2.2 Prozesssimulation
Filtern
Dokumenttyp
Sprache
- Englisch (32)
- Deutsch (22)
- Mehrsprachig (2)
Schlagworte
- CLP (8)
- Einstufung (7)
- GHS (6)
- Anerkennungen (5)
- Festlegungen (5)
- Prüfmethoden (5)
- Richtlinien (5)
- Zulassungen (5)
- Dangerous Goods (4)
- Fireball (4)
Organisationseinheit der BAM
- 2 Prozess- und Anlagensicherheit (56)
- 2.2 Prozesssimulation (56)
- 2.1 Sicherheit von Energieträgern (8)
- 3 Gefahrgutumschließungen; Energiespeicher (8)
- 2.0 Abteilungsleitung und andere (5)
- 8 Zerstörungsfreie Prüfung (5)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (5)
- 3.0 Abteilungsleitung und andere (4)
- 4 Material und Umwelt (4)
- 4.3 Schadstofftransfer und Umwelttechnologien (4)
- 3.1 Sicherheit von Gefahrgutverpackungen und Batterien (3)
- 2.3 Einstufung von Gefahrstoffen und -gütern (2)
- 7 Bauwerkssicherheit (2)
- 7.5 Technische Eigenschaften von Polymerwerkstoffen (2)
- 2.4 Prüfung und Bewertung von Explosivstoffen/Pyrotechnik (1)
- 3.2 Gefahrguttanks und Unfallmechanik (1)
- Z Zentrale Dienstleistungen (1)
- Z.1 Organisation, Controlling (1)
Eingeladener Vortrag
- nein (30)
Mit dem Handbuch für Prüfungen und Kriterien bezeichnet) wird das Klassifizierungsschema der Vereinten Nationen (UN) für gefährliche Güter im Rahmen der Beförderungsvorschriften und für gefährliche Stoffe und Gemische gemäß GHS (Globally Harmonized System of Classification and Labelling of Chemicals) beschrieben. Außerdem enthält es eine Beschreibung der als am geeignetsten angesehenen Prüfmethoden und -verfahren, welche dem "Klassifizierenden" die notwendigen Informationen für eine korrekte Einstufung liefern. Der Begriff "Klassifizierender" wird im gesamten Handbuch allgemein verwendet, um die Stelle anzugeben, die die Klassifizierung vornimmt. Für einige Reglungsbereiche kann dieses eine speziell zuständige Behörde oder eine benannte Prüfbehörde sein, in einem anderen Reglungsbereich, soweit es zulässig ist, kann es auch die Selbsteinstufung durch den Hersteller oder Lieferanten bedeuten. Der jeweilige Reglungsbereich sollte beim Auftreten dieses Begriffes berücksichtigt werden, um die für die Klassifizierung verantwortliche Stelle korrekt zu identifizieren.
Differential Scanning Calorimetry (DSC) may be used to avoid testing for explosive and self-reactive properties according to the legal regulations of chemicals substances and dangerous goods.
Demonstrated measured exothermic decomposition energy value significantly affected by numerous factors - choice of sample vessel, sample mass, baseline shape, peak shape, heating rate.
Introduction: Homogenously catalyzed reactions in multiphase systems, as they are used for example for the hydroformylation or reductive amination, offer a promising approach to produce base chemicals from renewable resources. The organic and gaseous educts react with the catalyst, which is designed to be soluble in water to provide a good separation from the likewise organic products. In the resulting gas/liquid/liquid systems, the reaction is controlled through interfacial and transport phenomena. These processes fail for long chained olefins – e.g. vegetable oils and fats – because of their low solubility in water. Therefore, surfactants can be added as an emulsifier to form micellar emulsion systems (MES) [1], increase reaction speed [2] and facilitate phase separation [3]. These systems form up to three liquid phases, depending on temperature and composition. For fast reactions, the gas/liquid mass transfer plays an important role. Due to the multiple phases present, the dispersion conditions of the particles and the resulting mass transfer are complex.
Methods: In this work, the mass transfer in MES is investigated. For simplicity, only the non-reactive material system without catalyst consisting of water, dodecane and the non-ionic surfactant Marlophen NP8 was investigated. Hydrogen was applied as gas phase. The phase behavior of the MES was characterized using settling experiments and by measuring the conductivity of the emulsions [4]. The mass transfer experiments were conducted in two different setups employing the dynamic pressure method.
In a pressurized stirred tank reactor, the mass transfer performance of the whole MES was determined under the complex dispersion conditions and a variety of different system parameters by measuring the volumetric mass transfer coefficient (kLa). The specific transfer area (a) was determined measuring gas hold-up and using optical endoscope measurements [5] to record bubble sizes. The non-spherical bubbles were analyzed with a trained convolutional neural network [6].
Using a falling film capillary in a closed pressurized system [7], the mass transfer of the single phases appearing in MES were quantified. The phases were removed and investigated separately after the settling experiments. A gravity-driven laminar flow with well-defined transfer area was established along the capillary and by measuring the pressure drop over time the mass transfer coefficient (kL) could be calculated.
Results: The mass transfer coefficients of hydrogen in the single phases of the micellar emulsion system covered a broad range. The kL of the aqueous phase was similar to pure water, while the third, bi-continuous phase forming in MES had very small kL values due to its high viscosity. The mass transfer coefficient of the organic phase was found to be far higher than of the aqueous phase.
In the stirred tank reactor, different phases formed the continuous phase in the whole MES mixture for the temperature range investigated. The fastest mass transfer was found for a continuous aqueous phase below 87 °C. At higher temperatures, a phase inversion occurred, and the organic phase became continuous. The high kL of the organic phase measured in the falling film contactor did not translate directly to a higher kLa in the stirred tank reactor as the value dropped compared to an aqueous continuous phase present. The change in continuous phase were found to affect the drop and bubble sizes in the system. For an organic continuous phase, the Sauter mean diameter of the bubbles were larger and the transfer area smaller, which was the main reason for the reduced kLa.
Introduction: Mass transport at gas/liquid interfaces depends on many factors including the gas and liquid properties and hydrodynamics. The mass transport of a gas through the liquid is a limiting step in many chemical reactions. To gain a fundamental understanding of multiphase interfaces, the rate of mass transfer has been measured for pure gases (H2, N2, O2, He) into a thin liquid film with a well-defined surface area and velocity profile. This enables the mass transfer rate to be broken down into one parameter, which is the gas/liquid interfacial area (a), and a second parameter, which is the mass transfer coefficient (kL). Using gases with varying diffusion coefficients enables a comparison of the measured rates of mass transport to the rates predicted by film theory and penetration theory.
Method: A gravity-driven thin water film 0.000180 m in thickness flowing along the outer surface of a capillary was contacted with a gas phase inside a closed system. The liquid was circulated continuously until it was saturated with gas and the equilibrium pressure was reached. In this device, there is laminar flow, and therefore, the hydrodynamics of the liquid film are well defined.
Results: Penetration theory predicts a non-linear relationship between diffusion coefficient (DAB) and mass transfer coefficient (kL). by means of falling film reactor the actual rates of gas-liquid mass transfer are higher than those predicted by theory. Also, a linear relationship between DAB and kL is observed experimentally. The mass transfer coefficient can even, as a rule of thumb, be assumed to be relatively constant with a value of around 10-4 m/s for aqueous solutions.
Self-reactive substances are unstable chemical substances which can easily decompose and may lead to explosion. For this reason, their thermal stability properties are required within regulatory frameworks related to chemicals in order to assess their hazardous properties. Due to the fast development and availability of computers, predictive approaches like QSPR models are increasingly used in the evaluation process of hazardous substances complementary to experiments.
In that context, the HAZPRED project (2015-2018) aimed to develop QSPR models to predict physical hazards of substances to fill the lack of knowledge on these hazardous substances quickly.
An experimental campaign, based on 50 samples provided by Industrial producers, was carried out on potential self-reactive substances, for which no QSPR model already existed. Their heats of decomposition were characterized using differential scanning calorimetry in homogeneous experimental conditions.
QSPR models were derived using the GA-MLR method (using a genetic algorithm and multi-linear regressions) using molecular descriptors calculated by Dragon software based on both 3D molecular structures from density functional theory (DFT) optimizations, to access three-dimensional descriptors, and SMILES codes, favoring the access to simpler models, requiring no preliminary quantum chemical calculations. All models respected the OECD validation guidelines for regulatory acceptability of QSPR models. They were tested by internal and external validation tests and their applicability domains were defined and analyzed.
If improved models should be expected with larger database (and a better ratio between size and chemical diversity), these first models already represent a screening tool capable to access early reactive hazards.
Organic peroxide and self-reactive are classified into seven types according to their hazards. In order to determine the substance type, it is necessary to determine the properties based on test methods. The types range from type A, which is not accepted for transport in the packing in which it is tested, to type G, which is exempted from the provisions for organic peroxides or self-reactive substances.