Twenty-five years ago (1962) a project team was constructing the first of two ammonia plants built at ICI’s Severnside site near Bristol. At the time of writing two new replacement ammonia plants are under construction. Many of the changes which have occurred during the intervening period can clearly be seen by comparing the two projects. Scientific progress in understanding biological nitrogen fixation has been made but has not so far provided an alternative to current industrial processes nor supplanted the need for them. Alternatives to ammonia manufacture as the primary industrial route to fixed nitrogen have made little progress despite some apparently powerful incentives. And so the investment cycle at Severnside is completing one revolution, with a very different set of factors leading to replacement with plants similar in capacity to those originally installed. In their day the original units were seen as prototypes of a new design of highly efficient single-stream plant of maximum practicable size; the modern plants are seen to be pioneering a combination of new technology and engineering technique specifically aimed at bringing the efficiency of state-of-the-art large plants to ‘small’ production units with minimum capital penalty. The financial performance of plants of differing size is discussed.
A Pinto and S G Trotter, ICI Chemicals and Polymers Group, Billingham, Cleveland, UK.
28 pages, 6 figures, 8 tables, 14 references.