Hazard and Safety Analysis for Fuel Rich Propellant Processing Facility

摘要

Fuel rich propellants are used as sustainer propellants in missiles with integrated rocket ramjet propulsion system. The propellant consists of a metallic fuel, solid oxidizer, organic binder and solid lubricant. The production of fuel rich sustainer propellant consists of a number of operations involving hazardous chemicals, which are handled or processed under hazardous operating conditions. In view of the critical nature of some of these operations a complete hazard and safety analysis of the propellant processing facility has been carried out with an aim to arrive at measures to eliminate or control them. Fire, Explosive and Toxicity Index (FETI) studies of the various sections of the facility indicate processing of fuel rich propellant, dry mixing of raw materials and powder compaction come in the highest category (Ⅲ) with respect to Fire and Explosion followed by naphthalene coating on magnesium in the medium hazard category (II) and magnesium sieving which is on the border line between medium and low hazard categories. Hazard and Operability Studies (HAZOP) of the propellant processing facility bring out the major hazards as Fire/Explosion and Dust explosion in dry mixing and powder compaction sections. Magnesium coating and sieving sections are associated with toxicity and health hazards. Fire/Explosion in mixer room has been identified as one of the major hazards requiring detailed assessment. Fault tree analysis has been carried out to bring out the critical basic failures leading to unwanted event of fire/explosion in mixer room. The fault tree analysis indicates that a fire/explosion can occur in planetary mixer room if there is fire during loading of ingredients into the mixing trough, during unloading of mix from the trough or in the kneading trough itself during mixing along with a simultaneous failure of the fire extinguishing system in the room. Each of these sub events has been further resolved into its contributory cause events. Based on this study safety measures in terms of probabilistic and deterministic features to be incorporated in the system have been recommended to enhance system safety.