Chemical Tankers / Day 2 / Day 2 Topic 2 Cargo Compatibility

Chemical Training

Cargo Compatibility, Reactivity & Solubility

Reactivity , Solubility, Compatibility

The principles of Reactivity, Solubility and Compatibility affect many aspect of chemical tanker operations.

Delegates to provide some examples……………..

Reactivity , Solubility, Compatibility

•Safe cargo handling and stowage

•Safe stowage and disposal of cargo samples

•Safe and efficient tank cleaning procedures

•Safe slop handling and stowage

•Safe use and stowage of tank cleaning chemicals

•Protection of tank coatings and stainless steel tanks

Basic understanding of terminology relating to this subject is Very essential

Reactivity , Solubility, Compatibility

Terminology:

•Solubility - The maximum weight of a substance which will dissolve in a given weight of water, ie: the tendency to dissolve.

In science, this is indicated as percentage by weight but, for our purposes, we tend to refer to that tendency as “Complete” or “Partial” (Tank Cleaning)

•In the case of a liquid dissolving in another liquid, the term Miscibility is commonly used

Reactivity , Solubility, Compatibility

• Compatibility - The ability of two materials to exist in close and permanent association for an indefinite period.

A factor that must always be considered when stowing cargoes is the compatibility of the liquid with the tank lining (coating)

The USCG Compatibility Guide is the foundation for safe stowage based on the potential reaction of two cargoes loaded in adjacent tanks if the common bulkhead between them should fail.

Reactivity ,Solubility, Compatibility

Remember that this is not the sole criteria that must be considered - tank coating, adjacent heating, tank location, reaction with any water in ballast tanks etc will also affect stowage decisions.

Reactivity ,Solubility, Compatibility

•Stability - The tendency of a product to react dangerously when exposed to conditions such as increased temperature or shock.

•Catalyst - A substance which accelerates a chemical reaction.

E.g: Water Vapor is the catalyst in the oxidation of iron (corrosion) Cleaning chemicals are all catalysts

Reactivity ,Solubility, Compatibility

•Inhibitor - A “negative” catalyst, one which retards, or slows down, a chemical reaction.

Blended in during the manufacture of a liquid chemical or afterwards as a powder additive to prolong its active life or stability.

Commonly added to Acrylates and Monomers.

Reactivity ,Solubility, Compatibility

INHIBITOR CERTIFICATES (Cargoes protected by additives)

Certain cargoes with a reference in column (o) of Chapter 17 IBC Code, by the nature of their chemical properties, tend, under certain conditions of temperature, exposure to air, or contact with a catalyst, undergo a chemical change.

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