Case Study: Safety Assessment of Plant Layout between Ethylene Storage Tanks and Process Equipment According to Capacity and Weather Conditions

In a chemical plant, even if an explosion occurs in a storage tank that handles flammable materials, the minimum separation distance is applied in a way to prevent chain explosion. This is because when an explosion occurs in a storage tank, thermal radiation affects nearby process equipment and causes a chain explosion. The separation distance between storage tanks and process equipment in a chemical plant depends on the global engineering guidelines PIP (Process Industry Practice) PNE00003 and GAPS (Global Asset Protection Services) GAP.2.5.2. However, there is a limitation in the global engineering guidelines that provide only a consistent separation distance according to the item types without considering the storage capacity and climatic conditions around the storage tank. This study analyzed the distance of thermal radiation (up to 37.5 kW/m2) according to the capacity of ethylene storage tank and climatic conditions by utilizing the Phast (DNV GL), which is widely used as a tool for quantitative risk analysis. The accident scenario was applied using the U.S. EPA (Environment Protection Agency)’s worst leakage accident scenario, considering climate variables, air temperature, wind speed, and atmospheric stability. In the simulation, atmospheric stability did not affect the radius of thermal radiation. Moreover, the thermal radiation tended to increase with increase in wind speed in the ambient condition and winter, but not in summer. Because both PIP PNE00003 and GAP.2.5.2 yield consistent separation distances without considering storage capacity and weather conditions, quantitative risk analysis of the results of thermal radiation is necessary to ensure safety.

Chain processes in cognitive dynamics

The article discusses the construction of circuits only within random-access memory, additionally limited by attention. We propose a model explaining the features of the dynamics of solving problems on insight using N.N. Semenov’s theory of chain branching chemical reactions. When referring to long-term memory (and return from it with the result on the construction of a representation) the real average length of generalized mental chains can only increase, since it is known that the concepts and objects in it branched and associated with others. In circuit theory, the condition when values of average length chains go to infinity means nonstationary mode of reaction (chain explosion). Thus, in the present model this mode of sharp increase in the average length of the chains is the most favorable conditions for the building the representation – any circuit (with a length of no longer than d) we take to build from existing units operated with all its branches - it is taken in our attention and has no time to break off. These conditions are most favorable for the building and restructuring the representations, and there is the insight moment in our model. Well-known literature data on the experimental investigation of insight and creativity are in good agreement with the requirements of this model towards insight parameters.

IR-Laser Induced Branch Chain Reaction of Hypofluorites With Hydrogen

The parameters of chain explosion occurrence in the mixture of CF3OF or CF2(OF)2 with hydrogen induced by a pulsed CO2-laser were studied experimentally. The ranges of inflammation for the both cases were obtained. IR-fluorescence spectra associated with the chain explosion were studied. The chemical reactions describing the observed process qualitatively are given assuming the chain energy branching.