Petroleum & Coal ISSN 1337-7027 Available online at www.vurup.sk/petroleum-coal Petroleum & Coal 55 (4) 361-365 , 2013 AN INVESTIGATION ON OXIDATIVE DESULFURIZATION OF GAS CONDENSATE Maryam Ghaedian* 1 , Mansoor Bazmi 1 , Amin Shafeghat 1 , Ali Khan Mohammadi 2 , Zahra Rabiei 1 , Fahime Naderi 1 1 Petroleum Refining Technology Development Division, Research Institute of Petroleum Industry, Tehran, Iran, E-mail: ghaedianm@ripi.ir; 2 Process Engineering Development Division, Research Institute of Petroleum Industry, Tehran, Iran Received September 26, 2013, Accepted December 23, 2013 Abstract In this research, both oxidation and extraction steps in oxidative desulfurization (ODS) process have been investigated for a gas condensate feedstock in order to derive optimum parameters. The evaluated parameters in the oxidation step were the effect of oxidant to gas condensate ratio, quantity of catalyst and the oxidation reaction time and temperature. In the extraction step, solvent to feedstock ratio for some different solvents have been studied. Results showed that desulfurization of about 83% would be achieved in low pressure and ambient temperature at optimum parameters. Key words: gas condensate; oxidative desulfurization; sulfone; extraction. 1. Introduction During two previous decades the environmental regulations for fossil fuels have become more and more severe. The major problem in using fossil fuels is their sulfur content. Thus, methods for reducing this impurity in petroleum products such as gasoline and gas oil have been developed very fast. In order to effectively control of air pollution due to diesel fuel combustion, the US EPA has released a new regulation requiring the use of low-sulfur diesel fuel. This regulation requires that the sulfur content of diesel fuel used in highway vehicles be limited to 15 ppm [3,5] . Hydrodesulfurization (HDS) is the conventional process for reducing organo-sulfur in gasoline, diesel and other intermediate distillates. This process is highly efficient for removing thiols, sulfides, disulfides, and some thiophene derivatives, but less effective for dibenzo- thiophene derivates with steric hindrance on the sulfur atom (refractory organo-sulfur compounds) such as 4,6- dimethyl dibenzothiophene (4,6-DMDBT), which are present in diesel fuel [8] . Possible ways to increase the efficiency of HDS for producing low sulfur product include use of higher temperatures and pressures, more active catalysts or longer residence times [4] . It is worth to mention that a great deal of CO 2 which is a greenhouse gas would be produced in this process. So, due to these restrictions and also increase in energy price, tendencies toward finding some cheaper methods of desulfurization have been increased. These methods are adsorptive desulfurization, Bio-desulfurization, oxidative desulfurization and so on. Oxidative desulfurization (ODS) process often takes place in the liquid phase and it has a lower operating and investment cost in comparison with the corresponding conventional method of hydrodesulfurization due to lower operating temperature and pressure. Furthermore, it is capable of removing refractory organo-sulfur compounds which have poor reactivity in HDS process [7-8] . Since there is no need of using hydrogen in ODS process, it could be considered as a proper choice while facing shortage or difficulties in providing hydrogen. Oxidative desulfurization can be a complementary and perhaps in some cases an alternative method for hydrodesulfurization process, because it is established for lower operating temperatures and pressures; by inexpensive catalysts, and with lower operating and investment cost. In recent years, many research studies have been done on ODS. Some researchers have done reviews on results that had been obtained from single and two phase systems,