Anti Foulant Coatings Decrease Surface Tension
 Background
Dresser-Rand Engineered Equipment Coatings,
EEC’s, were developed to protect Turbomachinery Equipment and reduce fouling of
rotating and stationary components. Foulant release is the property of a surface which
results from the inability of a substance to adhere to it during operation. It is a
function of surface energy that can be measured by the angle of contact between the
surface and a liquid deposited on that surface. D-R EEC coatings provide the
greatest contact angle of any currently available anti-foulant coating. Engineered
Equipment Coatings cause a reduction of this contact angle by creating a buffer layer.
This buffer provides, 1) a reduction of the surface tension between a foulant and the
machine internals, and 2) a protective sacrificial material . This buffer, the EEC
coated surface, in a fouling media, creates a greater contact angle between the foulant
and the unit’s internal surfaces as shown in the adjacent sketch. By increasing this
angle between the fouling material and the substrate it lessens the ability of a foulant
to stick to the compressor internals; thereby, producing a coating with release properties
which exceed that of the original components.
If fouling or contamination of component is a problem, then a
coating buffer layer will allow the unit internals to shed foulants while running. This
in-process cleaning action will also reduce the requirements for unit washing to remove
fouling materials during unit operation.
Dresser-Rand coating systems include a galvanic sacrificial
base as a second line defensive layer to protect process equipment from corrosive attack.
These multilayer combinations can reduce the maintenance down-time to remove process
clogging deposits, extend the operating life of unit components and increase unit online
availability.
Coating Heat Resistance
D-R Coatings have been tested to withstand standard
installation process procedures required by Dresser-Rand Turbomachinery. Equipment
components can be individually coated and then installed on the rotor shaft with no loss
of coating bond or surface finish. This eliminates any requirements for subjecting a
finished rotor to coating curing temperatures. D-R’s coatings are fully cured prior
to final installation therefore preventing any potential for rotor warpage, part movement
or damage during the coating curing cycle.
Applications
D-R Engineered Equipment Coatings are designed to be used on
industrial compressor and steam turbine components. The coatings have an effective
operating range of 2-9.5 ph. Components eligible for coating application* include but are
not limited to:
| Compressor Impellers |
Diaphragms |
| Inlet Guides |
Guide Vanes |
| Diffusers |
Turbine Blades |
| Wheels |
Diaphragms |
| Cases |
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*All coating applications will be
reviewed by Dresser-Rand Engineering for applicability to the design and service
conditions of the unit.
Typical Coating Properties
EEC-A2
Average Thickness - 3-5 mils
Surface Roughness <40 Ra
Coefficient of Friction >.02 (on new surfaces)
Max Continuous Operating Temp 500ºF
Peak Operating Temp - 550ºF
Coating Adhesion (ASTM D2247) - Excellent No pickoff
Thermal Shock, Impact Survival, Solvent Resistance - Excellent
EEC-C1
Average Thickness - 3-5 mils
Surface Roughness <40 Ra (on new surfaces)
Max Continuous Operating Temp 600ºF
Peak Operating Temp - 1000ºF
Coating Adhesion (ASTM D2247) - Excellent No pickoff
Salt Spray (ASTM B117 & CASE) - No coating failure
Thermal Shock, Impact Survival, Abrasion Resistance - in compliance
Type I Class 4 MIL-C-81751B
Other
Available Coatings
EEC-E3 Erosion Resistant
EEC-SH Smooth & Hard Top Coat (for Stationary Components)
For Additional Information
Contact your local Dresser-Rand Representative
OR
Dresser-Rand Co.
Tulsa Technology Center
1354 S. Sheridan Rd.
Tulsa, Oklahoma 74112
Phone (918) 835-8437
Fax (918) 832-7046
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