Pipe bundle

In contrast, Dunlap and Rushton [34] succeeded to correlate their measurements at cooling and heating in a vessel with a turbine stirrer and pipe bundle heat exchangers with Vis-0 4 because a thick boundary layer developed around the tubes. 

The following correlation for pressure drop describes flow perpendicular to pipe bundles for Re < 25xx/(x-l), where x is the ratio of pipe spacing to pipe diameter, v means the mean fluid velocity over the bundle front surface, 1 - the pipe bundle length in the flow direction, and d - the pipe diameter. In our case, we have two bundles in series with x=2 and with 1/d = 1 at a distance of more than 2xd, and d=d= le-4 m, so we can write here for the pressure drop ... 

If only small amounts of heat need to be transferred, the tank wall is a satisfactory heat transfer surface, when appropriately jacketed (Fig. 1.2). The wall surface often is inadequate for heat transfer, particularly in the case of industrial tanks, because upon scale-up the liquid volume increases according to D whereas the surface area only increases according to D. Additional heat transfer surfaces have then to be installed in the form of differently designed pipe coils or pipe bundles (helical coils, meander coils (cooling basket) tube bundles see Fig. 1.3). 

Increased vibration (up to 3g) of the superheater heat-exchange pipes located mainly along the pipe bundle periphery. 

The process gases enter a forced-circulation-type waste heat boiler at 800-1000 °C. Several changes have been made to the mechanical rapping equipment and cooling pipe bundles of the boiler to improve the performance and maintenance access. The gases exit the waste heat boilers at a temperature of 300-350 °C and pass through the hot cyclone separators and electrostatic precipitators into the mercury removal towers. Two electrostatic precipitators are installed simultaneously in both lines to ensure continuous processing. 

The commercial weight of a pipe bundle is about 75 kg with a maximum pipe diameter of about 60 mm. The bundle is lifted out of the coiler, wrapped with straw ropes and prepared for shipment. For the purpose of roughly determining the weight of a pipe bundle, the press is provided with a dial gauge indicating the extruded weight in dependence of the ram stroke. 

The main advantage of this approach is that a visual inspection of the feed water pipe can be performed directly due to the placement of the whole water distribution system over the primary pipe bundle. Using this system, any potential defects are easier to observe. Another advantage arises from the seven boxes with ejectors that mix the feed water with boiler water, thus decreasing the thermal load. An additional advantage is that it is possible to check and exchange of the distribution boxes if they get damaged. 

---