Systematic analysis and design of the hybrid processes
Systematic methods and tools for managing the complexity
Tools Integration - CAPE Methods & Tools (T4-10)
Keywords: hybrid process, process integration
The hybrid processes, involve integrated operations of at least two unit operations and offer opportunities for process improvements, which otherwise, would make the original processing route infeasible. In general, the hybrid processes can be characterized as an ‘offspring’ of two different unit operations. Two types of hybrid processes are generally distinguished. The first group consists of processes which essentially perform the same function, for instant the separation and separation (S-S). The second group contains ‘off-springs’ of processes which combine processes originally different in nature, for example, combination of the reactor and separator (R-S). The design of the hybrid processes has to take into account the performance of each constituent element and the optimisation of the design must take into consideration their interdependency. The methodology presented in this work consists of a systematic approach for analysis and design of the hybrid processes that is able to save time and resources by avoiding duplication of work and by efficient decomposition of the problem into integrated sub-problems.
The systematic model based framework for design of hybrid systems has been developed. The objective is to identify the best possible process set-ups for R-S and S-S systems with desired constraints of process parameters like yield, reaction time, selectivity, product purity, energy consumption, etc. The design algorithm consists of four main steps. At step 1, in case of R-S task reactant properties, reaction kinetics and impact of solvent are analyzed in order to define the feasible reaction conditions; for S-S task the analysis of mixture is performed which includes identification of azeotropic points, phase split, etc. In step 2, process parameters are specified (needed in step 4 to determine the feasible design). Step 3 combines all the collected knowledge with adequate models to generate the feasible hybrid process (design) alternatives. In the last step (step 4), the generated hybrid process alternatives are tested under different operational scenarios. Based on this, new feasible alternatives are identified.
Depending on reaction requirements and/or selection of separation technique, the methods for solvent and membrane selection are used. Steps 3 and 4 require appropriate models which would allow the simulation of various operational scenarios for different configuration of hybrid processes. Analysis of hybrid process operation requires analysis of different process models. These models could be sufficiently simplified by merging them, for example, embedding membrane sub-models into the reactor model and thereby leading to the easier hybrid process analysis. Note that the process models also consist of the property sub-models for both unit operations. The paper presents the systematic model-based framework, the generic models developed for it, associated computer-aided methods and highlight these through application examples. For R-S task the enzymatic esterification of cetyl oleate is investigated. In that case the possibility of integration with pervaporation is investigated because earlier studies have indicated that the product yield can be improved by the removal of water (a by-product in the reaction) at appropriate low pressure conditions. Dehydration of acetic acid is an example of S-S task which is a part of manufacturing terephthalic acid.
Presented Thursday 20, 09:02 to 09:20, in session Tools Integration - CAPE Methods & Tools (T4-10).
