Feed Flash Convention
Single phase feeds are always placed onto the feed tray - liquid feeds enter above the feed tray and vapor feeds enter below it. Two options are provided for handling mixed phase vapor/liquid column feeds. Feed flash convention can be provided at the feed stream level or at the global level. Flash convention provided at the global level is applicable for all feed streams in the column. Option provided at the individual feed stream level always gets precedence over the global option. If neither of the options is provided on the feed card, global default, not separate is used in the simulation by default.
Vapor and Liquid On the Feed Tray
This option is the default. Each feed is placed on the designated feed tray, regardless of the thermal condition of the feed. The liquid portion enters above the feed tray and the vapor portion enters below it.
Flash the feed adiabatically, ...
For this option, each feed is adiabatically separated into liquid and vapor portions. The liquid portion is placed on the designated feed tray and the vapor portion feeds the next higher tray in the column, simulating the flashing which occurs at actual column feed trays. Even if this option is specified, column feeds which are all vapor are placed on the designated feed tray.
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