Temperature of Burn and Freeze of Different Gas Types

In natural conditions, most fuel gases are extracted in a gaseous state at ambient temperature and pressure. However, they can condense into liquids at specific low temperatures, which is critical for storage and transportation, especially for liquefied gases like LPG (Liquefied Petroleum Gas) and LNG (Liquefied Natural Gas). Each gas has its peculiar temperature for freezing (or liquefaction) at atmospheric pressure.

Propane average temperature of freezing is about -188 °C (-306 °F), butane varies around -138 °C (-216 °F), methane (LNG) falls in the range of -162 °C (-260 °F), natural gas (varies depending on composition) ~ -160 °C (-256 °F), hydrogen ranges within -259 °C (-434 °F),  and oxygen (for reference) freezes at -218 °C (-360 °F).

It is important to notice that these values represent the boiling points rather than traditional "freezing" because gases like propane and methane do not freeze in the usual sense; they condense into liquid form when cooled under pressure. This is essential for LNG (Liquefied Natural Gas) applications, which require extremely low temperatures to maintain gas in liquid form for transport.

The burn temperature of a gas refers to the maximum flame temperature it can reach when combusted in air or oxygen. This value is crucial for applications requiring high heat, such as metalwork, engines, or heating systems. So, what are the approximate flame temperatures in air for commonly used fuel gases?

Propane average temperature of burning is about ~1,980 °C (3,596 °F); methane (main component of natural gas) falls in the range of ~1,960 °C (3,560 °F), butane varies around ~1,970 °C (3,578 °F), hydrogen ranges within ~2,045 °C (3,713 °F), and acetylene reaches as much as ~2,530 °C (4,586 °F).

Hydrogen and acetylene burn the hottest among these gases, making them perfect for cutting and welding operations. In contrast, propane and methane are more common for heating and fuel systems due to their stability and ease of transport.

It is important to note that these temperatures are measured in open air. In oxygen-enriched environments, flame temperatures can be significantly higher. This information is particularly relevant to industries that use oxy-fuel systems.

The following table provides a simplified comparison for quick reference

The temperature properties of gases influence their usability and storage. For example:

• Propane and butane are stored under pressure as liquids in cylinders or tanks (LPG (Liquefied Petroleum Gas)). They are widely employed in residential heating and cooking.

• Methane is stored as CNG (Compressed Natural Gas) or LNG (Liquefied Natural Gas), depending on application scale. LNG requires cryogenic tanks due to its extremely low liquefaction temperature.

• Hydrogen, though clean-burning, is difficult to store due to its low boiling point and small molecular size, which requires highly specialized containment.

In colder climates, gases like butane may become ineffective because they fail to vaporize below their boiling point. Propane, with a lower boiling point, remains more reliable in winter.

When selecting a gas type, both the combustion temperature and liquefaction point must be considered. These parameters affect different important aspects. The first one is safety, which means that gases with low boiling points need special containers to prevent leakage and explosion. Also, the factor of energy efficiency, when gases with high flame temperatures are better for high-heat applications. And the last is climate suitability, in the sense that gases, which remain in gaseous form at low ambient temperatures, are more suitable for outdoor or winter use.

For instance, propane remains gaseous down to -42 °C (-44 °F) at atmospheric pressure, making it suitable for most climates. However, if temperatures drop below this point, vaporization slows, and appliances may fail to function properly. Butane’s boiling point of -0.5 °C (31 °F) means it does not vaporize well in freezing weather, making it unsuitable for outdoor use in cold climates unless blended with propane.

When working with gases, it is important to consider more than just cost or availability. The burn temperature determines whether a gas is appropriate for high-heat applications like welding or metal cutting, while the freezing or liquefaction point affects how easily it can be stored and transported, especially in cold climates.

Propane stands out as a versatile option that performs well even in winter conditions, making it a reliable choice for home heating and cooking. Butane, while useful in warmer environments, is less effective in cold weather due to its higher boiling point. Methane and natural gas are relevant for large-scale applications such as central heating systems or electric power generation, particularly where long-distance pipeline delivery is possible.

Hydrogen and acetylene offer extremely high combustion temperatures, making them ideal for specialized industrial uses, although their storage requirements are more complex and expensive.

Understanding the burn and freeze characteristics of each gas type helps ensure safe handling, efficient energy use, and appropriate selection for specific applications. The I-Maximum team is committed to providing the information and resources you need to make sound decisions in the gas energy sector.