UPGRADING AMMONIA PLANT EMERGENCY SHUTDOWN SYSTEMS

摘要

An Emergency Shutdown systems (ESD) is the last line of defense for safe operation of an ammonia plant. They are expected to provide coverage in case of equipment failure, process upset or human error. Essentially these systems are expected to bring the plant to a predefined safe state through a set of logical actions on fulfillment of certain conditions i.e. process variable going to a safety high risk zone. This paper shares the experience of upgrading an old and obsolete pneumatic shutdown system of a 1970 vintage ammonia plant to state of the art Triple Modular Redundant (TMR) electronic system. It also covers the experience of adding new shutdown securities at furnace, compressor along with upgrading of control systems to avoid high hazardous events.