Optimal Design of a Hydrolysis Sugar Membrane Purification System Using a Superstructure-Based Approach

Abstract

As an alternative to gasoline, bioethanol can be produced from lignocellulosic biomass through hydrolysis using an ionic solution containing zinc chloride (ZnCl2). This method allows for a high yield of glucose from lignocellulose, but entails the removal of ZnCl2 from the hydrolysate using multiple nanofiltration membranes before the fermentation of glucose. This paper presents a mathematical technique for designing such a multistage membrane separation system. The optimization model for the synthesis of membrane networks is based on a superstructure with all feasible interconnections between the membrane units, and consists of mass balances, logical constraints and product specifications. A case study of the separation of a bagasse hydrolysis solution is used to demonstrate the application of the proposed model. Results show that using both types of nanofiltration membranes allows higher ZnCl2 removal ratios at each membrane unit, hence a decrease in the number of membrane units required and a reduction of about 35% in capital cost compared to the cases in which only one membrane type is used. Further analysis is performed to examine the effect of membrane performance on the economics of the separation system.

Special Issue on “Multi-Period Optimization of Sustainable Energy Systems”

“…Their method was tested using a case study of two distribution systems. Su et al [5] presented a superstructure-based optimization model for the design of multi-stage membrane separation systems and used a case study of the separation of a bagasse hydrolysis solution to demonstrate the application of their model.…”

“…Three contributions addressed multi-period optimization for negative-emission polygeneration plant design [1], biorefinery supply network synthesis [2], and inter-plant hydrogen integration [3]. In addition, two contributions dealt with multi-objective optimization for the allocation of distributed generation (DG) and electric vehicle charging stations (EVCSs) [4] and multi-stage membrane separation system design [5].…”