Membrane Contactor for Water & Heat Recovery and Electrification of Spray Drying

Savings of water and energy for the Food & Biobased Industries, in particular the dairy section, is an important target. The main part of energy consumption in their processing can be attributed to spray and bed drying. Currently, most energy is released in the form of latent heat in the exhaust air. In addition, water and resources/product are discharged at the same time with the humid exhaust air. Furthermore, resources are lost due to fouling throughout the system. As fouling of fines prevent heat recovery of heat exchangers, the exhaust air cannot be processed.

Closing loops of energy and water is possible by a “Membrane Contactor” by recovery of both energy and water present in the used drying air. The recovered heat can be reused as a heating source for other process steps in the food processing. This recovery and effective re-use of heat from the membrane contactor will be assessed based on various process integration schemes.

Objective and activities

Objective is to develop and demonstrate an innovative membrane contactor for recuperation of water and (sensible as well as latent) heat from (spray) drying air. The membrane contactor to be developed will combine several functions in one device: removal of water vapour from gas by absorption in a hygroscopic salt solution; heat exchange between salt solution and gas stream; complete physical separation between salt and gas, ensuring zero contamination risk of produced powders. This means a closed loop for gas and heat and enables a good performance at relatively low salt concentrations and therewith mild regeneration conditions. By electrification of the regeneration the overall heat consumption for spray drying will be minimised.

Various activities are foreseen:

• Design & development of closed loop dryer (electrification & use of heat)
• Experimental evaluation of the Key Performance Indicators in lab tests
• Process modelling
• Evaluation, including design of scaled-up units and cost assessment

Looking for partners

We are looking for partners to develop an innovative membrane technology for recovery of heat & water from gases and its process integration. End users of food and biobased products which use spray drying in their processing are especially invited, e.g. the dairy sector. In addition, we are looking for a potential system supplier who is active in the spray drying market and cooperates with the already selected manufacturer of the membrane contactor. Partners are asked for both cash and in kind contribution.