3/19/2021 0 Comments Tema Heat Exchanger Pdf
Lewis, in Heat Exchanger Equipment Field Manual, 2013 Channels Shell and tube exchangers have several different configurations with different types of heads and shells; these parts are inspected and repaired in similar ways Figure 3.114 is a large four-pass channel in very good condition Figure 3.114.
![]() Tema Heat Exchanger Full Thickness WithThe pass partitions are near full thickness with no mechanical or corrosion damage present, gasket surfaces are also in good condition, and bolt holes for the body flange are round as opposed to showing out of roundness damage There are several design reasons for using multiple passes in shell and tube exchangers One reason to increase fluid velocity in the tubes is to reduce fouling deposits View chapter Purchase book Read full chapter URL: Mechanical Equipment Roy A.Parisher, Robert A.Rhea, in Pipe Drafting and Design (Third Edition), 2012 Shell and Tube Exchanger The shell and tube exchanger performs its task by circulating a hot liquid around tubes that contain a cooler liquid. The hot liquid circulates in an enclosed area called the shell. Tubes containing the cooler liquid are looped through the shell. Hot liquid in the shell warms the cooler liquid in the tubes, whereas the cooler liquid in the tubes cools the warm liquid in the shell. Figure 6.10 provides a look into the shell and tube exchanger. Contact between the cool and hot liquids will naturally exchange heat from the hotter to the colder. Figure 6.11 shows the Plan and Elevation views of a shell and tube exchanger. Figure 6.10. Internal view of a shell and tube exchanger. Figure 6.11. Shell and tube exchanger Plan and Elevation views. View chapter Purchase book Read full chapter URL: Regulations and Standards Ian Sutton, in Offshore Safety Management (Second Edition), 2014 Two-thirds rule Shell and tube exchangers seldom have pressure-relief valves for fire exposure because vapors will quickly flow to the next pressure vessel from which they can be discharged. The two-thirds rule from API RP 521 states: For relatively low-pressure equipment, complete tube failure is not a viable contingency when the design pressure of the low-pressure side is equal to or greater than two-thirds the design pressure of the high-pressure side. Minor leakage can seldom result in overpressure of the low-pressure side during operation. If the above rule is satisfied, then a relief valve on the low-pressure side of the exchanger is not needed provided the following contingencies are true: An engineering study is performed to verify that the low-pressure side of the exchanger is able to absorb the flow rate through the rupture without over-pressuring the exchanger. There are no block valves, check valves, or automatic-control valves on the low-pressure inlet or outlet-piping systems that may isolate the exchanger. Operating procedures require that the high-pressure side be isolated before the low-pressure side. Operating procedures require that the exchanger be immediately drained after being removed from service. Also, the exchanger must remain drained while it is out of service. The valve isolating the vessel and the exchanger will generally be a horizontal stem and a manually operated gate that is locked open. The hot-side fluid is not hot enough to boil the cold-side fluid at the design pressure. View chapter Purchase book Read full chapter URL: Exchangers Rutger Botermans, Peter Smith, in Advanced Piping Design, 2008 Alterations to Exchangers Various alterations to shell and tube exchangers can be considered to suit the plant layout, operational aspects, maintenance, or safety: Interchange flowing media between the tube and shell side. This change often is possible, more so when the flowing media are similar, for example, liquid hydrocarbons. Preferably the hotter media should flow in the tube side to avoid heat losses through the shell or the necessity for thicker insulation. On most exchangers in petrochemical plants, these changes frequently are possible without affecting the required duty of the exchanger, if the tubes are in a double or multipass arrangement and the shell is in a cross flow arrangement. In exchangers where counter flow conditions can be arranged, the flow direction should be changed simultaneously in the tube and shell. Some points to consider when contemplating a flow change are these: Shell leakage. It usually is more economical to have high pressure in the tubes than in the shell, as this allows for minimum wall thickness shell. Corrosion. Corrosive fluids should pass through the tubes, thus allowing the use of carbon steel for the shell. Fouling. It is preferable to pass the clean stream through the shell and the dirty one through the tubes.
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