3D Printed Direct Air Capture
Imagine you were in charge of providing power for the United States. Easy enough right? A few nuclear station here a few dams there a couple solar panels in the south and bam. Easy enough?
What if I told you that the power generation would be generating around 10 billion tons of CO2 per year!
Every year there are 70,000 wildfires, 3.56 cm increase in sea levels per decade, and 0.8 degree Celsius increase per decade. Caused in part by the tremendous impacts of CO2 on our planet.
We could of course stop emitting CO2 emissions. But that would take a long time to incorporate electric vehicles, renewable energy sources and much more. To help transition to a net-zero future, we can make positive CO2 emissions. That’s where actions go past being net-zero and remove more CO2 than they emit. Like Direct Air Capture!
What is Direct Air Capture?
Carbon Engineering’s unconventional approach to carbon capture, Direct Air Capture (DAC) technology, starts with an air contractor. What is an air contractor? It is a massive fan that pulls air through thin sheets of plastic. The sheets of plastic are flowing with potassium hydroxide (KOH). The CO2 gets caught in the solution but the rest flows through. The non-toxic solution is then purified and compressed into small pellets through a series of chemical processes. The pellets can then be stored and transformed into a gas for soda companies to carbonate sodas, or used for Carbon Engineering’s AIR TO FUEL’S technology to produce renewable fuel. First water is electrolyzed with the help of clean energy (solar PV) which separates the hydrogen and oxygen. The hydrogen and CO2 react with each other to produce a fuel compatible with existing petroleum infrastructures.
My project
To further understand the process of Direct Air Capture, I made a small-scale simplified version. I set 3 goals to achieve for my project
- Efficient usage of Potassium Hydroxide
2. Further understand Direct Air Capture
3. Keep costs low
Assembly
Frame
Part of keeping the cost low was using budget-friendly materials. The obvious choice for making a hollow cube would be to use PVC-pipes. But instead I printed the 3D-Printed the frame. The structural part of the frame including the 12 edges and 24 corner connectors was made of black ABS (Acrylonitrile Butadiene Styrene) which was chosen for it’s rigid nature. These parts were printed with 4 perimeters, 20% gyroid infill and 5 top and bottom layers at a layer height of 0.28mm with a line width of 0.7mm from a 0.6mm nozzle.
And to hold the edges and Corner connectors together I used 24 clips made of red PETG (Polyethylene terephthalate glycol) because of it’s slight flexibility. The clips wereprinted with 4 perimeters, 5% gyroid infill and 4 top and 3 bottom layers at a layer height of 0.28mm with a line width of 0.4mm from a 0.4mm nozzle. The locking mechanism was made by 3D Printy!
Fan duct
To provide airflow I used a spare 92mm fan. And to mount the fan to the frame, I designed a fan duct in Fusion 360. The duct had a hole to allow the mist to go through and out the front. There were also 4 holes to mount the fan. And to mount it there was a slot at the top and bottom.
Seal the box
While making the CO2 from the carbonic acid and sodium acetate reaction, I had to keep as much of the CO2 inside of the box. So to seal the box as best as possible, I wrapped the frame in cellophane held in with the red clips. And for an even tighter seal around the edges. Duck Tape saved the day once again! For easy access to the inside I added a cardboard door. And to place things in the box without them falling through the cellopahne I added a cardboard base.
What is does
Using my small-scale version of Direct Air Capture involves 3 simple steps; creating the CO2, capturing the CO2, and reading the results.
Creating the CO2
First I had to fill the box with CO2. To do so I used the same reaction you likely used in Elementary school to make a volcano. I used a mixture of Acetic acid (viniger) and sodium bicarbonate (baking soda). After I used a CO2 monitor the measure the approximate level of CO2 in the chamber. It was 838 PPM. And as a control, I also measured the CO2 levels in the air which were 629ppm
Capturing the CO2
To first provide airflow, I removed the fan cover and attached my 92mm fan and connected it to a 12V 1A power supply. I then put the mister at the top of the duct and started misting to capture the KOH.
Results
After the running the fan and misting for 1 minute. The CO2 in the chamber reduced from 838ppm to 432ppm that’s a reduction of 51.56%! Not only did I capture the CO2 that I created, but also some of the CO2 in the air.
Conclusion
Goals
- Efficient usage of Potassium Hydroxide
- Some of the potassium hydroxide was wasted due to the spray bottle. Also some of the CO2 may have gotten past the KOH. This could be improved by using a mist nozzle on a hose with the KOH coming out at a higher pressure to increase the flow.
2. Further understand Direct Air Capture
- This was a success as I now understand the fundamentals of Direct Air Capture and how it can be used.
3. Keep costs low
- I was able to keep the cost relatively low by 3D printing the frame. This was much cheaper than if I were to have used PVC pipes or aluminum extrusions.
Overall, this project worked really well. I learned a lot about Direct Air Capture to help me with my next carbon capture project. And I was also able to challenge my CAD skills.
If you’ve enjoyed this article, I would love a follow and some claps. And if you’d like to learn more, here is a video of this project. Thank you!
