CIL's experience with a computerized ammonia plant trip system


  • A. J. Cobb,

    1. CIL, Inc., North York, Ontario, Canada
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    • Tony Cobb is a graduate of London University, and is a Member of the British Computer Society.

      Since the early 1960s he has worked on the computer control of both, batch and continuous chemical processes, his first live application being the optimizing control of an Octanol plant in 1963. Recent projects include the design and implementation of the trip system which forms the subject of this paper, and the application of expert systems to process control.

      He immigrated to Canada from the UK in 1981, and since then has worked in the Engineering department of CIL, in Toronto, Ontario.

  • S. Monier-Williams

    1. Simons AT, Don Mills, Ontario, Canada
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    • Stephen Monier-Williams has thirteen years of experience with process and control systems in the pulp and paper and chemical process industries. During the past year he has worked for a consulting engineering company specializing in process control technology.


The computerized trip system has been in use since August, 1985, at the CIL Ammonia II plant. Superior reliability, essential avoiding unnecessary shutdowns, while protecting the plant from accident, is obtained through use of a fault-tolerant configuration.