2.1 Sicherheit von Energieträgern
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As part of the development of a new standard testing procedure, a round robin study was conducted by six participating laboratories. This study involved the measurement of both the maximum explosion pressure and the maximum rate of pressure rise for hybrid mixtures comprising dust and vapor. Measurements were performed using a modified 20L-sphere. The primary objective of this collaborative effort was to assess the accuracy, reliability, and consistency of analytical and measurement methods across multiple laboratories, thereby increasing confidence in the obtained results. The method and protocol were developed as part of the NEX-HYS project and documented in a technical specification by the German Institute for Standardization Registered Association (DIN). The study revealed that precise pre-ignition pressure rise (PIPR) measurements and the use of a leak-free test apparatus significantly influenced the results of the measured maximum explosion pressure and maximum pressure rise rate.
Several standardized ignition sources are used to determine the safety characteristics of gases, vapours and dusts. Standards indicate the source of ignition but vary in specifying other features such as the burning duration, energy or the volume in which the energy is released. Since heat is not visible under normal conditions, a schlieren technique was used to visualize the entire igniting volume and not just the flames. This article focuses on the igniting volume, compares it among the four standardized ignition sources and displays its relationship to the size of the test vessel. Differences in the ignition behaviour of the ignition sources might lead to the determination of erroneous safety characteristics and with that to the unsafe operation of processes.
There is no applicable existing standard for the determination of safety characteristics for hybrid mixtures. While developing a new standard in a joint research project in Germany first results from parameter studies led to a standard procedure that can be adopted by laboratories that are already testing dusts in the so called 20L-sphere with as little additional effort as necessary. In fact, one of the main objectives of this research project was to keep modifications and adjustments from the generally accepted dust testing procedures as easy and minimal as possible so as to limit potential deviations from one laboratory to another.
In this first round robin test on hybrid mixtures ever, with methane as gas component and a specific corn starch as dust sample, the practicality of the whole procedure, the scattering of the results and the deviation between the testing apparatuses is investigated. This paper summarizes the experimental procedure adopted and objectives of the first round-robin phase involving three of the four original German companies, plus volunteering laboratories from Australia, Belgium, Czech Republic, France, Poland and P.R. China. The results will have an impact on the new standard and may lead to robust data for later simulation purposes.
Acetylene pressure cylinders are widely used in the industrial sector for welding, flame cutting, or heating.
Sometimes during work, not only with acetylene cylinders, fires occur and in this case the risk of destruction increases and the behavior of such an exposed cylinder is unpredictable. The purpose of this study is to identify those critical conditions when acetylene cylinders burst and explode in fires. In the present study, acetylene cylinders were exposed to fire conditions. For this purpose, a woodpile as a source of fire was chosen, tested, and evaluated. In addition to the fire condition, this option guaranteed reproducibility and similar conditions for all tests. The individual cylinders were equipped with thermocouples measuring the shell temperature, and half of them were prepared in order to measure the temperatures inside the cylinder. An important factor was the measurement of the amount of pressure that was achieved during the destruction of the cylinder. For this purpose, a pressure transducer was attached to the outlet of the cylinder valve. Exposed to direct fire, they can explode in 10 min, which was confirmed. The critical pressure of 40 bar has been reached in 6 min, followed by destruction after 7 min in fire. Cylinders with internal thermocouples were destroyed when lower pressure was achieved. This confirms the fact that any change of the pressure cylinder affects the original properties. After the tests, the fragments of the selected cylinders were subjected to material tests. The results obtained in these tests are the main source of information for understanding the behavior of acetylene cylinders in fire and the possibility of increasing the safety of intervening rescue services in an emergency.
The article summarizes a short review of the literature focused on safety in the field of alternative energy sources. With an increasing orientation towards sustainable and renewable energy sources, new technologies will come to the fore. These facts must be demonstrated in occupational health and safety. Several studies focused on alternative energy sources are mentioned and show the trends for the future. Especially in the area of hydrogen and battery technologies, systems should pay attention to acquisitions as a normal part of our lives.
Safety research is essential for the acceptance of cleaner, efficient, and sustainable future.
There are several standardized ignition sources in use for the determination of explosion characteristics of gases, vapors and dusts. In the standards the ignition source is stated, but they vary in stating other characteristics like burning duration, energy or burning volume. Since heat is not visible under normal circumstances a Schlieren-Technique was used to make the full heating volume and not just the flames visible.
While an earlier paper of the authors focused on the ignition energy and burning duration of four standardized ignition sources, this paper focuses on the initial igniting volume, the ratio between initial igniting volume and the test-vessel size and other phenomena that were observed with the Schlieren-Technique-.