Shell tube exchanger

Uc overall clean heat transfer coefficient for shell tube exchange, Btu/h ft2 °F... 

Shell/Tube Exchanger Practical Design/Rating Equations... 

The preceding equations are equally applicable to designing a shell-tube exchanger. Specifically, apply Eq. (5.8), using a selected Rd value for your particular service. In Eq. (5.8), remember that hd = 1/Rd. Thereby selecting an Rd value, you then calculate Ud, applying Eq. (5.8). 

Conclusion. Having now gone through an eight-step procedure to not only rate a shell-tube exchanger, but also to design a new exchanger,... 

The base cost of a major equipment module is herein defined as the specific equipment item fabrication cost, such as that of a fractionation column, a field-erected furnace, a shell/tube heat exchanger, or process pump. Each of these items will be given a fabrication cost. A figure cost curve will be presented for each major equipment item, and will have cost of the item vs. a key process variable. These key process variables could be the furnace absorbed-heat duty, the shell/tube exchanger tube surface area, and the pump discharge pressure/gpm product number. 

Figure 8.3 s cost curve is based on floating-head shell/tube exchanger construction with carbon steel shell and tubes. The cost figures may reasonably be extrapolated up to 10,000 ft2 of bare outside tube surface area. The subsequent tables, Tables 8.8 to 8.12, include factors for design type, materials of construction, and design pressures up to 1000 psi. Cost factors for foundations, field materials, field labor, and indirect cost may be obtained from these tables. Add each applicable factor, then multiply by Fig. 8.3 base cost. You may interpolate between values shown. 

The shell/tube exchanger base cost is as follows ... 

TABLE 8.12 Shell/Tube Exchanger Module Associated Cost Factor Additions, in Percent... 

For a quick estimate of a shell/tube exchanger module package installed cost, multiply the vendor shop quotation of the unit times 319.2. If you need a quick 25% vendor shop FOB cost, then use Fig. 

Shell Tube Exchanger Fouling Troubleshooting Delayed... 

The Stainicaibon process is described in Figures 3—7. The synthesis section of the plant consists of the reactor, stripper, high pressure carbamate condenser, and a high pressure reactor off-gas scmbber. In order to obtain a maximum urea yield pet pass through the reactor, a pressure of 14 MPa (140 bar) and a 2.95/1 NH —CO2 molar ratio is maintained. The reactor effluent is distributed over the stripper tubes (falling-film type shell and tube exchanger) and contacted by the CO2, countercurrendy. This causes the partial NH pressure to decrease and the carbamate to decompose. 

Impervious graphite heat exchangers machined from solid blocks are also available (15,16). The solid block constmction is less susceptible to damage by mechanical shock, such as steam and water hammer, than are shell and tube exchangers. Block exchangers are limited in size and cost from 50—100% more than shell and tube units on an equivalent area basis. 

If the CO is not completely combusted to CO2 in the regenerator, a CO boiler is used to complete the combustion. The resulting heat of combustion and the sensible heat of the flue gas along with any heat from auxiUary fired fuel are recovered in the form of high pressure steam. When the regenerator is operated in total CO bum, the CO boiler is replaced with either a shell and tube exchanger or a box-type waste heat boiler (see Heat... 

Kettle-type reboilers, evaporators, etc., are often U-tube exchangers with enlarged shell sec tions for vapor-liquid separation. The U-tube bundle replaces the floating-heat bundle of Fig. 11-36. ... 

Transverse fins upon tubes are used in low-pressure gas sei vices. The primary application is in air-cooled heat exchangers (as discussed under that heading), but shell-and-tube exchangers with these tubes are in sei vice. 

Impervious graphite heat-exchanger equipment is made in a variety of forms, including outside-packed-head shell-and-tube exchangers. They are fabricated with impervious graphite tubes and... 

Cost data for shell-and-tube exchangers from 15 sources were correlated and found to be consistent wrien scaled by the Marshall and Swift index [Woods et al., Can. J. Chem. Eng., 54, 469-489 (December 1976)]. 

Induced-draft units are less likely to recirculate the hot exhaust air, since the exit air velocity is several times that of the forced-draft unit. Induced-draft design more readily permits the installation of the aircooled equipment above other mechanical equipment such as pipe racks or shell-and-tube exchangers. 

Ground area and. space requirement.s. Comparisons of the overall space requirements for plants using air cooling versus water cooling are not consistent. Some air-cooled units are installed above other equipment—pipe racks, shell-and-tube exchangers, etc. Some plants avoid such inst ations because of safety considerations, as discussed later. 

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