“We’re All in This (Atmosphere) Together…”
Tanay N -
Hello everyone! As always, I hope you enjoyed today’s blog post’s title! 🙂
This week is the final week of senior projects before the presentation, so the rest of my week will be spent working on my presentation and poster.
This past week, however, was one of the most EXCITING times I’ve had during my senior project. This was because we actually started doing runs on Sapling. The pictures below depict me running experiments on Sapling.
How Sapling Works
Essentially, the sorbent set inside Sapling captures CO2 from ambient (regular) air over time. Then, we pull vacuum on this system. All this means is that we are pulling the excess air out. Now, we add in some steam. The heat from the steam releases the CO2 from the sorbent, and then we pull the CO2 through our CO2 sensor. From there, we just run a quick calculation to find how much we captured.
The interesting thing about this steam is that it is <100 degrees Celsius. If you recall, water boils at 100 degrees Celsius, so how are we able to generate steam that is LESS than 100 C? This is because we are pulling vacuum. The vacuum relieves the atmospheric pressure on the water molecules, so the H2O molecules can move around and vibrate easier.
What I Aim To Find
Essentially, the main change between Aether (my at-home unit) and Sapling is that Aether’s sorbent, Calcium hydroxide, undergoes a chemical change into a completely new compound (Calcium carbonate). Sapling’s sorbent doesn’t change into a new compound, instead it sort of has “holes” in which the CO2 will “roll” into. Think of it as a golf ball going into the hole. This makes the sorbent reusable, furthering our sustainability goals.
Furthermore, Sapling allows us to recycle the CO2. This CO2 that has been captured can be sold off to companies to create a “Carbon Neutral Loop”. When we introduce the heat from the steam, it will release CO2. However, different temperatures, such as 40 C and 60 C work differently. So for example, 40 C will release 87% CO2, whereas 60 C will release 96% of the captured CO2.
Now, it’s important to note that it takes a lot of extra energy to make 60 C steam compared to 40 C steam. So overall, I aim to ask: Is it worth it to input that 20 C extra heat to release only 9% more CO2?
Basically, I want to figure out the lowest temperature I can go without harming CO2 release rates.
Challenges
The first run we had to do was a CO2 calibration run. I had to do this because we needed to know exactly how our CO2 sensor was reading and to account for any error.
While doing this run, we ran into a major problem: the data file was not recording the data correctly. So, we had to spend countless hours trying to figure out how to fix the code to make it so that all the sensors were logging correctly.
Additionally, I kept on forgetting to close a valve in the system. This essentially means we have to redo the run again, because since we are pulling vacuum on the system (pulling all the air out), we can’t have a valve open that will put air back into the system. Much of our time was spent on making sure our vacuum was working.
Despite these pitfalls though, my site mentor, Mr. Matthew Ryan, taught me enough information so that I was able to carry out experimental procedures by myself! This meant filling Sapling up with deionized water, filling up Sorbents, heat-sealing sorbent bags, taking apart locks to add fans into the system, and many other interesting things. Below you can see another picture of me working in the lab.
Calculations
As a result of all this, I learned many programming techniques and how vacuums work. I was fascinated by the application of Chemistry topics I learned in school to the lab.
For example, during data analysis I needed to calculate the total moles of CO2 that had passed through the sensor. To do this, I applied the Ideal Gas Law equation, which some of you may recognize as (Pressure x Volume = Moles x 8.314 x Temperature). This was exciting, because I was applying something I had learned in AP Chemistry!
Obviously, this time it was a lot more complex, as I had to analyze 10,000 lines of data for this, but the concept was still the same. I’m excited to share the results during my final presentation, which is on Wednesday April 23rd, at 1:15pm. The picture below depicts some of the data I’ve had to analyze.
As always, I’d like to say thank you to my amazing mentors, Ms. Brittany Holtzman and Mr. Matthew Ryan. As I wrap up this project, I can’t help but think about all the support I’ve received and how much I was able to achieve these past couple months because of my mentors.
I also am truly grateful for all of you who have been reading, commenting, and following my journey since the first blog post. My next blog post will be the final one, and I hope through these blogs you have gained an understanding of Direct Air Capture and how we can use it as a whole to decrease the rate of global warming.
Thank you!
– Tanay Naik 🙂
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