process intensification using self-cleaning fluidized bed ... · process intensification using...

Process Intensification Using

Self-Cleaning Fluidized Bed Heat Exchangers

KLAREN International BV, Hanzeweg 35N, Barneveld, The Netherlands.

Email: [email protected], Website: www.klarenbv.com 1

Presented by

Dr. Ir. Dick G. Klaren M.Sc.Principal Adviser & Chief ScientistKLAREN International

November 2014

mailto:[email protected]

http://www.klarenbv.com/

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Our Interpretation of Successful Process Intensification

Improvement in process performance (i.e. heat transfer) and consequently, a substantial reduction in hardware volume (i.e. installed

heat transfer surface) at lowest possible energy cost (i.e. pumping power) and being environmentally friendly (i.e. no use of chemicals).

Additionally,

self-cleaning fluidized bed heat exchangers for severely fouling liquidscan have an enormous impact on process design in a positive manner.

…for your ZERO fouling heat exchangers…

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A Proven Example

Table 1: Comparison conventional heat exchanger versus self-cleaning fluidized bed heat exchanger.


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Consequences and Cost of Fouling

Loss of energy. Loss of production or reduced capacity operation. Over-sizing and / or redundancy of equipment. Excessive maintenance cost. Hazardous cleaning solution handling and disposal.

Annual global fouling costs are estimated at US$ 150 billion, i.e. US$ 150 x 109.


Principle

Figure 1: Self-cleaning heat exchanger with stationary fluidized bed of glass beads installed in vertical MSF evaporator

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How it started in seawater desalination


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Principle (Continued)

The heat exchanger (condenser) for the horizontal conventional MSFrequired a total tube length of 180 m with a liquid velocity in the tubes of1.8 m/s, a k-value of 2500 W/(m2K) and

a pressure drop of 450,000 N/m2.

The fluidized bed heat exchanger (condenser) for the vertical MSF requireda tube length (height) of 12 m with a liquid velocity in the tubes of 0.12m/s, a k-value of 2500 W /(m2K) and

a pressure drop of 171,000 N/m2, including 12 m lifting height


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Improvements of the Principle

Figure 2: Self-cleaning heat exchanger with internal circulation of cleaning

solids

Figure 3: Self-cleaning heat exchanger with external circulation of cleaning

solids


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Operating Experience Example # 1

Figure 4: Self-cleaning fluidized bed heat exchanger in operation at chemical plant since 1991 eliminates reboiler fouling. Houston, Texas, USA.


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Operating Experience Example # 2

Figure 5: Installation in 1998 of 4,600 m2 self-cleaning fluidized bed surface replacing 24,000 m2 conventional surface. Geismar, Louisiana, USA.


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Operating Experience Example # 2 (Continued)

Table 2: Comparison conventional heat exchanger versus self-cleaning fluidized bed heat exchangers, state-of-the-art 1998 and 2005


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Revamping Conventional Fouling Exchangers into Self-Cleaning Configuration

Figure 6: Evaporator equipped with conventional heat exchanger

Figure 7: Conventional evaporator revamped into self-cleaning

configuration.


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Revamping Conventional Fouling Exchangers into Self-Cleaning Configuration (Continued)

Requirements for the majority of revamps:

The same process conditions should be maintained as in the originalinstallation.

The connections to the column should be maintained. The installed pumps can be used because pumping power requirements

are generally lower for the self-cleaning fluidized bed heat exchangers than for the conventional severe fouling shell and tube exchanger.

As many components of the existing installation should be used in the revamped configuration, like bundle, channels or maybe even modified channels.

The revamp must be carried out within the available space. This often means that a revamp can only be carried out when the existing installation has already a vertical position.

The advantages of most revamps are much lower maintenance cost, an increased production and smoother operation.


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Example of Revamp

Figure 8: Conventional coolingcrystallizer

Figure 9: Revamped into self-cleaning configuration

Separator

Controlchannel

Down-comer

Cooler

Discharge

Feed

4 500 m³/hdP = 0.3 bar

Cooler

Discharge

Feed

4 500 m³/hdP = 0.3 bar


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Example on Offshore Platform

Figure 10: Offshore platform with air coolers on top deck indicated by arrow


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Example on Offshore Platform (continued)

Table 3: Comparison gas cooling systems on offshore platforms

m2

kW

Unit Air coolers Indirect seewatercoolers

Directseawater coolers

(self-cleaning bed)

Heat duty

Gas temperature (In-, Outlet)Gas pressure

Seawater temperature

WeightPlot area

Power 80

19040

850

350530

2 000

300

90

150120 43

26 50

46⁰C

⁰C

MW

bar

tonne


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Example Foul ‘Produced’ Water SteamGeneration

Figure 11: Conventional system using a Falling Film Evaporator (FFE) with Mecha-nical Vapor Recompression (MVR) and a Once-Through Stem Generator (OTSG)


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Example Foul ‘Produced’ Water Steam Generation (Continued)

Figure 12: New proposed system consisting of a Self-Cleaning Rising Film Evaporator (SC-RFSG) and a Fired Thermal Oil Heater (FTOH)


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Example Foul ‘Produced’ Water Steam Generation (Continued)

Table 4: Comparison both systems


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Conclusions

Thank you

We hope that you have appreciated our contribution to process intensification

Any Questions?


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