The Steam-Methane Reforming Process Purifies Hydrogen

Hydrogen, the most abundant element in the Universe (also the lightest) is actually rare to find in a pure form here on Earth.  This is due to hydrogen’s willingness to bond with other atoms and molecules.  Despite its abundance it needs to be separated from these other atoms and molecules in order to be available in a pure form.

Hydrogen is useful to humans and is useful in some important industries.   Pure hydrogen is primarily used to make ammonia (which is in turn used to make fertilizer) and methanol (which is usually turned into fuel).  However it needs to be separate from all of the atoms and molecules it likes to bond to in order to be of any industrial use to humans.

95% of purified hydrogen produced today is made from the Steam-Methane Reforming Process.  This process produces hydrogen from a hydrogen generating source, this is usually natural gas or oil, however other sources can be used.

Molecular sieve’s role in producing hydrogen doesn’t occur until the end of the steam-methane reforming process.  Before molecular sieve gets used the feed stock(most likely natural gas) must go through a hydrodesulfurization process, a steam reforming process, a heat recovery process and a CO conversion process.  These processes further breakdown the complex molecular structure of the feedstock preparing it for the final stage for hydrogen purification.

The final stage in purifying hydrogen is to use a Pressure Swing Adsorption (PSA) process.The PSA process will use either a 5A molecular sieve, which is usually used to create high purity hydrogen or a 13X molecular sieve to adsorb larger hydrocarbons and other impurities if they are there.

5A  specializes in separating straight and branch chained hydrocarbons from one another.  13X molecular sieve will specialize in removing any additional C02 or NH3 if there is any remaining at this point, it will depend on what you used as a feed stock.

There are over 200 Hydrogen producing plants in the world, most of them should be listed in the link below.  Hydrogen plays an important role in various industrial and scientific applications and molecular sieve plays an important role in making it pure.

List of Hydrogen Plants: http://bit.ly/wsYzKM

Sources:

http://www1.eere.energy.gov/hydrogenandfuelcells/production/natural_gas.html

Molecular Sieve Basics: Crystals Help Determine the Pore Size of Molecular Sieve

This article is a kind of a continuation on an article we wrote in 2011 that discusses the pores sizes of molecular sieve.

Molecular sieve are crystalline metal aluminosilicates that belong to the zeolite family.  That means that the molecules and atoms that make up a molecular sieve are made out of alumina, silicon, and oxygen and because they are crystalline they have a strong degree of order in the way they are laid out.

Molecular sieves specialize in separating very small molecules and atoms apart from one another.  Being part of the zeolite family, molecular sieve has a three dimensional network of pores which can adsorb molecules of a specific size.  The pores on a molecular sieve is what makes sieve special, this is because they can separate any substance down to the 1/10,000,000,000th of a meter, or an Angstrom.  There are four standard pore sizes that a molecular sieve can have:

• 3A, 3 Angstrom pore size
• 4A, 4 Angstrom pore size
• 5A, 5 Angstrom pore size
• 13X, 10 Angstrom pore size (depending on the manufacturer the pore size may be either 8 or 9 Angstrom)

The pores on molecular sieve could have one of two structure types: A structure or X structure.  3A, 4A, and 5A are made from an A structure while 13X is made from an X structure.  The A structure is smaller and more square-shaped than the X structure which is larger and circle shaped.

Aluminum Hydroxide, Sodium Hydroxide, Sodium Bicarbonate, and clay are used in the sieve manufacturing process, when the process is created this combination of material will make 4A molecular sieve when created with a type A structure or 13X molecular sieve when created with a type X structure.

3A and 5A molecular sieve are made once they are ion exchanged with the originally cre

ated 4A sieve.  4A molecular sieve is ion exchanged with potassium to create 3A sieve, the potassium molecules are larger than the sodium molecules they were exchanged with shrink the pore size.  5A sieve is created when 4A sieve is ion exchanged with calcium, calcium molecules are exchanged in a 1:2 ratio.  Every calcium molecule removes two sodium molecules thus increasing  the size of the pore.

The various pore sizes of molecular sieve offer a great variety of services to anyone looking to separate different combinations of molecules from one another.

The Far Reaching Effect Zeolite Has On Everyday Human Lives

Some of the natural occurring forms of zeolite that can be seen on Earth.

Before reading this article here are four questions to consider:

1. Have you ever drank a glass of tap water?
2. Have you ever been to a hospital and seen someone receive medical oxygen?
3. Do you heat up your home with gas?
4. Have you ever washed your clothes with laundry detergent?

The majority of people in Western society would have to answer yes to at least one of these questions, if not all of them.  These are just but a few of the many diverse  medical, practical, and  luxury based purposes and products that zeolites have made possible for humans in everyday life.  This broad spectrum of uses makes zeolite one of the most widely used minerals on Earth, yet most people have never heard of it before.  So the question is, what is zeolite and where does it come from?

Zeolite is a natural occurring group of microporous aluminosilicates that are found here, naturally on Earth. Their widespread use amounted to just under 3,000,000 tons of Zeolite being mined around the world in 2010.

Zeolites are naturally formed under low grade metamorphic conditions.  Low grade metamorphism occurs naturally in the cavities of volcanic rocks, where at temperatures between 200 -320 degrees Celsius, and while under low pressure, zeolites can be formed.  However they have been synthetically formed by humans as well, allowing the creation of a wide variety of different zeolites with many different uses.

Note: Some of the most recently created zeolite was made on-board the Columbia Space Shuttle.The reason for creating zeolite in space is to minimize nucleation effects and eliminate sedimentation.

There are 45 different minerals that are classified as zeolites but they only have three different structure types.  These three structures include chain structure, sheet structure, and framework structure.  Chain structure has crystal pores that form prism shaped crystals, sheet structure has crystal pores that are flat, and framework crystal pores have relatively equal sized pore dimensions.

As of November 2011 there are 201 different frameworks (pore classifications) for each of the three different structure types that have been discovered or synthesized by humans.  This combination of having variable structures and having many different pore (framework) sizes and shapes give zeolite the ability to perform many different tasks because of all of the different variations it can be produced in.

How does zeolite work?

Zeolite is microporous.  On its surface are millions of tiny pores that adsorb different materials which is based on the size and shape of the pore and what type of mineral the zeolite is.  Zeolite is also used to make other adsorbents like molecular sieve which is very effective at separating and purify chemicals.  These tiny pores can filter out material that is not needed for a specific application.

Molecular sieve (pictured above) is one of the products that is created and designed from the structure of zeolite.

Referring to the questions asked at the beginning:

Have you ever drank a glass of tap water?

In the case of tap water, zeolite or molecular sieve collects contaminants in water and removes them so you can drink it.

Have you ever been to a hospital and seen someone receive medical oxygen?

Medical oxygen requires pure 100% oxygen before it can be used.  This pure oxygen is frequently made by removing the other elements like nitrogen and argon from the air that occurs naturally here on Earth.  In this case a 13X molecular sieve is used to remove all other components (that are not oxygen) in our atmosphere so that pure oxygen can be made and administered to patients.

Do you heat up your home with gas?

When natural gas (which is turned into the gas that heats your home) is first harvested from the Earth, it is harvested with a lot of other different elements that could be dangerous for human consumption.  Water also needs to be removed from natural gas streams and again these processes require the use of zeolite based molecular sieve.

Have you ever washed your clothes with laundry detergent?

Laundry detergent uses zeolite as a water softener by removing calcium and magnesium from water.  These elements can interfere with the cleaning benefits that the soaps in the laundry detergent provide.

These are only a few of the many different functions zeolites can provide a person, but there importance in the development of technology and in our everyday lives is undeniable.

Sources:

Metamorphism: http://www.tulane.edu/~sanelson/geol111/metamorphic.htm

Zeolite grown in space: http://www.tubitak.gov.tr/tubitak_content_files//spaceworkshop/presentations/Bac.Nurcan.pdf

Zeolite structures: http://www.galleries.com/Zeolite_Group

Zeolite production: http://minerals.usgs.gov/minerals/pubs/commodity/zeolites/mcs-2011-zeoli.pdf

Amount of Zeolite mined: http://minerals.usgs.gov/minerals/pubs/commodity/zeolites/mcs-2011-zeoli.pdf

More Structures: http://www.iza-structure.org/

Oxygen Therapy Relies on Purified Oxygen

On earth oxygen occupies approximately 21% of the air in our atmosphere (the other 78% is nitrogen and 1% is argon, carbon dioxide and other gases).  In medical situations you may need a higher concentration of oxygen than what is available in our current living conditions.  This is where 13X molecular sieve and Lithium LSX are used, they purify oxygen.  13X and Lithium LSX do this by adsorbing nitrogen, argon, and the other gases from natural air leaving you with pure oxygen.

Oxygen is the third most common element found in the universe (only hydrogen and helium are more abundant) and it is the element that is most commonly associated with life on our planet.  Technology has allowed us to make oxygen industrially but it can also be used medically.  Higher purities of oxygen are needed in the medical world for both chronic conditions and emergency medical situations and 13X molecular sieve and Lithium SLX both play crucial roles in purifying oxygen so that they can be used medically.

Oxygen in the medical world is primarily used in oxygen therapy.  Oxygen therapy helps treat chronic conditions like chronic obstructive pulmonary disease (COPD) with the most common COPD being emphysema.  Pure 100% oxygen has also been shown to be able to stop the onset of cluster headaches so long as pure oxygen is administered before the peak of the attack occurs.  Cluster headaches are medically believed to be one of the most painful experiences a human being can endure and pure oxygen can help release the tension of the blood vessels that are constricting the nerves, thus relieving a person from tremendous pain.

Oxygen therapy can be essential in saving lives during emergency medical situations and is frequently used during resuscitation. Oxygen tanks and liquid oxygen are usually used during these situations and the oxygen stored in these devices must be purified, which again is the responsibility of molecular sieve.

One of the most common devices used for medical oxygen purification is an oxygen concentrator, which is type of portable oxygen generator that can be used at home as well as in a hospital.  These devices use either 13X molecular sieve or Lithium LSX to purify their oxygen.  The difference between Lithium LSX and 13X is that the Low Sodium X in Lithium LSX has been lithium exchanged.  Both are used in portable oxygen generators but Lithium LSX is used in smaller generators while 13X is used in larger generators.

The oxygen generators range from 100 liter/minute to 3 liters/minute and can be found everywhere from hospitals to MASH units in Iraq or Afghanistan to someone afflicted with COPD. Technology in the medical world has improved to the point that some of these pressure swing units that purify the oxygen can be made so small that they can be worn on a belt, inside a backpack or be plugged into a 12 volt power source.  They can also run on lithium batteries or be plugged into a 120 volt source allowing them to run in a home, field hospital or a domestic hospital.

13X molecular sieve and Lithium LSX have improved our quality of life by allowing oxygen to be purified and used for various forms medical treatment.  This life saving technology is available due to the abilities of  molecular sieve and the scientists and engineers who continue to improve our way of life.

13X Molecular Sieve is Crucial to Making Steel

13X molecular sieve has many different applications and can complete a large variety of tasks.  One industry 13X molecular sieve can be used in is in the steel industry.  Before explaining 13X’s role in the steel industry, here is brief overview that describes how steel is created.

Steel is made from iron and this is done by removing iron’s impurities like silica, phosphorus, and sulfur.  Steel must also have a consistent concentration of carbon (between 0.5% and 1.5%).

Modern steel making has been done using the Bessemer Process (Developed by Henry Bessemer) or one of its modern variants.  The Bessemer Process was developed in 1858 and it was designed to use oxygen to generate steel at a faster rate.  Since separated oxygen was difficult to produce during Bessemer’s time, the patent to this process went mostly unused until the mid 20^th century when new improvements in oxygen generating technology were developed.

The primary modern improvement of Bessemer’s Process uses a basic oxygen furnace instead of a open-hearth furnace to create steel.  A basic oxygen furnace blows high purity oxygen (95%+ pure) through molten iron which lowers carbon, silicon, manganese, and phosphorus levels in iron thus helping to convert it to steel.  The oxygen furnace works approximately 10 times faster than its older counterpart.

Note: Sulfur and phosphorus levels are further reduced by chemical cleaning agents called fluxes in the steel making process.

It’s safe to say that oxygen is a key component to producing steel, and creating pure oxygen is where 13X molecular sieve becomes useful.  Pure oxygen is usually created using the Pressure Swing Process to separate ambient air into two streams.  One stream contains nitrogen, carbon dioxide, and other impurities while the other stream contains over 95%+ pure oxygen.  (The remaining 5% of air in the oxygen stream are noble gases, for example elements like helium).

Pure oxygen that is created from the Pressure Swing Process is then fed into steel furnaces under high pressure to oxidize the impurities inherent in iron.

Cryogenic oxygen generators are also used to purify oxygen for steel production.  These cryogenic generators also require air to be pretreated by molecular sieve in order to remove impurities that are commonly attached to oxygen.

Manufacturing high quality steel requires the use of the Pressure Swing Process or a cryogenic oxygen generator and both require the use of molecular sieve. Without sieve modern high quality steel manufacturing would be impossible today.

Sources:

Smil, Vaclav (2006). Transforming the twentieth century: technical innovations and their consequences, Volume 2. Oxford University Press US

http://science.howstuffworks.com/iron4.htm