Over-pressure and Explosion Protection
Where prevention techniques and systems alone do not have the necessary robustness, over-pressure protection will be required.
Chemical Reaction Hazards
In the case of uncontrolled chemical runaway reactions, safety options may include enhanced process control measures linked to:
Where there is sufficient evaporative cooling, a correctly sized reactor vent and disposal system can ‘temper’ a runaway, as shown in the diagram. Controlling the reactor venting pressure prevents the reaction rate increasing and this can be achieved with vents of modest size. Care is needed, however, to ensure that a secondary (and more violent) decomposition cannot arise when the solvent (providing the evaporative cooling) has boiled off!
Similar methods are employed for fuel-air explosions arising from deflagrations:
These techniques may not provide complete protection since consideration is required of interconnected equipment and supplementary trips / isolation features such as rotary valves, slam-shut valves, chemical barriers or explosion chokes (diverters), etc.
Our consultants help clients to gain an understanding of the potential explosion hazard and select the most appropriate ‘basis of safety’; simply bolting on protection systems is not a cost effective approach.