What Is Anhydrous Ammonia, What Is It Used For, and How Should It Be Handled?

Anhydrous ammonia is a compound used in many industries across a vast array of applications. It’s used to grow the food we eat, the clothes we wear, and even some of the medicines we take.

However, since this substance is so widespread, it’s important to note that anhydrous ammonia presents certain safety concerns. The gas has a built-in safety feature as no one can stand to breathe it, but that doesn’t mean that those that work with it shouldn’t be prepared to handle accidental exposure or sudden release.

So what is anhydrous ammonia? What is it used for? And how can those that work with it stay protected? Here’s what you need to know. 

What Is it: About Anhydrous Ammonia

Anhydrous ammonia is an inorganic chemical compound of one Nitrogen atom and three Hydrogen atoms that can be written with the scientific formula NH3. It’s stored in highly pressurized containers in liquid form, but then rapidly changes to a gaseous state when released into the air.

One of the biggest distinguishing characteristics of anhydrous ammonia is what it lacks: Water. Unlike aqueous ammonia, also called ammonium hydroxide, which is a solution of ammonia dissolved in water, anhydrous ammonia is pure. It exists at atmospheric pressure and temperature in a gaseous state.

This pure form of ammonia is very pungent and boils at the temperature of -28℉. As a gas, it’s colorless and is around 40 percent lighter than air. 

Industrial anhydrous ammonia is carefully manufactured through a process called the Haber-Bosch Method, which affixes nitrogen to hydrogen, creating ammonia. This process was developed in the early 1900s and is a widely used method to manufacture industrial ammonia for a whole range of applications.

NH3 is a hygroscopic compound, which means that one of its notable properties is that it seeks out moisture from the nearest possible source. This makes it suitable for a multitude of uses and in many different environments.


What Is It For: Uses and Applications of Anhydrous Ammonia

One of the biggest uses of anhydrous ammonia across the country and throughout the world is in agriculture. Anhydrous ammonia contains nitrogen, which is why it is used to fertilize soil to foster healthy plant growth. 

As the name implies, anhydrous ammonia contains no water, which means that it “aggressively seeks out moisture,” according to the Minnesota Department of Agriculture. This means that it seeks out moisture in other places, like soil, which is what makes it such an efficient fertilizer. 

Just how common is anhydrous ammonia used as a fertilizer? More than 80 percent of all the anhydrous ammonia produced here in the US is intended and used for agriculture. As a result, it’s responsible for 50 percent of the food we put on our tables each day.

Additionally, anhydrous ammonia is used as a refrigerant. While the overwhelming majority of anhydrous ammonia is for fertilizer applications, a mere 2 percent of anhydrous ammonia goes towards refrigeration. 

Just how is anhydrous ammonia used in refrigeration systems? The ammonia is put under immense pressure through a compressor, which forces the gas to heat up. From here, the anhydrous ammonia gas travels into a condenser, where the heat is dissipated in a series of coils. At this point, the ammonia condenses, changing into a liquid form that remains at a high pressure. In this state, the ammonia moves into a lower pressurized expansion valve, where the ammonia boils at a very low temperature of -27℉, thus cooling the surrounding air and the refrigeration system. The ammonia then gradually heats up, starting the cycle anew. 

Other uses of anhydrous ammonia include:

  • For the purification of water supplies
  • In the creation of plastics and polymers
  • For use in the making of explosives
  • To create certain textiles and to treat leather
  • To manufacture pesticides and other chemicals
  • As a component in certain dyes
  • In the manufacture of some pharmaceuticals

It’s important to note that anhydrous ammonia is a critical component in the manufacture of illicit methamphetamines, which is why it is a highly controlled substance that must be distributed, handled, and stored with care.

How To Manage It: Safe Handling of Anhydrous Ammonia

The same property that makes NH3 so effective as a fertilizer is also what makes it dangerous. Since anhydrous ammonia is a hygroscopic compound that seeks out moisture from any nearby source, the moisture-rich tissue of our bodies is at risk.

What does this mean? Exposure to anhydrous ammonia can be very dangerous, especially to the eyes, lungs, and mucous membranes, which have high moisture levels. If exposed to anhydrous ammonia, nearby persons should flush affected areas with potable water for 15 minutes or more. If anhydrous ammonia is inhaled, it can cause a person’s throat to close, resulting in suffocation, asphyxiation, and death. Since it is so cold, it can also cause frostbite to internal and external tissue (including the respiratory tract). All these are reasons why any exposed person should seek out medical attention immediately.

The concentration of anhydrous ammonia as a fertilizer is pure—approximately 1,000,000 parts per million (ppm). However, the US Department of Agriculture shares on its Safety and Health page that even a brief exposure at concentration levels of just 2,500 to 6,500 ppm can be fatal.

These kinds of exposure incidents may be limited or prevented through the safe handling of anhydrous ammonia.  

All workers who use anhydrous ammonia must wear the correct personal protective equipment (PPE), have the proper response supplies on hand, and know how to respond appropriately in an emergency. 
PPE should include:

  • Ventless goggles and a full face shield
  • Rubber gloves with long cuffs rolled to catch drips
  • A long-sleeved shirt

It is also recommended that those who wear contact lenses should not do so when handling anhydrous ammonia, as it can trap the gas between the lens and the eye, fusing the two together.

Additionally, those using anhydrous ammonia should have access to ample potable water to flush the eyes and skin while seeking medical attention. This means that those who transport anhydrous ammonia in vehicles must carry a 5-gallon container of clean water. Plus, all people who work with the compound should carry a 6- to 8-fluid-ounce squeeze bottle of water on them to respond as quickly as possible. 

Anhydrous ammonia should also be transported, transferred, and stored by knowledgeable individuals and in regularly-maintained, thoroughly-inspected equipment.

Airgas Specialty Products: Committed to Safe, Reliable Distribution of Quality Anhydrous Ammonia

At Airgas Specialty Products, we value two things above all else: Safety and reliability. When supplying you with the industrial ammonia you need for your operations (and the services to support you), we know you can’t wait. That’s why we offer round-the-clock service all week long. 

What’s more, we have an outstanding safety record. When it comes to delivery and maintenance, we’re here for you with the protocols, supplies, and services you need to keep you and your team safe. We can even educate your team with training catered to your unique uses and resources.

Safety and reliability. These two focuses give us the reputation for exceptional service you can count on. To learn more about how we can best serve you, connect with our friendly team of experts today.

About Airgas, Inc.

Airgas, Inc. (NYSE: ARG), through its subsidiaries, is one of the nation's leading suppliers of industrial, medical and specialty gases, and hardgoods, such as welding equipment and related products. Airgas is a leading U.S. producer of atmospheric gases with 16 air separation plants, a leading producer of carbon dioxide, dry ice, and nitrous oxide, one of the largest U.S. suppliers of safety products, and a leading U.S. supplier of refrigerants, ammonia products, and process chemicals. Approximately 17,000 associates work in more than 1,100 locations, including branches, retail stores, gas fill plants, specialty gas labs, production facilities and distribution centers. Airgas also markets its products and services through e-Business, catalog and telesales channels. Its national scale and strong local presence offer a competitive edge to its diversified customer base. For more information, please visit www.airgas.com.

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