Importance of Tests in the Design of Explosion Protection Systems

A large chemical company in England had been using a large spray dryer system for many years. They thought that the risk of explosion was reduced by installing explosion damping systems in the main dryer and a flameless explosion cover in the cyclone and filter. After installation, these explosion prevention systems were used more than 30 times to prevent actual explosions, and so far the system had done its job.

However, the frequency of activations increased and eventually an explosion in the main filter caused damage to the plant despite the explosion protection system. The chemical company asked several suppliers for a solution to this explosion prevention problem, including the company that installed the explosion suppression system, and each supplier conducted various experiments with their own devices. Each supplier began testing by leaving its explosion detection system on top of the spray dryer.

When the next explosion occurred, the event was detected only by RSBP. For this reason, the explosion prevention systems currently used and the systems of other suppliers that were tested were found to be unreliable. In detailed incident investigation of RSBP, it was determined that the explosion data (Kst 430, Pmax = 8.9) used in the current system design may not be accurate. RSBP’s experience in product characterization testing on both 20 Liter sphere and 1m3 test vessels led us to believe that the 20 Liter sphere test was likely to produce inaccurate results and it was decided instead to repeat a full set of tests along with a new test.

RSBP tested the spray dryer treated product on four different 20 Liter test spheres and the test results were very close to those done before. However, tests in the 1m3 test vessel resulted in a much lower Kst value. This information was critical in designing the explosion dampening system. As a result of different Kst and Pmax values in the raw material test, it was decided that the design of the current system was faulty and should be replaced with the RSBP system. RSBP explosion damping system was installed on the main dryer, cyclones, main filters and channels.

The most vital element of the previous safety system was the application of a flameless explosion cap to the filter. RSBP considered that the flameless explosion cap should not be applied to the filter based on its size (>250m3) because the size of the filter exceeds the usage limits of the flameless explosion cap.

RSBP initiated a turnkey explosion protection project. This project included the entire project management, from process analysis to positioning of the explosion damping system, installation and commissioning of electrical and mechanical systems. 50 damping tubes and 20 detection points were determined in the project and all works were completed on time.

Following the successful installation and commissioning of the RSBP explosion damping system, almost the entire system was tested one by one. During commissioning, an explosion test with natural gas was carried out. The end user injected natural gas into the spray dryer system and ignited the gas. Although RSBP’s explosion detection damping system was not installed against a natural gas explosion, it detected the explosion and dampened it as designed, preventing the explosion from damaging the spray dryer and other equipment.

The RSBP explosion damping system has been protecting the process at this chemical company for several years. As a result of this example, it has been seen that with the right criteria and an experienced and knowledgeable design team, it is possible for important processes to operate safely with explosion protection systems. RSBP explosion protection systems not only prevent loss of life and damage to valuable assets, but also reduce additional operating problems such as unplanned downtime and loss of production.

For more information about RSBP and Elva’s explosion protection solutions, please contact us;