Flowsheet Monitoring – How, what and why?

Within the 5th CAPE-OPEN US Conference, held as a Topical Conference at AIChE 2008 Annual Meeting on November 19, 2008 in Philadelphia, Jasper van BATEN (AmsterCHEM) gives a paper (397c – PDF 362 Kbytes) on his proposal of new interfaces to add the flowsheet monitoring functionality to CAPE-OPEN.

Jasper begins by explaining what is a flowsheet and especially what are its elements from a conceptual point of view. What is of interest here are streams, whatever their nature (material, energy, information) and unit operations. It is worth noting that a given unit operation knows only about the streams that are connected to it while the thermodynamic sub-system of any Process Modelling Environment (PME) does not know about streams and unit operations. The PME is knowing about all streams and all unit operations.

Next he is describing what flowsheet monitoring is as a functionality.  What is at stake here is to introduce an element that wants to carry calculations based on multiple flowsheet elements that may or may not be directly connected. Nowadays that can only be done by the PME. You may want to easily customize to your needs what the PME may do. This calls for a new software component, a Flowsheet Monitoring Component which is given access to all flowsheet elements, that is to the properties of each stream as well as to the public parameters of each unit operation, but also to the thermodynamic sub-system, while not being allowed to modify data in existing streams and unit operations.

Jasper then points to a number of applications where flowsheet monitoring may be used. Making an overall balance is an application, determining phase envelopes on given streams is another one, or predicting wax formation in any pipe, that is in any stream connecting two unit operations.

The analysis of flowsheet monitoring in terms of CAPE-OPEN comes next. It is there that Jasper proposes the new CAPE-OPEN interfaces that will be needed to cover the added functionality. He then assesses what will be the various impacts on PMEs to adopt the new interfaces before summarizing what is the status: mostly an interface specification proposal has been made with prototyping made through implementions in COFE and in two components, one from AmsterCHEM, one from US EPA.