Loss Prevention

1
Loss Prevention

• Prevent
• Material loss (plant, equipment, chemicals)
• Human loss (injury, death)
• Environmental loss (pollution, contamination)
• By
• Anticipating potential hazards
• Applying safety measures

2
Loss Prevention Issues

• Increased plant size and complexity
• More rigorous operating conditions
• Increased potential for loss
• Incentives
• Moral, public perceptions
• Legal
• Economic

3
CPI Accidents

• Flixborough (UK) 1974 - 28 deaths, 400 injuries
• Cyclohexane explosion - reactor start-up
• Flame 100m gt 20 min
• 90 site buildings damaged
• Bhopal (India) 1984 3,800 deaths, 200,000
  injuries
• 36 tonnes methyl isocyanate released
• Poor isolation of storage tanks
• Large scale storage of hazardous material

4
CPI Accidents - Australia

• Coode Is (Vic) 1991
• 27/47 storage tanks destroyed / damaged
• 1st explosion damaged tank drenching system
• Explosions followed in a another 12 tanks
• Costs 2 million (fire fighting), 50 mill
• Minimise stock holding

5
CPI Accidents - Australia

• Kurnell (NSW) 1995
• Power failure Boiler shutdown
• Fires in cat cracker crude distillation
• 7 days production lost

6
Longford Gas Plant Accident

• Victoria 1998
• 2 deaths
• 8 injuries
• No gas supplies to industry and domestic
  consumers in Victoria for 3 - 4 weeks
• Plant loss
• Downstream production loss

7
Hazards Classification

• 1st Degree identify potential for problems
• Presence of hazardous materials
• Heat
• Oxygen
• Ignition sources
• Human error
• Mechanical failure
• Requires good engineering and design

8
Major Hazards

• 2nd degree hazards possible outcomes
• Fire
• Explosion
• Release
• Impact
• Falling
• Need to be minimized

9
Material Hazards

• Toxicity
• Lethal Dose (LD), Threshold Limit Value (TLV)
• Flammability
• Flash point, auto ignition, flammability limits
• Explosion
• Detonation, deflagration, unconfined vapour cloud
  (UVCEs), boiling liquid, expanding vapour (BLEVEs)

10
Ignition Sources

• Electrical equipment
• Static electricity
• Process flames
• Matches
• Friction

11
Other Hazard Sources

• Ionizing radiation
• Noise
• Operating deviations
• Vacuum

12
Types of Safety

• Intrinsic
• A process in which safe operation is inherent in
  the nature of the process
• Factors
• Chemicals
• Process route and equipment

13
Extrinsic Safety

• A process which is rendered safe by careful
  design and the application of safety systems
• Factors - engineered safety
• Control systems
• Relief devices
• Automatic shutdown
• Fire fighting systems
• Blast protection
• Plant layout

14
Potentially hazardous processes

• Explosive reaction or detonation
• React energetically with water
• Spontaneous polymerization/heating
• Intrinsically unstable compounds
• Exothermic
• Flammables at high temperatures and/or pressures

• Flammable liquids above atmospheric boiling point
  due to pressure or
• Operating in or near explosive ranges
• Toxic materials, dangerous bacteria, radioactive
  chemicals
• Dust of mist explosion hazards
• Large inventory of stored pressure energy

15
Design Considerations

• Basic Process Design
• Choice of Process route
• Process materials
• Operating conditions
• Reaction pathways and systems
• Operational Mode
• Continuous or batch

16
Process Design Considerations

• Inventory - Intensification
• Emissions and Effluents
• Type and mode of disposal
• Applicable regulations
• Transportation of materials
• Quantities
• Physical state

17
Detailed Design Considerations

• Mechanical design
• Equipment within operating limits
• To recognized standards (AS, BS, ANSI)
• Reliability of equipment
• Fail Safe Design
• Control valves
• Cut-off valves
• Pressure relief systems

18
Plant Layout

• Recommended separation distances
• Access
• Ventilation
• Emergency routes
• Building locations (control rooms)
• Separation policy

19
Environmental Aspects of Design

• Types of problems
• Air, water, noise pollution
• Questions to be answered
• Source distribution of pollutant?
• Toxicity levels?
• Ecology of pollutant?
• Elimination or control measures?

20
Dealing with Pollutant Emissions

• Elimination of operation (entire or part)
• Modification of operation
• Intensification, substitution, attenuation
• Relocation
• Application of appropriate control technology
• Combinations of the above

21
Useful References

• Perrys Chemical Engineering Handbook, McGraw
  Hill, 7th edition, 1998, Section 26
• Coulson Richardsons Chemical Engineering,
  Volume 6 Chemical Engineering Design, Butterworth
  Heinemann, 3rd edition, 1999, Chapters 9 and 14