Nozzle Elevation and Orientation

Nozzles must be elevated to meet the internal requirements of the tower and oriented for maintenance and 

A maintenance access is usually located in the bottom top, and intermediate sections of dte tower and is used to gain entry to the tower during shutdowns for internal inspection and component removal. Maintenance accesses must not be located at downcomer sections of the tower. Qtte must be taken at sections of the tower diat contain internal piping to avoid blocking the maintenance, access entrance. Exhibit 10-28 shows typical elevation and orientation requirements for maintenance accesses. 

Feed connections to trayed lowers usually must be 

If specified, reboiler connections are usually located at the bcMtom section of the tower. For the horizontally mounted thermosiphon reboiler, the drawoff nozzle is located just below the bottom tray. For the vertically mounted recirculating thermosiphon reboiler, the draw-off nozzle is located at the bottom head. For both systems, the return nozzles are located just above the liquid level. Exhibit 10-31 shows both of these arrangements. 

The vapor outlet is usually a vertical nozzle located on the top head of the tower. It is usually a single nozzle, but in certain cases (e.g., towers with very large diameters), more than one nozzle is specified. On large-diameter vapor lines, the vessel connection could be butt-welded instead of flanged. In addition, the vent and relief valve could be located on the top head instead of attached to the overhead piping. Exhibit 10-32 shows a typical top head arrangement. 

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