Investigating Adsorptive Deep Desulfurization of Fuels Using Metal-Modified Adsorbents and Process Intensification by Acoustic Cavitation

Abstract

The harmful impact on the environment due to SO x emissions from fuels and increasingly strict norms over the years have amplified deep-desulfurization challenges, consequently enhancing attractiveness of adsorptive separations. The present work focuses on investigating metal modifications and process intensification using acoustic cavitation for improving sulfur removal behavior and selectivity. The proof of concept was elucidated using two model adsorbents: one commercial Shirasagi TAC adsorbent and another newer adsorbent derived from Cassia fistula biomass. Single- and double-metal modifications were studied using zinc, cobalt, nickel, and copper. An attempt was made to further improve the sulfur removal using process intensification using acoustic cavitation coupled with adsorption. The removal of three refractory sulfur compounds (viz. thiophene, benzothiophene, and dibenzothiophene) was studied, and the performance was compared for both single- and double-metal modifications apart from process intensification. In the case of TAC, a high capacity for sulfur removal, up to 23 mg S/g, was obtained, especially for dibenzothiophene. Process intensification using cavitation coupled with adsorption further improved sulfur removal to the extent of 100%, and for metal-modified TAC, a capacity increase up to 38 mg S/g for dibenzothiophene was obtained. The results indicate that the combined effect of metal modification and process intensification can substantially improve the sulfur-removal efficiency of carbon adsorbents.

Improving efficiency for removal of ammoniacal nitrogen from wastewaters using hydrodynamic cavitation

“…The flow characterization in vortex diode is well discussed in the literature and will not be repeated here [27] , [30] , [33] , [34] . Recently [1] , [20] , [35] , [36] , have discussed degradation of organics such as dyes, solvents and degradation of organics from real industrial wastewater. However, no systematic studies have been reported specifically for removal of ammoniacal nitrogen using hydrodynamic cavitation.…”

Cavitation based cleaner technologies for biodiesel production and processing of hydrocarbon streams: A perspective on key fundamentals, missing process data and economic feasibility – A review

“…Various types of adsorbents, known as carbon-based, silica-based, metal-modified adsorbents and graphene-based adsorbents, have been reported to be used in the desulfurization of fuels by means of acoustic cavitation ( Supplementary material ; Table S2: Nr 2, 4, 12, 14, 21) . Carbon-based adsorbents, such as Shirasagi TAC (trade name for a commercial activated carbon) and CFP-450 (derived from Cassia fistula biomass at 450 °C) modified with single metals (Ni, Zn, Co, Cu) and double metals (Ni and Cu), successfully improved the sulphur removal up to 100 % in 15 min processing [ 102 ]. Total desulfurization was firstly attributed to the intense cavitation and microstreaming, which increases the interaction surface area between adsorbent and sulphur molecules, herein, the power density for this system was found to be 25,000 (W/L) ( Table 2 ; Nr 2) .…”

A Review of Nano-catalyst Applications in Kerosene Desulfurization Techniques

“…An adsorption technique is commonly designed to provide selective sulfur compound elimination, work at ambient conditions with no difficulty of process control, attain high sulfur removal from fuel oils at a reasonable cost, and easiness of restoration with low chemicals and operating power, contrary to the HDS process [28]. Adsorption happens when a gas or liquid accumulates on the absorbent material's surface in a succession of phases.…”

“…The first set of experiments was conducted utilizing model oil, prepared by using dibenzothiophene (DBT) in cyclohexane; the best performance obtained was 99.4%. Suryawanshi et al [28] studied metal modifications and their impact on sulfur elimination selectivity. For their experimental setup, they used two adsorbent types, a commercial TAC, and the other was a homemade prepared from Cassia fistula biomass.…”