Presentation on theme: "STORAGE OF SOLVENTS/GASES. Storage of Solvent Common Solvents : – Acetone, Acrylamide, Benzene, Methanol, Toluene, etc. Solvent Properties: – High volatility."— Presentation transcript:
Storage of Solvent Common Solvents : – Acetone, Acrylamide, Benzene, Methanol, Toluene, etc. Solvent Properties: – High volatility at ambient temperature – Inflammable – Toxic
Difficulties faced Loss of solvent due to: – Breathing losses: Vapor pressure variation with temperature – Filling losses: Discharging and Refilling losses – Boiling losses: Vapor pressure higher than atmospheric pressure
Types of Tanks Standard Fixed-Roof Storage Tank Variable Volume Tanks – Vapor Lift Roof Type – Internal Floating Roof Type – External Floating Roof Type (a)Pan (b)Pontoon (c)Double-Deck
Accessories Seal Drains Pipe Supports Vents Manholes Rolling Ladder Anti-Rotation Device Gauge Platform
Example: Methanol Storage Type of storage tank: Floating roof tank Safety accessories: – Provision for fire-fighting – Provision for raw water sprays incase of increased temperatures – Pressure and temperature indicators – Biofilter and scrubber assembly to avoid environmental pollution due to filling losses.
Standards for VOCs Capacity (litres)Vapor Pressure (mm Hg)Type > 151,40078-570Floating roof >151,400>570Floating roof with vapor recovery system >946.25>78Permanent submerged fill pipe Source: KRS Chapter 77 Air Pollution Control
STORAGE OF GASES Currently more than 200 substances shipped in compressed cylinders Two major groups: liquefied & non-liquefied Compressed gases lumped into families – Atmospheric Gases – Fuel Gases – Refrigerant Gases – Poisonous Gases
Hazards associated with gases in cylinders Fire / Explosion from the release of flammable gases near ignition sources Spontaneous combustion from oxidizing gases Exposure to toxic or corrosive gases Asphyxiation Gases stored under 100’s of atmospheres of pressure
Pressure Related Hazards Valve damage – leakage of gas Cryogenic/Liquefied Gases-Frostbite on release Heating/Impact – Explosion/Shrapnel Denser than air gases – tend to collect Rapid release & Expansion – Cold Hazard Large gas cylinders – severe strain from inappropriate handling
Gas storage vessels Low Pressure Storage Tanks (LPST) Static Mobile Pressure Vessels (SMPV) Spherical Storage vessels Horton spheres
LARGE SCALE AMMONIA STORAGE AND HANDLING Why are these facilities needed? Why is refrigeration needed? What are the major components? How is ammonia transported to and from the facilities?
Major Components Low Pressure Storage Tank Compressor Flash Tank / Intercooler Condenser Receiver
Refrigeration in an Ammonia Storage Facility Superheated vapor passes from storage tank to 1st stage of compression Hot vapor from 1st stage cooled in flash tank preparation for 2nd stage Vapor at saturation temperature passes to 2 nd stage compression Hot vapor passes to the condenser: Heat rejected to environment Condensed ammonia gravity drains into the receiver
Refrigeration (contd.) Receiver level control sends liquid to flash tank Flash tank level control sends liquid, at intermediate pressure, to the storage tank Flare for burning ammonia vapor during refrigeration system interruption Knockout pot protect the compressors from damaging liquid entry are also utilized
Huge Molasses Tank Collapsed 15 m tall; 27 m dia. Unleashed an immense wave of molasses Moving at 56 km/hr and 200 kPa Causes: Poor Construction & Improper Testing Rise in air temperature Fermentation: Production of Carbon di Oxide