Decision support system for unsteady-state reactors design using case-based reasoning approach
Systematic methods and tools for managing the complexity
Process Synthesis & Design - II (T4-1b)
Keywords: decision support system, forced unsteady-state reactors, case based reasoning
The design and simulation of forced unsteady-state chemical reactors involves the mathematical modelling of transport phenomena and reactions in processes that take place in multi-phase systems. The detailed mathematical models of these systems that account for inter and intra-phase gradients as well as exchange or interaction between the phases are often complex and may be expressed in the form of several partial differential equations in two or three spatial coordinates and in time. In addition, these detailed models contain a large number of physical-chemical parameters. There are regions of the parameter space in which the rates of some of the transport or reaction processes are much slower or faster compared to others parts of this space. It results in a big complexity of the phenomena that take place inside the reactors, making the models very often inadequate for analysis or computation. The numerical procedures to solve mathematical models related to forced unsteady state reactors, required a lot of work focused on reduction of computational time. It is realized by using highly-efficient numerical methods, by simplifying mathematical models to one dimension and by fixing the boundary values in time at the beginning and end of the half cycle to avoid the need to solve over the long transient period before the establishment of the stationary conditions.
Despite a large body of literature in this field, there is no standard procedure developed for the design of reverse flow reactors. The design is carried out by trial and error, coupled with extensive and tedious detailed numerical simulations.
Concerning above mentioned general characteristics of the forced unsteady-state reactors design, this work attempts to provide a method for new problems solving by adapting solutions that were used to solve past similar problems. To illustrate this a case based reasoning (CBR) approach have been used in order to provide the insight into reverse flow reactor behavior needed for design decisions; taking into account the experience and solutions provided by the most similar past cases in order to solve new ones.
This approach generates automatically the alternative representations, provides computational information for modeling using previous design experiences, generates new ideas, frames the problem, and evaluates and adapts design alternatives. An example of methodology of design characteristics retrieval related with forced unsteady-state reactors was given to illustrate the proposed design method.
Presented Tuesday 18, 16:00 to 16:20, in session Process Synthesis & Design - II (T4-1b).
