High Volume Low Concentration (HVLC) Collection Systems, 1998 Cluster Rule Symposium Proceedings

High volume low concentration (HVLC) gas typically has volatile organic compounds (VOC) content of less than 25% of the lower explosive limit (LEL). Low VOC concentration is maintained primarily through air infiltration and dilution. Sources to be collected, per Cluster Rule, include brownstock and oxygen delignification system washers, filtrate tanks, intermediate stock chests, knotters, screen systems, weak black liquor tanks, and deckers. Some exemptions may apply for knotters, screens, deckers and weak black liquor tanks . Total source volume flows range from 20,000 to 60,000+ acfm before conditioning. Collection systems include equipment for enclosures and source collection, cooling and moisture removal, gas transport, venting, and oxidation pre-treatment. Separate area collection systems should be implemented for operational flexibility. Collection system controls and interlocks are key to a safe operation. Heating and cooling requirements (water and steam) should be determined up front for their impact on overall mill operations.