Claire Lloyd reports on the latest developments in high-pressure rupture discs
The production of certain plastics such as LDPE requires demanding process conditions including pressures up to several thousand bar and temperatures over 300˚C. The LDPE process is a highly exothermic reaction that is nearly impossible to control and difficult to stop. Autoclaves, tubular reactors and process elements require special overpressure protection measures to ensure that the process is safe.
A common solution
Since rapid pressure relief is required, rupture discs are a common solution to overpressure protection but the challenging environment in these high pressure/high temperature applications can cause traditional rupture discs to fatigue over time. The common solution for high-pressure applications is a rupture disc manufactured with a weld seam. This has an influence on the burst pressure and, after installation, the applied pressure is nearly fully loaded on the welding joint. Over time the weld seam fatigues under pressure and results in an unnecessary rupture disc response that can even take place at a lower pressure than the defined burst pressure.
In comparison, Rembe HPRD rupture discs have a much longer life time than the traditional discs as the pressure load applies only on the seat of the disc. By moving the weld seam out of the pressure loaded area of the disc, the burst pressure is defined only by well controlled parameters such as material thickness and it is not influenced by the strength of the weld seam. This precise control over the rupture disc response pressure also allows the tightest burst tolerances of +/- 3% and lower.
“The challenge of high pressure applications such as LDPE production is one that our engineers relish and we are proud to be able to protect such processes,” says Claire Lloyd from Rembe.
The HPRD rupture discs protect various high-pressure processes around the world. This long-life version for high pressure applications has a lifetime that is 5-10 times higher than that of a standard rupture disc. That saves money and installation time by eliminating downtime caused by unwanted responses. An increasing number of companies are benefitting from reduced down-time and large cost savings by using a long-life rupture disc in their production facilities.
Rembe was recently approached by one of the leading multinational companies in this field to protect its polymer plant in Belgium and help to bring it in line with European regulations on pressure equipment.
Claire Lloyd is with Rembe