The Logic Behind The Magic."Flare System "

High Pressure (HP) and Low Pressure (LP) flare system are provided to safely dispose of gas relief valve, starting gas, and blowdown from vessel. Each system consists of a gathering header, KO drum, a flare tip and ignition system, During normal operation, the flare system should only have a small purge gas flow, The HP and LP KO drums separate liquid and gas from the flared gas system.

HP Flare System
The HP Flare KO drum is designed to handle the capacity of flare system and accommodate the liquid knockout under the maximum relieving scenario. i.e. during emergency total platform blowdown

 

The HP Flare network collects hydrocarbon gas and liquid discharge from various high pressure equipments and routes them to the HP flare KO drum. Any liquid is separated in the KO drum, While the gas is directed towards the HP flare tip. The liquid in the HP flare KO drum is pumped to the LP flare KO drum by HP flare pump.

Control Loop Description  

Level control in the HP flare KO drum is performed by level controller by srating and stoping the pump between various levels. The pumps are 2x 100% and configure in lead/lag logic and shall be configured within the PCS.

 At "ON" level. if the level continues to rise and reaches LAH level, the lag pump will also be started. At "OFF" level, both lead and lag pumps are stopped. LAH and LAL shall be alarmed on the HMI

LP Flare System

The LP Flare network collects hydrocarbon gas and liquid discharge from various low pressure equipments and routes them to the LP flare KO drum.The LP Flare KO drum also serves as closed drain drum. Liquid is separated in the KO drum, while the gas is directed towards the LP flare tip. The liquid in the LP flare KO drum is pumped to either the export pipeline or back to Separator via LP flare recovery pumps

Control Loop Description  

Level control in the LP flare KO drum is performed by level controller by srating and stoping the pump between various levels. The pumps are 2x 100% and configure in lead/lag logic and shall be configured within the PCS.

 At "ON" level. if the level continues to rise and reaches LAH level, the lag pump will also be started. At "OFF" level, both lead and lag pumps are stopped. LAH and LAL shall be alarmed on the HMI