Reappraisal of the role of turpentine vapor in noncondensible gas explosions

Turpentine has been identified as the cause of numerous fires and explosions within the pulp and paper industry. Explosions in the noncondensible gas (NCG) collection systems caused by total reduced sulfur (TRS) compounds have usually been minor and caused minimal damage, but explosions caused by turpentine could be catastrophic. When flammable conditions have been created by insufficient dilution, air leakage into the system, or accumulation and breakthrough of TRS gases or turpentine vapor at a chip bin, it is conceivable that turpentine vapor created near-optimum flammable mixtures more often than TRS gases did. In these cases, the burning velocity would have been close to the maximum. On the other hand, when flammable conditions were created due to insufficient dilution of a stream of high volume, low concentration gases (HVLCs) or due to air leakage into a stream of low volume, high concentration gases (LVHCs), then the flammable mixture formed would be expected to have been off-stoichiometric: lean in the former case and rich in the latter case. In both cases, the burning velocity could have been much lower than in the near-stoichiometric mixture. The violence of explosions caused by turpentine is attributed to its capability to form near-stoichiometric mixtures more easily than the other components of NCGs.