Once the exchanger system was decided upon, a rigorous analysis of the primary heat exchanger was necessary. A diagram of what this exchanger might look like is included in Figure 2. The removable tube bundle allows the tubes to be cleaned easily, which would most likely be done by hydroblasting. Access for cleaning is essential to the function of the system. U-tubes were chosen because they allow for expansion of the tube bundle.
Expansion joints are costly and a potential source of hazardous leaks.
The two pass shell design is most common and delivers higher efficiency in heat exchange. In order to minimize the necessary utility costs, maximum cooling must occur in the exchanger, and this is assured with the two pass shell design. In addition to its high temperature tolerance, incoloy should be used in this system because it is resistant to hydrogen attack. The tubes will also be thicker-walled than standard to contain the high pressures in both streams. The surface area necessary for this exchange was calculated by Aspen to be 120.2 m 2 .