Reader Comment - 12-11-09 - Water Sprays II

Fred Millar, a long time reader and frequent commentor, provided a lengthy commentary on my blog about the water spray mitigation system used at the CITGO refinery that experienced the explosion and fire this summer. Fred has been actively involved in the movement to get refineries to change over from HF to sulfuric acid or solid catalyst use. As is usual with his comments, he provides a great deal of information and his entire comment is certainly worth reading. Fred makes the point that: “The question is the adequacy of such systems and the reliability of these. Even an accident in an HF refinery reportedly often damages and renders inert the water systems.” He also points to tests done by industry in the 80’s that demonstrate the extent of the hazard from an HF release without mitigation. The fact that there were no off-site deaths associated with the Corpus Christie HF release provides encouraging information about the importance of properly designed mitigation measures. The term ‘properly designed’ is the key part of that statement and is the reason for the CSB issuing their emergency recommendation for work on those systems. The calculation that 4,000 lbs of HF escaped the water spray system is a major concern for local residents and facility employees. Fred also makes a valuable point about the survivability of these systems in the types of devastating accidents that too frequently occur in refineries. The huge amounts of volatile explosively flammable chemicals found in these facilities mean that safety systems of all sorts must be designed to withstand violent explosions and fires. A system that does not work when there is an explosion that causes a catastrophic failure of the HF containment is useless. Fred does not explicitly make the point here (though he has in other venues) that water sprays alone are insufficient to protect on-site workers and facility neighbors. Alarm systems to detect and track releases, notification systems and training for those affected to soon to evacuate, and a well planned and exercised evacuation plan are all measures that need to be in place in addition to spray mitigation systems. All of those procedures as well as hardening HF storage systems are necessary if facilities are unwilling (or unable) to follow the real recommendation that Fred and many others make that these refineries should make the process changes to remove HF from their refineries. While that is a complex debate being carried out in a number of venues, there is no argument that the only way to completely remove the threat of a potential HF release is to remove the HF from the facility.