3-Geometry(tasc)HTFS的培训资料.pptVIP

Shell and Tube Geometry Contents Standards Shell and head types Tubes: arrangement, type, selection Baffles: type, cut, orientation Clearances Fluid allocation Standards The mechanical design and construction of ST exchangers is usually based on TEMA 7th Edition 1988. TEMA supplements the ASME Pressure Vessel code. TEMA provides 3 letter designation Shell types E-type shell should be used if possible but F shell gives pure counter-current flow with two tube passes (avoids very long exchangers) Note: longitudinal baffles are difficult to seal with the shell especially when reinserting the shell after maintenance More shell types Often only used for horizontal thermosyphon reboilers (with the shell-side flow upwards) Longitudinal baffle then more a distribution plate - may be perforated Still more shell types J X give low shell side Dp Dividing J called I by HTFS Summary of shell types E-type shells are standard G and H shells are normally only used for horizontal thermosyphon reboilers J and X shells are used if allowable pressure drop can not be achieved in an E shell For services that need multiple shells and removable bundles, F shells should be considered as alternative K type is only used as a reboiler Note that TASC also handles “double-pipe” exchangers Front and rear heads Front head types A-type is standard for dirty tube side B-type for clean tube side duties. Use if possible since cheap and simple. More front head types C-type with removable shell for hazardous tube-side fluids, heavy bundles or services that need frequent shell-side cleaning N-type for fixed for hazardous fluids on shell side Summary of front head selection B type standard for clean tube side fluids A type standard for dirty tube side fluids Consider C type for Hazardous tubeside fluids Heavy tube bundles Frequent shellside cleaning Consider N type for fixed tubesheet exchangers with hazardous tubeside fluids Consider D type (or bonnet welded to tubesheet) for high pre