Analysis of available technologies for the separating nitrogen and carbon dioxide from natural gas

In the Serbia there are more gas reservoirs with reserves of more than 10 million Sm3 of natural gas. One of the reasons why they have not been exploited yet is that they contain nitrogen and carbon dioxide, that should be separated during the production process. Today, there are many developed technologies for separation of nitrogen and carbon dioxide from natural gas such as cryogenic processes, membrane technology, molecular sieves, nitrogen spinners, etc. So far, none of the mentioned technologies has been applied in our country. The paper presents technologies for separating nitrogen and carbon dioxide from natural gas. In this paper is presented an analysis of the possibility of applying these technologies from the aspect of the capacity, pressure and content of nitrogen and carbon dioxide in natural gas. In particular, it should be noted that all technologies are already commercially applied in the world. Investment and operating costs for the presented technologies were determined. The economic viability of selected technologies for separating carbon dioxide and nitrogen from natural gas directly depends on the required process capacity. For low daily production rate, membrane technology and molecular sieves are excellent for gas reservoirs in our country. Investment costs are the lowest in implementing the membrane technology and molecular sieves and they are ranging from 9.89 to 11.40 $ / Sm3 , while exploitation costs range from 0.010 to 0.020 $ / Sm3 . This is very important for the reasons of the project economic sensitivity when the small gas reservoir are considered.