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3.7.6. Identifying Procedures for Conducting Container Vapor Flaring Operations. Before ASME tank maintenance tasks can be done, it may be necessary to evacuate propane liquid and flare the propane vapor . In this module, you will learn to :
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3.7.6 Identifying Procedures for Conducting Container Vapor Flaring Operations Before ASME tank maintenance tasks can be done, it may be necessary to evacuate propane liquid and flare the propane vapor. • In this module, you will learn to: • Identify procedures for conducting vapor flaring operations
4.3.2.3 of NFPA 58 requires that LP-gas be burned at least 25 feet from combustibles. Conducting Vapor Flaring Operations Flaring is the process of burning LP-gas removed from storage containers in a controlled and safe manner. NFPA 58 2001 edition
Conducting Vapor Flaring Operations Figure 1.Figure 2.Figure 3.
Conducting Vapor Flaring Operations Figure 4b. Top of Flare Tower Burning Propane from Cylinder Figure 4a. Electronic Ignition Flare Tower
Conducting Vapor Flaring Operations Although the flaring operation is simple, it does involve an open flame. As a result, certain safety precautions should be followed when selecting a site for flaring the container. These safety precautions will limit the danger of an accidental fire while the flaring burner is operating. Figure 5. Recommended Site for Flaring Containers (At Bulk Plant)
Conducting Vapor Flaring Operations NOTE: The flaring burner should be located at least 25 feet away from the container being flared, any transfer area or important building.
Conducting Vapor Flaring Operations • Flaring equipment should have these features: • An orifice or other gas flow controlling device • A built-in shutoff valve • Designed for vapor service • An approximate input rating of 500,000 BTU/hr. or less • Should incorporate a regulator
Conducting Vapor Flaring Operations It is important to select a burner with both a built-in shutoff and a regulator. This allows for adjustment of the output of the burner and prevents any excessive withdrawal from the cylinder or tank being flared. Remember, excessive withdrawal could easily cause the tank or cylinder to temporarily stop vaporizing enough gas to supply the burner. This condition may be noticed when a frost line appears on the container, yet sufficient liquid may remain to re-pressurize the container when it regains heat from surrounding air.
Conducting Vapor Flaring Operations Figure 6. Supply Hose for Flaring Burner
Conducting Vapor Flaring Operations Figure 7. Flaring Burner Support
Conducting Vapor Flaring Operations Figure 7. Flaring Burner Support
Conducting Vapor Flaring Operations During Step 6, observe the pressure gauge on the service valve (or purging adaptor). When the pressure drops below 15 psig, temporarily shut down the burner and allow the pressures in the tank or cylinder to increase. (Because of the high demand of the burner, the container may refrigerate during the flaring operation. If a frost line develops on the cylinder, temporarily shut down the burner and allow the pressure in the container to increase.) When the vapor pressure no longer increases above 15 psig, flare the remaining vapor until the burner extinguishes.
Check with your supervisor or any company-specific procedures that may apply to flaring operations. Conducting Vapor Flaring Operations • Flaring operations should incorporate the following safety practices and recommendations: • Flaring operations should never be left unattended and qualified personnel should continuously monitor flaring equipment and conditions. • If qualified personnel must leave the flaring operation for any reason, the operation should be shut down and the valve(s) on the container being flared should be closed.
Time to See If You Got the Key Points of This Module… • Complete the Review on pages 10. • See if you are ready for the Certification Exam by checking off the performance criteria on page 11.
