of plate-type heat exchangers - apex group...1 status of development of plate-type heat exchangers...

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STATUS OF DEVELOPMENT

OF

PLATE-TYPE HEAT EXCHANGERS FOR

HEAVY-DUTY APLICATIONS

Mircea Dinulescu

APEX International Holding,

Voorburg, The Netherlands

© Mircea Dinulescu – Calgary 2011

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HEAVY-DUTY APLICATIONS

• Corrosive gases from industrial processes

• Long operating periods without shut down

• High effectiveness

• Operating close to cold-end corrosion point

• Very large volumes of gas


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LARGE VOLUMES OF GAS Single module


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LARGE VOLUMES OF GAS Multi-module unit in fabrication shop


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LARGE VOLUMES OF GAS Multi-module unit during field assembly


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HISTORICAL BACKGROUND

• Over 60 years of industrial experience

• Numerous geometries have been developed

Geometries can be classified as:

- enhanced heat transfer geometries

- plain, smooth surfaces

NOTE: Tubular products are not included in

this analysis


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1. Enhanced heat transfer

- After 1950s it was taken for

granted that “enhanced heat

transfer” is the only acceptable

concept

-The related technical literature

exploded after 1960s

- The main aim was to reduce the

heat transfer area at the detriment

of the pumping power


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1. Enhanced heat transfer

- Developed during periods of low energy cost

(1950-1970)

- Most successful types:

- corrugated plates

- undulated plates

- extended surfaces

- boundary layer breakers


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2. Flat, smooth surfaces

- The author of this article evaluated the basics of heat

transfer based on increased energy costs in 1970s.

- He found out that the flat, smooth surfaces have

distinct advantages

- Based on his studies, industrial applications were

developed in late 1970s

- Over 30 years of applications these exchangers have

proven their advantages and underwent an exponential

growth


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HISTORICAL BACKGROUND Summary

- Over 60 years industrial experience with enhanced

heat transfer equipment

- Over 30 years industrial experience with flat, smooth

surfaces

- This presentation will:

- draw the lessons from this pool of experience

- suggest directions of future developments


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TYPICAL APPLICATION

H.T. Area = 50,000 m2

Q = 160 MW

Typical large unit for

DENOX installations

15m x 12m x H 12m

Weight 600,000 kg


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CRUCIAL EVALUATION CRITERION

A diversity of evaluation criteria have been proposed:

- the goodness factor j/f [2]

- evaluation of entropy/exergy formation [5]

- Nue/Nuo vs fe/fo graphs [6]

Based on practical experience, however, we conclude

that a more reliable critical criterion is:

- The Metal Temperature


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CRUCIAL EVALUATION CRITERION The metal temperature

- When (Condensation Temp.)< Inlet Temp. of cold gas

operation is safe: no condensation and no corrosion

- This situation is typical for HVAC (heating, ventilation

and air conditioning)

- Not representative for industrial processes


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- For industrial processes: (Condensation Temp)>> Inlet

Temp of cold gas

- When (Metal Temperature)< Condensation Temperature

plugging and corrosion will result.

- Metal Temperature field must avoid the black triangle


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Flat smooth surfaces

- Velocity & temperature are uniform, steady & monotonous

-Means are available for maximizing the metal temperature

at the cold end ( AIR CURTAIN )


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Corrugated / undulated surfaces

- Boundary layer is broken at small intervals

- Flow is time dependant , non uniform

- Saw-tooth patterns develop along the flow path

- Stone & Vanka, 1997 report high fluctuations of

temperature & velocity


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-Alawadhi & Bourisli report

saw-tooth Nu distribution

-Mohamed et al report

saw-tooth Nu distribution


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Metal temperature faults under condensation temperature


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By comparison we repeat the temperature profiles

of flat smooth surfaces


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LESSONS FROM 60 YEARS EXPERIENCE

1. Enhanced transfer concept has played over 60 years

and continues to play an important role.

2. Flat, smooth concept has developed during the last

30 years as a significant alternative with distinct

advantages in the major fields of applications.

2.1. Handling large volumes of gas

2.2. Oil and gas industry

2.3. Power industry

2.4. DENOX installations


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LESSONS FROM 60 YEARS EXPERIENCE Flat-smooth concept

Main technical strong points

• Uniform fields of temperatures and velocities

• Metal Temperature above Condensation Temperature

• Flow layout close to pure countercurrent becomes

possible

• Strong benefit from CFD flow distribution simulations

• Optimization of the metallic structures by FEM (finite

element methods)


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CFD SIMULATION & VALIDATION

Experimental result

I. E. Idelchik,

Handbook of

Hydraulic Resistance

CFD simulation


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Experimental result

I. E. Idelchik,

Handbook of Hydraulic

Resistance

CFD simulation


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Experimental result

I. E. Idelchik,

Handbook of Hydraulic

Resistance

CFD simulation


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Experimental result

I. E. Idelchik, Handbook of

Hydraulic Resistance

CFD simulation


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CFD simulation details


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Flow simulation in a fire heater system


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Flow distribution in a complex air preheating system


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FEM SIMULATION

Ansys results.

Experimental results.

Analysis results


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DIRECTION OF FUTURE DEVELOPMENTS

Very large glass-coated

exchangers

Typical large unit for

glass-coated installation

8m x 10m x H 6m

Weight 200,000 kg


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Near pure countercurrent plug-flow pattern

for high effectiveness units


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Develop the flat-smooth geometry for applications in

new fields:

- Environmental projects

- Bio-mass energy projects

- CO2 subterranean storage


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REFERENCES

[1] I.E. Idelchik, Handbook of Hydraulic Resistence, 3rd ed.

[2] K.M. Stone, S.P. Vanka, Numerical Study of Flow and Heat Transfer in Wary

Passages ACRC TR-118, May 1997

[3] E.M. Alawadhi, R.I. Bourisli, The Role of Periodic Vortex Shedding in Heat

Transfer Enhancement for Transcent Pulsatile Flow Inside Wary Channels,

World Academy of Science, Engineering Technology 46, 2008

[4] Nabou Mohamed et al., Heat Transfer and Flow Field in the Entrance Region

of a Symmetric Wary-Channel with Constant Wall Heat Flux Density, Int.

Journal of Dynamics of Fluids, 1 (2007), pp. 63-79

[5] J.F.Fan, et al. , A performance evaluation plot of enhanced heat transfer

techniques oriented for energy-saving, Int. Journal of Heat and Mass

Transfer, June 2008

[6] N. Sahiti et al. , Strategy for selection of elements of heat transfer

enhancement, Int. Journal of Heat and Mass Transfer 49 (2006)


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Contact Information

• Mircea Dinulescu, Harrie Neefs

• APEX International Holding

• [email protected],

[email protected]

• Tel.: +31703004242


mailto:[email protected]

mailto:[email protected]

of plate-type heat exchangers - apex group...1 status of development of plate-type heat exchangers...

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