Acid: (1) Chemical that neutralizes alkalis. (2) Chemical that is corrosive to most metals and dissolves some metals. (3) Molecule or ion that can donate a proton or accept an electron pair in chemical reactions. Lethal Service: UW-2(a) - When a vessel is to contain fluids of such a nature that a very small amount mixed or unmixed with air is dangerous to life when inhaled. End Note 85 - By “lethal substances” are meant poisonous gases or liquids of such a nature that a very small amount of the gas or of the vapour of the liquid mixed or unmixed with air is dangerous to-life when inhaled. For purposes of this Division, this class includes substances of this nature which are stored under pressure or may generate a pressure if stored in a closed vessel. Oxygen Service: Process in an oxygen rich environment. Thorough cleaning is required to remove combustible contaminants from the surfaces of all equipment in direct contact with an oxygen rich environment. Reflux: The condensation of vapors and subsequent return of the condensate to the system from which the vapors originated. Reflux Condenser: Typically a vertical shell and tube exchanger where vapor(s) enter the bottom channel and flow upward through the tubes counter-current to condensate flowing downward on tube walls. Commonly used in vent applications for tanks and distillation column overhead. Note: Properly designed reflux condensers can also be designed for horizontal installation. Surfactant: A compound that lowers the surface (interfacial) tension between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may be use as detergents, dispersants, emulsifiers, foaming agents, and wetting agents. |
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