Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/1019735
ENERGY WHERE IT MATTERS: DELIVERING HEAT TO THE MEMBRANE/WATER INTERFACE FOR ENHANCED THERMAL DESALINATION • Team: University of California, Los Angeles • Project Name: Location: Los Angeles, CA • DoE Award Amount: $1,995,249 • Awardee Cost Share: $516,644 • Principal Investigator: David Jassby A steam iron doesn't need a boiler tank, so why should a polymeric membrane distil- lation (MD) system? Dr David Jassby and colleagues at the University of California, Los Angeles, have devised a system that heats the surface of a polymeric membrane where it meets the water rather than the entire feed stream, reducing the amount of energy required by the system. As well as having high thermal conductivity, the layers of material also have high elec- trical conductivity, minimising the amount of soiling, includ- ing organic soiling. As billed, it quite literally delivers "energy where it matters." It was during research into conductivity that Jassby's team developed the plans for which they received a $2m grant from the DoE. "We were working on MD tech focused on electrical con- ductivity for several years and published a study on how you can apply resistive heat to the surface of a membrane. It had some nice results. We got to thinking, how can we conduct the heat from the outside? Our material boasts minimal verti- cal heat transfer, so you don't lose the heat that is the driving force for the evaporative pro- cess," says Jassby. The high cost of MD-based evaporative processes is largely driven by the complex heat management schemes needed to capture and reuse all of the heat in the system eŠ ciently. This results in cascades of heat exchangers making up the greater part of the capital costs of the systems. "With our system, you only need one heat exchanger, the most expensive part, and everything else is plastic. You feed things back into the beginning of the pro- cess for very high single-pass recovery, at low cost." How low? "Based on our initial calculations, it's looking quite positive and collecting solar heat is relatively straight- forward; it's fairly inexpensive to generate very high tempera- tures from a solar re' ector. The DoE's target is $1.50 a cube; we believe we can achieve that." The modular and scalable systems are designed to treat high-salinity brines from oil and gas operations, which can amount to several million US gallons per well, in addition to wastewater from chemical industries. This brine, Jassby calls "very salty stu— ", or more than 100g of salt per litre of water. Currently, such water is trucked for long distances to deep-well injection sites or disposed of in evaporation ponds. How- ever, deep-well injection has been implicated in local enhanced seismic activity (i.e., earthquakes) and can incur large transportation costs. Meanwhile, evaporation ponds can leach dangerous chemicals and minerals into the groundwater if not properly lined, harming local wildlife. There is a strong incentive to develop local and e— ec- tive treatment solutions. The remaining brine does require disposal, either through injec- tion or a zero liquid discharge process, such as a crystal- lizer, but the volume is greatly reduced along with costs. The project is expected to get underway within the next few months when the location is decided. LOOP THERMOSYPHON ENHANCED SOLAR COLLECTOR • Team: Advanced Cooling Technologies • Location: Lancaster, PA • DOE Award Amount: $1,500,000 • Awardee Cost Share: $500,000 • Principal Investigator: Fangyu Cao Solar loop thermosyphons obvi- ate the need for a pump, with heat driving the mixed ' uid and vapour around the system. The loop itself eliminates the ' ooding limit which is the bane of traditional thermosyphons, driving up the power potential and bringing down the cost. Pennsylvania-based Advanced Cooling Technologies is working with nano' uids that absorb more sunlight, and a two-phase thermosyphon which makes the system more eŠ cient, as well as making the collection of solar- thermal energy easier. cess for very high single-pass recovery, at low cost." How low? "Based on our initial calculations, it's looking quite positive and collecting solar heat is relatively straight- forward; it's fairly inexpensive to generate very high tempera- tures from a solar re' ector. The DoE's target is $1.50 a cube; we believe we can achieve that." The modular and scalable systems are designed to treat high-salinity brines from oil and gas operations, which can amount to several million US gallons per well, in addition to chemical industries. This brine, Jassby calls "very salty stu— ", or more than 100g of salt per litre of water. Currently, such water is trucked for long distances to deep-well injection sites ever, deep-well injection TOPIC AREA 2 Low-cost solar- thermal energy collection and storage Based on initial calculations it's positive — the DoE target is $1.50 per cube; we believe we can achieve that Advanced Cooling Technology's solar desalination design for the DoE. A loop termosyphon solar collection system for efficient, low cost, solar-thermal desalination, the design does not require fluid to be actively pumped throughout the system, reducing cost and expanding the market for creating fresh water from otherwise unusable waters. 32 Far Site September 2018 Water. desalination + reuse