You may have wondered about the differences between propane and natural gas, especially because natural gas actually contains some propane. The key is that there are also other fuels in natural gas, including ethane, methane, and butane. Propane can generate fuel on its own, and it can be stored in a tank in its liquid form. But can you put natural gas in a propane tank?
Although it is technically possible for natural gas, in its gaseous state, to be put in a propane tank, it would have a low density and you wouldn’t be able to store a usable amount. Household propane tanks can’t store natural gas because its molecular structure makes it harder to liquefy.
Regardless of what you may have heard, a low temperature is not what keeps household propane in a liquid state. It’s high pressure that gets the job done. A pressure of about 850 kPa is what the tank needs to be at, and a strong metal tank can handle this. Natural gas, meanwhile, can be stored in liquid form in a room but the room has to maintain a pressure of around 32,000 kPa! A household metal tanks can’t handle that kind of pressure.
What Is Natural Gas?
Natural gas is characterized as being renewable, non-toxic, colorless, odorless, and flammable. Not only does it have methane as its major component, at about 70-90%, but it is also a gas mixture. Other gases such as ethane, butane, and propane and part of the mixture.
To get the fuel we use for our day-to-day activities, natural gas needs to be combined with crude oil after it has been extracted from the ground. It is during this process that the other gases (butane, propane, and ethane) are extracted.
Natural gas is eventually pumped to households for their daily use through pipes in the gas state but it doesn’t start from there. It starts from where it is extracted from the ground, passes through a certain process, and then is stored at refinery plants.
What Is Propane?
Another name for propane is LPG, or liquefied petroleum gas. After its extraction, propane undergoes a separation process from natural gas at a processing facility before being stored as a liquid. Propane is usually colorless, non-toxic, and odorless. It also has to undergo compression before being stored in a liquid state.
Propane is not only clean, but it is also a reliable and safe energy source. It has a unique smell (similar to that of rotten eggs, a skunk’s spray, or a dead animal) and that’s one of its safety features. There’s a sulfur-based compound added to propane called ethyl mercaptan. This compound can be detected when using propane.
Key Differences Between Propane and Natural Gas
When it comes to fueling or heating vehicles, both propane and natural gas are very well-known. Although they share a lot of similarities such as both of them being odorless, clean-burning, and colorless, they do have some significant differences.
One of the yardsticks for comparing the two fuels is how much energy can be derived from consuming the same amount fuel. British Thermal Units (BTU), a measurement of thermal energy, will be used for this comparison.
Using a cubic foot of natural gas yields 1,030 BTUs, while a cubic foot of propane yields 2,516 BTUs. The meaning of this is that we will get 2.5 times more energy from the same amount of propane.
Cost is the next thing to consider after energy efficiency. Fortunately, making comparisons between natural gas and propane prices is quite easy. You first have to convert the price of the propane to cubic meters/feet if you get the price in gallons.
Next, you just have to multiply the natural gas price by 2.5. Doing this will be able to cover the amount of energy for the calculated prices.
Cleanness is one of the similarities that both propane and natural gas have. Amongst fossil fuels, propane is the cleanest burning one, just a little ahead of natural gas on the queue. This brings us to the idea of propane being considered a green fuel while, interestingly, natural gas is not.
When fuel is said to be green, it means that it has passed the eco-friendly check not only before its combustion but also after it. Propane possesses this test but natural gas does not.
Propane does not cause any reason for panic if it is leaked into the atmosphere but the same thing can’t be said about natural gas. Methane is the major component of natural gas, and this is the major reason why a natural gas accident or leaks to the atmosphere should be prevented.
Household Use and Transportation
When it comes to heating and cooling at home, propane and natural gas are both common options. However, they have separate delivery methods and that happens to be the biggest difference that exists between the two fuels.
Pipelines are used for the delivery of natural gas. In other words, gas is available 24/7 to the home as long as gas pipelines are connected to it.
Meanwhile, propane is usually stored in propane tanks while in its liquid state. The advantage of this is that the tanks can be delivered anywhere. However, a major drawback is that using propane requires refilling and if there’s no option for refilling, the household can be left without heat.
Because both natural gas and propane are colorless and odorless, manufacturers decided to include chemicals like ethyl mercaptan to help make the fuels easier to detect. Although the chemicals added to the gases are largely harmless, their unpleasant odor helps make them detectable.
The density of the two gases is one of their major differences. While natural gas is lighter than air, propane is heavier. What this means is that if there is a leak, like in a home (a closed space), natural gas will be concentrated at a high level while propane will settle towards the ground.
Can You Use a Propane Tank for Natural Gas?
You can’t. You would have to liquefy a gaseous fuel if you want to get a useful amount of it into a reasonably-sized tank. Propane has a booking point of -44˚ Fahrenheit at normal atmospheric pressure while natural gas, on the other hand, has a boiling point of -260˚ Fahrenheit at normal atmospheric pressure.
This means that if you want it to be turned to a liquid storable in a tank, natural gas has to be cooled to a much lower temperature than propane.
What Happens if You Run a Natural Gas Appliance on Propane?
To convert gas appliances to either propane or natural gas, you first have to change the internal parts so you can adequately compensate for the contrasting pressures between the fuels. Any appliance fueled by either propane or natural gas can be adapted to run on either of the two provided a recommended gas conversion kit is used.
There are a couple of factors that should be considered if an appliance is to be converted for use with another gas, whether propane or natural gas. These factors include the following:
Appliance Regulator: Delivery and inlet pressures are among the differences that exist between propane and natural gas appliance regulators. You would get an imbalanced (too high or too low) outcome if you use the wrong kind of gas appliance regulator.
This is why you have to ensure that the pressure is moderated and not applied too heavily or too little. You should also ensure that you take care of your regulators by servicing them, allowing a licensed professional to help you convert or change them as needed.
Appliance Burners: Incomplete combustion can take place if a direct relationship is established between the delivery pressure supplied by the regulator and orifices on a burner function, especially if it is not properly sized or if it is done wrongly.
Also, there is a high tendency that a burner can damage an appliance if the conversion requires smaller or larger orifices to be in place around or on the burner.
Burner Air Shutter: At this point, gas and air mixed before going into the burner are used to toggle or change the flame condition. There are different types of air shutters and this very important gas/air mixing mechanism must be a moderate or recommended one and must also be toggled or changed so that complete combustion occurs.
The reality is that acquiring a new appliance may be the more affordable option to go for instead of trying to go through the entire process of converting an appliance that is already designed to be used with either natural gas or propane.
Even if the recommended appliance conversion kits are available for certain equipment, the conversion process still requires the expertise of a professional and licensed technician. This is because you would, of course, want all the necessary adjustments to be done properly.