Ship-Type Operations

UNITAS

Session 11

Tankers

Introduction

• Oil tankers

• Chemical tankers

• Gas carriers

Ship-Type Operations

UNITAS

Session 11

Chemical tankers

• As for oil tanker, normally smaller vessels.

• Design arrangements influenced by

IBC Code and damage stability

requirements.

• Cargo heating such as on asphalt

carriers brings problems of thermal

expansion and can create problems

in the cargo holds.

Ship-Type Operations

UNITAS

Session 11 Chemical Tankers

Cargo transported:

• Easy Chemicals such as:

Acetone, Xylene

Methanol, Vegetable oils

Edible Liquids

Relevant Rules:

• SOLAS 74

• MARPOL Annex II

Tanker FLS

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

Cargo transported:

• Chemicals: Acids, alcohols,

Carbon Disulfide, etc

Relevant Rules:

• SOLAS 74, as amended

• IBC Code,

• MARPOL Annex II

Ship-Type Operations

UNITAS

Session 11 Chemical Tankers

3 CATEGORIES OF NLS (Revised MARPOL Annex II)

X Major Hazard

YHazard

Z Minor Hazard

OSOther substances

Present no harm

• IBC Ch.17, types 1,2 & 3

Prohibition of

discharge

Limitation onquality & quantityof discharge

Less stringentrestriction on discharge

Not subject to

requirements of Annex II

• IBC Ch.17 or 18

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

Hazards of chemicals

• FLAMMABILITY

• TOXICITY

• HEALTH

• CORROSIVITY

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

Hazards of chemicals (2)

REACTIVITY

• With other products• With water

• With themselves• With oxygen

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

Hazards of chemicals (3)

POLLUTION

• Water pollution

• Air pollution

• Marine pollution

• Categorization

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

CARRIAGE OF DANGEROUS CHEMICALS IN BULK

• BCH CODE (1971)

• IBC CODE (1983)

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

SHIP SURVIVAL CAPABILITY

• Type 1 Ship: maximum preventive measures

• Type 2 Ship: significant preventive measures

• Type 3 Ship: moderate preventive measures

Ship-Type Operations

UNITAS

Session 11 Chemical Tankers Cargo Tanks location

TYPE 1 TYPE 2

Available space• • for cargo

tanks

760mm

> B/15 OR 6 M

> B/5 OR 11.5 M

Available spacefor cargo

tanks

S.L.L.

760mm

Available spacefor cargo

tanks

S.L.L.

TYPE 3

S.L.L.

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

STANDARD OF DAMAGE

• Type 1

• Type 2, L>150m Damage anywhere

• Type 3, L>225m

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

STANDARD OF DAMAGE (1)

• Type 2, L<=150m

• Type 3, L > 125mAs per type 1, but no damages to E.R bulkheads

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

STANDARD OF DAMAGE (2)

• Type 3, L<= 125m: As per Type 1, but no damages in E.R

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

CARGO

TRANSFER

DEEPWELL CARGO

PUMP

(Source: FRAMO)

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

• INERTING - REPLACES AIR IN THE CARGO TANK BEFORE LOADING THE CARGO. INERTING MAY BE CARRIED OUT USING: BY INERT GAS FROM THE COMBUSTION OF FUEL BY NITROGEN

• USUALLY COMBUSTION GASES, DUE TO HIGH IMPURITY CONTENT, AREONLY USED FOR GAS FREEING PRIOR TO INERTING WITH NITROGEN. INSTALLATIONS ARE AS PER OIL TANKERS INSTALLATIONS, EXCEPT THAT THERE IS DECK WATER SEAL AND THE SYSTEM IS PROVIDED WITHDRYING TOWERS.

INERTING AND PADDING SYSTEMS

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

INERTING AND PADDING SYSTEMS

• PADDING - REPLACES CARGO VAPOUR TO AVOID CHEMICAL REACTION WITH AIR.

• NITROGEN FOR PADDING OR INERTING IS OBTAINED FROM HIGH PRESSURE

NITROGEN BOTTLES OR FROM A NITROGEN GENERATION PLANT.

• NITROGEN FROM HIGH PRESSURE BOTTLES IS SENT TO THE CARGO TANK FOR

PADDING AT 0.1 BAR, TO THE BALLAST TANK FOR INERTING AT 0.07 BAR AND TO THE

BALLAST TANK FOR INERTING AT 0.07 BAR AND TO THE CARGO PIPING AT 7 BAR.

••

• ON NEWER SHIPS, MEMBRANE SYSTEMS DRIVEN BY AIR COOLED COMPRESSORS ARE

USED.

Ship-Type Operations

UNITAS

Session 11 Chemical Tankers

• Combustionair fan

• IG Generator

• Pressure/VacuumBreaker

• Oil FuelPump • Deck water seal

INERT

GAS

SYSTEM

(Source:SMITOVENS)

Ship-Type Operations

UNITAS

Session 11

Chemical Tankers

N2MEMBRANE

GENERATOR

(Source:DOW)