 64.9°F.
Step 2: Calculate NTUhot and
NTUcold. From Eqs. 2 and 3, NTUhot =
(200 – 175)/64.9 = 0.38 and NTUcold
= (168 – 60)/64.9 = 1.66.
Step 3: Read hhot from the appro-
priate chart. Use Figure 5, the chart
for hydrocarbons when 0.25 < NTU
< 2.0. Although there is not a vis-
cosity line for 215 cP, the line repre-
senting 100 cP can be used for vis-
cosities up to about 400–500 cP. The
heat exchanger will be pressure-
drop-limited and the heat-transfer
coefficient will not change apprecia-
bly over this viscosity range for
plate-and-frame exchangers. Read-
ing from the chart, a pressure drop
of 15 psi corresponds to hhot ≈ 50
Btu/h-ft2-°F.
Step 4: Read hcold from the chart.
Use Figure 2, which applies to water-
based liquids when 0.25 < NTU < 2.0.
Again, the exact viscosity line needed
for pure water (0.33 cP) in this case is
not available. However, the 1.0 cP
line provides a very good estimate of
the heat-transfer coefficient for pure
water. Reading from the chart, a pres-
sure drop of 15 psi corresponds to
hcold ≈ 3,000 Btu/h-ft2-°F.
Step 5: Calculate U. Assume a
stainless steel plate with a thick-
ness of 0.50 mm is being used.
Type 316 stainless steel has a ther-
mal conductivity of 8.67 Btu/h-ft-
°F. Then from Eq. 4, 1/U = (1/50 +
0.000189 + 1/3,000) and U = 49
Btu/h-ft2-°F.
Heat Exchangers
34 www.cepmagazine.org September 2002 CEP
s Figure 2. Heat-transfer correlations for water-based fluids, 0.25 < NTU < 2.0.
Pressure Drop, psi
h=LocalHeat-TransferCoefficient,
Btu/h-ft2-˚F
h=LocalHeat-TransferCoefficient,
W/m2-K
Pressure Drop, kPa
5 10 15 20 25 30
3,500
3,000
2,500
2,000
1,500
1,000
500
0
18,000
15,000
12,000
9,000
6,000
3,000
100
1 cP
2.5 cP
5 cP
10 cP
100 cP
50 200150
Water-Based Fluids
s Figure 3. Heat-transfer correlations for water-based fluids, 2.0 < NTU < 4.0.
Pressure Drop, psi
h=LocalHeat-TransferCoefficient,
Btu/h-ft2-˚F
5 10 15 20 25 30
3,500
3,000
2,500
2,000
1,500
1,000
500
0
18,000
15,000
12,000
9,000
6,000
3,000
100
1 cP
Correction: For liquids with average viscosities
less than 2.0 cP, reduce the local heat-transfer
coefficient by 15% from 3.5 < NTU < 4.0.
2.5 cP
5 cP
10 cP
100 cP
50 200150
h=LocalHeat-TransferCoefficient,
W/m2-K
Pressure Drop, kPa
Water-Based Fluids
s Figure 4. Heat-transfer correlations for water-based fluids, 4.0 < NTU < 5.0.
Pressure Drop, psi
h=LocalHeat-TransferCoefficient,
Btu/h-ft2-˚F
5 10 15 20 25 30
3,500
3,000
2,500
2,000
1,500
1,000
500
0
18,000
15,000
12,000
9,000
6,000
3,000
100
1 cP
2.5 cP
5 cP
10 cP
100 cP
50 200150
h=LocalHeat-TransferCoefficient,
W/m2-K
Pressure Drop, kPa
Water-Based Fluids
4. Now let’s consider another exam-
ple. 150,000 lb/h of water is being
cooled from 200°F to 100°F by
150,000 lb/h of NaCl brine. The
brine enters the exchanger at 50°F
and leaves at 171°F. The average
viscosity of the water passing
through the unit is 0.46 cP and the
average viscosity of the brine in the
unit is 1.10 cP. The maximum-allow-
able pressure drop through the plate
heat exchanger is 10 psi on the hot
(water) side and 20 psi on the cold
(brine) side.
The LMTD is calculated to be
38.5°F. NTUhot and NTUcold are 2.59
and 3.14, respectively. From the
charts for 2.0 < NTU < 4.0 (water
based), hhot ≈ 2,000 Btu/h-ft2-°F
and hcold ≈ 2,500 Btu/h-ft2-°F. Al-
though the material of choice may
be titanium or palladium-stabilized
titanium, the properties for stain-
less steel are used for preliminary
sizing. U is calculated to be 918
Btu/h-ft2-°F.
Implications of size reduction
Alternative technologies offer
significant size advantages over
shell-and-tube heat exchangers.
Let’s now consider the implications
of this.
The individual exchangers are
smaller, and the spacing between
process equipment can be reduced.
Thus, a smaller plot is needed for
the process plant. If the plant is to
be housed in a building, the build-
ing can be smaller. The amount of
structural steel used to support the
plant can be reduced, and because
of the weight saving, the load on
that structure is also reduced. The
weight advantage extends to the
design of the foundations used to
support the plant. Since the spac-
ing between equipment is reduced,
piping costs are lower.
However, we stress again that the
savings associated with size and
weight reduction can only be
achieved if these advantages are rec-
ognized and exploited at the earliest
stages of the plant design.
CEP September 2002 www.cepmagazine.org 35
s Figure 5. Heat-transfer correlations for hydrocarbons, 0.25 < NTU < 2.0.
Pressure Drop, psi
h=LocalHeat-TransferCoefficient,
Btu/h-ft2-˚F
5 10 15 20 25 30
1,000
800
600
400
200
0
5,400
4,600
3,800
3,000
2,400
1,600
800
100
1 cP
2.5 cP
5 cP
10 cP
100 cP
50 200150
h=LocalHeat-TransferCoefficient,
W/m2-K
Pressure Drop, kPa
Hydrocarbon-Based Fluids
s Figure 6. Heat-transfer correlations for hydrocarbons, 2.0 < NTU < 4.0.
Pressure Drop, psi
h=LocalHeat-TransferCoefficient,
Btu/h-ft2-˚F
5 10 15 20 25 30
1,000
800
600
400
200
0
100
Correction: For liquids with average viscosities
less than 2.0 cP, reduce the local heat-transfer
coefficient by 15% from 3.5 < NTU < 4.0.
50 200150
5,400
4,600
3,800
3,000
2,400
1,600
800
1 cP
2.5 cP
5 cP
10 cP
100 cP
h=LocalHeat-TransferCoefficient,
W/m2-K
Pressure Drop, kPa
Hydrocarbon-Based Fluids
s Figure 7. Heat-transfer correlations for hydrocarbons, 4.0 < NTU < 5.0.
Pressure Drop, psi
h=LocalHeat-TransferCoefficient,
Btu/h-ft2-˚F
5 10 15 20 25 30
1,000
800
600
400
200
0
5,400
4,600
3,800
3,000
2,400
1,600
800
100
1 cP
2.5 cP
5 cP
10 cP
100 cP
50 200150
h=LocalHeat-TransferCoefficient,
W/m2-KPressure Drop, kPa
Hydrocarbon-Based Fluids
5. Reduced plant complexity
The use of alternative heat ex-
changer technologies can signifi-
cantly reduce plant complexity by
reducing the number of heat ex-
changers through improved thermal
contacting and multi-streaming.
This adds to the savings associated
with reduced size and weight and
also has safety implications. The
simpler the plant structure, the easi-
er it is for the process operator to
understand the plant. In addition,
plant maintenance will be safer,
easier and more straight-forward.
Mechanical constraints play a
significant role in the design of
shell-and-tube heat exchangers. For
instance, it is common to find that
some users place restrictions on
tube length. Such a restriction can
have important implications for the
design. In the case of exchangers
requiring large surface areas, the
restriction drives the design toward
large tube counts. If such large tube
counts lead to low tubeside veloci-
ty, the designer is tempted to in-
crease the number of tubeside pass-
es in order to maintain a reasonable
tubeside heat-transfer coefficient.
Thermal expansion considerations
can also lead the designer to opt for
multiple tube passes, because the cost of a floating head
is generally lower than the cost of installing an expan-
sion bellows in the exchanger shell.
The use of multiple tube passes has four detrimental
effects. First, it leads to a reduction in the number of
tubes that can be accommodated in a given size shell,
thereby leading to increased shell diameter and cost.
Second, for bundles having more than four tube passes,
the pass-partition lanes introduced into the bundle give
rise to an increase in the quantity of shellside fluid by-
passing the tube bundle and a reduction in shellside
heat-transfer coefficient. Third, it results in wasted
tubeside pressure drop in the return headers. Finally,
and most significantly, the use of multiple tube passes
results in the thermal contacting of the streams not
being pure counter-flow, which reduces the effective-
mean-temperature driving force and possibly produces
a temperature cross (i.e., where the outlet temperature
of the cold stream is higher than the inlet temperature
of the hot stream, as shown in Figure 8). If a tempera-
ture cross occurs, the designer must split the duty be-
tween multiple heat exchangers arranged in series.
Heat Exchangers
s Figure 8. The situation on the left does not involve a temperature cross, while the one on the right does.
200˚F
168˚F
175˚F
One shell-and-tube exchanger
One plate exchanger
60˚F
No Temperature Cross
200˚F
171˚F
Three shell-and-tube exchangers
One plate exchanger
50˚F
100˚F
Temperature Cross
36 www.cepmagazine.org September 2002 CEP
s Figure 9. A single plate-and-frame exchanger handles three process streams …
160˚F
Styrene, 290,285 lb/h
130˚F
248˚F
∆P = 14.6 psi
Styrene, 290,285 lb/h
285˚F
Styrene, 100˚F
∆Ptotal = 30 psi
112˚F
∆P = 9.5 psi
Water, 248,655 lb/h
80˚F
160˚F
s Figure 10. … whereas the equivalent shell-and-tube design requires
six units.
Styrene
(Hot)
Styrene
(Cold)
Cooling
Water
6. Many of the alternative heat-exchanger technologies
allow the application of pure countercurrent flow across
all size and flow ranges. This results in better use of the
available temperature driving force and the use of single
heat exchangers.
Multi-streaming
The traditional shell-and-tube heat exchanger handles
only one hot stream and one cold stream. Some heat ex-
changer technologies (most notably plate-fin and print-
ed-circuit exchangers) can handle many streams. It is
not uncommon to find plate-fin exchangers transferring
heat between ten individual processes. (The principles
behind the design of multi-stream exchangers and the
operability of such units are discussed in Ref. 1.) Such
units can be considered to contain a whole heat ex-
changer network within the body of a single exchanger.
Distribution and recombination of process flows is un-
dertaken inside the exchanger. The result is a major re-
duction in piping cost.
Engineers often overlook the opportunities of using a
plate-and-frame exchanger as a multi-stream unit. As
mentioned earlier, this is a common oversight when ex-
changer selection is not made until after the flowsheet
has been developed.
A good example of multi-streaming is a plate heat ex-
changer that serves as a process interchanger on one side
and a trim cooler on the other. This arrangement is par-
ticularly useful for product streams that are exiting a pro-
cess and must be cooled for storage.
Another popular function of multi-streaming is to
lower material costs. Some streams, once they are cooled
to a certain temperature, pose much less of a corrosion
risk. One side of the exchanger can be made of a more-
expensive corrosion-resistant alloy while the other side
can utilize stainless steel or a lower alloy.
Figure 9 shows a plate-and-frame unit applied to three
process streams. A single exchanger with 1,335 ft2 of ef-
fective surface area is used. Figure 10 is the equivalent
shell-and-tube solution — to avoid temperature crosses,
six individual exchangers are needed: the cooler having
two shells in series (each with 1,440 ft2 of effective sur-
face area) and the heat recovery unit having four shells in
series (each with 2,116 ft2 of surface area). So, the plate-
and-frame design involves the use of 1,335 ft2 of surface
area in a single unit, whereas the equivalent shell-and-
tube design has 11,344 ft2 of surface area distributed
across six separate exchangers.
Budget pricing correlations
For plate-and-frame heat exchangers with a design pres-
sure up to 150 psi and a design temperature up to 320°F,
the following cost equations can be used to estimate the
purchased cost.
For areas (A) less than 200 ft2:
C = 401 A 0.4887 for Type 316 stainless steel (5)
C = 612 A 0.4631 for Grade 1 titanium (6)
For areas larger than 200 ft2:
C = 136 A 0.6907 for Type 316 stainless steel (7)
C = 131 A 0.7514 for Grade 1 titanium (8)
Typical installation factors for plate-and-frame heat ex-
changers can range from 1.5 to 2.0, depending on the size
of the unit.
Up next
Being able to estimate the area and prices of plate-
and-frame heat exchangers is an important first step in
including alternative heat-transfer technology in process
synthesis. The remaining articles in this series (which
will appear next month) focus on the integration of
plate-and-frame (and other compact technology) into
pinch analyses. CEP
CEP September 2002 www.cepmagazine.org 37
Literature Cited
1. Picon Nunez, M., and G. T. Polley, “Recent Advances in
Analysis of Heat Transfer for Fin Type Surfaces,” Chapters 9
and 10, Sunden, B., and P. J. Heggs, eds., WIT Press,
Southampton, U.K. (2000).
CHRISTOPHER HASLEGO is a design engineer with the Process
Technology Div. of Alfa Laval (5400 International Trade Dr., Richmond,
VA 23236; Phone: (804) 236-1318; Fax: (804) 236-1360; E-mail:
chris.haslego@alfalaval.com). His focus is heat transfer in the
inorganic base chemicals industry. He received a BS in chemical
engineering from West Virginia Univ. A member of AIChE, he also
maintains a website dedicated to chemical engineering entitled “The
Chemical Engineers’ Resource Page” at www.cheresources.com.
GRAHAM T. POLLEY (Phone: +44-1229-585-330; Fax: +44-1229-585-708;
E-mail: gtpolley@compuserve.com) is retired from the Univ. of
Manchester Institute of Science and Technology, Manchester, U.K.,
where he was the director of the Centre for Process Integration. To
promote the application of process integration technology, he has
developed the website www.pinchtechnology.com. His research
activities have involved condensation heat transfer, boiling heat
transfer, heat-recovery-system design and the development of process
and equipment design methodologies. He is the current president of
the U.K. Heat Transfer Society. In 1990, he was awarded the Moulton
Medal by the Institution of Chemical Engineers for his work on oil
refinery revamping, and in 1992, he and Dr. Nasr were awarded the
Ackrill Trophy by the U.K. Heat Transfer Society for their work on
heat-transfer enhancement. He holds BTech, MSc and PhD degrees
in chemical engineering from Loughborough Univ. of Technology,
and is a member of AIChE.
Correlations used to formulate charts were developed by Alfa Laval
(formerly Alfa Laval Thermal) through comprehensive research and
development and decades of industrial experience.