Transcriber: Denise RQ Reviewer: Helena Bowen
It was 2009, and I was visiting my grandfather in Beijing, China.
One morning, I looked out the window and saw something that looked like this.
It was shocking to see how bad the pollution was.
I could barely even see the building right across the street.
You couldn't go outside without putting a mask on,
and I started to wonder, why did it have to be this way?
As with most things relating to energy and the environment,
it comes down to one thing: carbon.
Carbon is an amazing element.
It's what gives us life and energy, but it's also just as dangerous.
Carbon dioxide is one of the major greenhouse gases,
and carbon soot is a major air pollutant.
So I dug a little deeper, and it turns out that the smog I saw that morning
was in large part caused by the burning of coal
to generate electricity.
China and many other countries, including the U.S.,
rely on coal to produce power.
The problem with coal is that it is an incredibly dirty fuel.
It produces lots of CO2 when you burn it,
and not only that, it releases toxic pollutants,
like nitrogen oxides and sulfur oxides.
These can contribute to smog.
Clearly, coal is an unsustainable fuel, and we need to look for alternatives.
(Applause)
Of course, we can turn to renewables, like photovoltaics and biofuels,
but the problem with those technologies is that they're very expensive.
They cost around $800 just to prevent one ton of CO2 emissions.
A promising solution that we can use as we transition fully into renewables
is the combined cycle power plant.
A combined cycle power plant is a power plant that uses natural gas,
and it produces energy in a two stage process,
to make it much more efficient than a traditional coal power plant.
Natural gas has enormous advantages over coal.
It has half the CO2 emissions,
and it doesn't come with the toxic byproducts
that are found in coal.
Naturally, natural gas has begun
to take up a larger chunk of the energy pie.
Production is expected to increase 20%, by 2035,
and a large portion of that increase
is due to the increase in shale gas production, shown in green.
Shale is a sedimentary rock,
and it often contains natural gas trapped inside.
It is especially relevant to us here in Colorado,
because we have one of the largest reserves of shale gas in the country.
In fact, we are ranked fifth in top natural gas producing states,
and we're likely to move even farther up that list
as natural gas production increases.
So, natural gas seems like a great fuel, it seems natural.
Why aren't we using it?
It turns out natural gas is starting to get expensive.
Before you can use natural gas to heat your house or to turn on your stove,
it actually needs to be purified.
When natural gas is mined out of the well, it comes as a mixture of different gases.
It can contain up to 50% carbon dioxide, small amounts of other gases,
such as nitrogen, water, and helium,
and about 50% methane, the stuff we can actually burn.
It's especially important to remove CO2 for two reasons.
First, it decreases the energy content of the gas,
and second, CO2 can form carbonic acid in the presence of water,
and that can destroy our pipelines.
So what's the solution?
It's detergent.
It turns out you can do this at home.
You take detergent, add natural gas, and stick it in your washer.
(Laughter)
Just kidding.
(Laughter)
The actual solution--
(Laughter)
is something that's an ingredient in natural gas called zeolites.
Zeolites are a type of mineral
composed of aluminum, silicon, and oxygen.
They form crystals, and from the outside, they just look like ordinary rocks.
They're something you might see on the side of a hiking trail.
But when we take a closer look at zeolites,
they become so much more interesting.
Zeolites actually have pores on the nano scale,
the same size as an individual gas molecule.
There's over 200 different types of zeolite structures,
and all of them are so incredibly beautiful.
At the University of Colorado at Boulder,
we've been working with one type of zeolite called Sapo-34.
Sapo-34 has very small pores: 0.38 nanometers in size,
and that's the same as the diameter of a single methane molecule.
That's incredibly small.
Sapo-34 is very stable.
It can function under a wide range of pressures,
and it can take temperatures up to 700 degrees Celsius,
which, for you non-conformists out there, is 1300 degrees Fahrenheit.
(Laughter)
So we discovered we can actually synthesize Sapo-34
as a very thin layer of interlocking crystals,
and this layer is only 1 micron to 5 microns thick.
That's incredibly small, because 1 micron is 1/1000th of a millimeter.
This very thin layer of crystals can actually act as a membrane.
This is an example of one of the membranes we've created,
next to a pencil, for comparison.
What you're seeing here isn't the membrane itself,
but rather the supporting tube that holds it together.
The membrane is actually grown
as a very thin layer on the inside of that tube,
and it's too small to see with the naked eye.
We're able to test our membranes by placing them in a gas flow-chamber,
so you can simulate an actual natural gas well
by feeding mixtures of carbon dioxide and methane from the left side.
Because CO2 is actually a lot smaller than methane,
it has a very easy time passing through the tiny little pores in the membrane,
and it can actually permeate through the membrane,
exiting at the bottom in what is called the permeate flow.
Whereas the methane, being very large, has a hard time getting into the membrane.
It is retained in the original gas mixture in what is called the retentate gas flow,
and that exits to the right.
So what we found in testing our membranes
is that we can actually convert a 50:50 mixture of CO2 to methane
into a 1:99 mixture of CO2 to methane,
or better, and that's remarkable,
especially when you consider the advantages of a membrane.
(Applause)
The current techniques for removing CO2 from natural gas
involve the use of a liquid chemical which absorbs the CO2 and captures it,
but the problem is it is very energy intensive
because you have to apply heat or create a vacuum
in order to pull off the CO2 and reuse the liquid.
On the other hand, with a membrane, you can simply put it in to a gas mixture
and it will continuously separate gases, with no need for energy input.
So it's much more environmentally friendly and cost-effective.
We've discovered other applications for these membranes too,
including hydrogen gas purification for hydrogen gas fuel cells,
and helium purification,
and we're working with Fortune 500 companies
to implement this technology.
(Applause)
The next step in our research is to increase the size of our membranes.
The membrane you saw earlier
had a surface area of about 5 square centimeters,
and we're looking to increase that by 2,000 times to about one square meter.
We're going to do this by increasing the length of our membranes
and adding in multiple channels.
This will allow us to separate gases
at even higher pressures and higher fluorides,
which are necessary for commercial applications.
We're taking what we've developed on the nano level
and applying it to the macro.
Nano technology is all about seeing things up close
and applying them in a new way.
And indeed, small things can solve big problems.
(Applause)
It's truly remarkable what nature can accomplish on the small scale.
Indeed, it's the little things in life that really matter.
It's amazing how the things we can't see can have such a big impact on our lives
in the present and in the future.
Something I've learned from this experience
is that anyone can do science; it doesn't take a genius.
(Laughter)
I was just a curious little 12-year-old boy
when I looked out the window and saw this.
So I encourage you to go look out your window.
Try to discover the emerging ideas and solutions
that will make our world a better place,
because sometimes, the most beautiful things are right in front of our eyes,
and we don't even notice,
because we're either too busy or too afraid to take a closer look.
(Applause)