When evaluating a flare system package, a technical recommendation must be prepared to ensure the package meets the specific requirements of the project. The components of a flare system package typically include a flare stack with flare tip and molecular seal, water seal drum, and knock-out drum. Various calculations and measurements must be taken into consideration to determine the suitability of the package.
These include the height of the stack, the materials used for the flare tip and molecular seal, the design of the ignition panel and pilot burner, the smokeless capacity, the water seal height, sizing details of the knock-out drum, and the pressure drop in the flare. Additionally, it is recommended to include the supporting structure in the vendor scope. By adhering to these considerations, plant operators can ensure their flare system packages meet their specific requirements and are safe to use.
Technical Bid Evaluation for Flare System
Flare System Technical Bid Evaluation
Evaluating the Flare Stack and Flare Tip
When evaluating a flare system package, the height of the stack needs to be calculated, taking into account the heat radiation and ground-level concentration of toxic gaseous effluents, according to Vol. I Ch 13/API RP-521. Additionally, the material used for the flare tip should not be refractory in nature. If the vendor is supplying material for the flare tip that is different from the one specified, the design temperature for the material should be verified to ensure it meets the required value.
Molecular Seal and Velocity Seal Design
The molecular seal or velocity seal design should be carefully checked and evaluated.
Ignition Panel and Pilot Burner
The ignition panel should be forced draft type (using plant air) with electric spark ignition. The air/Fuel ratio for a pilot burner for alternate fuels should be asked from the vendor.
Smokeless Capacity
The smokeless capacity is normally specified for the greater of the normal load or 10% of the maximum load. However, it is important to check project-specific requirements as well.
Water Seal Height
The water seal height should be checked for minimum back pressure in the flare header to avoid the seal from breaking, as per API RP-521.
Knock-Out Drum
If the knock-out drum is in the vendor’s scope, sizing details of the knock-out drum should be obtained from the vendor. The basis of sizing should typically be specified in the inquiry. A consideration of 5-10% in the flare header can be assumed as a basis.
Pressure Drop in Flare
The pressure drop in the flare is important for a low-pressure system like atmosphere storage tanks. This should be obtained from the vendor.
Supporting Structure
It is recommended to include the supporting structure in the vendor scope.
Read Main Article related to this Technical Bid Evaluation:
Technical Bid Evaluation Criteria and Vendor Offer Review