Abstarct: The development of human societies depends on the more and efficient use of the energy resources. Using of fossil fuels is more than other sources of energy due to easier access and easier operation of reservoirs. Petrochemicals and refineries are major consumers of fossil fuels and producer environmental pollutants, therefore, reducing energy consumption and emitting less environmental pollutants, has been a concern for these industries. One of the main sources of energy waste in these industries is the burning of gases in flares. Actually, flaring can be described as a waste of billions of dollars and an environmental tragedy. On the international scale, the Kyoto Protocol has also obliged countries to reduce emissions of environmental pollutants. In this paper, authors provided an economical technical analysis for the production of valuable products from gases are sent to flare. The composition and flow rate of gases sent to Fajr Jam, Iran refinery flares is selected as a case study. The most important issues in recovering flare gases are the non-constant flow rate and excessive in the flare gas composition. The PRICO refrigeration cycle was employed in the flare gas recovery process. In this cycle, the mixed refrigerant is used as the working fluid. The differences in the boiling points of flare gas compositions, was the main idea for the separation of hydrogen sulfide, LNG and NGL from flare gas. Consequently, flare gases are separated into several parts during a number of successive cooling and heating stages and passing through phase separators. Finally, the results showed that about 70% of the flare gases could be converted to LNG and NGL with the allowable amount of . The annual loss of 12 million cubic meters of gas in refinery flares is prevented by using this process. Furthermore, about 11,000 tons of LNG and 1230 tons of NGL are produced in the year. Finally, an economic evaluation was carried out, showing a payback period of about 1.5 years.