OPRC Level 1
Oil Skimmers
Version Νο.1 – 12.05.2013
Aim
• Knowledge of common types of
skimmers as well as their advantages /
disadvantages
Outline
• 1. Skimmer definition
• 2. Performance terminology
• 3. Types of skimmers advantages/disadvantages
Skimmer Definition
• A skimmer is defined as any mechanical
device specifically designed for the
removal of oil (or oil/water mixture) from
the surface of water without altering its
physical and/or chemical characteristics.
Measures of Skimmer
Performance
• Recovery rate
o Rate at which skimmer recovers pure oil from an oily
environment
• Recovery efficiency
o Relation between recovered oil and recovered fluids
(oil / water mixture)
• Throughput efficiency
o Relation between recovered oil and encountered oil
Skimmer Types
• Weir Skimmers
• Oleophilic Skimmers
• Vacuum Skimmers
• Mechanical Skimmers
Weir Skimmer
Weir Edge
Oil to Storage
Weir Skimmer
Weir Skimmer
Weir Skimmer
Weir Skimmer
Weir Skimmers:
Advantages & Disadvantages
• Advantages
o Low cost
o High recovery rate
o Wide viscosity range
o Simple maintenance
o Small and light
o Removable pump
• Disadvantages
o Difficult adjustment of
weir opening
o Low efficiency in
waves
o Low recovery in thin
slicks (10%)
o Not good with very
high viscosity oil
o Sensitive of debris
Vacuum Skimmer
Vacuum Skimmer
Vacuum Skimmers:
Advantages & Disadvantages
• Advantages
o Small operational
units
o Simple technology
o Easy to maintain
o Inexpensive local
manufacture
• Disadvantages
o Often low recovery
o Vacuum truck hose
= <10%
o More advanced
types = 60-70% in
optimal conditions
Oleophilic Skimmers
• Disc Skimmers
• Rope Mop Skimmers
• Belt Skimmers
• Brush Skimmers
Disc Skimmer
Scraper
Oil to Storage
Oil
Disc Skimmer
Disc Skimmers:
Advantages & Disadvantages
• Advantages
o Good performance
with light oil
o High recovery
efficiency
o Not sensitive to
debris
o Simple
maintenance
• Disadvantages
o Low recovery rate:
often 10-60m3/h
o Limited viscosity
range
o Sensitive to sea
grass and waves
Rope Mop Skimmers
Rope Mop Skimmers
Rope Mop Skimmers
Rope Mop Skimmers
Rope Mop Skimmers:
Advantages & Disadvantages
• Advantages
o Low water content
in recovered oil
(10%)
o Good performance
in debris
o Flexible ropes
cover large area
o Easy maintenance
• Disadvantages
o Low recovery rate
o Limited viscosity
range
o Difficult to deploy
correctly
o Sensitive to sea
grass
Belt Skimmer
Direction for
Skimming
Debris
Belt
Pump
Belt Skimmer
Belt Skimmers:
Advantages & Disadvantages
• Advantages
• Disadvantages
o High recovery rate
o Often very large
o High recovery
efficiency
o Require large
vessel and heavy
o Effective over wide
cranes
for
viscosity range
operation
o Effective in high
waves
o Very expensive
Brush Skimmer
Brush Skimmer
Brush Skimmers:
Advantages & Disadvantages
• Advantages
• Disadvantages
o High recovery
efficiency
o Large volume
o High recovery rate
o Limited viscosity
range
o Good performance o Expensive
in waves < 1m
o Easy maintenance
Mechanical Skimmer
Mechanical Skimmer
Mechanical Skimmers:
Advantages & Disadvantages
• Advantages
o Simple equipment
o Always available
locally
o Not sensitive to
debris
o Can handle very
heavy and
emulsified oil
• Disadvantages
o Very low recovery
efficiency
o Often difficult to
manoeuvre units
o Works only in very
heavy oil
Summary
• Weir skimmers – mostly for open sea
operations
• Oleophilic – many advantages in near shore
or onshore operations
• Vacuum skimmers – uncomplicated and
small
• Mechanical – normally only for heavy oil
and debris