Sulfur Removal Process Research Articles

The design of molecularly dispersed tungstovanadate catalyst via ionic liquid linkers for oxidative desulfurization

The sulfur removal process in diesel is one of the key technologies to produce clean energy using polyoxometalate (POM)-based catalyst with excellent catalytic active sites. Herein, a molecularly dispersed POM supported catalyst CNT@(C4mim)4VW12O40 (CNT@C4VW12) was designed by introducing imidazole ionic liquids (IL) [C4mim]Br as counterionic linkers for oxidation desulfurization (ODS). For the model oil, 100 % desulfurization rate and product selectivity can be achieved within 30 min, and it can be recycled for 5 times without obviously decrease. Moreover, CNT@C4VW12 also displayed excellent performance in real hydrotreated diesel with a removal rate of 97.4 %. Overall, a stable and molecularly dispersed catalyst was constructed by the cooperative effect of π-π stacking, hydrogen bonding and electrostatic force interaction among the CNT, [C4mim]+ and [VW12O40]4−, which would provide new inspirations for design of heterogeneous catalyst towards excellent ODS process.

ENERGY EFFICIENT SOLUTIONS FOR STEEL REFINING IN FOUNDRY CLASS ELECTRIC ARC FURNACE

Analysis of recent research and publications. The technological period in foundry class electric arc furnaces (EAF) is usually long term, is determined by desulfurization of steel and accompanied by significant energy loss through emissive surface of shallow steelmaking bath. Known mathematical models of Sulphur removal do not take into attention the impact of hydrodynamics factors due to deepening of the steelmaking bath of the same volume. Purpose. The task is to show feasibility of energy savings in foundry class EAF due to implementation of “deep” bath with forced pneumatic mixing. Method. Numerical modeling of sulfur removal in the steelmaking bath under conditions of forced pneumatic mixing. Research findings. Mathematical model takes into account removal of sulfur on interfacial surface of thin steel film, covering gas bubbles, geometry of bath and two-phase region, hydrodynamics, coalescence of bubbles. Simulation showed that in a “deep” bath, having shape factor (diameter to depth ratio) 2.5, rate of desulfurization, increases up to 5-6.7 times compared with a standard not forcibly stirred bath with shape factor 4.5, due to amplification of mass transfer in two-phase region and film desulfurization, reaching at least 23-28 % in overall process. Rise of porous plug radius contributes to increase sulfur removal velocity due to enlargement of threshold flowrates, corresponding to transition bubble - jet mode and bath "breakdown” mode. Effect of bath deepening in overall improvement of desulfurization kinetics is on average 23%. Practical significance. The obtained results allow to expect a shortening of the technological period due to increase of sulfur removal processes by an average of 1.5 times. Taking into account the share of the technological period in the total duration of melting on average 25-30%, the reduction of melting time will be 8-10%, and the saving of electricity, with an average specific consumption in small-capacity arc furnaces of 850 kWh/t, is expected to be 60-70 kWh per ton of crude steel.

The effect of reflux ratio on sulfur disproportionation tendency in anaerobic baffled reactor with the heterotrophic combining sulfur autotrophic processes under high concentration perchlorate stress.

In a laboratory scale, an anaerobic baffled reactor (ABR) consisting of eight compartments, the heterotrophic combining sulfur autotrophic processes under different reflux ratios were constructed to achieve effective perchlorate removal and alleviate sulfur disproportionation reaction. Perchlorate was efficiently removed with effluent perchlorate concentration below 0.5 μg/L when the influent perchlorate concentration was 1030 mg/L during stages I ~ V, indicating that heterotrophic combining sulfur autotrophic perchlorate reduction processes can effectively achieve high concentration perchlorate removal. Furthermore, the 100% reflux ratio could reduce the contact time between sulfur particles and water; thus, the sulfur disproportionation reaction was inhibited. However, the inhibition effect of reflux on sulfur disproportionation was attenuated due to dilute perchlorate concentration when a reflux ratio of 150% and 200% was implemented. Meanwhile, the content of extracellular polymeric substances (EPS) in the heterotrophic unit (36.79 ~ 45.71 mg/g VSS) was higher than that in the sulfur autotrophic unit (22.19 ~ 25.77 mg/g VSS), indicating that high concentration perchlorate stress in the heterotrophic unit promoted EPS secretion. Thereinto, the PN content of sulfur autotrophic unit decreased in stage III and stage V due to decreasing perchlorate concentration in the autotrophic unit. Meanwhile, the PS content increased with increasing reflux in the autotrophic unit, which was conducive to the formation of biofilm. Furthermore, the high-throughput sequencing result showed that Proteobacteria, Chloroflexi, Firmicutes, and Bacteroidetes were the dominant phyla and Longilinea, Diaphorobacter, Acinetobacter, and Nitrobacter were the dominant genus in ABR, which were associated with heterotrophic or autotrophic perchlorate reduction and beneficial for effective perchlorate removal. The study indicated that reflux was a reasonable strategy for alleviating sulfur disproportionation in heterotrophic combining sulfur autotrophic perchlorate removal processes.

Pervaporative Desulfurization: A Comprehensive Review of Principles, Advances, and Applications

Pervaporative desulfurization is a potential method for removing sulfur compounds from liquid hydrocarbon streams, having many advantages over existing methods. This overview covers the fundamentals, recent breakthroughs, and different applications of pervaporative desulfurization. The paper begins by explaining pervaporative desulfurization's core concepts, focusing on how polymeric membranes selectively separate sulfur molecules from liquid hydrocarbons. It explores membrane properties, operating conditions, and feed composition in pervaporative separation. It highlights how pervaporative desulfurization may reduce sulfur content to ultra-low levels and meet strict environmental and fuel quality standards. Finally, this comprehensive review paper concludes with a discussion on the future prospects and research directions in the field of pervaporative desulfurization. It highlights the need for continued innovation in membrane materials, module design, and process optimization, as well as the importance of addressing challenges related to scale-up and industrial implementation. Overall, this review paper provides valuable insights into the advancements, challenges, and potential applications of pervaporative desulfurization, offering a comprehensive understanding of this technology for researchers, engineers, and all parties involved in the development and implementation of sustainable sulfur removal processes.

Investigation and comparison of technologies and methods of sulfur recovery and production processes

Sulfur is found at the land's surface, in quarries, and as a natural sulfur resource. However, most of the part sulfur is obtained during the sulfur removal processes from crude oil or gas. These recovery processes are essential for the global energy resource market. Approaches to sulfur mining and recovering techniques are discussed and compared during the literature review and description analysis. Methods that are majorly used in the industry, their process flow diagrams, and principal of work are explained and compared relative to the modern methods of sulfur removal processes.

Synergetic Effect of Fe2O3 Doped-CeO2 Nanocomposites Prepared via Different Techniques on Photocatalytic Desulfurization of Heavy Gas Oil

The photocatalytic performances of three Fe2O3–CeO2 nanocomposites were investigated toward the sulfur removal from a petroleum heavy gas oil (HGO) sample. The three composites were prepared by three different routes namely; auto-combustion, post-precipitation and precipitation. The physio-chemical features and optical properties of the presented composites were determined via proper analytical techniques. Formation of Fe2O3–CeO2 solid solution in all the prepared composites was verified via XRD analysis. These composites were then employed in photo-desulfurization of HGO and their activities were investigated at several operating conditions. The highest photocatalytic desulfurization exploit (91.5%) could be detected for the composite which was prepared via auto-combustion technique, denoted as (Fe20Ce80)ac. This maximum percentage of sulfur removal could be obtained under visible light irradiation at the following optimum operating conditions: 15 g/L (as photocatalyst dose), time of 6 h and 2:1 of H2O2 to oil ratio. The subsequent implementation of a solvent extraction step using N-methyl pyrrolidone was needed to attain the deepest desulfurization of HGO. The efficiencies of the presented composites against the process of sulfur removal were discussed in spot of their textural and optical characteristics as well as the available oxygen vacancies through their lattices structures.

IMPLEMENTATION A COMBINATION OF BIO-DESULFUSIZATION AND TRICKLING FILTRATION TECHNOLOGIES WITH A VARIETY OF COCONUT SHELL CHARCOAL FILTER MEDIA IN REDUCING THE CONTENT OF H2S AND TSS IN THE LEATHER-BASED CLOTHING INDUSTRY

<p>Waste generated as a result of the leather processing industry can be in the form of solid, liquid and gas waste. Waste generated from the textile industry made from clothing H2S and TSS which if not treated properly, will be very dangerous for health and the environment. One of the efforts to overcome this problem, is offered in the form of a simple, inexpensive and efficient H2S and TSS waste treatment technology, namely by using a combination of bio-desulfurization and trickling filtration methods as a means of treating liquid waste in the leather-based textile industry, especially for parameters, H2S and TSS. Bio-desulfurization is a sulfur removal process by utilizing the metabolism of microorganisms, namely by converting hydrogen sulfide into elementary sulfur, and trickling wastewater filtration is a treatment process by spreading wastewater into a pile or media bed consisting of Coconut Shell Charcoal to reduce H2S and TSS content in leather-based clothing industry wastewater. The results of the study for H2S parameters in wastewater treated in bio desulfurization reactor and trickling filter with Coconut Shell Charcoal filtering media, the biggest decrease was in filter media with a thickness of 60 cm with a contact time of 30 minutes of 4.43 mg/lt or 88.84%. Likewise, the largest decrease in TSS parameter content was found in a 60 cm filter media thickness with a contact time of 30 minutes of 47.67 mg/lt or 82.54%.</p>

A Review of Nano-catalyst Applications in Kerosene Desulfurization Techniques

The production of clean liquid fuels is critical to maintaining a healthy life and environment around the world. To meet the new sulfur standard requirements, sulfur compounds must be effectively and completely removed from fuel oil. Therefore, researchers' attention turned to research into different techniques to remove sulfur from kerosene. This review focused on discussing a variety of catalysis approaches and emerging technologies for ultra-deep desulfurization of refinery streams for ultralow sulfur, such as hydrodesulfurization, catalytic-oxidative desulfurization, and adsorption desulfurization to form clean liquid fuels. This review discusses the most important industrial parameters that influence sulfur removal processes and has focused primarily on the main role of the catalyst and its type in impacting the efficiency of the process. Also, it will discuss the concepts of nano-catalysts, their preparation methods, and the most common forms, were described such as graphene, carbon nano-tubes (CNTs), metal-organic frames (MOVs), and zeolites. A comparison between the nano-catalyst and the conventional catalyst was also discussed to show the great effect of the nano-catalyst in improving the removal processes, which will lead to the development of innovative, efficient desulfurization methods that produce zero-sulfur fuels. In addition, understanding the most important challenges in nano-catalysts.

Experimental evaluation of the impacts of diesel-nanoparticles-waste tire pyrolysis oil ternary blends on the combustion, performance, and emission characteristics of a diesel engine

In the present research, pyrolytic oil is obtained from the waste tire chips, and then acid washing process, clay and calcium oxide process, distillation process, and oxidative sulfur removal processes are used to improve its properties. Then it is blended into conventional diesel fuel with/without Al2O3 nanoparticles, and the performance, combustion, and emission characteristics of a single-cylinder, air cooled, and naturally aspired diesel engine are discussed in this study. Tests were performed at varying engine loads from 3 to 12 Nm with the gaps of 3 Nm under a constant engine speed of 2400 rpm. In this study, three types of fuels were tested, namely D100 (100% diesel fuel), P10 (90% diesel fuel and 10% pyrolytic oil), and P10 + 1 g Al2O3 (obtained by adding 1 g of Al2O3 nanoparticles to P10 fuel). The addition of Al2O3 nanoparticles increased the brake thermal efficiency while reducing the maximum in-cylinder pressure, heat release rate, specific fuel consumption, exhaust gas temperature, hydrocarbon emissions, NOx emissions, and CO emissions compared to other test fuels. Namely, with the addition of Al2O3 nanoparticles, BTE was improved by 4.51% and 1.59% compared to P10 and pure diesel fuel, respectively. According to this, the BSFC value increased by 4.29% for P10 test fuel and then is reduced by 2% for P10 + 1 g Al2O3 test fuel as compared with conventional diesel fuel. Compared to diesel fuel, the CO, NOx, and HC emission values deteriorated by 17.5%, 5.69%, and 18.6%, respectively, with the addition of pyrolysis oil, and these deteriorated properties were improved by 10%, 6.82%, and 13.95%, respectively, with the addition of Al2O3 nanoparticles. In the light of this study, it was observed that while waste tire pyrolysis oil worsened engine performance, emission, and combustion characteristics, these deteriorations could be improved with nano Al2O3 supplementation.

Revealing the effect of multiple nitrogen sources on sulfide oxidation by progressively changing nitrate to nitrite

Nitrate or nitrite may be utilized as solitary electron acceptors for biological sulfide oxidation. In the presence of a limited sulfide concentration (360 mg S/L), the effect of multiple nitrogen (N) sources on the synchronized sulfur and nitrogen removal process was investigated based on the reactants biotransformation, product generation and bacterial genera analysis. Upon gradual transition from nitrate to nitrite, sulfide and nitrogen elimination percentages dropped from 99.46 ± 1.11% and 96.41 ± 1.30% to 71.57 ± 1.33% and 12.31 ± 6.80%, respectively. Synchronously, the elemental sulfur conversion percentage increased from 58.94 ± 1.21% to 90.49 ± 2.64%. A simulation model was established to investigate the contribution of reduced nitrate and nitrite towards sulfur- products separately. According to Pearson correlations, no significant relationship was observed amongst community richness/diversity and influent nitrogen source; while Principal component analysis (PCA) suggested that each phase formed a distinct group. Sulfurovum and Sulfurimonas were the dominant genera in all phases.

Extractive desulfurization using piperidinium based ionic liquids with Lewis acids

This work includes the preparation of ionic liquid 1,4-dimethylpiperidinium iodide [MMPip]I and its salts with ferric chloride as Lewis acid in different molar proportions [MMPip]I/nFeCl3 (n=1,2,3). The prepared compounds were diagnosed by spectroscopic and physical methods such as 1H-NMR, FT-IR, elemental analysis (CHN) and other techniques. The thermal stability of these compounds was studied to use in the extractive desulfurization process (EDS). The efficiency of these compounds in removing sulfur compounds from the petroleum model was examined using dibenzothiophene (DBT) with a concentration of 1000 ppm dissolved in the solvent of normal hexane. The results showed that the compounds used had an acceptable efficiency of up to 30% despite using medium amounts of the extracted agent relative to the oil model; these compounds have a promising future in extractive sulfur removal processes.

Mathematical modeling and experimental study of sulfur removal process from light and heavy crude oil in a bed occupied by ferric oxide nanocatalysts

The elimination of hydrogen sulfide from the crude oil considered as an important process in the oil refineries which reduces sulfur concentration of crude oil Application of nanocatalysts in the elimination of sulfur from oil considered as a modern method. In this research, the ferric oxide nanocatalyst with diameter of 54 to 91 nanometers has been used in the refinement of sour crude oil. In this work, the theoretical equations have been driven in order to investigate the sour oil desalination process in a nanocatalytic bed, mathematically. Several experiments have been designed to evaluate the process of hydrogen sulfide separation from sour crude oil. Two different types of crude oil have been used in this research. The API of heavy crude oil is 18.6 and the API of light sample is 33.4. The effects of various operational parameters such as operating conditions, geometric parameters have been studied in this study. In addition, the effect of nanocatalyst size variation on the sweetening process is evaluated. Based on the obtained results, temperature of 55 °C and pressure of 1.6 bar have been introduced as optimal temperature and pressure, respectively. Also, the experimental data show that the maximum amount of sulfur compounds is separated from sour oil when the diameter of the catalytic bed is 2.5 cm. • In this study, two samples of light and heavy oil have been sweetened. • Ferric oxide nano catalyst was used for sweetening. • Operating and geometric conditions of laboratory tower have been studied. • Results show that temperature of 55 °C and pressure of 1.6 bar are the best operating condition.

Removing Simultaneously Sulfur and Nitrogen from Fuel under a Sustainable Oxidative Catalytic System

An effective process to remove nitrogen-based compounds from fossil fuels without harming the process of sulfur removal is an actual gap in refineries. A success combination of desulfurization and denitrogenation processes capable of completely removing the most environmental contaminates in diesel under sustainable conditions was achieved in this work, applying polyoxometalates as catalysts, hydrogen peroxide as oxidant, and an immiscible ionic liquid as an extraction solvent. The developed process based in simultaneous oxidative desulfurization (ODS) and oxidative denitrogenation (ODN) involved initial extraction of sulfur and nitrogen compounds followed by catalytic oxidation. Keggin-type polyoxomolybdates revealed much higher reusing capacity than the related polyoxotungstate. Effectively, the first catalysts practically allowed complete sulfur and nitrogen removal only in 1 h of reaction and for ten consecutive cycles, maintaining the original catalyst and ionic liquid samples.

Validation of effective role of substrate concentrations on elemental sulfur generation in simultaneous sulfide and nitrate removal process

Simultaneous nitrogen and sulfur removal process has broad application prospects, which can accomplish simultaneous sulfide and nitrate removal to recover elemental sulfur from wastewater. The effective role of substrate concentrations in elemental sulfur generation was investigated through substrate removal, product conversion, characteristics and distribution of elemental sulfur along microbial community structure. Furthermore, a multivariate linear fitting equation was used to simulate the contribution of substrate concentration on elemental sulfur generation. Based on the statistical analysis (Multiple comparisons, Pearson correlation analysis and Principal Component Analysis), it was confirmed that substrate concentration elevation exerted a significant positive effect on the generation of elemental sulfur regardless of its presence in either effluent or sludge (p < 0.05). The results showed that bulk of the produced elemental sulfur mainly existed in the effluent of the reactor (76.59–88.28% of total elemental sulfur), rather than in the sludge (11.72–23.41% of total elemental sulfur). Zeta potential of elemental sulfur in the effluent was in the range of −15.70 mV to −18.92 mV. Sulfurovum was the dominant genus enriched by high substrate concentration whose relative abundance was higher than 79.46%.

Synthesis and characterization of AFe2O4 (A: Ni, Co, Mg)-silica nanocomposites and their application for the removal of dibenzothiophene (DBT) by an adsorption process: kinetics, isotherms and experimental design.

The kinetics, equilibrium, and statistical aspects of the sulfur removal process from hydrocarbon fuels by AFe2O4–silica nanocomposites (A: Ni, Mg, and Co) have been investigated in the present study. Nanocomposites were prepared via the auto-combustion sol–gel method and then employed in the adsorptive desulfurization (ADS) process. Next, the prepared samples were characterized by different analytical methods including XRD, SEM, TEM, FT-IR, TGA, and BET. The contributions of conventional parameters including adsorbent dosage and contact time were then studied by central composite design (CCD) under response surface methodology (RSM). Based on the statistical investigations, optimum conditions for ADS were an adsorbent dosage of 7.82 g per 50 ml of the model fuel and a contact time of 32 min. The adsorption amounts reached 38.6 mg g−1 for DBT. The quadratic model was applied for the analysis of variance. Based on the experimental data, the pseudo-first-order (PFO) model could explain the adsorption kinetics of the compounds. Furthermore, the Langmuir isotherm demonstrated considerable agreement with the experimental equilibrium data. According to the results, the NiFe2O4–SiO2 nanocomposite showed the best performance compared to other compounds. The sulfur removal efficiency increased from 63 to 94% upon increasing the NiFe2O4–SiO2 dosage from 3 to 9 g per 50 ml of the model fuel.

Features of ladle desulfuration of pipe steel with low sulfur content

At the present time the sulfur content in pipe steel is strictly regulated. Under conditions of PJSC “Magnitogorsk Iron and Steel Works” the metal is smelted in BOF shop with preliminary desulfurization of molten iron, treatment of tapping steel by a solid slag-forming mixture and final desulfurization in the “Ladle-Furnace” unit (LP-unit). In order to increase the efficiency of the sulfur removal process, the influence of the covering slag composition on metal desulfurization is considered. Statistical processing of production data array consisting of 14 melts of steel grade 10Г2ФБЮ with K60 strength class was performed. The dependences of the sulfur content in the metal after desulfurization in the LP-unit on the oxidizing ability, covering slag basicity and the content of magnesium oxide was established: it is shown that the amount of sulfur removed during the ladle treatment process increases with the increase of the covering slag basicity and with the decrease of the magnesium oxide content in slag. For describing this dependence, a new parameter was proposed – the ratio of slag basicity to MgO content in it, %–1. A high content of magnesium oxide in the “white” slag was revealed. This fact indicates a significant amount of converter slag getting into the ladle due to its poor cut-off in the process of metal tapping from the unit. The study of the influence of the coating “white” slag composition on the metal desulfurization process in the LP-unit showed, that for the effective sulfur removal, it is necessary to provide not only welldeoxidized slag with a total content of iron and manganese oxides of less than 1%, but also to ensure the ratio of its basicity to the magnesium content in this slag not less than 0.60–0.65%–1.

Effect of pre-desulfurization process on the sulfur forms and their transformations during pyrolysis of Yanzhou high sulfur coal

To achieve the utilization of high sulfur coals efficiently and economically, the effects of different pre-desulfurization processes including flotation, acid washing, ultrasonication and stepwise treatment on sulfur removal and changes of sulfur forms in a high sulfur coal, sulfur transformation behavior during pyrolysis and sulfur distribution in char were investigated. Flotation removed almost all the sulfate and partial pyrite from the raw coal, while ultrasonication was more effective in removing some low molecular-weight organic sulfur together with weakening the C-S bond in some sulfur species. The process of HCl-HF-HNO3 and stepwise treatment reduced the ash content and sulfur content to a larger extent, with ultrasonication after flotation and acid treatment having the highest sulfur removal from raw coal. The sulfur forms on coal surface were more modified after different pre-desulfurization processes, together with different sulfur transformations during pyrolysis. The accumulated amount of sulfur-containing gases during pyrolysis of coals after stepwise treatment, in particular of coals treated by the combination of flotation, acid washing and ultrasonication, generated the highest amount of sulfur-containing gases. For the utilization of high sulfur coals, in particular, of high organic-sulfur coals, the above-mentioned treatment of combination of traditional flotation technique and organic sulfur removal process should be considered, which could remove the inorganic sulfur and organic sulfur simultaneously, and release the most sulfur-containing gases during pyrolysis. Besides, it would be helpful to choose the utilization methods based on the sulfur species in raw coal, and the effect of pre-desulfurization process on sulfur transformation behavior.

Highly uniform molybdenum oxide loaded N-CNT as a remarkably active and selective nanocatalyst for H2S selective oxidation

Selective oxidation of H2S to elemental sulfur is a low cost and highly efficient process for sulfur removal from H2S-containing hydrocarbon streams in medium scale (i.e. 0.2–10 ton sulfur/day) for environmental protection and prevention of emitting toxic gases to the atmosphere. In this research, in order to prepare a highly active and selective nanocatalyst for selective oxidation of hydrogen sulfide, for the first time, molybdenum oxides were loaded uniformly over nitrogen- doped carbon nanotubes through incipient wetness impregnation. Different metal loadings including 5, 10, and 15 wt% Mo were considered in the synthesis procedure to achieve the optimized performance and provide complete environmental protection. The Mox/N-CNT nanocatalysts were thoroughly characterized via TEM, FE-SEM, XPS, N2 adsorption/desorption, and XRD techniques. The characterization methods confirmed that the Mo oxides nanoparticles were successfully distributed over the N-CNT support uniformly in nanoscale in which there was no sign of agglomeration. The catalytic experiments on Mox/N-CNT were performed in temperature range of 190–230 °C in which the feed gas was composed of 3000 ppm H2S and 1500 ppm O2. The results showed that the Mox/N-CNT samples were highly active at all considered temperatures providing the H2S conversion of almost 100% from which almost no H2S was emitted. Furthermore, by loading the Mo oxide over the N-CNT support, selectivity toward elemental sulfur was increased significantly at high temperatures (i.e. above 190 °C) suggesting that the progress of side reactions on the nanocatalyst has been minimized. The best result was obtained with the sample containing 15 wt% Mo at 230 °C providing the H2S conversion of 100% and selectivity of 89.7%. According to these results, Mo oxide/N-CNT is introduced as a potential candidate for catalytic H2S removal processes toward environmental protection in industrial plants.

Electron Equilibrium Analysis of Integrated Autotrophic and Heterotrophic Denitrification Process Under Micro-aerobic Conditions

The integrated autotrophic and heterotrophic denitrification (IAHD) process, which can simultaneously degrade sulfide, nitrate, and organic carbon with nitrate as a solo electron acceptor, has gained increasing attention as a key unit in industrial wastewater treatment. Micro-aerobic technology, which introduces trace oxygen as an additional electron acceptor, has been demonstrated as an effective strategy for enhancing the IAHD performance. This study focus on the electronic balance calculation of the IAHD process and reveals for the first time that the IAHD process can efficient proceed with an insufficient supply of electron acceptors (nitrate) under micro-aerobic conditions. In the IAHD batch tests, the highest sulfide, nitrate, and acetate removal efficiencies and rates were obtained with an electronic deletion rate peak at 55.1%. Further sulfide oxidizing batch tests demonstrated that the electronic deletion rates were 18.7% and 38.2% under oxygen contents of 5 mL and 10 mL, respectively, in the biological sulfide oxidizing process. Illumina sequencing was used to analyze the microbial community structure in the sulfide oxidation process and indicated Thiobacillus, Thauera, Mangroviflexus, and Erysipelothrix dominated in all community compositions, in which the relative abundance of Thiobacillus increased with an increase in the electronic deletion rate. This study reveals a potential linkage between the electronic gap and the enhanced IAHD performance, which proves new insights into the simultaneous sulfur, nitrogen, and organic carbon removal process.

CFD Studies on Efficacy of Flow Modulation in a Hydrotreating Trickle-Bed Reactor

Hydrodesulfurization (HDS), a pivotal process for sulfur removal that is essential in deep processing of crude oil, is typically carried out in steady-state trickle-bed reactors (TBRs). Being famil...