Michael L. Michelsen

Obituary of Professor Michael L. Michelsen

Wednesday 16 Sep 20


Georgios Kontogeorgis
DTU Chemical Engineering
+45 45 25 28 59


Kim Dam-Johansen
Professor, Head of Department
DTU Chemical Engineering
+45 45 25 28 45
Professor Emeritus Michael L. Michelsen passed away on 26 August, 2020.

He retired from DTU on 31 December 2012 but continued as an active Emeritus until the end of his life. His last co-authored manuscripts are in the process of being published in the journal Fluid Phase Equilibria.

Michael was educated chemical engineer from the Technical University of Denmark (DTU) and since 1973, he was a faculty member of DTU, at the Department of Chemical and Biochemical Engineering. For many of these years he was a member of the research centre IVC-SEP, later CERE.

For four decades Professor Michelsen has been one of the world’s great authorities in thermodynamics, and in particular in the development of algorithms for the efficient and fast computation of phase equilibrium for non-ideal mixtures. He developed numerical procedures for multicomponent, multiphase phase equilibria, which is the typical situation in practice (industry and nature). Such algorithms are of paramount importance for the design and operation of complex processes and they have found widespread use in the chemical and petroleum industry.

Professor Michelsen has also shown how enhanced understanding of the mathematical interrelations can result in new advanced models and opportunities never conceived before. For example, he was the pioneer in the development of advanced mixing rules for cubic equations of state and thus showed how the classical solution models, originally developed for low pressures, can be employed at higher pressures of interest to many industrial applications. Later, prof. Michelsen showed how the newly developed association models (for mixtures with complex interactions like hydrogen bonds) can be formulated in ways that permit their efficient implementation and use for challenging and demanding applications.

Professor Michelsen has been always in the forefront of science, continuously following the developments and contributing not just to thermodynamics but to a large variety of disciplines. He has made significant contributions especially in relation to numerical methods in fields like reaction engineering, transport phenomena, and material science with emphasis to polymer solution thermodynamics.

A worthy follower of thermodynamic giants (and Nobel Prize winners van der Waals, 1910; Debye, 1936; L. Pauling, 1954; Lars Onsager, 1968; Paul Flory, 1974; Ilya Prigogine, 1977, Kenneth Wilson, 1982; Walter Kohn and John Pople, 1998), professor Michelsen’s algorithms have brought thermodynamics from the “middle ages” of the middle 20th century to the modern computational tools we have today. Tools which have brought a profound change in the engineering practice.

He has published about 150 scientific articles and co-authored three books. In particular, the most recent one co-authored with Jørgen Mollerup has been the basis of a PhD course, which they started 25 years ago. The course is still taught every year in August by current faculty members of CERE.

Michael was also an excellent teacher and he will be remembered for his brief but often very accurate and direct statements about applied thermodynamics and other topics.

His students remember him as an excellent professor, always willing to help but also a demanding teacher setting high expectations for students and colleagues. One should always listen carefully (and take notes) when talking to Michael! His contributions will have global impact on chemical engineering thermodynamics for many years to come. His scientific spirit and inspiration will remain with us at DTU, where we will miss his genius and great personality.

- Professor Michael L. Michelsen (14 February, 1944 – 26 August, 2020) -

May his memory live on!


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