Abstarct: Due to the enormous resources of natural gas with neighboring countries and the priority of exploiting these shared resources, it is necessary to use these resources. Due to the high cost of building a natural gas pipeline across the country, especially rural areas, the need to exploit new technologies for natural gas is required. One of the problems with the use of natural gas transmission lines is the severe pressure drop in peak consumption time during the cold season. In order to solve this problem and prevent gas interruptions for various uses, both urban and industrial, the need to use mini-LNG units is strongly felt. In this research, according to the data collected on the losses of industrial units at the time of the disruption of urban gas, the construction of mini-LNG units has been investigated. At first, the cycles used in LNG production were studied and then, considering the economic situation and the many constraints on investment, four suitable processes with the conditions of use in the country were selected so that the low investment cost and equipment used in the cycles could be built in Inside the country. The four simulated cycles are the refrigeration cycle using nitrogen refrigerant with a heat exchanger and an expander, a refrigeration cycle using nitrogen refrigerant with two heat exchangers and two expanders, a refrigeration cycle using methane refrigerant with a heat exchanger and an expander, and a refrigeration cycle without the use of methane-single expander. The simulation results show that the highest investment is in the second cycle, with the most used equipment. The simulation results show that the highest investment is in the second cycle, with the most used equipment. On the other hand, energy consumption in the second cycle is the lowest compared to other cycles. The results show that the return time of the investment with zero interest rate for first to fourth cycles is 2.4, 6.1, 4.8, and 1.4, respectively.