The energy sector depends on the gas. Over 50% of heat is being generated from this sector. There are different variants of gas such as LPG, LNG, and CNG. Today we will show the comparison between the two most used gases LPG & Natural gas.
Here are some factors on which we will observe the comparison-
- Energy supplied
- Chemical Composition
- Required air for combustion
- Liquification process
- Operating pressure
LPG and LNG industries have been running their business for several decades. In this long run, they both have made their product almost risk free.
The explosion of an LPG or LNG cylinder is nearly impossible. But still, accidents occur and take the lives of innocent people only because of some negligence and lack of knowledge.
So apparently both gases are safe, but if you look comparatively, then LNG is slightly safer than LPG. The specific gravity of LPG is 1.52 i.e. it is 1.52 times heavier than air. This means that if there is any leakage, then it will be stored in the lowest part of your residence. An exhaust fan can not suck it out.
LNG’s specific gravity is 0.5537 which means it weighs almost half of the air. So, if you have any leakage it will go up and with an exhaust fan running, it will suck the gas out.
They sell LPG in the local market in kg or ton, but LNG sellers are using BTU (British Thermal Unit). There is a calculation for conversion from kg to BTU. By doing those calculations and observing the local market, we found that LPG is slightly cheaper than LNG. But if you calculate it only by considering the price of gas, then LNG will appear as the cheaper one. The reserve of natural gas is reducing day by day. Suppliers of natural gas have to give charge for being connected to the natural gas pipeline. So, LPG is now cheaper than LNG in the modern era.
#3. Energy Supplied
The efficiency of any fuel depends on the amount of energy it can produce. If we have a fuel that has a higher “Calorific Value” that means this fuel will produce more heat energy. LPG’s calorific value is higher than natural gas. The calorific value of LPG is 93.2 MJ/m3 and that of LNG is 38.7MJ/m3.
#4. Chemical Composition
Alkene is a hydrocarbon. First four alkene is methane (CH4), ethane(C2H6), propane(C3H8) and butane(C4H10). Among these alkenes’ methane natural gas. We use propane and butane as LPG. We compress propane and butane into a liquid. We store it in a cylinder or a vessel. We store LNG in cryogenic tanks. Methane is liquified cryogenically at -161°C.
#5.Required air for combustion
Oxygen is a must for combustion. Air is a free source of oxygen. 1 kg LPG requires 25kg air, 1 kg LNG requires 10kg air.
#6. Liquefaction process
LPG is liquified by applying pressure. LNG is turned into liquid cryogenically. Liquefying LPG requires 10-14 bar pressure. But LNG liquefying is a bit complicated. At first impurities like CO2, Mercury, hydrogen Sulphide and water are separated. Then through the heat exchanger, it is taken to cryogenic temperature -161°C and store in the storage.
LPG is stored in cylinders and then distributed to your kitchen. The reticulated system will help you remove the cylinder from the kitchen. The cylinder will be in the garage and you will have a continuous supply through a pipeline.
We distribute LNG through a pipeline. We use sophisticated sensors at a definite distance in the pipeline. We also use vaporizers for distributing LNG.
#8. Operating pressure
LPG burners operate at 2.75kPa and LNG burners work at 1.1kpa. LNG produces less CO2 than LPG.
LPG differs from natural gas, but it is a byproduct of natural gas. When natural gas is processed from petroleum and crude oil, we produce LPG. We can easily transform LPG into SNG, which can an alternate for natural gas. Both LPG and LNG are odorless. RAW natural gas contains liquified petroleum gas. We also name LNG as PLG (Piped natural gas). So, the difference between PLG and LPG is also the same as the difference between LNG and LPG.
Comparison between LPG and LNG at a glance
|LPG vs Natural||LPG||Natural Gas|
|Calorific value: MJ/m3||93.2||38.7|
|Calorific value: Btu/ft3||2572||1011|
|Calorific value: MJ/kg||49.58||52.5|
|Boiling Temp: ℃||-42||-161.5|
|Flame Temp: ℃||1967||1950|
|Flame Temp: ℉||3573||3542|
|Gas Volume: m3/kg||0.540||1.499|
|Density @15℃: kg/m3||1.899||0.668|
In an overall discussion, I will prefer using LPG instead of LNG cause it’s cheaper, portable and produces higher energy. Though LNG will have a slight advantage in terms of safety, you cannot use it in many situations.