Diesel Fuel Desulfurization via Adsorption with the Aid of Activated Carbon: Laboratory- and Pilot-Scale Studies

Abstract

The present work is an experimental investigation of commercial diesel fuel liquid desulfurization via adsorption under mild conditions. The sorbent employed was a commercial high surface area activated carbon (AC) and studies involved both lab-and pilot-scale experiments performed in dedicated fixed bed setups. Under lab-scale conditions, maximum sulfur removal measured exceeded 90%, while according to breakthrough curves obtained the total sulfur content remained below 2 ppmw for up to 20-22 ml processed diesel/g AC. Process scaling-up by a factor of 15 showed a moderate negative effect, with the respective breakthrough fuel amount (total sulfur ≤ 2 ppmw) being approximately 15-17 processed fuel/g sorbent. Several sorbent regeneration strategies were studied under lab-scale conditions. The one with the highest restoration of initial (i.e. fresh state) AC performance involved heating under vacuum (200 mbara) up to 200 o C and subsequent washing of the material with a binary organic solvent. The amount of solvent required was 50-55 ml /g sorbent. However, even under such conditions, desulfurization performance was only partially restored upon repeated desulfurization/regeneration cycles. From the 2 nd and up to 7 th cycle, desulfurization efficiency of the material was essentially stable but from cycle number 8 and on further performance degradation was identified. Based on fresh/regenerated sorbent post analysis, it was found that cycle-to-cycle degradation was due to gradual decrease of the sorbent's surface area, mainly attributed to residual amounts of diesel-derived species remained in its structure thereby partially blocking its porosity. The main properties of processed fuel remained essentially unaffected, however removal of di-and poly-aromatic compounds was notable.

On the Removal and Desorption of Sulfur Compounds from Model Fuels with Modified Clays

“…As observed in Table 1, all the adsorbents presented n larger than 1. Other adsorption studies of DBT and BT with activated carbon [5][6][7] show lower adsorption capacities than the ones reported in this work, with q values around 25 mg/g at low pollutant concentration [5] and 12.16 mg of sulfur per gram of pristine activated carbon [6].…”

“…Synthetic gasoline and diesel were prepared based on their major components, according to the literature [5][6][7]. Hexadecane was chosen as synthetic gasoline and a 1:1 volume mixture of decane and hexadecane was used for diesel.…”

“…Activated carbon is well known for its adsorption properties, including phenolic compounds, dyes, metals and organic molecules in general. Therefore, its application to the elimination of sulfured compounds has been subject of research in the past [5][6][7]. Unfortunately, the next question this raises is: is activated carbon not prepared by burning organic materials?…”

Desulfurization Kinetics and Regeneration of Silica Gel-Supported TiO2 Extrudates for Reactive Adsorptive Desulfurization of Real Diesel

“…With the advantages of low-cost operation, avoiding the emissions of SO x generated during the oxidative regeneration process, and recoverability of the organosulfur compounds, solvent elution − has been reported as an environmentally benign method to achieve the regeneration of the adsorbents. In this work, three types of solvents (aromatic, polar, and alkaline solvents) were chosen to investigate the effects of π–π interaction, “like-dissolve-like” principle, and alkalinity on the regenerability of CN 2 extrudates.…”

Fixed Bed Adsorption and Modelling for Desulphurization of Diesel Using Coconut Shell Activated Carbon

“…Investigators were carried out both laboratory and pilot scale experiments performed in dedicated fixed bed setups. Under laboratory scale conditions, maximum sulfur removal measured was exceeded 90%.The continuous tests were performed in a vertical fixed bed adsorption reactor and were employed for the generation of dynamic total sulfur breakthrough curves [2]. Alain Favre Re et.al were studied deep desulfurization of diesel feedstock by selective adsorption of refractory sulfur compounds.…”