(100c) Desulfurization and Denitrogenation Of Silica-Based Adsorbents For CLEAN Fossile Fuels

DesuLfurization and denitrogenation of silica-based adsorbents for clean fossile Fuels

Chang Ha Lee

Department of Chemical and Biomolecular Engineering, Yonsei University,

50 Yonsei-ro, Seodaemun-gu, Seoul, 120-749, Korea
E-mail: leech@yonsei.ac.kr

Due to increasingly stringent environmental regulations for transportation fuels, the desulfurization and denitrogenation of fuels have become very important research topics in the production of clean automotive fuels with ultra-low sulfur levels. According to the new environmental protection agency (EPA) Tier II regulations, the maximum allowable sulfur content in US diesel fuel is less than 15ppmw. In addition, some fuel cells will require deep-desulfurized fuels with sulfur content <1 ppmw in order to avoid poisoning and deactivation of the reformer catalyst.

Heavy low-quality crude oil and natural gas are rich in highly refractory nitrogen and sulfur compounds. During catalytic hydrotreating, denitrogenation (HDN) and desulfurization (HDS) are performed simultaneously. The ability to adsorb nitrogen compounds is generally higher when compared to aromatic thiophene derivatives, which have to compete with nitrogen compounds for active sites on catalysts during HDS processes. In addition, the HDN is the most difficult hydrotreatment reaction and slower than the HDS. Therefore, nitrogen compound residue remains on active sites longer than sulfur compounds. In addition, the removal of sulfur-containing compounds from natural, municipal or shale gas has also traditionally been achieved by the catalytic HDS process operated at elevated temperatures and pressures.

As an alternative method, selective adsorption appears to be a promising approach to ultra-deep desulfurization and denitrogenation because the process can be run at ambient temperature and atmospheric pressure without consuming pressurized hydrogen or oxygen gas.

In the presentation, a class of highly sulfur- and nitrogen-compounds selective silica-based porous adsorbents (Zr-Si cogel, mesoporous YSP, magnetite-mesoporous silica composite, MCF-Li, MgO silica composite) is introduced. Adsorption and desorption equilibrium by using real residue hydrodesulfurization diesel (RHDS DSL) were studied at ambient temperature and pressure. The dynamic behaviors of adsorption and desorption for RHDS DSL and municipal gas will be also presented.  

Keywords: Silica, Adsorption, desulfurization, denitrogenation, fossil fuel

References

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