On-line process economics optimizers were developed in the oil refining
industry, and have since been adopted by chemical producers who make primarily
basic chemical building blocks.
The industry was made possible by process computer control, which began by
using computer subroutines to control individual process variables in a chemical
manufacturing operation. These were designed to maintain technical setpoints
established by process design engineers. As the industry matured, it incorporated
cascade control to optimize (at the technical level) a group of process variable
parameters.
While technical process control optimization using computer subroutines was
being employed within manufacturing plants, oil refiners developed off-line
linear programming techniques (ex. PIMS) to optimize the economic performance
of their refineries. Refiners later installed their linear programming computer
models onto their process control computers, and would periodically run the
linear program (once a day, once an hour) to manipulate the technical variables
of the plant to satisfy an economic optimum objective function.
Chemical producers familiar with refining (ethylene producers) adopted the
know-how employed by oil refiners in computer process economic optimization,
and began expanding both the range of applications and the type of mathematics
used, in order to provide more meaningful economic setpoints on a more frequent
basis than the cumbersome linear programming models used in refining.
This study identifies the organizations that sell commercial economic optimization
computer programs designed to run on process control computers. This study
indicates what chemical applications (chemical products) optimizer routines
have been developed for, the mathematical bases used in the routines, the
types of algorithms used, and the commercial results claimed that justify
the capital investment required, and the ongoing software support effort.
This study also provides case studies of several chemical manufacturers that
actively employ economic optimizers, and reports upon the actual results obtained
and the benefits actually achieved. Finally, it pinpoints areas of possible
improvement in future developments.
