FIG. 3.8.5 The oxychlorination step of the vinyl chloride process with oxygen feed. (Reprinted, with permission, from Smith and Patela, 1992.)

processing introduces a safety problem downstream of the reactor; unconverted ethylene can create explosive mixtures with oxygen.

This problem can be avoided when a small bleed of nitrogen is introduced. Since nitrogen is drastically reduced in the feed and essentially all ethylene is recycled, only a small purge must be vented. This method results in a 20-to-100-fold reduction in the size of the purge compared to a process that uses air as the oxidant (Reich 1976).

0 0

Post a comment