Basic Flowchart Symbols and Meaning

This PFD of jet fuel mercaptan oxidation treating was redrawn from Wikipedia file: ConvLPGMerox.png. [en.wikipedia.org/ wiki/ File:ConvKeroMerox.png]
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported icense. [creativecommons.org/ licenses/ by-sa/ 3.0/ deed.en]
"Merox is an acronym for mercaptan oxidation. It is a proprietary catalytic chemical process developed by UOP used in oil refineries and natural gas processing plants to remove mercaptans from LPG, propane, butanes, light naphthas, kerosene and jet fuel by converting them to liquid hydrocarbon disulfides.
The Merox process requires an alkaline environment which, in some of the process versions, is provided by an aqueous solution of sodium hydroxide (NaOH), a strong base, commonly referred to as caustic. In other versions of the process, the alkalinity is provided by ammonia, which is a weak base.
The catalyst in some versions of the process is a water-soluble liquid. In other versions, the catalyst is impregnated onto charcoal granules.
Processes within oil refineries or natural gas processing plants that remove mercaptans and/ or hydrogen sulfide (H2S) are commonly referred to as sweetening processes because they results in products which no longer have the sour, foul odors of mercaptans and hydrogen sulfide. The liquid hydrocarbon disulfides may remain in the sweetened products, they may be used as part of the refinery or natural gas processing plant fuel, or they may be processed further.
The Merox process is usually more economical than using a catalytic hydrodesulfurization process for much the same purpose." [en.wikipedia.org/ wiki/ Merox]
The process flow diagram (PFD) example "Jet fuel mercaptan oxidation treating" was drawn using the ConceptDraw PRO software extended with the Chemical and Process Engineering solution from the Chemical and Process Engineering area of ConceptDraw Solution Park.