Papers by Author: S.S.X. Chiaro

Abstract: Ultra-low sulfur diesel (ULSD) is obtained by Light Gas Oil (LGO) and Light Cycle Oil (LCO) feedstocks (middle fractions from distillate petroleum). In addition to the environmental requirements related to the production of fuels with a lower content of nitrogen, technical specifications refineries also stimulate the need to remove such compounds. Nitrogenous compounds, for example, are strong inhibitors for hydrodesulfurization reactions. As Brazilian oil has a high amount of nitrogen compounds, an alternative process for nitrogen removal has been investigated, such as adsorption. In this paper, the nitrogen removal was investigated. The adsorption tests were carried out in a shaking water batchs, by performing kinetic and isotherm tests. Two commercial clays were used: Fuller's earth and bentonite.

Abstract: The use of adsorbents in the final steps during petroleum fuels refining is still the usual practice in Brazilian refineries. The production of kerosene via the Bender process still demands that the fuel goes through a bed of clay to remove nitrogen contaminants. Thus, several studies are being developed based on adsorption over clays for the removal of nitrogen and sulfur compounds. However, the major problem is the sharp decrease in the adsorbents durability. The procedure currently employed by the refineries is the one recommended by the annex 1 from ASTM D2007 methodology. By this method, the evaluation of the adsorbent capacity is done without any pretreatment for water removal. This study aimed to establish a comparison between the results obtained by ASTM D2007 with the results obtained by a procedure developed on a bench unit which comprises a pretreating stage to remove water from the adsorbents before feeding the column. The results show that the water content strongly influences the adsorption capacity of the clays, and may even spoil high-capacity adsorbents if they are not pretreated for water removal.