Loading of Noxious Liquid Chemicals in Bulks

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Cargo loading operation - Chemical tanker guideline

Loading of various noxious liquid chemicals involved numerous hazards. It is important to exercise safety during all stages of cargo loading. If, at any stage during or immediately after the loading operation, a non-conformance (which may include cargo quantity, quality, temperature and colour etc.) is believed to exist, all operations should be suspended until such time as the situation is resolved.

Modern Chemical tanker cargo manifold

Fig:Modern Chemical tanker cargo manifold


Commencement & execution of loading

Immediately prior to commencing the loading the valve setting and the lines on all tanks have to be checked once more. The responsible officer must be satisfied that the cargo system is, in all respects, ready and all the information of the cargo has been received.

The following precautions must be observed:

1. The quantity and grade of the cargo to be loaded has been agreed to
2. The loading rate has been agreed to shore or ship stop has been agreed to
3. Ships personnel are ready
4. Ship/Shore checklist completed
5. High and Hi/Hi level alarms MUST be operational and switched on
6. Loading must start at a low rate. In this stage the cargo line, manifold, connections, drain points etc. must be checked for leakages. The full loading rate should not commence before both ship and shore are satisfied that there is no leaks in the system and the filling pipe in the tank is covered. When system is satisfactory shore can be informed to increase the loading rate to the agreed level.
7. During the loading at least one deck officer must be on duty and available at all times. At least one crewmember must be on deck/manifold throughout the cargo operation. The officer on duty is obliged to carry out the loading in accordance with the instructions received from the Chief-Officer, which should at least encompass the agreements made with the Loading Master as well as the Surveyor.
8. Some cargoes loaded in hot climates are chilled and cause bulkheads to sweat on loading. Consideration must therefore be given to sequences of loading. (e.g. Styrene Monomers)
9. During the whole loading a detailed cargo log has to be kept.
10.Sufficient ullage space should be maintained after loading to allow for heating cargo as required by the Shipper.
11.Loading one product in more than one tank simultaneously may increase the risk of an overflow, and the responsible officer must ensure that tanks that are “topped off” are properly isolated from tank(s) still being loaded.
12. When nearing completion of loading the shore should be notified and the loading rate reduced


Handling of high vapour pressure cargoes
When handling high vapour pressure cargoes, particularly in high ambient temperatures, high rates of vapour generation may occur during either loading or discharging. As a high vapour pressure petroleum cargo enters an empty tank there is a rapid evolution of gas, as a result it may be necessary to reduce the loading rates. During the loading of high vapour pressure cargoes a very high concentration of hydrocarbon gas, approaching 100% by volume, may be vented to atmosphere.



SOURCE: http://www.chemicaltankerguide.com/cargo-loading.html