In Kaolin production, the kaolin is dried in so called spray dryers. Kaolin slurry is sprayed into a gas flame of 1050°F (566°C) where the kaolin is dried to powder that is falling down to the bottom of the spray dryer and transported away to a silo. The surface temperature of the spray dryer is 400°F (205°C) and the spray dryer is insulated both for reduction of heat loss and for worker protection. Normally the insulation consists of a 4 inch (100 mm) cementitious mineral wool insulation, reinforced with chicken wire and covered with a glass fabric wrapping.
A problem is, that due to the heat, the insulation cracks after some time. Therefore it is necessary to re-insulate the spray dryers at certain intervals.
To repair the spray dryer, it is necessary to remove all the insulation and afterwards to re-insulate it.
Maintenance work consequently means that the production has to be stopped for several weeks: The spray dryer must cool down before removal of old insulation and application of new one. Afterwards the new insulation needs time to harden.

The Kefa Heat Protection Solution

All old insulation is removed and the spray dryer is coated with Kefa Airless at a thickness of 80 Mill (2 mm). After one hour the operation of the spray dryer can be started again.
After a few weeks, Kefa Airless has sintered to a hard, mineral like substance.

Test dryer and result

A pilot spray dryer (Picture) was treated in March 1997. The Kefa Airless was applied at 50 mils (1,2 mm). The spray dryer is used for R&D and quality control work and is therefore running at longer and shorter periods. This means that the Kefa Airless insulation is frequently exposed to large temperature variations, i.e. a more extreme situation than a continuous production creates.
The test went on for 320 days. (Ended in Jan 1998)
At full operation of the spray dryer, the surface temperature of Kefa Airless measures 135-140°F (57-60°C), a reduction of 265°F (130°C) = 66%.
There is no discoloration and no visible deterioration of the coating.
No smoke or fumes from the coating have been observed during the test period

Full scale applications

After the successful results of the pilot plant, 5 full scale spray dryers have
been treated with Kefa Airless. These have all been applied with an 80 mill (2 mm) thick coat.
The surface temperature has decreased from 400°F (205°C) to 105°F (41°C).

The Kefa Airless coat replaces a cementitious mineral wool insulation of 4 in. (100 mm).

In 2003 there was a burn through in one of the Kefa Airless treated spray driers. With the old, conventional insulation it used to take several weeks before a burn through was discovered. This usually results in damages to the equipment and high repair costs. Under all circumstances the production has to be closed down and all insulation must be removed and replaced.

This time the burn through was detected in a few hours, due to discoloration of the Kefa Airless surface. The repair was easy. Loose paint was removed and the damaged area was recoated with Kefa Airless, a matter of a few hours.

Advantage

Kefa Airless is less expensive than conventional insulation – both material and labour cost are lower.
Maintenance and repairs of the spray dryer is simplified.
Repair can be done without removing the coating.
Damages to the Kefa Airless coating can be repaired without stopping production.
A productivity improvement has also been recorded – the dried kaolin contains 2% less water, indicating that there is a reduced heat loss in the production.
Consequently gas consumption is reduced.

Rust is caused by the influence of water, oxygen and time. Air pollution and contaminants on steel surfaces speed up the corrosion process.
When corrosion is caused by condensation water, a micorporous coating can considerably enhance traditional corrosion protection in 4 distinct ways:
1. It delays the forming of condensation on the surface
2. It absorbs the condensation into the micro-pores during heavy condensation periods, spreads it in the porous matrix and makes it evaporate at a much faster speed than from a smooth surface. Thus it reduces the time corrosive contaminants are in contact with the surface.
3. It is anti-static and does not attract the various substances that air pollution consists of.
4. It reveals imperfections of the rust protection.
The Micorporous Coating is consequently both reducing the corrosion activity time and minimizing the amount of aggressive substances contained in condensation that speed up the corrosion process.
Laboratory tests as well as full scale objects show that the life span of a traditional corrosion protection will be two to three times longer with a topcoat of KEFA Airless than without one. In addition KEFA Airless acts as an early warning system in case of defective or damaged corrosion protection.

Location – Basement

Existing Condition

All below grade walls showed signs of extensive water infiltration and the existing coatings were delaminating on all affected walls. At the customers request no abrasive blasting was done All affected walls were hand scraped to remove as much of the existing coating as possible. Severely deteriorated mortar joints were repaired using repair mortar mix with acrylic emulsion added to assist in adhesion. All mortar joints were treated using and water and acrylic emulsion mixture to aid in adhesion and harden existing mortar. Walls were cleaned prior to application. All surfaces and equipment adjacent to the area of application were covered and protected.

Before After

NorØrn

The Problem

Modern fishing boats are more or less floating food-processing factories. Most of the North European and Canadian fishing fleets operate in arctic waters, where the outdoor temperatures can be very low;

-30°C or below. The climate inside the ship is room temperature and the relative humidity, RH, is generally rather high due to the processing of fish.

It is unavoidable that vapour penetrates through the vapour barriers and forms condensation in the insulation. The effect is that the efficiency of the insulation is reduced and in many cases, the condensation water freezes. It happens that the ice will be so heavy that the insulation bursts and falls down.

The solution

Modern fishing boats are more or less floating food-processing factories. Most of the North European and Canadian fishing fleets operate in arctic waters, where the outdoor temperatures can be very low;

-30°C or below. The climate inside the ship is room temperature and the relative humidity, RH, is generally rather high due to the processing of fish.

It is unavoidable that vapour penetrates through the vapour barriers and forms condensation in the insulation. The effect is that the efficiency of the insulation is reduced and in many cases, the condensation water freezes. It happens that the ice will be so heavy that the insulation bursts and falls down.

The result

In 1988 and 1989 four fishing boats, NorØrn, Northern Eagle, Crystal Viking and Crystal Clipper were insulated with GrafoTherm under the Rockwool insulation. In the spring of 2000, the insulation of NorØrn was inspected. It was intact and no moisture related damages – deterioration of insulation material, mould or rust – could be observed.

Kristian Gerhard Jebsen Skibsrederi use Kefa in their Gear Bulk ships for transportation of paper and pulp.

The first series of three bulk ships were built in 1990/91. When in 2000 a new series of similar ships were to be built Kefa was specified as condensation protection, due to the good experience of the product.

The Problem

Paper pulp release large quantities of water during the transport. This water condenses in the roof of the garage and drips down on the cargo. To avoid damage the Gear Bulk ships are supplied with high capacity dehumidifiers, to keep the indoor air below dew point.

At loading and unloading the doors must be opened and then the dehumidifiers do not work any more. Especially wintertime, during cold weather, the humidity released by the paper pulp forms large quantities of condensation in the roof. Not until the doors are closed the dehumidifiers can start working again and even then it takes time before the indoor air is below dew point and during that period dripping continues.

Jaeger Arrow has got a special problem. The ship loads paper pulp in north Canada and in wintertime is on the Atlantic Ocean and enters the warm and humid Gulf Stream the inside of the garage is exposed to a condensation chock. The steel walls of the hull are still very cold and condensation water literarily pours down the hull sides.

The Solution

A 2 mm thick Kefa Standard Marine coat was sprayed in 4 coats in the roof and 6 metres down the hull sides. The corrosion protection was a dull zinc rich epoxy that gave a good adhesion to the Kefa coat. The application took place in January and to create the necessary conditions for the drying and film forming process, the deck was covered with tarpaulins, under which hot air was blown. Also the inside of the garage was heated.

The Result

During loading and unloading Kefa acts as a buffer, which absorbs and stores the condensation water, thus preventing it from dripping and running. When the ship is loaded and the doors are closed, the dehumidifiers can start working. Kefa releases the accumulated water in the form of vapour to the air. The condensation water may freeze to ice during the loading, but that constitutes no problem. Kefa will hold for that stress. Due to the micro porous structure of Kefa the evaporation of water is almost three times as fast as from a metal or painted surface.

Also the condensation problems at the entrance of the Gulf Stream are taken care of by the Kefa treatment.

Johannesburg, South Africa

Problem: After expanding parking facilities in 1995 to include areas above the existing parking garage, extensive seepage began in the parking structure below.

Existing Condition in 1996: Extensive efflorescence, salts and contaminates. Damage to vehicles as high as $30,000.00 for one month as well as slip hazards at walking surfaces.

Preparation: In 1996 All surfaces were cleaned using wire brushes to remove efflorescence and salts.

The surface was then rinsed using clean potable water and allowed to dry completely.

Application: Kefa Airless was applied over directly over the existing concrete coffers at a spread rate of +/- 55 mils. The photo to the left was taken in 2004 after 8 years of service.

Conclusion: The customer occurred no further losses due to vehicle damage. All walking areas remained dry and safe. The customer has since successfully used Kefa Airless on other underground parking facilities.

Typical basement view. Water infiltration below exterior grade.

Extreme mold and mildew growth. Wall thickness +/- 32”.

Same basement view one year later. Area was treated and cleaned for mold and mildew. +/- 80 mils Kefa Airless 8125 applied to affected area.

The problem
Water supply plants generate large amounts of water vapor that condenses on the water tanks, pipes, pumps and other equipment. Water Supply Berlin was built in the 50-th and had deep-seated rust and other severe corrosion problems. The equipment has been repainted several times but due to the damp environment the corrosion was soon back again. A special problem was that condensation water accumulated under the Bollman filters.

The solution
KEFA Coatings improve the corrosion protection by reducing the corrosion time – the time when the surface is damp. It also eliminates the worst corrosive form of water – the drop.

KEFA specified a treatment program:
The roof and all equipment to be coated in order to reduce the vapor load.

Roof:
1. Cleaning from soot and grease
2. Application of 40 mills of KEFA Airless.

Tanks, pipes, pumps etc:
1. Blasting to SA 2 ½.
2. Corrosion protection with good rust protection paint.
3. A KEFA Airless coat of 40 mills.

The Water Supply wanted to use their own paint contractor and his corrosion protection system. The treatment started, but after only a few days, rust spots showed on the treated surfaces.
KEFA was called for and could immediately establish that the contractor had done a poor corrosion protection job. The KEFA coat will immediately expose defective rust protection.

Now KEFA insisted on engaging a certified contractor and the use of a polyurethane anti-corrosion paint that can be used on a surface that is near or under dew point.

The result
The surfaces are completely spotless after 20 months.
The indoor climate has improved and is much drier.
The effect of the KEFA treatment is measured by the use of a new monitoring system, developed by KEFA in co-operation with IMO-Lab. Room temperature, surface temperature, relative humidity, absolute humidity and outdoor temperature are continuously monitored by computerized equipment that can be read via the web.

Ready To Eat Food Production
Gunnar Dafgård AB, Sweden
The treatment was done in December 2002.

The problem
Dafgård has very rigorous sanitary rules and some of the production is produced in clean rooms. One of the companies most popular products is Stuffed cabbage leave. The preparation of cabbage leaves has been a headache for years. The cabbage arrives to the preparation line steaming hot and the room is always hot and humid, air temperature 80ºF and RH 90 – 97 %. The production in the adjacent areas requires low temperature for sanitary reason. The walls in the cabbage room are consequently rather cold (64ºF and dew point 77ºF) Condensation water was always running on the walls. The roof had to be dried several times a day to avoid condensation water dripping down on the production line. In spite of daily cleaning and sanitation, mould was forming on walls and ceiling.
Conventional anti-mould paints did not even last a year.

The solution
All walls and ceiling were cleaned from grease and fat and all loose paint was removed. Finally the surfaces were sanitized with KEFA BioWash. All walls were covered with a KEFA Airless coat of 40 mills and the ceiling with a coat of 50 mills. The ventilation was increased in order to allow KEFA Coating to evaporate condensation water during the low moisture load periods.

The result
The last follow up in June 2006 (after 43 months) gave the following result:The workers claim that the indoor climate has improved considerably. The temperature is still 80ºF, but the RH is lower and varies between 70 and 85%. There is no mold and the problem of condensation water forming in the ceiling is gone. The maintenance management is of the opinion that they could reduce the cleaning routines but this would be in violation of the company’s strict maintenance policies.

Aircraft Hangar
NATO Air force, UK
The treatment was done in 1981. The picture was taken during the application work.

The problem
The hangar is a concrete construction with a mold cast of steel on the underside of the roof. During the cold season these constructions are exposed to condensation. The cold accumulated in the concrete makes the underside of the roof much colder than the indoor air. The problem increases when the aircrafts are brought in, due to the heat and steam from the engine. The hot humid air raises and creates a microclimate under the roof with a RH near 100%.
This is not only a question of comfort to the pilots and mechanics serving the aircraft. Water drips falling down can contain small fragments of concrete that can harm the aircraft during flight. The hangar also contains electronic equipment that can be damaged.
Besides the steel sheets in the roof had started to rust.

The solution
The roof was cleaned from rust and grease.
The corroded areas were wire brushed and painted with a rust primer.
Finally a coat of 40 mills KEFA Airless was sprayed on.

The result
The condensation problems stopped. The mechanics serving the aircraft are of the opinion that the indoor climate feels dryer and warmer. Since no reading of the temperature and RH were allowed after the treatment, there is no means to verify these statements. However, this observation is common after a KEFA treatment and can probably be explained by the fact that the RH normally sinks after the treatment. Dry, cold air feels warmer than humid, cold air.