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Niels Jensen - CTO

Computer technology has been a part of Niels' life since the early days at DTU, when punched cards decks were submitted to the university IBM mainframe or punched paper tapes to the Gier computer at the Department of Computer Science. In those days turn-around time from job submission to debug output was available was counted in hours. Nonetheless an interest in computers and their usage to solve problems was awakened. By the time Niels graduated the mainframe had been equipped with a fast turnaround - only some minutes - remote terminal system, However input was still on punched cards, and output on line-printer paper - although a few LISP programmers had online access through Dec-writers.

Following graduation and military service a year went with modifying and improving sewage dilution modelling programs on a Digital PDP 11 computer at the Danish Isotope Center. Upon arriving at the University of Alberta in Edmonton in early 1976 a whole new world opened up. The university gave students online access to an Amdahl mainframe computer, which even included a text processing applications we could use to write our thesis, and the Department of Chemical Engineering had an IBM 1800 minicomputer connected to several experimental setups, e.g. a double effect evaporator, a single tube heat exchanger and a distillation column as well as some other minor pieces of equipment, such as a gas chromatograph. Around 1980 the IBM 1800 was replaced by 3 HP 9000 minicomputers taking less than 25% of the space of the IBM 1800, and being much faster. Except on one point: I/O multiplexing on the HP's was miles behind that on the IBM 1800. But we learned to live with it. The university mainframe was also upgraded and access was provided through Dec-writers and CRT-terminals with graphics capability - and the line printers were replaced by two page printers capable of printing 6000 pages each per hour. Niels used the mainframe to develop the GEMSCOPE suite for programs for frequency domain design of multivariable controllers using techniques based on the ideas of Rosenbrock and MacFarlane from the UK, and well as attempting to simulate an FCC. Among the novel technology at the Computer Science Department at University of Alberta at the time was a system, which allowed students to simulate laboratory experiments by using drag and drop on special screen to make the experimental setup, and introduce simulated chemicals into it.

Joining Imperial Oil in Sarnia after graduation meant introduction to a different kind of computer technology. Exxon Chemicals had basically standardized on Honeywell PMX process control computers at the time, while many of the refineries used IBM mainframes, which told the operator, that feed temperature was 21.3256 C or the flow was 876.4532 scfh.  The Honeywell PMX computers at the time had around 200 K of core memory, and multiplexed programs at 102 levels. PMX of course is an abbreviation of Process Monitoring eXxon. Similarly system was at the time used by Syncrude and by several nuclear power plants. The system was equipped with color character-based screens for the operators, and black and white terminals for the controls engineers development work. 

One interesting piece of technology developed by the team of control engineers on SPEP project was a standard approach of displaying input tags and their measurements. It was a  3 x 8 character field. The middle line was the input tag name on the form XXYZZZZ, where XX indicated the part of the plant, e.g. catalyst production or reactor, Y the type of measurement, e.g. F for flow, T for temperature, A for analyzer and so on, and ZZZZ was a unique tag number. Above the tag name was shown the setpoint of the controller and below the process measurement. The eight digit of the middle line indicated wether the controller was in manual (M), automatic (A) or computer (C) control mode. If the controller was wound-up this was indicated by a character in front of the process measurement: cannot move valve (*), cannot close valve (<) and cannot open valve (>). Finally the process measurement turned red, if either the high or low limit was exceeded. A few times a fourth line was added to indicate valve position. 

As mentioned earlier the Unipol polyethylene reactor was controlled by a multivariable controller based on laboratory measurements of polymer properties (density and melt index) and on-line gas chromatograph measurements of reactor gas composition. Another need development in HMI design from the SPEP project was a display indicating sheeting problems. Sheeting is a well known phenomena of UNIPOL reactors involving rather thick sheets of polyethylene building up on the inside of the reactor wall, and then suddenly falling down. Unless broken up into smaller pieces by the fluidization such sheeting will eventually lead to a reactor shutdown - a rather expensive event. To detect sheeting a radioactive source is placed at the center of the reactor, and then a number of detectors are placed around the perimeter of the reactor at about the same level. During normal operation these detector can go in and out of alarm for short periods - i.e. seconds, and this is of no concern. In stead of filling the alarm display with these meaningless alarms a special computer display was created, which the operator could call up during periods of sheeting. On this display each detector would change to red at the corresponding point went into alarm. Additionally a message could be generated to the operator when more than a certain percentage of detectors were in alarm (Imperial Oil discoraged the generation of alarms from computer programs, and therefore only a message was generated).
During a period when control engineers with computer skills was in high demand a number of knowledgeable people left, and Niels moved from SPEP to the light ends of the gas cracker. There together with another control and intrumentation engineer he modernized the operator interface to computer control applications to make it easier for the operator to turn these on and off, e.g. when an analyzer was out of service, and simultaneously eliminate a significant chunk of control engineer work. At the gas cracker statistical process control (SPC) monitoring of both the furnaces and the light ends was successfully introduced, so plant overview displays with this information could be presented at biweekly operations meetings. Around this time the first personal computers appeared on the Sarnia site, and by the middle of 1987 our IBM contacts told us not to buy any more 286 computers, since they would not be able to run the new operating system to be released the following year. Also at this time Niels was bypassed for a temporary assignment to the Statoil Refinery at Kalundborg in Denmark, which was planning a major expansion. This togehter with the continued downturn in the industry properly influenced the decision to move to Denmark at the end of 1987 to become an associate professor in the Department of Chemical Engineering at DTU.  

At the Department of Chemical Engineering Niels was involved the buying the first PC's for student usage early in 1988. Simultaneously the interest in safety became clearer and clearer, and from 1992 as manager of the department he was also secretary of the department safety committee. Together with the late chairman of the department Professor Knud Østergaard he introduced a system for risk assessment of experimental setups in the department laboratories based on ideas from Exxon Chemical Basic Chemical Research Center in Baytown, Texas and the Sarnia Site. Initially this system involved the experimenter writting a risk assessment, Niels reviewing it, and recommending approval to the safety committee. Over the years the systems turned out to be ahead of requirements introduced in the late nineties for all university laboratories. During this period computers moved from nice to have to need to have for both research and teaching, and teaching moved from process control to risk assessment.
The original risk assessment course at DTU was only for Danish students, and involved a set of notes developed by the former teacher over almost 15 years. The course was fundamentally changed to align itself with the safety report idea of the Seveso II directive, and then the different tools, such as Dow's Chemical Exposure Index, was introduced to perform some of the task needed by the safety report. It turned out to be much more difficult than expected to get the students to pick up the safety report format - they wanted to document, what they had done.