1. Mild Conductive Thin Film Drying: Energy Efficiency & Product Quality
Cluster: Drying and dewatering (DR-20-03)
Project Leader: Maarten Schutyser (WUR)
Researcher: Jun Qiu (WUR)
Partners: ISPT, WUR, Bodec, ECN, ILVO, Unilever
Project duration: February 2015 – March 2019
Motivation:
Conductive thin film drying processes consume ~40% less energy than spray drying. However, these conductive drying processes yield different powder properties. In this project we investigate the principles of conductive film drying at lab and pilot scale to improve powder functionality and energy efficiency.
Experimental set-up: Vacuum Thin Film Dryer (DryVaGram)
This custom built experimental setup is used to mimic and thus study (vacuum) drum drying (Figure 1). Mass and temperature changes during drying are monitored in-line (Figure 2).
Objective:
To establish mechanistic insight on film drying behaviour via lab-scale experimentation and development of transient drying models.
Systematic comparison of pilot-scale film dryers to develop knowledge-based guidelines for (vacuum) drum drying and ATFD drying.
Experimental setup: Agitated Thin Film Dryer (ATFD)
This lab-scale ATFD dryer is built to investigate agitated thin film drying. (Figure 3). The ATFD drying mechanism based on new experiments is presented in Figure 4.
Figure 3. Equipment of ATFD set-up
Figure 1. Equipment of the vacuum thin film drying set-up
Sample products
Inlet hot water
Outlet hot water
Vapour
+ Vacuum
Blades
Heating jacket
Stage 1: Liquid
Bow wave growth
Stage 2: Paste
Lump accumulation
Stage 3: Solid
Powder formation
Drying chamber
Powder collector
Figure 4. Schematic representation of ATFD drying.
Figure 2. Mass (left) and temperature (right) during evaporation of a 1 mm thick film of water with the DryVaGram.
This project is co-funded by TKI-E&I with the supplementary grant 'TKI- Toeslag' for Topconsortia for Knowledge and Innovation (TKI’s) of the Ministry of Economic Affairs and Climate Policy.