Corrosion of Linings
177
dedicated to holding one product at more or less constant time and temperature conditions is relatively easy because such tanks present predictable conditions for coating selection. Conversely, tanks that see intermittent storage
of a variety of chemicals or solvents, such as product carriers, present a more
difficult problem because the parameters of operation vary. Consideration
must be given to the effect of cumulative cargoes. In addition, abrasion resistance must be considered if the product in the tank is changed regularly with
complete cleaning required between loadings. Workers and equipment will
abrade the lining.
When selecting a coating system, it is necessary to determine all the conditions to which the lining will be subjected. The conditions to consider fall
into two categories:
1. Chemicals to which the lining will be exposed
2. Conditions of operation
As a result, it is necessary to verify that the chemical resistance and physical/
mechanical properties of the lining are suitable for the application.
To specify a lining material, it is necessary to know specifically what is
being handled and under what conditions. The following information must
be known about the material being handled:
1. What are the primary chemicals being handled, and at what concentrations?
2. Are there any secondary chemicals? And if so, at what concentrations?
3. Are there any trace impurities or chemicals present? This is extremely
important because concentrations in the ppm range can cause serious problems.
4. Are there any solids present? And if so, what are the particle sizes
and concentrations?
5. Will there be any agitation?
6. What are the fluid purity requirements?
7. What will be present in the vapor phase above the liquor?
The answers to these questions will narrow the selection to those coatings
that are compatible. Following are the more common lining materials and
their general area of application:
High-bake phenolics
•
: excellent resistance to acids, solvents, food products, beverages, and water; most widely used lining material but has
poor flexibility compared to other lining materials.
177
dedicated to holding one product at more or less constant time and temperature conditions is relatively easy because such tanks present predictable conditions for coating selection. Conversely, tanks that see intermittent storage
of a variety of chemicals or solvents, such as product carriers, present a more
difficult problem because the parameters of operation vary. Consideration
must be given to the effect of cumulative cargoes. In addition, abrasion resistance must be considered if the product in the tank is changed regularly with
complete cleaning required between loadings. Workers and equipment will
abrade the lining.
When selecting a coating system, it is necessary to determine all the conditions to which the lining will be subjected. The conditions to consider fall
into two categories:
1. Chemicals to which the lining will be exposed
2. Conditions of operation
As a result, it is necessary to verify that the chemical resistance and physical/
mechanical properties of the lining are suitable for the application.
To specify a lining material, it is necessary to know specifically what is
being handled and under what conditions. The following information must
be known about the material being handled:
1. What are the primary chemicals being handled, and at what concentrations?
2. Are there any secondary chemicals? And if so, at what concentrations?
3. Are there any trace impurities or chemicals present? This is extremely
important because concentrations in the ppm range can cause serious problems.
4. Are there any solids present? And if so, what are the particle sizes
and concentrations?
5. Will there be any agitation?
6. What are the fluid purity requirements?
7. What will be present in the vapor phase above the liquor?
The answers to these questions will narrow the selection to those coatings
that are compatible. Following are the more common lining materials and
their general area of application:
High-bake phenolics
•
: excellent resistance to acids, solvents, food products, beverages, and water; most widely used lining material but has
poor flexibility compared to other lining materials.