Energy effective and green drying technologies with industrial applications
Peer reviewed, Journal article
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Original versionChemical Engineering Transactions. 2018, 70 145-150. 10.3303/CET1870025
Heat pump drying is a green technology with zero global warming potential and zero ozone depletion potential when operating with natural fluids. A well designed heat pump dryer can be several times more energy efficient and less costly than conventional dryers. This dryer beneficially contributes to a sustainable society while providing superior products at competitive cost. It is an advanced engineered drying technology ready for implementation by modern industries wishing a return of investment while contributing to a sustainable society. This paper covers the advances in heat pump and superheated steam drying technologies. These drying processes are in the category of green technologies because they are highly effective and advantageous for the environment and climate change. Descriptions and layouts are given covering design of heat pump and steam dryers. Details are provided in their beneficial operation in single and multistage with vapor compression and drying chambers placed in series. The drying modes covered are atmospheric sublimation and evaporation for improved capacity and superior characteristics of dried materials. The future trend is heat pump drying with natural fluids and superheated steam drying complying with proper industrial practice and with regulations reducing damage to sea, soil and water as well as zeroing contribution to global warming and to climate change. These technologies have been built and extensive R&D has been done at Norwegian University of Science and Technology in Trondheim. The technology has progressed to pilot scale and industrial applications indicating a small but real contribution to a better society today and tomorrow. Lastly, this is an advanced engineered drying technology ready for implementation by modern industries wishing a return of investment while preserving the environment.