PECM Issue 34 2018 | Page 133

HEALTH & SAFETY PRESSURE RELIEF REMBE HOW TO PROTECT WHAT – PRESSURE RELIEF FOR COLUMNS, STEAM CRACKERS AND FLARE STACKS Columns Fractional distillation is used to separate the various components of crude oil. The crude oil is heated using high pressure steam so that the various components transfer to vapor phase. The vapor enters the fractional distillation column filled with trays or plates. As the vapor passes through the column it rises, cooling at each level. Each substance condenses when it reaches its boiling point and the trays collect the various liquid fractions. Rupture discs are commonly used as overpressure protection on fractional distillation columns. Steam Crackers High temperature steam (above 800 degrees C), controlled by heat exchangers, is also used to heat ethane, butane and naphtha and break it into ethylene, benzene and propylene used in the chemical industry. The steam cracker and the surrounding equipment are protected against over pressure by the use of rupture discs. Flare Stacks As an accurate and reliable solution, rupture discs can be used as primary relief, secondary relief, or in combination with a traditional safety valve for optimal protection. If the pressure in the gas recovery system of a flare stack rises, the rupture disc as primary relief will burst, re-establishing the path to the flare which is ignited to burn the waste gas. In some applications, the rupture disc can be installed in parallel to the safety relief valve to provide a direct path to the flare in case the mechanical valve should fail to open. www.rembe.de Issue 34 PECM 133