Heat Recovery in the Drying Process of Milk Powder by Using a Liquid Sorption System

Heat Recovery in the Drying Process of Milk Powder by Using a Liquid Sorption System

Pineda Quijano, D.F.

Infante Ferreira, C.A. (mentor)

Mechanical, Maritime and Materials Engineering

Process and Energy

2016-08-30

The last step in the production of milk powder is drying, a very energy intensive process that demands 30% to 40% of the total energy input of a typical plant. It takes place in Spray Dryers (SD), where concentrated milk is sprayed and placed in direct contact with hot and dry air that cools down and gains humidity as water is evaporated from milk. The warm and humid air leaving the SD contains a small portion of potentially recoverable sensible heat and a large portion of latent heat that is impractical to recover by direct condensation due to the low dew point of this stream and due to the presence of milk powder particles that become sticky at high relative-humidity values. In this research, the feasibility of a liquid sorption system for the recovery of the aforementioned latent heat was investigated. The system proposed has two main advantages: the dehumidification of air in the absorber for reuse in the SD, and the production of high pressure steam in the regenerator for integration to the steam network of the plant. A mathematical model of the system was implemented in Matlab, and several system configurations were evaluated. The calculations showed that a SD equipped with this system can achieve energy savings above 55% when using aqueous solutions of phosphoric acid as liquid desiccant. The challenge with this liquid desiccant remains on the construction materials

liquid sorption
heat pump
drying
heat recovery
energy efficiency
phosphoric acid
sodium hydroxide

http://resolver.tudelft.nl/uuid:07499c0a-c23d-4af7-a4e3-b41ad8e69954

2021-08-31

Student theses

master thesis

(c) 2016 Pineda Quijano, D.F.