Efficient immobilization of acids into activated carbon for high durability and continuous desulfurization of diesel fuel

Abstract

Fuel contaminants are the most critical issues in human health, cars' engines life and performance, and refinery equipment, and have an ultimate consecutive economic negative impact over time. Nowadays, sulfur is considered as one of the most dangerous contaminants in fuel, and different approaches have been carried out for desulfurization processing. In this study, new modified activated carbon (AC) for adsorptive diesel fuel desulfurization is carried out. To increase the robustness and effectiveness of a continuous adsorptive desulfurization (ADS) process, the study provides a new surface modification technique of the AC. Real diesel fuel (RDF, sulfur content 7510 ppm) and model diesel fuel (MDF, dibenzothiophene content 637 ppm) were used in a series of ADS tests carried out in a fixed-bed adsorption column under atmospheric pressure and temperature. To achieve zero emissions of diesel fuel, the process parameters were optimized using the experimental findings. The AC and modified AC were tested via Brunauer–Emmett–Teller and Fourier Transform Infrared to evaluate the effect of the modification process on adsorbent characterization. The liquid hourly space velocity of the feedstock, the height of the absorber bed, and the kind of AC were the optimization parameters. In these circumstances, the ADS procedure was examined to address the impact of the feedstock flow rate on the effectiveness of ADS. The sulfur removal efficiency was 85.3% for RDF and 94% for MDF at 9 cm bed height, 8 h−1 LSHV, and 10 g bed weight, respectively. This is the first time that AC has been used to examine the stability of continuous ADS and to examine how acid immobilization affects sulfur removal. The investigation showed that the modified AC had a high rate of stability and was effective in the continuous ADS process. The spent modified AC was regenerated via a solvent extractive regeneration process to evaluate the durability of the ACs. The results proved that the regeneration performance of various solvents for modified activated carbon 1 decreases as follows: iso-octane > ethanol > methanol > acetonitrile.