Creating Liquid Nitrogen from Thin Air!

Table of Contents

1. Introduction
2. The Composition of Air
3. The Process of Making Liquid Nitrogen
   • Compressing Atmospheric Air
   • Separating Oxygen and Moisture
   • Storing the Nitrogen gas
   • Cooling the Nitrogen gas
   • Condensing and collecting the Liquid Nitrogen
4. The Role of Helium Compressor
5. The Cooling System for the Helium Compressor
6. Energy Consumption and Time Required
7. Acquiring the Equipment
8. Pros and Cons of Making Liquid Nitrogen
9. Conclusion

Article

Introduction

Liquid nitrogen is a fascinating substance that is widely used in various fields, from science experiments to industrial applications. Many people are curious about the process of making liquid nitrogen and the equipment involved. In this article, we will delve into the step-by-step process of creating liquid nitrogen and discuss the essential components necessary for this procedure.

The Composition of Air

Before understanding the process of making liquid nitrogen, it is crucial to grasp the composition of air. When we take a deep breath outdoors, we inhale a mixture of gases, primarily composed of 20% oxygen, 79% nitrogen, and 1% other gases. Liquid nitrogen is made by compressing and cooling the nitrogen present in the air.

The Process of Making Liquid Nitrogen

Compressing Atmospheric Air

The first step in making liquid nitrogen is to compress the atmospheric air into a container capable of withstanding high pressure. This container holds the air that will later pass through a nitrogen membrane, separating oxygen and other gases from the pure nitrogen gas.

Separating Oxygen and Moisture

When the compressed air passes through a nitrogen membrane, the oxygen and moisture present in the air are separated, leaving behind pure nitrogen gas. Removing moisture is crucial to ensure the purity of the nitrogen gas.

Storing the Nitrogen Gas

After obtaining clean and dry nitrogen gas, it needs to be stored under pressure. This is achieved by using a tank specifically designed for storing compressed gases. A regulator is added to control the flow of the gas and ensure a steady release.

Cooling the Nitrogen Gas

In order to convert the nitrogen gas into liquid form, it needs to be cooled to a temperature lower than its boiling point. This is achieved by utilizing a helium compressor, which acts as an advanced cooling system. The helium compressor, operating on Boyle's law, compresses the gas, cools it down, and then rapidly expands it, resulting in extremely low temperatures.

Condensing and Collecting the Liquid Nitrogen

Once the gas is cooled sufficiently, it needs to come into contact with a surface colder than the boiling point of liquid nitrogen. When a vapor of nitrogen gas is blown towards this cold surface, it condenses into tiny droplets that eventually drip down. These droplets are captured in a container, such as a Dewar flask, allowing them to accumulate and form liquid nitrogen.

The Role of Helium Compressor

The helium compressor plays a crucial role in the process of making liquid nitrogen. As mentioned earlier, it is responsible for compressing and cooling the nitrogen gas, allowing it to reach temperatures below its boiling point. By exploiting the properties of helium, which has a significantly lower boiling point than nitrogen, the compressor creates ideal conditions for liquefaction.

The Cooling System for the Helium Compressor

To ensure the efficient operation of the helium compressor, a cooling system is required. In an improvised setup, a combination of a furnace blower, a radiator, and a heat exchanger is utilized. The furnace blower draws in large amounts of air, which is blown through the radiator, dissipating the heat from the compressed helium. Poly hoses are used to carry the cooled liquid back to the compressor for further cooling.

Energy Consumption and Time Required

The energy consumption of the liquid nitrogen production process varies depending on the specific equipment and setup. While the exact power usage may be difficult to determine, it is generally not significant enough to impact monthly electricity bills. However, it is important to note that creating liquid nitrogen is a time-consuming process. It typically takes several weeks to produce enough liquid nitrogen to fill a Dewar flask with 30 liters due to the slow drip-by-drip accumulation.

Acquiring the Equipment

The equipment required for making liquid nitrogen can be found through various sources such as Amazon, eBay, or university surplus. The necessary components include a nitrogen membrane compressor, a helium compressor, a cryo head, and a liquid cooling system. However, it is worth mentioning that even when sourcing and assembling the equipment independently, the cost can still be relatively high.

Pros and Cons of Making Liquid Nitrogen

While making liquid nitrogen can be a fascinating and rewarding endeavor, it is essential to consider the pros and cons before investing time and resources into it.

Pros:

• Cost-effective in the long run for individuals with regular liquid nitrogen needs.
• Enables experimentation and scientific exploration.
• Can be used for various applications, from cooling electronics to cryogenic preservation.

Cons:

• Requires specialized equipment and knowledge.
• Initial setup costs can be relatively high.
• Time-consuming process.

Conclusion

Making liquid nitrogen involves compressing and cooling nitrogen gas from the atmosphere to extremely low temperatures, resulting in its liquefaction. The process requires specialized equipment, such as a helium compressor, and careful control of temperature and pressure. While the initial setup may be costly and time-consuming, it offers a unique opportunity to explore the fascinating properties of this cryogenic substance. Whether for scientific experimentation or industrial applications, liquid nitrogen continues to be a valuable resource with a wide range of uses.