District Heat-Driven Water Purification Via Membrane Distillation: New possibilities for applications in various industrial processes
2016 (English)Report (Refereed)
Water purification is an important separation process that can be found in various industrial applications. Process water quality varies between applications, but the trend of increased reuse or recycling of process streams in combination with stricter emission regulations lead to additional needs for water purification in the future. Membrane technology such as reverse osmosis, ultrafiltration and nanofiltration are often employed. However even if these technologies are mature there is still a need to explore alternatives that can lead to more robust performance, lower energy consumption, reduced environmental effects, and lower costs. Membrane Distillation (MD) is such an alternative. The process is heat driven and can be paired up with district heating when a high degree of purity is desired.The purpose of this project is to develop MD’s role within a district heating perspective. The following three sub-goals have been investigated:Sub-goal
Sub-goal 1 considered a mapping of water purification in relevant industrial processes. Various possible application areas were identified, including treatment of flue gas condensate, ultrapure water, processes in the food industry, reconcentrating, desalination, and others. Three case studies with relevance to MD driven by district heating were identified for further analysis.Sub-goal 2 encompassed system analyses and optimization studies for the particular case studies:
• Wastewater treatment at Astra Zeneca in Södertälje. It is theoretically possible to place MD between the district heating network and end users in order to achieve advanced treatment for a smaller wastewater line. The district heating demand would increase by about 7-13%, and costs (excluding retrofitting) are estimated to increase by 60% compared to the available treatment method (activated carbon).• Reconcentrating of ethanol from CO2 scubber water at Agroetanol inNorrköping. The concept involves off-loading of the distillation column via introduction of MD technology. Exchange between steam (distillation column) and district heating (MD system) is roughly balanced which implies significant cost savings potential with MD.• Water purification and reconcentrating at Arla Foods, Kalmar facility. A poor thermal integration yields a high district heating demand for MD in this particular application.For sub-goal 3 experimental investigations were conducted for two MD prototypes. A newer generation of MD prototype showed a marked reduction in heat losses with increase in yield, which in turn leads to lower energy demand.
Place, publisher, year, edition, pages
Energiforsk AB , 2016. , 68 p.
Membrane Distillation, District heating, Heat demand, Energy efficiency, Techno-economy, Pharmaceuticals, Bioethanol, Dairy, Wastewater
Research subject Energy Technology
IdentifiersURN: urn:nbn:se:kth:diva-182484ISBN: 978-91-7673-229-8OAI: oai:DiVA.org:kth-182484DiVA: diva2:904612
QC 201602262016-02-192016-02-192016-02-26Bibliographically approved