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Access our collection of papers and articles below.

Topics include Process Optimisation, Formulation Design, Real-Time Control/Monitoring, Operator Alarms and Process Improvement

Process control takes flight

A technology used in the prevention of in-flight aircraft collisions is also the basis for a user-friendly way of viewing process data.

Advanced Process Visualisation

Suzanne Gill reports on Advanced Process Visualisation, an interesting graphical technology which can reduce variability in process operation, with the added benefit of also reducing operating costs.

Geometry Unifies Process Control, Production Control and Alarm Management

When you lift your hand to catch a ball it is very unlikely that your brain actually formulates or solves the equations of motion in working out when and where to place your hand to catch the ball. It’s much more likely that you use, unconsciously, something that’s much more akin to the geometrical methods underlying the all-new Geometric Process Control Technology described in this article.

Geometric Process Control (GPC) combines the three key plant applications of Process Control, Production Control (i.e. Achievement of Business Objectives such as producing in-spec product, maximising Yield or Recovery, minimising waste and many other Key Performance Indicators) and Alarm Management. It improves all three applications which were previously quite separate as they lacked a unifying mathematical basis. They came together only in the different brains of individual process operators hence inconsistently. Substantial economic and safety improvements result.

New Dimensions for Improving Refining Profitability

This paper describes a very different analysis technology based upon multi-dimensional geometry and made possible by a novel co-ordinate transformation that allows for a two-dimensional representation of a multi-dimensional space. It has the advantage of being easy to learn and to use. It does not require the user to have any knowledge of multi-dimensional geometry.

The essentials of the method are described and the method is then applied to process variable history data for a refinery Steam Boiler in order to demonstrate its utility. Considerable insight is developed into the behaviour of the boiler and estimates are derived from the operational data of the financial incentives for process improvement. ‘Holes’ in process behaviour have been observed and are reported here, it is believed for the first time, as a new and important process phenomenon. Black Holes are internal regions of a process variables' range where good product has never been made yet where the plant has frequently operated and continues to operate. Examples are identified in this paper during the Boiler analysis and briefly discussed in terms of their possibly profound implications for, in particular, process control and process modelling.

Choosing Cut Points to Optimise Product Yields

This paper investigates the method of selecting Cut Point values within Modes and their effect upon Final Product Yields. It combines a proprietary non-linear CDU model with a linear Mode selection and blending model built in a spreadsheet . It shows the advantage in Final Product Yields that can be obtained by optimising Extreme Cut-Point values compared to using the design-fixed Extreme Cut Point values still used by many refiners. It uses a new multi-dimensional data visualisation based upon parallel co-ordinate mathematics to make all the results of the Mode model simultaneously visible. This has considerably reduced the depth to which users need to understand how the model works before being able to use its results.

Graphical representation of formulation data for analysis and optimization

Parallel coordinate geometry (PCG) is a graphical methodology that enables multidimensional data to be displayed in two dimensions. Such methods are capable of allowing the formulator insight into the critical relationships and interactions within a formulation, and to explore the effect of formulation variations without recourse to detailed statistical analysis.

This article describes the application of two PCG programs - Curvaceous Visual Explorer and Curvaceous Response Surface Visualiser - to evaluate a topical gel formulation. Pharmaceutical formulations are examples of high dimensional problems in which a number of physical ingredients are processed to yield a product with numerous properties. In the development of a commercial formulation, it is necessary to investigate the interactions between the ingredients, processing conditions and properties. The results are then subjected to statistical analysis to generate a model that may be used to identify an optimum formulation.

Visualising Design Space, Control Space and Operating Space make QBD and PAT Easy

This article explains the use of the n-dimensional geometric methods of Geometric Process Control (GPC) to allow visualisation of the n-dimensional Design and Control Spaces that are the foundation of QBD and their extension into the real-time Operating Spaces that are the implicit foundation of PAT.

For PAT applications the multi-variable graph is utilised to choose a set of ‘Best Practice’ operating points. These are multi-dimensional points whose coordinates are the values of all the variables which gave good results in the past. The multi-dimensional envelope of the chosen points can now be constructed to form a solid object. The operating objective to re-achieve in the future the same ‘Best Practice’ objective by which the original points were chosen is transformed into the geometric objective of being an interior point of the solid object. A new-format Operator Display is an inherent part of the method so that no separate project is required to design and implement a Human-Machine Interface..

Viewing Formulation Data Multi-Dimensionally For Improved Understanding and Optimisation

Parallel co-ordinate geometry is a methodology that allows the visualization of multi-dimensional data in two dimensions. It permits formulators to explore the data and discover new relationships between the product properties and processing variables, thus improving their understanding of the formulation. This article presents the findings of a study in which parallel co-ordinate geometry was applied to a tablet data set.

Multi-dimensional geometry such as parallel co-ordinates allows the visualisation of many variables simultaneously. More importantly it reveals the interactions between them, allowing formulators to explore these, improve their understanding of the process and hence produce better or optimum formulations. This paper describes the concept of parallel co-ordinates and how it can be applied to a tablet formulation data set.

Boundary Control of Operating Envelopes increases process profitability

Normally processes are operated to achieve conditions near an ideal or ‘optimal’ point to achieve a set of business objectives. The operating space, the range of conditions around this point that still achieve target objectives, is rarely considered and nearly never used in process control. Relaxing this constraint, implicit in today’s control methods, can achieve great operational benefits by reducing demand on dynamic process controllers and achieving secondary objectives such as catalyst lifetime while still achieving the primary goals.The volume of operating space within which one or many objectives can be simultaneously realised is the Operating Envelope of those objectives. It involves many variables so requires more than 3 dimensions to describe it geometrically.

Operating Windows ignore variable interactions and so provide a first approximation to an Operating Envelope by forming a multi-dimensional rectangular shape or hypercube. Because of the additional constraints imposed by variable interactions, operating envelopes are always smaller in volume than their enclosing operating window. This is used to advantage in applications such as predictive alarming, fault detection and prediction and condition monitoring where the window of good or normal operation consists of the operating limits placed upon many individual variables. Finding the usable volume of the envelope provides a convenient real--time graphic to allow the process operator to see where the process is operating within the overall multi-variable operating envelope and which variables are most and least constrained.


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