**Table 3.**

*Specification of nanotubes [1].*


#### **Table 4.**

*Composition of natural gas [1].*

surface area of the nanotubes for adsorption increases. As the outer diameter of carbon nanotubes increases, their adsorption capacity increases (**Figure 7**). It has been proven that by doubling the diameter of the nanotube, the absorption of

**Figure 7.** *Adsorption capacity at different diameters of the nanotubes [1].*

*Storage of Natural Gas by CNTs DOI: http://dx.doi.org/10.5772/intechopen.103814*

natural gas in the pipes will increase by 45%. With an increase in the diameter of the nanotube, nanotube walls increase, and due to its density per unit mass, the adsorption capacity increases.

To prove that less porosity causes more gas to be absorbed, the porosity values of 70, 80, 90, and 98 were considered. The other parameters are listed in **Table 5**. Based on this, the mass loaded in the container increases if the porosity decreases, resulting in an increase in the total amount of gas adsorbed in the nanotube. The adsorption capacity of the tubes will not change continuously with changes in porosity (**Figure 8**) [1].
