Desalinator

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Square and HARC channels
Sponsors
Team Name Saline Solution
Duration Fall 2015 - Spring 2016
Faculty Advisors
Mentor
  • Theo White
  • Austin Doutre
Students
  • Jessica Drouin
  • Essa Essa
  • Cody Moldenhauer
  • Ryan Ready
  • Kevin Woodruff

With an increasing need for fresh water, new low-energy and cost-efficient green technology to extract salt from water has become attractive. Our team uses electrical fields and high surface area nanomaterials to create a lossy capacitor that separates the sodium and chlorine ions.


Problem Definition[edit]

Background[edit]

Severe droughts in many parts of the world along with demands for fresh water have led to groundwater depletion . Approximately 71% of the world is covered by water but unfortunately, 96.5% of that water is undrinkable. Current methods of desalination use large amounts of energy. A device that can produce fresh water from seawater or reduce its salinity at a lower cost compared to current methods would ease many of these problems.

Deliverables[edit]

  • Mathematical models for predicting ion motion in brine under magnetic and/or electrical field
  • Extensive measurements on brine flows in channel/pipe under magnetic and/or electrical field
  • Extensive measurements on the patent-pending prototype machine
  • 15% reduction in salinity with a decent flow rate
  • Measurement of energy required to create that reduction in salinity

Specifications[edit]

This project doesn't have specifications for a final design. Rather, this project has been a series of experiments designed to develop specifications for a final prototype and process.

Project Learning[edit]

Client Interview[edit]

  • Wrote a list of technical, budget, and miscellaneous questions for client to make sure we approached this project fitting our client's needs
  • From the answers we obtained, we were able to build a better foundation for starting this project

Lead Instructor and Technical Advisor Meetings[edit]

  • Every week
  • Topics such as due dates, technical progress, budgets, and brainstorming are all discussed during these meetings

Capacitive Deionization[edit]

An electric potential is applied to carbon electrodes across a brine filled channel.

Alt text
Capacitive Deionization

There are currently 4 different process types that use forms of Capacitive deionization. These are:

  • Flow-by mode in which brine water flows through a channel or channels that have charged electrodes as walls. This mode is simple to construct and model but has an inefficient discharge method.
  • Flow-through mode in which brine can flow directly through porous electrodes. A more complex method that requires porous electrodes.
  • Flow-electrode CDI is a type of continuous CDI in which a membrane separates the brine from a charged, moving mixture. This method is complex.
  • CDI with wires is a type of continuous CDI in which wires are placed in a brine solution, charged, and then discharged in a different solution. This method is also complex and involves moving parts.

The most simple method (flow-by) is the one used for this project

Mathematical Model[edit]

This shows the equations used in our model to calculate the expected reduction of salinity. These equations used the geometry of the channel and electrodes along with the applied voltage to calculate how much charge (Qelectrode) could be collected on each electrode. This picture links to an article about water properties that was used.





Prototype Designs[edit]

Prototype 1 Description Testing Results
  • This is a simple channel flow design using a 1 inch square tube. The electric field is applied to the channel by way of two copper strips along the outside. At the end is the flow separator device which collects brine from each side and the middle of the channel.
  • This prototype did not measurably reduce the salinity of the brine.
Prototype 2 Description Testing Results
  • Prototype two is a short simple channel flow design similar to prototype one but with conducting strips of graphite on the interior sides of the channel.
  • Graphite is a good conductor with a high surface area to collect sodium and chlorine ions.
2016 desalinator SQRE.png
2016 desalinator GRAPH2.png
Prototype 3 (HARC) Description Testing Results
  • This is a prototype of our High Aspect Ratio Channel (HARC). The channel cross-section width was increased to 4 inches and the height reduced to .25 inches in order to maintain the same volume as prototype two while increasing the available surface area for collection. This channel is also coated with graphite on the interior top and bottom.
2016 desalinator TABLEHARC.png
2016 desalinator GRAPH.png

Team Information[edit]

2015 desalinator Jessica.jpg
Jessica Drouin Interests: Mechanics, Thermodynamics, Fluids, and Computer Aided Design
Mechanical Engineering
Email: drou6296@vandals.uidaho.edu
2015 desalinator Essa.jpg
Essa Essa Interests: Power, Electronics, Distribution Systems, Latest technology.
Electrical Engineering
Email: essa0445@vandals.uidaho.edu
2015 desalinator Cody.jpg
Cody Moldenhauer Interests: Power systems, Alternative energy, Latest technology.
Electrical Engineering
Email: mold4329@vandals.uidaho.edu
2015 desalinator Ryan.jpg
Ryan Ready Interests: Power generation and distribution, Alternative energy, Archaeology, and many others.
Electrical Engineering
Email: read6404@vandals.uidaho.edu
2015 desalinator Kevin.jpg
Kevin Woodruff Interests: Mechanics, Fluids, Machine Component Design, Stress Analysis, Data Acquisition.
Mechanical Engineering
Email: wood9725@vandals.uidaho.edu