FIRST SUCCESSES IN PROCESS INTENSIFICATION

Hydrogen membrane separation, Reverse-flow reactors, Dividing-wall Column Distillation and Reactive distillation all had their first implementations between 1977 and 1987. There are two reasons for this: First, between 1920 and 1970 the focus of the petrochemicals business was on bringing new products to market. Then it changed to globalisation and increasing the markets for these products [1]. This required more plants and more efficient plants. Second, two oil crises and environmental concerns, such as about acid rain, global warming and limited resources began to be raised in the 1970's, as highlighted by “Limits to Growth", the report of the Club of Rome,

The four technologies mentioned above fitted these new constraints by lowering cost and emissions to the environment. Technology providers took the opportunity to launch their innovative PI technologies with these features. In-house pilot plant test facilities, combined with reliable scale-up methods, reduced the risk of failure. The development cost could be spread over many implementations, allowing for attractive offers to the oil refinery and base chemical companies. With their offer of novel technologies, proven by pilot plant tests and robust scale-up methods, allowing for rapid decisions they probably also removed internal mental barriers inside these large conservative companies.

Two pieces of evidence support this hypothesis. Somewhere in the period 1997-2000, prof. Hans Kuipers, then of Twente University, gave a lecture at Shell for a large group of reaction engineering experts on the theory and modelling of reverse flow reactors. One of the experts asked whether this technology was already applied on a commercial scale. Professor Kuipers said that he did not know of any commercial application. A lively discussion started over whether the technology would be applied in Shell. The common feeling was that this would be unlikely as reliable operation was hard to foresee, given the number of valves that had to be opened and closed every minute. A few months later, my colleague Rene Bos told me that shell had a RFR in commercial operation at Shell Moerdijk to remove VOC from a carbon dioxide rich gas stream. He became aware of its existence when a control problem appeared and Rene was asked to analyse the problem. He even obtained a patent on an improvement of the technology [2].

The second piece of information is for reactive distillation. A reactive distillation for a specific process has been in use on a commercial scale at Shell Chemicals in 1953 [3].

No other application happened anywhere in Shell in over 30 years, until CDTECH approached Shell with their reactive distillation technology. After pilot plant tests, the first implementation in 1987 was a revamp of a distillation column at Shell Motiva refinery, by placing bags with catalysts on the distillation trays [4]. After this implementation a total 12 reactive distillations where implemented in Shell [5]. Many implementations in many different oil refineries and petrochemicals then followed [4].

By Jan Harmsen (Harmsen Consultancy BV)