5.3　Arrangement for Shell and Tube Heat Exchangers

5.3.1　Heat exchangers associated to towers，such as tower bottom reboilers and overhead condensers，should be located near to the towers as per P&ID.

5.3.2　Heat exchangers for heat exchanging between two fluids should be arranged as close as possible to the inlet and outlet piping of these two fluids.

5.3.3　Heat exchangers for one fluid to heat exchange with several other fluids should be grouped.

5.3.4　Heat exchangers in structures should have the centerlines of their saddle aligned at one end.Heat exchangers on the ground may have the centerlines of their saddle aligned at one end，or have the inlet and outlet centerlines of tube sides aligned.

5.3.5　Two heat exchangers may be stacked if required.Heat exchangers with shell diameter equal to or larger than 1.6m should not be stacked.

5.3.6　Equipment handling flammable/combustible fluid shall not be installed above and beneath the heat exchangers at operating temperature equal to or higher than the self-ignition point of the fluid or at operating temperature higher than 250℃unless partition made of non-flammable materials are installed to protect the heat exchangers.

5.3.7　The clearance between heat exchangers and from heat exchanger to other equipment should not be less than 0.8m.

5.3.8　Heat exchangers should be arranged on the ground，however，if many heat exchangers are installed，they may be located in structures.

5.3.9　Floating head type heat exchangers on the ground shall comply with the following requirements：

1　A clear area in width not less than 0.8m should be provided on each side of the floating head，and a clear area in width not less than 1.5m should be provided in front of the floating head；

2　A clear area in width not less than 0.8m should be provided on the two sides of the channel end，and a clear area 1.5m longer than the tube bundle length should be provided in front of the channel end.

5.3.10　Floating head type heat exchangers in structures shall comply with the following requirements：

1　A clear area in width not less than 0.8m should be provided on each side of the floating head，and the clearance to the platform in front of the floating head should not be less than 1m；

2　A clear area in width not less than 0.8m should be provided on the two side of the channel end，the clearance of the platform in front of the channel should not be less than 1m，and space shall be reserved for bundle withdrawing；

3　The height of structures shall meet the hoisting requirement for heat exchanger channels and floating heads；

4　If vertical floating head type heat exchangers are installed in structures，spaces shall be reserved for bundle withdrawing.

5.3.11　Elevation of heat exchangers shall comply with the following requirements：

1　Elevation of heat exchangers shall be designed to ensure that the clearance from the bottom of piping to ground or platform shall be not less than 150mm，and the clearance from drain valve end to ground or platform shall not be less than 100mm；

2　In case heat exchangers are designed with draw-off pumps，the elevation of heat exchangers shall be greater than the net positive suction head（NPSH）r；

3　In case fluid is drawn out from the bottom of tower or vessel through heat exchangers，heat exchangers shall be located near to and under the towers or vessels；

4　In case two heat exchangers for different fluid service are stacked，the elevation difference of the centerlines of two heat exchangers shall meet piping arrangement requirements.

5.3.12　Vertical heat exchangers directly related to reactors may be arranged in reactor structures，and spaces shall be reserved for tube bundle withdrawing by mobile hoist.Permanent hoisting facilities shall be provided if mobile hoist is unavailable.