(182a) A Study of Vent Sizing for Chemical Reaction Runaway

Chemical plants have possibility that pressure rise in equipment occur because of process-upsets on reaction, pressurization or transfer operations. Therefore safety valve is installed for prevention of equipment rupture if pressure rise would be supposed. Assumptions of typical initiating abnormal events for pressure rise are abnormal shut on and off of control valve located before and after equipment, cooling system failure of reflux or internal coil of reactor, tube failure of heat exchanger and fire case etc. Though there are many considerations, pressure rise caused by reaction runaway is difficult to estimate. Especially, in case of two phase flow occurring by reaction runaway it is hard to say all equipment have sufficient size safety valves.

Vent sizing method for two phase flow by reaction runaway was developed by DIERS under the auspices of AIChE in 1987, and ISO 4126-10 was published in 2010 and JIS B 8227 was done in 2013, adopting the method. Here, the content of JIS is the one translated into Japanese from ISO.

The purpose of this study is to present vent sizing example about a reactor producing organic peroxide by JIS and also trial analysis example about safety measures for reducing vent size.