Study of Adsorptive Denitrogenation of Diesel Fuel over Mesoporous Molecular Sieves Based on Breakthrough Curves

Abstract

Adsorptive denitrogenation of model fuel and commercial diesel containing organic nitrogen compounds was studied over three typical mesoporous molecular sieves (Ti-HMS, HMS, and MCM-41) in a fixed-bed adsorption system at ambient pressure. The adsorbents were characterized by X-ray diffraction, UV−visible spectroscopy, transmission electron microscopy, N 2 physical adsorption−desorption, and temperature-programmed NH 3 desorption techniques. The adsorption capacities for various compounds (pyridine, quinoline, pyrrole, and indole) were examined and compared on the basis of the breakthrough curves, which provided insight into the adsorption behaviors over the different adsorbents. It is shown that the breakthrough time is shortened at increased temperature and liquid hourly space velocity (LHSV). The adsorption performance of HMS and Ti-HMS depends dominantly on the acid−base interaction. In addition, the polarity of the adsorbate is another factor that influences the adsorption capacity. The introduction of Ti improves the acidity of Ti-HMS, which thus exhibits a higher adsorption capacity than HMS, as confirmed by UV−visible spectroscopy and temperature-programmed NH 3 desorption. The adsorption performance of nonacidic MCM-41 depends principally on the molecular weight of the adsorbate. For commercial diesel, the adsorption competition between sulfur and nitrogen compounds influences the adsorption of total nitrogen.

Nitrogen compounds removal from oil-derived middle distillates by MIL-101(Cr) and its impact on ULSD production by hydrotreating

“…For a given NOC % removal from SR1LC the accumulated raffinate volume augmented by decreasing operating LHSV (Fig. 5) as by increasing contact time more NOC could be retained on the adsorbent surface sites [70]. According to previous reports [35] total saturation of MIL-101(Cr) could be reached after treating 755 bbl ton À1 (12 Â 10 À2 m 3 kg À1 ) of SRGO/LCO (80/20 vol/vol, mixture originally containing 321 ppm N), operating at LHSV = 0.8 h À1 .…”

Review of Denitrogenation of Algae Biocrude Produced by Hydrothermal Liquefaction

“…Mesoporous molecular sieves (Ti-HMS, HMS, and MCM-41) have shown perfect performance in the adsorptive denitrogenation of model fuel (octane containing pyridine, quinoline, pyrrole, and indole) and commercial diesel [119,120]. HMS and Ti-HMS exhibited higher adsorbability to indole, whereas MCM-41 showed better affinity with indole and quinoline.…”

Adsorption removing various basic nitrogen compounds from model diesel over allochroic silica gel

“…Main techniques for the denitrogenation of diesel oil include hydrogenation refining which needs strict operation conditions and huge instrument investment and nonhydrogenation refining such as liquid-liquid phase partitioning, nitrogen removal methods by solid adsorbents, and so on. These adsorbents for removing the nitrogen from diesel oil mainly include activated carbon (Schmitt et al, 2017;Wen et al, 2017), silica gel (Gaudino et al, 2016;Mushrush et al, 2011), metallic oxide (Silva et al, 2014;Silveira et al, 2015), metal-organic framework crystalline materials (Imteaz et al, 2013;Imteaz and Sung, 2014;Nazmul et al, 2017), modified NaY (Hong and Tang, 2015a;Liu et al, 2008), mesoporous materials SBA-15 (Shahriar et al, 2012;Zhu and Shen, 2012) and MCM-41 (Tang and Hong, 2016;Zhang and Song, 2012) and clays (Baia et al, 2017;Mambrini et al, 2013). Presently, there are some studies on adsorption denitrogenation over silica gel; Mushrush et al (2011) used silica gel to remove nitrogen from 20 kinds of diesel fuels from different parts of the world and almost all organic nitrogen could be removed.…”