Milestone Explosion Protection/Pressure Relief
Milestone Explosion Safety/Pressure Relief
Competence in Safety Matters
Explosion Safety in the Food Production Industry
Nowadays nobody would deny that the purity law is a guarantor for the quality of beer. It is also undisputed that the raw material malt poses a risk of explosion. Endangered plant elements include conveyors, silos, mills or elevators. If the plants are inside a building, it will become particularly tricky. Since neither the potentially explosive atmosphere nor ignition sources can be safely avoided here, explosion protection is the essential factor.
The flameless explosion venting technology invented by Rembe offers an elegant solution for the explosion safety in buildings, even in breweries. With the products Q-Rohr, Q-Box and Q-Ball a secure venting will be guaranteed. The flames are cooled extremely efficiently in the mesh filter of the flame absorber and are extinguished immediately. Neither flames nor pressure will escape. Complex safety concepts with complicated vent ducts can thus be avoided and the production plant can be set up in a process-optimised manner. The filter construction also guarantees that no burned or unburned substances can escape.
The latest coup in flameless explosion venting for elevators from the “Sauerland Professionals” is the Q-Ball E: “Thanks to the innovative design, the weight of the Q-Ball is very low. While comparable products from other suppliers weigh between 100 and 200 kg, the Q-Ball is an absolute lightweight with just 25 to 50 kg,” explains Mr. Lottermann. This actually simplifies both the handling during installation and the requirements for an attachment to the elevators. “For more safety, we have also improved the venting effectiveness,” says the Rembe expert.
Process Safety — Mastering the Pressure
Even if explosions are not an issue: Overpressure and vacuum are present in almost all production processes in the chemical, pharmaceutical, food, oil and gas industries. If the pressure exceeds or falls below the defined limits, serious damage can be caused to the affected plant components, and personal injury can also occur. This can result in production stoppages and thus high economic losses. Therefore, in the event that the pressure is no longer within the permissible operating values, a reliable and fast reacting pressure relief system is required. The means of choice is often the rupture disc. In many cases it is even superior to safety valves:
- Instant response: Excessive overpressure and vacuum is relieved in milliseconds.
- Full bore opening available for pressure relief: While the mass flow of safety valves is limited, the rupture disc allows a maximum cross section opening.
- Leak-tightness: A rupture disc can be used to prevent leakages during normal operation.
What makes the “metal plate” with precisely defined breaking points so special? As is so often the case, the devil is in the detail. “There is no ready-made concept for the design of a rupture disc. We tailor each solution individually to the specific operating conditions,” emphasises Orhan Karagöz, Head of Process Safety Business Unit at Rembe. He and his colleagues must consider at least 53 different parameters, so that the rupture disc responds reliably to the defined burst pressure. These include the plant elements to be protected, process medium, operating pressure, vacuum/cycles, burst pressure and temperature, required nominal pipe size or mass flow to be discharged. “The rule of thumb hereby is: The earlier we get on board and the more comprehensive our information on the specific process conditions is, the more reliably the rupture disc will protect the process,” explains Karagöz.
Pressure Relief in the Chemical Industry
Many processes in the chemical industry require high pressures as well as clean surfaces, and entail risks of crystallization or the danger of bonding developments due to polymerization, e.g. in the plastics production. In these cases, the KUB reverse-acting rupture disc demonstrates its advantages. This highly dynamic product can, for example, be freed from deposits with a solvent without impairing its function. “That can not be said about other rupture discs. After all, they can not be touched,” Karagöz clarifies. In addition, the closed surface facilitates the cleaning. This is made possible by Rembe's specially developed, laser-based production process.
Another bonus: The reverse-acting rupture disc masters an operating pressure ratio of up to
98 % — depending on the application. This enables plant operators to increase their operating pressures, and thus also the yield. A fatigue of the rupture disc is not to be feared. Service personnel will also benefit from the robust rupture disc. Because it can be easily removed and reinstalled. “This is unique,” assures Karagöz. A special holder system prevents the rupture disc from being installed incorrectly. Special tools are not required for this. The KUB is also not damaged by the installation, since the burst pressure of the rupture disc is independent of the torque and therefore the required torques can be used for the flange gaskets.
Pressure Relief in the Food Production Industry
In order to protect aromatic oils from oxidation, for example, storage tanks are filled with nitrogen. The overpressure in the tanks also prevents contamination, as no foreign particles can penetrate from the outside. The nitrogen used is normally under pressure — for example in a 300 bar bottle. At least one reduction stage is required to feed it safely into the tank. After all, the fill pressure in these cases is only ten to 40 mbar. The nitrogen is fed in using a control valve. It ensures that the defined fill pressure is kept constant.
Nevertheless, there is a risk that either a reduction stage or the control valve will not function properly and that more pressure than required will be introduced into the storage tank. In this case a safe pressure relief device is required. Due to the low pressures, a rupture disc is out of the question. It would simply be too large to be installed on the small storage tanks. The choice thus falls on a pressure and vacuum relief valve that has to meet the highest demands: fast opening, high mass flow, easy cleaning. Here, standard valves quickly reach their limits, in contrast to the Elevent breather valve. Standard valves for pressures up to 100 mbar are usually made of cast housings whereas the Elevent housing, however, is made of deep-drawn stainless steel. A great advantage when cleaning. While the process medium in a cast housing can penetrate deep into the pores of the housing, causing unacceptable deposits, it can easily be removed from the smooth stainless steel surface of the breather valve.
Rupture discs are also suitable for processes with higher pressure. The crux of the matter: the type of installation. In less hygiene-sensitive organization units, a rupture disc can be installed between flanges or in a rupture disc holder. For sectors with high hygiene requirements, the KUB clean is used for an installation into a Tri-Clamp flange system. Due to the smooth surface of the sealing membrane, the integrated gasket and the direct installation in Tri-Clamp flange systems, there are no score lines, indentations or notches on the process side eliminating trapped product residues during production or cleaning cycles. In addition, the side of the KUB clean in contact with the process is designed in such a way that it is easy to clean.
Conclusion: An adequate protection of process plants safely against overpressure and explosions requires more than just any random component. Holistic concepts and individually tailored protective elements are required. It is good to have a partner by your side who does not compromise on safety.