Bottom-head nozzle arrangement

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 liquid outlet is located on the bottom head of die tower. If the tower is supported by a skin, the nozzle is routed outside the sldrt. As with the vapor outlet, more than one nozzle may be specified. The elevation of the nozzle is dictated by the constraints discussed previously in this chapter. The orientation can be at any angle, but generally it is dictated by pump suction piping flexibility. Exhibit 10-33 shows a typical bottom head arrangement. 

Figure 7 shows nozzle locations and support arrangements for a typical horizontal vessel (7). The saddles used for support are sustained by concrete pedestals or steel stmctures. Sufficient clearance between the bottom nozzles and the support saddles needs to be provided for access to the nozzle flange bolts. The manway can be located on the end head of the vessel, the topside of the vessel, or the side of the vessel. The preference is for an end manway wherever possible for accessibiHty, except when it is limited by the level gauges and controls that are commonly mounted off the heads. 

All test accumulators (pressure vessels) were mounted direcdy below the test table. These vessels were mounted vertically with 2 1 ellipsoidal heads on top and bottom. The top head has a well-rounded outlet nozzle sized equal to the SRV inlet to be tested. To test smaller-orifice SRVs, ring-shaped adapter plates having an opening equal to the SRV inlet are used. This arrangement reduces the possibility of starving the flow to the valve. 

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