Modeling a boiling-liquid, expanding-vapor explosion phenomenon with application to relief device design for liquefied ammonia storage

This paper addresses a fictitious accident scenario involving an ammonia st orage tank in a refinery. Ammonia is used in a deNOx system. In a selective catalytic reduction environment, a refinery stack gas containing nitric ox ide and nitrogen dioxide is decomposed into nitrogen and water vapor. In th is study, a cylindrical ammonia tank is "bleved" (boiling-liquid, expanding -vapor explosion (BLEVE)) with an external fire. We developed a computer mo del in order to determine the thermal response of a horizontal ammonia tank involved in fire engulfment accidents. The assessment of the separation di stance between tanks and protection measures such as water spray cooling we re also discussed. Further, we examined the relief device design and studie d the open-system thermal response as well as pressure response effects in the event of a BLEVE for the ammonia tank.