Fluid knock out vessels is integrated to flare systems for removing liquid droplets or condensation ahead of the flame. While going up the flare stack, some gases cool off due to pressure condition within the apparatus and it turns to liquid droplets. These droplets, when combined with flares at the releasing end, causes an undesirable phenomenon known as flaming rain. This can cause damage to stack tip and pilot systems. For removing these hazardous droplets, fluid knock-out drums or vessels are implemented.