Selective Adsorption of Neutral Nitrogen Compounds from Fuel Using Ion-Exchange Resins

Abstract

Adsorptive removal of hydrodesulfurization inhibitors, that is, nitrogen-containing compounds (N-compounds), was studied using model fuel which contains carbazole and dibenzothiophene in an n-dodecane-toluene mixture over ion-exchange resins (IXRs) in batch and in fixed-bed adsorption systems. The adsorptive capacity and selectivity for neutral N-compounds were examined. The high affinity for neutral N-compounds present in hydrocarbon feed was explained by hydrogen bonding between the chloride anion (with nonbonding electrons) and the neutral N-compounds. However, the presence of a flat charged cation, that is, N-alkylated pyridinium, is essential to ensure the adsorption of neutral N-compounds. The regeneration of the sorbent could be easily performed using polar organic solvent like methanol. Commercially available IXR bearing pyridinium chloride functionality (HPQ) was further evaluated with straight-run fuel oil. The N/S selectivity decreases, but analysis of the adsorbed compounds by gas chromatography/mass spectroscopy (GC/MS) shows that no paraffin and no monoaromatics were adsorbed. The results obtained provided new insight into the fundamental understanding of the adsorption mechanism of neutral N-compounds from hydrocarbon feed.

Review of Denitrogenation of Algae Biocrude Produced by Hydrothermal Liquefaction

“…Reuse of this polymer showed consistency in the selective removal of nitrogen compounds, with a continuous and unchanging removal rate. Some commercially available ion-exchange resins bearing pyridinium chloride functionality have exhibited much higher adsorptive capacity and selectivity for neutral nitrogen compounds [117]. The nitrogen concentration was greatly reduced in model fuel (dodecane-toluene mixture) and heavy gas oil.…”

Remarkable adsorptive removal of nitrogen-containing compounds from hydrotreated fuel by molecularly imprinted poly-2-(1H-imidazol-2-yl)-4-phenol nanofibers

“…Adsorptive denitrogenation (ADN) is about the most recent method that is being applied to remove organonitrogen compounds in fuel oil. So far, many adsorbents such as activated carbon, zeolites, silica, ion-exchange resins have been used for the ADN, [18][19][20][21] with less selectivity in the removal of organonitrogen compounds in fuels. However, sorbent materials such as molecularly imprinted polymers (MIPs) fabricated through imprinting of templates unto polymers suffice as potential adsorbents for the adsorption of these compounds.…”

Remarkable improvement in adsorptive denitrogenation of model fossil fuels with CuCl/activated carbon, prepared under ambient condition

“…So far, several materials have been studied on a laboratory basis for applications in the ADN process. These include activated carbon (AC) [7][8][9][10], Cu(I)-Y zeolites [6,11], ion exchange resins [12], meso-silicas [13,14], Ti-HMSs [15], microporous carbons [16], activated aluminas [17], Ni-based adsorbents [17], Si-Zr cogel [18] and metal-organic frameworks (MOFs) [19][20][21][22][23].…”