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Coatings and linings
Flake coatings, high voltage coatings, rubber linings, knowledge center for coatings and linings
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Coatings and linings
In the flue gas desulphurization (FGD) plant of coal-fired power
stations rubber coatings, flake coatings and glass blocks are
applied for protection against erosive and corrosive attack. Strict
requirements are set to these coatings and linings to be able to
guarantee plant life under severe chemical conditions. Failure of a
coating has serious financial consequences. To be able to manage
these problems, the Industrial Plastics group has founded
the Knowledge Center Coatings & Linings in collaboration
with the energy industry.
The extensive experience we have gained with the application of
these coatings and linings is currently being used successfully for
other applications. For instance, the Industrial Plastics group has
given expert advice on such widely varying subjects as protection
of manure tanks, the application of reflecting strips on trailers
and the application of flake coatings in the process engineering
industry.
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Rubber linings
The success of the rubber linings in particular is enhanced in
large measure by mutual cooperation between designer, construction
engineer, manufacturer, supplier and plant operator. In actual
practice, the service life of rubber linings is limited by a
combination of factors, including increased temperature, mechanical
wear caused by solid particles, wrong selection of materials,
object construction and design, improper application, overdue and
incorrect repairs. By attacking the rubber linings, the medium can
penetrate ever deeper into the rubber. In the long run,
medium-filled blisters will form until they burst open, enabling
the medium to freely reach the steel. This may cause considerable
corrosion damage, which may put the flue gas desulphurization (FGD)
plant – and hence the entire power station – out of operation.
KEMA can perform regular tests and inspections to determine how
far the medium has penetrated into the rubber lining; based on
these tests, predictions can be made and KEMA can give you advice
on the residual life of these linings. This will give you the
opportunity to evaluate in good time when the need arises to renew
the protective lining. Tests on rubber linings can be performed
either destructively, removing samples for testing in a laboratory,
or by means of non-destructive techniques, which means that the
original lining is examined in situ. These procedures are also
documented in the "Coatings and Linings Manual" authored by
KEMA.
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Coatings for high voltage lines
Until recently, high-voltage lines were provided for corrosion
protection with coatings containing a lot of volatile hydrocarbons
as a solvent. Such solvents are catalysts in ozone formation in the
lower air layers of the atmosphere, which affects human health. As
part of the KWS 2000 Action Plan prepared by the Ministry of
Housing, Regional Development and the Environment, it was decided
to reduce emissions of organic solvents drastically in the very
short term.
To meet their effort commitment in this field, the energy
distribution companies started research on alternative types of
paint for high-voltage lines, which are in conformity with the
prevailing environmental requirements. An alternative coating with
lower initial emissions of organic solvent in comparison with the
established chlorinated rubber paints must still be of similar or
better quality.
Significant reduction of organic solvent emission can be
achieved in a number of different ways:- less, or a different type of, solvent
- longer life
- thinner layers.
The coating itself should be repaintable after its life has
expired. Life is an important factor also for minimizing
labor-intensive maintenance cost.
In this project KEMA conducted experimental research on a number
of different coatings, performing tests relating to service life,
environmental pollution, application and repaintability, combined
with quantitative paint specifications. Based on the results of the
coatings tested, a general classification was made according to
environmental pollution in relation to expected service life.
Moreover, various cost aspects were also considered.
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Knowledge center coatings & linings
The flue gas desulphurization (FGD) plant is an essential component of a coal-fired power station. Operating this type of power station without an FGD plant would be inconceivable in the present environmental era.
In the FGD plant the flue gases are neutralized at a temperature up to 200ºC using a calcium suspension. Conditions in FGD plants are so aggressive that extremely strict requirements must be set to the materials used to coat the steel constructions. The coating serves to protect the construction material from attack (corrosion, erosion, wear) by the highly acidic condensed flue gases and by abrasive particles. Depending on specific conditions in the different parts of the plant, rubber top coatings, flake coating and glass blocks are applied. If the coating fails, this will cause substantial damage to the plant in a short time. This is why it is very important to have in-depth knowledge of the long-term behavior of the coatings.
KEMA has established the Knowledge Center Coatings & Linings to collect and combine the available knowledge in this field.
For more information, please contact us.
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