Integrated Dynamics has a new home
In the next week, we’ll be moving into the Nick Holonyak Micro & Nanotechnology Lab’s BioNanotechnology Lab, where we can house and operate our own equipment on our own time for the foreseeable future. Best perk: they have nitrogen.
As of last week we’ve also reincorporated as a Delaware C-Corp, and are excited to finally accept our $20,000 in winnings from the Cozad NVC. Budget wise we’re still running quite lean and we expect to be able to complete our 1L tests as planned without needing any further investment. Letters of intent and building a proof of concept are still our biggest goals for the summer, and now that school’s out, we’re excited to start cooking with gas.
This brings us to our most pressing research question: how do we actually measure the hydrogen? Our previous experiments with the M1 and M2 relied on the assumption that we’d have access to gas chromatography, which is unfortunately not the case for the summer. I call that a “$1000 methodology,” which was good enough for our earlier tests, but doesn’t provide the data resolution nor repeatability for a robust proof of concept.
what hydrogen, if any?
“So, what options do we have?” you ask. These are our options:
The original approach: batch GC (gas chromatography).
We take samples of the gas generated, find their hydrogen composition, and do some quick math that tells us the mass of hydrogen we’ve produced. It is pretty simple to build and only requires a few needles and vials, which makes it the inexpensive choice. But, this method also requires constant access to a GC, or the hydrogen might leak from our samples and skew our results. Recalibration must be done often and is challenging/expensive.
The direct approach: hydrogen measurement.
There exist a few sensors on the market that can directly measure inline hydrogen flow from 0-100%, which would be perfect if the sensors, calibration, and plumbing didn’t come to >$15,000/unit. The sensors are also sensitive to hydrogen sulfide poisoning, which shouldn’t be an issue do to our ethanolamine sweetening process. For context, mono-, di-, and triethanolamine are used in petrochemical hydrogen production to selectively strip hydrogen sulfide and carbon dioxide from a “sour” gas stream. We’ll likely use this method later on, when we have the funds for it.
The indirect approach: everything-else measurement.
If we can guarantee that the only three gasses that exist post-treatment are H2, CO2, and N2, we could also just measure the other two gasses to eventually find the amount of hydrogen we’re generating. CO2 sensors are pretty inexpensive and robust, but nitrogen measurement is not feasible in our situation.
The crafty approach: combustible gas measurement.
Sub-LEL (lowest explosive level) volatile gas sensors are ubiquitous and inexpensive, which could make them a competitive choice for hydrogen measurement if we can guarantee the only volatile gas present is hydrogen. Unfortunately, they only measure up to LEL concentration (around 4% for hydrogen) and require oxygen in the environment for the sensor to work. Given that we must maintain anaerobic conditions for our archaea to survive and we might be producing up to 20% hydrogen, these sensors are pretty unsuitable.
The craftier approach: hydrogen fuel cell measurement.
Certain types of hydrogen fuel cells show a linear-ish relationship between the power they generate (wattage) and the rate that fuel is pumped into the cell (mass flow rate) up until a certain hydrogen saturation. If we buy a bunch of fuel cells and calibration gasses, we should be able to calculate the mass flow rate of hydrogen through the cell and measure the associated power, and then use our findings to closely estimate the hydrogen our process is generating by measuring the energy/power output of the cell stack. All we’d need for this method is a microcontroller (<$100), calibration gasses (~$1000), some fuel cells (~$500), assorted chemicals and bubblers (~$500), and some elbow grease.
$2000 for a handful of sensors sounds a whole lot better than $15,000 for one. It looks like we’re getting craftier.
-Henry Markarian