Loading, carrying & discharging of Sulphuric acid - regulatory requirements & special handling methods
Chemical tankers safety guide
Loading , carrying at sea & discharging of Sulphuric acid involve high risk and require sophisticated handling for safety, health and loss prevention reasons. They need careful consideration prior loading , tank coating compatibility, cross compatibility with other cargoes carried, environmental controls if required (inerting).
ACID Product Characteristics
Product safety data sheets may be available from various sources. For safety preparation, until the specific product safety data sheet can be obtained, the Chemical Data Guide for Bulk Shipment by Water (U.S. DoT), should be used. Concerning the IBC/BCH code (respective 16.2/5.2) the master should request the specific product safety data sheet before commencement of loading. The safety data sheet posted must be in a language understood by ship's Officers and Crew (English).
Sulphuric Acid is regulated for bulk transportation by the IMO, BCH and IBC codes. Following is the summary of the codes' minimum requirements
Special arrangements - Sulfuric acid
Ensure that there is on board sufficient acid resistant hoses for the cargo transfer. Ensure that there is on board sufficient acid spray shields to cover flanges on manifold and hose connections according to IBC code 15.11.4 and BCH code 4.8.4.
Preloading precautions & loading sulfuric acid
Preparations for Loading
Discharging Sulfuric acid
Because of the high specific gravity of Sulphuric Acid, very high pump pressure may be experienced. In such cases care must be taken not to quickly open or close valves in the pump system as this causes pressure surges that may rupture lines or hoses
Cleaning and slop
Sulphuric Acid in 30-70% concentrations is non-oxidizing and attacks the steel rapidly, particularly at elevated temperatures. When concentrated Sulphuric Acid is diluted the reaction is exothermic and the temperature of acid will rapidly increase. If the tank is cleaned with inadequate quantities of water, the acid will become hot, as it is diluted, and rapid attack will occur on the stainless steel until sufficient water is introduced.
Large quantities (preferably fresh water) must be put into the tank to rapidly pass the dangerous concentration range and heat increase. Preferably if stainless steel hoses were used on the manifold for discharge should be replaced with non-stainless steel acid resistant hose(s) before the cleaning operation starts.
Slop disposal and arrangements :
The slops are to be disposed according to: Regulations for control of pollution by noxious liquid substances in bulk, IMO, MARPOL Annex II.
Acid resistance of stainless steel
Due to various resistance of stainless steel materials consult the specific manufacturer's manual/information when necessary.
We have summarized below some of the special chemical cargoes frequently carried onboard chemical tankers
Handling benzene & methanol safety precautions
Handling carcinogens requirements for certain chemical cargoes
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