FUNDAMENTALS
OF FOULING
The
recovery of the cost of fouling at any facility must begin with a comprehensive understanding . . .
|
. . .of the various Types of Fouling
. f
- Precipitation
/ Crystallization -
dissolved inorganic salts with inverse solubility characteristics
- Particulate
/ Sedimentation
- suspended solids, insoluble corrosion products, sand,
silt
- Chemical
Reaction - common in petroleum refining and polymer
production
- Corrosion
- material reacts with fluid to form corrosion products,
which attach to the heat transfer surface to form nucleation
sites
- Biological
- initially micro-fouling, usually followed by
macro-fouling
- Solidification
- ice formation, paraffin waxes
of the sequence of events typically referred to as the
Fouling Mechanisms
- Initiation
- most critical period - when temperature, concentration
and velocity gradients, oxygen depletion zones and crystal
nucleation sites are established - a few minutes to a few
weeks
- Migration
- most widely studied phenomenon - involving tranport of
foulant to surface and various diffusion transport mechanisms
- Attachment
- begins the formation of the deposit
- Transformation
or Aging
- another critical period when physical or chemical changes
can increase deposit strenght and tenacity
- Removal
or Re-entrainment - dependent upon deposit strength
- removal of fouling layers by dissolution, erosion or spalling
- or by . . . "randomly
distributed turbulent bursts"
AND
FINALLY . .add some appreciation. for the Conditions
Influencing Fouling
|
Operating
Parameters
|
Heat
Exchanger Parameters
|
Fluid
Properties |
| velocity |
exchanger
configuration |
suspended
solids |
| surface
temperature |
surface
material |
dissolved
solids |
| bulk
fluid temperature |
surface
structure |
dissolved
gases |
| |
|
trace
elements |
.
. . and you will be fully prepared to eliminate heat exchanger
fouling problems with a few Heat Transfer
Advances that
are here today!
- A
Survey of 90 Heat Transfer Specialists -
was conducted by HTFS in 1987 and later summarized in the
September 1991 issue of Chemical Engineering Progress.
- The
Top Five Most Significant Advances -that were expected
by the year 2000 were -
| 1.
Compact Heat Exchangers |
| 2.
Computational Fluid Dynamics |
| 3.
Expert Systems |
| 4.
Fouling Prevention and Control* |
| 5.
Improvements in Shell and Tube Exchangers* |
*
Dynamic enhancement of heat transfer surfaces with self-cleaning
heat exchanger technologies are here TODAY.
AFTER you have defined those ANNUAL COSTS OF FOULING at your facility,
accepted the fact that you do have a problem and decided to
pursue a cost-effective solution - it will
be time to consider -
DYNAMIC
ENHANCEMENT & SELF-CLEANING HEAT EXCHANGER TECHNOLOGIES
We would like to offer our products and services to assist you in resolving your heat exchanger fouling problems and in reducing the cost of fouling at your facility .
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