oil tankers
DESCRIPTION
General Oil Tanker principlesTRANSCRIPT
Inert Gas Systems
Oil Tankers
By
Siddharth Sid Chandrasekar
How ?
Tanker Structures
CBT & SBT
SBT
Ballast water is taken on board to maintain stability, such as when a vessel is sailing empty to pick up cargo or after having unloaded cargo. Ballast water contained in segregated ballast tanks (SBT) never come into contact with either cargo oil or fuel oil
CBT
To have so-called dedicated clean ballast tanks (CBT) means that specific cargo tanks are dedicated to carry ballast water only.
Oil Discharge Monitoring & Control System
General Precautions on Tankers
Strict smoking regulations, no smoking signs
No naked lights outside accommodation
Portable UHF -intrinsically safe
Fixed electrical equipment - secure earth connections
General Precautions
Portable electrical equipment
Portable pumps and fans - can develop static charge
Clothing No static charge potential
Deck maintenance tools (grinders, grit blasters, chippers)
General Precautions
Main engine Soot blowing
Portable pumps and fans - can develop static charge
Aluminium based primer paints interact with the rust and provide an ignition source if subsequently stuck hard by a metal object
Mobile phones
General Precautions
Cold Weather Precautions anti freeze for deck seal & P/V breaker, fire mains drained
Enclosed Space Entry
Pumproom Entry Permits
Hot Work Permits
General Precautions
Arrival into Port
Pre arrival Ship-terminal questionnaire
Mooring System Checklist
Ship Shore safety checklist (ISGOTT)
Load / Discharge Operation Checklist
Checklists
Ship / Terminal Information Exchange Checklist
Handling of Cargo & Ballast
Constant supervision Ship & Shore
Cargo sampling Open & Closes systems
Correct line up
Incremental rate with further checks
Cargo Operations
Dont close valves against positive flow
Load / Discharge Plan
Obligations to MARPOL regulations & Ballast Water Management
Stability criteria, Free Surface Effect
Stresses and bending moments
Contamination (oil) of ballast water
Ballast Operations
Minimum depth at berth and stern trim
VECS
Collect and treat vapour via shore based infrastructure
The vapour return line ashore is fitted with sensors and alarms to monitor tank pressures
A flame arrestor will be fitted within the system on the shore side
A stud is located on the presentation face of the reducer flange prevents wrongful manifold connection
A different colour coding system
VECS
Inert Gas Systems
Inert Gas Systems
Why ?
Primary means of fire / explosion prevention on tankers
Maintain a low, positive pressurised, inerted cargo tank atmosphere at all times
Removes the possibility of oxygen entering the tank
Prevents the cargo tanks atmosphere from entering the flammability range
Inert Gas Systems
Types
Flue Gas Generator
Types
Inert Gas Generator
Inert Gas Systems
Basic flue gas composition:
O2 - content: Approx. 5% by vol.
CO2 - content: Approx. 13% by vol.
SO2 - content: Approx. 3000 ppm.
N2 - content: Balance
Inert gas composition:
O2 - content: No change
CO2 - content: No change
SO2 - content: Less than 100 ppm
N2 - content: Balance
Gas outlet temperature:
Max. 5C above sea water temperature.
Relative humidity: 100%
Carry over of water droplets: Less than 1 g/kg dry gas.
IMO requirement
Flammability Diagram
AB - Hydrocarbon gas/air mixtures without inert gas
C & D LFL & UFL of HC gas in air
CE & DE Explosive limit when IG is inserted
Purging
The introduction of inert gas into a tank already in the inert condition (O2