Background

The equilibrium position of a polycondensation reaction can be shifted towards higher conversion rates by removing water. Within an industrial project at IMVT, the possibility of a continuous removal of water during the polycondensation of sugars using porous membranes is investigated. The water is to be separated in gaseous state through the pores of a hydrophobic membrane.

Membrane distillation is a technique of separating water vapour from a liquid flow through hydrophobic membranes. The driving force of the process is the difference in water partial pressure between the aqueous feed solution and a dry gas in the permeate side. So far, this technique has been used for temperatures below 100°C. The polycondensation reaction takes place at temperatures higher than 100°C. Mass transport as well as heat transfer processes in the feed and permeate side and through the membrane pores play an important role during the process.

Figure 1: Overview of the process

Figure 2: Sketch of the process modelling [1].

Tasks / planned work

Within the scope of the work, a theoretical model for the separation of water vapour from pure water as well as from sugar solutions with increasing sugar concentration by means of membrane distillation is to be developed.

Tasks of the work are:

• Literature research of already existing models;
• Development of a suitable model;
• Implementation of the model in MATLAB ©;
• Evaluation of different process configurations (temperature of the flows, velocity, co-current or counter-current configuration, membrane material, concentration of the feed).

Conditions:

• Chemical engineering / process engineering students.
• The results of the work are summarised in a written paper and presented within an institute seminar.
• The thesis can be written in English or German.
• Starting date: immediately

 
Examiner:              Prof. Dr.-Ing. habil. Roland Dittmeyer
Supervisor:           Sara Claramunt
Contact:                sara.claramunt∂kit.edu
Tel:                         0721/608-24052

Sources:
[1] A. Mourgues, N. Hengl, M.P. Belleville, D. Paolucci-Jeanjean, J. Sanchez, Membrane contactor with hydrophobic metallic membranes: 1. Modeling of coupled mass and heat transfers in membrane evaporation, Journal of Membrane Science, Volume 355, Issues 1–2, 2010, Pages 112-125, ISSN 0376-7388, https://doi.org/10.1016/j.memsci.2010.02.040.