Bag House Chemical Corrosion Protection Coating

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During the operation, the gases entering the bag house with high velocity, loaded with fine dust is forced to hit the internal surface of the doors, structures in all directions abrading the metal substrate leading to erosion of metal. Along with this, chemical attack is taking place on the bag house doors due to the reaction from released oxides of sulphur in the presence of moisture forming mild Sulphuric Acid , which is getting settled over the mild steel substrates. This is giving rise to an electrochemical reaction leading to high degree of corrosion, causing loss of metal thickness, that which can be seen as thick rust flakes and also causing pin holes due to localized attack. The formed corrosion deposits is getting removed due to the abrasion of dust particles, thereby exposing fresh metal to further chemical attack. The air from the atmosphere entering the system through these pin holes, is giving rise to increase in energy consumption for operation of the bag house.

The surface inside was blast cleaned twice using copper slag abrasive medium to remove thick corrosion deposits followed up with detergent cleaning & hydro jet water washing. Once the surface was dried up, blast cleaning process was repeated to ensure a surface roughness of 75+ microns average to Sa 2.5 Swedish Standards. Over the prepared surface coating application was carried out using nylon rollers and tynex brushes. The applied coating was checked for thickness levels using Elcometer WFT Gauge intermittently and cross-verified using Elcometer DFT Gauge on curing. Holiday Spark Testing was carried out over the entire coated surface to make sure complete coating integrity and examine any flaws during the application works.


After completion of the coating works & quality checks being performed, the bag house was put back into operations again. Based on the operating conditions of this huge bag house equipment, the blast cleaning and application of coating was carried out in a phased manner in order to implement quality applications methods that play a key vital role in offering rigid protection

Back Wash Filter Internal Protection

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Back Wash Filter of Billet Caster internal surface is undergoing extreme corrosion along with localized pitting due to continuous immersion in raw water with chemical contamination. Formed rust thus has been clogging the filter vents leading to poor filtering efficiency.


After first round of copper slag blast cleaning to Sa 2 standard, entire internal surface was scrubbed with detergent to remove the chemical contamination and further rinsed with fresh water jet to ensure contamination freeness of back wash filter internal surface.


After surface was dried up, second round of chilled iron grit blasting was carried out to achieve Sa3 i.e., white metal finish with an average surface profile of 125 microns to attain exceptional mechanical interlocking, polar-polar adhesion and chemical bonding of ProCoat advanced chemical and abrasion resistant polymer coating system.

With thorough hand pressure, initial wetting coat of ProCoat was applied followed by thickness build up coats with tynex bristle brush and synthetic roller over internal surface of back wash filter and allowed for full curing.


Quality checks like wet film thickness checks during application, dry film thickness after curing, coating integrity check with Elcometers were performed to ensure flawlessness in work.


After a continuous operation of 6 months, back wash filter was opened and water washed for inspection of applied ProCoat coating. Excellent condition without any sign of corrosion and no change in surface texture is noticed, which indicates absolute protection being offered by ProCoat.


Electrostatic Tar Precipitator Corrosion Protection

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External surface of these Electrostatic Tar Precipitators are constantly in contact with vapours of ammonia which is being liberated from the surrounding process equipments. Though the ETP surface has been painted with conventional paint system yet great amount of corrosion is observed.


Initially the surface was neutralized by means of water washing and scrubbing the surface to eliminate the deposited traces of corrosion causing elements.


The neutralized surface was thoroughly blast cleaned using copper slag abrasive medium to SA 2.5 surface profile to near white metal finish ensuring the surface is also free from adsorbed contaminants.

Over the prepared surface, ProCoat coating was applied using Airless Spray Method to evenly deposit the material all over the surface. This method was adopted not only to apply the coating material evenly, but also not to expose the prepared metal surface for longer periods of time to the vapours of Ammonia which gets continuously expelled into the working environment. Intermittent checks were made using Elcometer WFT gauge to ensure the desired thickness of coating as per the requirements.


Once the coating was cured Dry Film Thickness was measured using the Elcometer DFT Gauge & checked with Holiday Spark Testing to ensure coating integrity. Six such Electrostatic Tar Precipitators have been coated using ProCoat Advanced Polymer Coating Systems providing the reliable protection to these equipments for almost three years now.

Screw Conveyor Corrosion & Abrasion Protection

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This slurry coming out of the scrubber is meant to reach the thickener via this screw conveyor pathway. The slurry medium being corrosive in nature has resulted in corroding the vanes, shaft of the screw along with corroding the screw supporting housing structure. To enhance the life of this equipment ProCoat was the primarily chosen coating material as it not only reduces the corrosion & abrasion effect, but also being smooth in finish does not allow the slurry medium to stick to the surface thereby helps in efficiency improvisation of the operating system.

On dismantling the parts separately, ProCoat team has carried out the surface preparation using blast cleaning method initially & checked for the presence of adsorbed salts, and thereupon relevant methods were incorporated for removing the contamination by means of detergent cleaning, neutralizing the surface with thorough water jetting cleaning and carrying out second round of blast cleaning to ensure a rough, contamination free surface to the desired surface profile.


Over the prepared surface, application of ProCoat Coating System was carried out using synthetic rollers to the desired thickness levels.


The coating deposited over the surface was checked for complete and firm adhesion to the desired thickness which was measured using Elcometer Wet Film & Dry Film Gauges followed up with Holiday Spark Testing to enhance proper coating integrity.

Conveyor Structure – Saline Corrosion Protection

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Severe deterioration of metal surface is noticed over vertical legs, horizontal channels and roller supports of this conveyor structure which is due to continuous exposure of saline salts and condensation, in-spite of having conventional paint over them. Existing paint was unable to prevent the ingress of these corrosive substances and in turn allowing the underneath corrosion that resulted in blistering and localized deterioration of metal surface

Newly fabricated roller supports and rest of the conveyor structures were blast cleaned with coarse copper slag to achieve “Near White Metal Finish of Swedish Sa2.5 standard” along with an average 50 microns surface roughness with due checking of salt freeness. All these three aspects i.e., cleanliness, roughness and contamination freeness will directly influence the adhesion of coating in terms of polar-polar, chemical and mechanical interlocking with surface of conveyor.

Over very thoroughly prepared surface, ProCoat coating system was applied directly with very thorough wetting coat with high hand pressure application followed by low hand pressure coat with synthetic roller carried out to meet the recommended thickness of coating.


All desired quality checks such as “surface contamination”, surface cleanliness, surface roughness were checked with Elcometer instruments, and after application of coating, wet and dry film thickness checks alongside coating integrity check with Elcometer instruments were carried out to ensure complete integrity of ProCoat coating in all respects


In a phased manner, over & top of the fully and thoroughly completed areas of ProCoat coating, a top coat of dark grey colour weather resistant polyurethane was applied by brush and roller to the desired thickness levels. The purpose of this top coat is to maintain colour code as per the customer’s in- dustrial norms, as well as to give additional protection from weathering apart from the saline corrosion protection offered by ProCoat Advance Polymer Coating System.


Gas Pipeline External Corrosion Protection

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These pipeline external surface is in continuous contact of the gaseous chemicals emanated from the process equipments in a coke oven plant. Though the pipeline surface has been painted earlier yet over a short period of time the metal surface has been corroding due to the failure of paint and prevailing operating conditions.

The surface of this pipeline was blast cleaned initially & checked for the presence of adsorbed salts, and thereby relevant methods were incorporated for removing the contamination by means of detergent cleaning, second round of blast cleaning and neutralizing the surface with thorough water jetting cleaning ensuring a rough, contamination free surface to the desired surface profile.


Over the prepared surface, application of ProCoat Coating System was carried out using rollers. The coating deposited over the surface was checked for complete and firm adhesion to the desired thickness which was measured using various Wet Film & Dry Film Gauges followed up with Spark Testing to enhance coating integrity.


Proper planning, quality workmanship & safe work methods followed have resulted in performance of the coating applied over the pipeline surface to resist the severe corrosive conditions since almost five years now.

LRS Tank Internal Corrosion Protection

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Mild steel internal surface of LRS tank is always coming in contact with chemical water which contains sodium chloride and sodium hydroxide. Due to these electrolytic media the conductivity increases, which lead to corrosion reaction which got accelerated to form severe rusting on the LRS tank as the medium is highly conductive to electrons due to presence of salt & alkali. Apart from the chemical nature of medium inside LRS tank, variable temperatures of medium is highly influencing to the rate of corrosion.

The surface of the LRS tank was checked for the presence of adsorbed salts, and thereby relevant methods were incorporated for removing the contamination by means of blast cleaning and neutralizing the surface with thorough water jetting cleaning ensuring a rough, contamination free surface to the desired surface profile.


Over the prepared surface, application of ProCoat Coating System was carried out using rollers. The coating deposited over the surface was checked for complete and strong adhesion to the desired thickness which was measured using various Wet Film & Dry Film Gauges followed up with Spark Testing to enhance coating integrity.


Final view of the coated tank before being put back into operations.


Ship Unloader Structural Saline Corrosion Protection

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This huge ship unloader structure which is stationed at the tip of the sea has great exposure to saline humid conditions of the Arabian Sea. Along with the salty atmospheric conditions, they get soaked in the cement dust which is the main intended raw material that gets unloaded at this location all round the year.
The combined effect of the saline working conditions & alkaline cement dust has been the crucial factor, inducing severe degree of corrosion over the mild steel surface of this gigantic ship unloader structure.


Abiding to all the necessary working permits & safety norms inline with the competent authority, applicators team of ProCoat has executed surface preparation of the metal surface by means of copper slag blasting to near white metal finish, ensuring the desired surface roughness & by also implementing the quality checks to establish a contamination free surface.


On preparing the metal substrate the surface was applied with ProCoat Advanced Polymer Coating System using necessary tools and tackles. To complete this enormous task, the work was carried out in phased manner with proper planning following safe work methods.



Various quality checks were performed all throughout the surface preparation & application works to ensure essential coating performance. Checks such as presence of salts & other contaminants over the metal surface, wet film coating thickness checks during the application, dry film coating thickness checks after curing were followed. Holiday Spark Testing was carried out over the coated surface to ensure complete coating integrity.


As per the duty-bound requirements & to maintain the colour-coding system of the substrate surface over & top of the ProCoat coated surface a yellow colour coding weather resistant coating was applied.



Structures of the ship unloader after being coated with colour coding system.


Final view of the ship unloader under the protection of ProCoat Coating System.

Degasser Tank External Corrosion Protection

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These degasser tanks are subjected to corrosion, abrasion & cavitation due to continuous contact of fumes of chemicals which are exhaled from the surrounding process equipments in a chemical industry. A uniform & pitting type of corrosion is found over the surface.

On identifying the causing factors of corrosion over the surface, necessary protection methods have been implemented to safeguard the tank from falling prey to freely hovering corrosive agents. The tank surface was blast cleaned and made contamination free using relevant test methods ensuring the surface to Swedish standard of Sa2.5, i.e., near white metal finish along with average surface profile of 75 μ i.e., surface roughness.

Prior to the application of protective coating, at few places reclamation of metal on tank surface was carried out on with ProCoat Metal Repair & Reclamation Compounds. Sequentially the entire surface was coated with chemical resistant coating system to the recommended thickness, which has been measured using relevant measuring devices most importantly ensuring coating integrity.


Sequentially the entire surface was coated with chemical resistant coating system to the recommended thickness, which has been measured using Elcometer Wet Film Thickness Gauge to ensure the deposition of recommended coating thickness.


Once the coating was cured Dry Film Thickness was measured using the Elcometer DFT Gauge & checked with Holiday Spark Testing to ensure coating integrity. As per the clients need over and top the applied ProCoat Chemical Corrosion Protection Coating System a weather resistant coating was applied for dual protection of chemical & weather degradation, which also serves the purpose of color- coding.


Vertical Circulating Water Pump

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In power plants, vertical circulating water pumps internal surface is subjected to corrosion, abrasion & cavitation due to continuous operation and always in contact of cooling medium i.e., seawater / raw water along with suspended silt. At the same time, being continuously immersed in water, external surface of pump undergo severe corrosion. Vertical pump’s column pipes, bell mouth, bowl & impellers being protected with ProCoat advanced polymer systems which increase the life of pump as well as enhances the efficiency and outflow.

Prior to reclamation & protection work, all parts of pump both internal and external surface prepared to Swedish standard of Sa2.5, i.e., near white metal finish along with surface profile of 75 µ i.e., surface roughness after ensuring contamination freeness to ensure polar-polar adhesion, chemical adhesion and mechanical interlocking of ProCoat systems with the metal.


Over thoroughly prepared surface, ProCoat polymer repair system is used to reclaim the pitting, cavities to obtain an acceptable profile. This repair cures to a tough, machinable, cavitation resistant deposit and will prevent further propagation pitting and deterioration of metal.


After reclamation of deteriorations over pump parts, both internal and external surface of bell mouth, column pipes, casing are coated with ProCoat, 100% solids, high performance Novolac polymer coating system designed to offer abrasion, corrosion protection. Coated surface becomes extremely smooth, low friction which reduces the contact time of water with coating and increases flow rate by reducing the frictional losses and hence increases the pump efficiency along with long term protection.