AUTOMATIC SYNTHESIS OF CONTROLSTEPS IN BATCH PROCESS OPERATIONS

Abstract

In general, a batch chemical plant is used to produce multiple products and its key characteristics is flexibility. The flexibility means that the same processing equipment units may be employed to produce different products or the same product may be produced in different processing equipment units. In order to produce a desired product, the processing requirements specified in the product recipe must be converted to a set of control steps or operating procedures. In practice, this kind of tedious and time-consuming work is done by the process engineers based on their experience. A three-step synthesis strategy for the automatic synthesis of control steps in batch process operations is presented in this paper. The first step is pre-operation which consists of a set of process operation checks, safety checks as well as user-specific checks that must be considered before the starting of the basic process operation. The second step is operation which is described by a set of basic control steps such as open valve and start pump. The third step is post-operation which is described by a set of instructions that must be performed when the basic process operation is terminated. The emphasis is how to perform the required basic process operations in the specified processing equipment units. In this strategy, object-oriented programming (OOP) is used to represent the processing equipment units and the master recipe procedures. The plant topology and the processing equipment units are represented by a process matrix, and the processing requirements are represented by a master recipe which is converted from a general recipe. The three-step synthesis strategy has been implemented as part of a recipe management system. These control steps may be passed to the control engineer or a control computer for the generation of the control code.