Friday, 8 November 2013

Systematic Process Plant Design: state of the literature

As part of preparation for writing my plant design book, I've been reading previous attempts to set out a process plant design methodology for beginners- "Total Design" was just one of many.

Here are my comments on a few more:

Billy Vaughn Coen: "Discussion of the Method" - deep, dense and philosophical, but he does know what design is about - his koan is "all is heuristic". Worth reading.

William D Baasel: "Preliminary Chemical Engineering Plant Design" - written by an academic who did a placement in industry, who came to understand that process design is really plant design, and the importance of what is glossed over in academia. Pity it's so old, but still worth reading.

Backhurst and Harker: "Process Plant Design" - its heart is in the right place, as it understands that what engineers do differs from what uni teaches them, but the authors' academic background makes them emphasise a few areas which they themselves describe as arbitrarily chosen rather than system level design. Don't bother with it - too old, and partial.

William L Luyben: "Principles and Case Studies of Simultaneous Design" - "simultaneous design" considers both steady state economics and dynamic controllability aspects of the process, reminding me of the bar in the Blues Brothers which has both kinds of music. Design for controllability is strongly emphasised in this approach, supported by computer modelling.

The problem is that in achieving his stated aim of producing something smaller and less encyclopaedic than Perry's, he has chosen only two elements. These are without a doubt important partial design elements, but optimising only two variables will not produce an optimal solution- this is process design, not plant design, partial rather than total design, and substitutes modelling for design.

Sandler and Luckiewicz: "Practical Process Engineering, a Working Approach to Plant Design" - Old, but an academic and a practitioner get together get together to try to remedy the shortcomings of academic engineering courses. Has  great deal to say about drawing, and practical hydraulics, but very sketchy and partial indeed when it comes to unit op design - "vessels" covers everything from reactors to storage tanks. Has useful stuff about trace heating lagging and electrical power and motors. Though partial and old, it has useful stuff that none of the others cover. I'm going to expand upon and update some of this unique content in my book.

Peters, Timmerhaus and West: " Plant Design and Economics for Chemical Engineers" - As the title suggest, has a lot to say about economics - also has stuff on technical report writing and delivery. A textbook on partial design for undergraduate teaching written by academics.

Wells and Rose: " The Art of Chemical Process Design"- great title, but unfortunately written by an academic and a software company rep. who think that design starts in the lab and proceeds via simulation and modelling. At least recognises the iterative nature of design, but there is no art here. This looks to be the precursor to the misguided recent books by academics on "Process Design/ Intensification/ Synthesis" which I shall not mention further.

Van Koolen: "Design of Simple and Robust Process Plants" - Simplicity and robustness are indeed  heuristics in plant design, and has some useful summaries of the implications of ten approaches to process or process plant design. Quantifies complexity, which is an interesting and potentially fruitful approach, but then loses itself in combinations of partial approaches, and academia's pointless attempts to substitute modelling and simulation for design. Worth a cautious read.

Pahl and Beitz: "Engineering Design  A Systematic Approach" - Once again, a general text captures the essence of  design in a way that so many chemical engineering texts do not. The Google books review says that " No other book in English provides so detailed and thorough an approach to engineering and design methodology", a claim I am quite willing to believe.

It includes quite a bit of stuff on systematic techniques to supposedly enhance creativity (which I'm not that convinced about) but I'd rather emphasise something which is genuinely a useful aspect of design than things which are not.

The book suggests both explicitly and implicitly that German design teaching is far more closely aligned with professional practice than in the English-speaking world. If true, might this to be to do with the high status of the engineer in Germany? Definitely worth a read, though it's a bit old.

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