Protective Measures for a Vent Manifold System

Example 1—Protective Measures for a Vent Manifold System 

This example illnstrates several protective measnres that were provided for a vent manifold system in an actnal aromatics chemical plant. 

Fignre 9-1 is a schematic drawing of the major eqnipment and protective measnres that comprise the vent manifold system. In the system shown, the vent vapors (offgas) from the condensers of two vacnnm col-nmns are collected in a manifold which goes to the vacnnm pnmp system. From the vacnnm pnmp system, the vapors go to a seal dmm (hydranlic flame arrester), and then to the firebox of a process heater, where they are incinerated. 

The offgases from the two vacnnm colnmns, at the vacnnm pnmp discharge, normally contain 1.3 mole percent organic vapor (Cg to Cg aromatics) in air, which slightly exceeds the lower flammable limit of the 

FIGURE 9-1. Vent manifold system protective measures. 

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