Process Control


Scope of the Process Control activity

The analysis of a production plant leads to split down the system into hierarchical levels ranked from 0 to 3, each level receiving its specifications from the upper level.

Level zero controllers are mainly flow rate control loops (FRCs),

level 1 (simple or cascaded) controls process variables such as temperatures, concentrations, qualities. Sherpa acts mainly at that level.

The static optimization is at level 2 and level 3 corresponds to production planning.

 

 

Sherpa applies Predictive Control and exploits its industrial experience for solving problems corresponding to some of the following topics :

 

Process Control

 
At Sherpa Engineering the Process Control is performed by an experienced team (ex-ADERSA), which made lots of industrial applications worldwide.

Control and optimization of units operations follows a step by step procedure which yields successful automation projects.
The advanced control methodologies used at Sherpa Engineering make use of 'Model Based Predictive Control' and rely on proven software.
This activity is applied to a wide range of industrial sectors : oil industry, petrochemical and chemical industries, water treatment, food industry, steel, metallurgy and others.

The units which are the usual targets for such control techniques are those whose specifications are badly fulfilled by regular control such as the classical PID, but also the processes running far from their constraints and showing an important give away. Among them : distillation columns, evaporators, chemical reactors, reformers, separators, dryers, pH control, rolling mills, concentrators and so on.
In the process control field, Sherpa Engineering offers services covering all the project steps from the analysis of the producer requirements up to the control start-up on site. 

 

Throughout an advanced control project, one of the phases is the process modelling. If some physical model is available or if it can be reasonably built, the analysis and the exploitation of such a model can be helpful.

Physical models

This possible physical model is generally not the one which will be used in real time by the controller, but it can help evaluate non linearities if any, which may be taken into account in the controller model.



Predictive controllers

This kind of controller is based on a model of the process which has been identified beforehand. Using models makes possible the simulation of the closed loop including the whole control structure in a CAD tools environment. Tuning and testing on simulator yield the best conditions for performances and robustness.

 

SHERPA SERVICES

The services from Sherpa Engineering in the process control activities covers all the phases of an advanced control project from the requirements analysis up to the start-up on site.

This activity takes place in a wide range of industrial sectors : oil, petrochemicals, chemicals, environment, food industry, steel, metallurgy, glass, etc.

The processes which are the usual targets of these predictive control techniques are those which are not well controlled by traditional PID controllers or which are operated too far from their constraints. Among these processes : distillations, evaporators, catalytic reforming, separators, pH control, concentrators, cold and hot rolling mills, chemical reactors, ...

 

Sherpa Engineering applies Model Predictive Control and brings its deep industrial for solving problems including all or parts of : the objectives :
  • Decrease the standard devioation of qualities, temperatures, ...
  • Reduce the moves magnitude of the actuators
  • Increase the feed rate while respecting the contsraints
  • Minimize the energy consumption
  • Respect the hard constraints (material resistance, pollution,...)