Synthesis and Characterization of New nano catalyst Mo-Ni /TiO2- γAl2O3 for Hydrodesulphurization of Iraqi Gas Oil

A new nano-sized NiMo/TiO2-γ-Al2O3 was prepared as a Hydrodesulphurization catalyst for Iraqi gas oil with sulfur content of 8980 ppm, supplied from Al-Dura Refinery. Sol-gel method was used to prepare TiO2- γ-Al2O3 nano catalyst support with 64% TiO2, 32% Al2O3, Ni-Mo/TiO-γ-Al2O3 catalyst was prepared under vacuum impregnation conditions to loading metals with percentage 3.8 wt.% and 14 wt.% for nickel and molybdenum respectively while the percentage for alumina, and titanium became 21.7, and 58.61 respectively. The synthesized TiO2- γ-Al2O3 nanocomposites and Ni-Mo /TiO2- γ-Al2O3 Nano catalyst were then characterized by XRD, AFM, and BET surface area, SEM, XRF, and FTIR. The performance of the synthesized catalyst for removing sulfur compounds was conducted through the pilot HDS laboratory unit, various temperatures range 275oC to 375°C, LHSV 1 h-1 were studied; moreover, the effect of LHSV 1 to 4 h-1 on the percentage of sulfur removal was also studied at the temperature of the best removal with constant pressure 35 bar and H2/HC ratio 200cm3/200cm3. The sulfur content results generally revealed that there was a substantial decrease at all operating conditions used, while the maximum sulfur removal was 87.75% in gas oil on Ni-Mo/TiO2-γ-Al2O3 catalyst at temperature 375˚C and LHSV 1h-1.

Modern view on steel desulfurization

Modern technological schemes of steel production do not allow to achieve low (< 0.01 % S) and ultra-low (<0.005 % S) sulfur content on the production of in the metal directly. That is why out-of-furnace steel treatment is often used to remove sulfur. Desulfurization process of steel depends on the chemical composition of the slag, the time of its formation in the ladle, metal oxidation, conditions of mixing of steel in a ladle, additional technological operations and ladle metal processing. Methods are widely used for desulfurization of steel treatment of steel with solid slag-forming mixtures, synthetic slag, lime-aluminous slag, silico-calcium and other powdered materials. Modern approaches to the process of steel desulfurization in conditions steel production are analyzed in the Study. In particular, the Ukrainian (on the example of PJSC ‘Azovstal Iron & Steel Works’ and PJSC ‘Dneprovsky Integrated Iron & Steel Works named after Dzershinsky’) and foreign (on the example of PJSC ‘Severstal’ and PJSC ‘Magnitogorsk Iron & Steel Works’) experience of desulfurization under oxygen converter production. The use of technological complexes ‘Installation of pig iron desulfurization steel making unit’ and ‘Cast iron desulfurization installation steel making unit is ‘oven-bucket’ installation’ provides a deeper desulfurization of steel, the possibility of optimizing the cost of steel production, expands range of scarce products and eliminates a number of restrictive conditions that complicate current production. The analysis of steel C80D desulfurization process is given in the conditions of JSC ‘Moldova Steel Works’, in which partial sulfur removal occurs in an arc steel making furnace, and the ultra-low content is achieved by creating a highly basic refining slag in the process out-of-furnace processing of steel. The study of the kinetics of the desulfurization process of 20GL steel in the conditions of JSC ‘Tashkent Mechanical Plant’ with the use of solid slag-forming mixtures and modification of steel with rare-earth metals is analyzed. The issue of desulfurization of electric steel in the conditions of OJSC ‘Byelorussian Steel Works’ with injection of powdered materials through the installation ‘Velko’ during out-of-furnace processing of steel is considered. Keywords: steel desulfurization, desulfurizer reagent, degree of desulfurization, cast iron desulfurization installation, out-of-furnace processing of steel, ‘‘oven-bucket’’ installation.

Total Systems Approach to Reduce Fouling and Improve System Efficiency Using Hydrogen Sulfide Scavengers

The Cotton Valley sand and Haynesville shale formations are situated in East Texas, USA, producing oil, gas, and condensate on land. Most of the producing assets are mature and souring, and the presence of hydrogen sulfide in the produced fluids and gas provides both operational concerns in terms of solids deposition and asset integrity in the production facilities as well as complexity when considering the processing, export, and sale of condensate and gas. Produced gas was traditionally treated with MEA triazine hydrogen sulfide scavenger prior to liquification by LNG plant. There have been historical issues with both the levels of hydrogen sulfide left in the gas and also solids formation in the process, which threatened periodic shutdown of the LNG plant. A holistic approach was used to improve the overall sulfur removal process. This includes the reduction or elimination of solids formation as well as improvement in the system scavenging efficiency. The approach considered current operating procedures, system parameters, equipment design (contactors), and H2S scavenger chemistry.

Comparative Study on Refractory Gold Concentrate Kinetics and Mechanisms by Pilot Scale Batch and Continuous Bio-Oxidation

Most studies conducted have focused on the pulp density, Fe3+ concentration and sulfuric acid concentration, etc., of bio-oxidation, and few have reported on the influence of different bio-oxidation methods on kinetics. In this study, a comparative investigation on refractory gold concentrate by batch and continuous bio-oxidation was conducted, with the purpose of revealing the kinetics influence. The results showed that improving the removal rates of the gold-bearing pyrite (FeS2) and arsenopyrite (FeAsS) yielded the best results for increasing gold recovery. The removal rates of S, Fe and relative gold recovery linearly increased when compared to the second-order equation increase of the As removal rate in both batch and continuous bio-oxidation processes. The removal kinetics of S and Fe by continuous bio-oxidation was 12.02% and 12.17% per 24 h day, approximately 86.64% and 51.18% higher than batch bio-oxidation, respectively. The higher removal kinetics of continuous bio-oxidation resulted from a stepwise increase in microbe growth, a larger population and higher dissolved Fe3+ and H2SO4 concentration compared to a linear increase by batch bio-oxidation. The cyanidation gold recovery was as high as 94.71% after seven days of continuous bio-oxidation, with the gold concentrate sulfur removal rates of 83.83%; similar results will be achieved after 13 days by batch bio-oxidation. The 16sRNA sequencing showed seven more microbe cultures in the initial residue than Acid Mine Drainage (AMD) at genus level. The quantitative real-time Polymerase Chain Reaction (PCR) test showed the four main functional average microbe populations of Acidithiobacillus, Leptospirillum, Ferroplasma and Sulfobacillus in continuous bio-oxidation residue as 1.08 × 103 higher than in solution. The multi-microbes used in this study have higher bio-oxidation activity and performance in a highly acidic environment since some archaea co-exist and co-contribute.

The influence of a magnet field on sulfur removal from liquid iron by hydrogen plasma arc melting

In this work, the static magnetic field was applied to plasma arc melting (PAM) method. The influence on sulfur removal from iron by Ar-20%H2 (PAM) was investigated experimentally. The results show that, sulfur content decreases more noticeably with the magnet field. The mechanism of sulfur removal by hydrogen plasma arc melting (HPAM) was found to obey a first-order rate law. From kinetic analysis, the adoption of magnet field enhanced purification efficiency about 45% under the same conditions. The numerical simulations were necessarily carried out to investigate the fluid flows of the melt. The results show that the magnet field changes the flow regime and strengthens the flow velocity of the melt. Moreover, the dead zone in melt by typical HPAM was eliminated. It is reasonable that dissolved sulfur atoms transferring to the top interface to react with active hydrogen atoms was promoted. In addition, during solidification process, thermoelectric magnetic (TEM) flows promote solute atoms that discharged from the solid–liquid interface moving to the upside of specimen. As a consequence, iron with much lower sulfur content could be obtained at the bottom of specimens, and sulfur removal was enhanced further during solidification under a static magnetic field.

Warm Plasma Application in Tar Conversion and Syngas Valorization: The Fate of Hydrogen Sulfide

Warm plasma techniques are considered a promising method of tar removal in biomass-derived syngas. The fate of another problematic syngas impurity—hydrogen sulfide—is studied in this work. It is revealed that processing simulated syngas with a microwave plasma results in hydrogen sulfide conversion. For different gas flow rates (20–40 NLPM) and hydrogen sulfide concentrations ranging from 250 ppm to 750 ppm, the conversion rate varies from ca. 26% to 45%. The main sulfur-containing products are carbon disulfide (ca. 30% of total sulfur) and carbonyl sulfide (ca. 8% of total sulfur). Besides them, significantly smaller quantities of sulfates and benzothiophene are also detected. The main components of syngas have a tremendous impact on the fate of hydrogen sulfide. While the presence of carbon monoxide, methane, carbon dioxide, and tar surrogate (toluene) leads to the formation of carbonyl sulfide, carbon disulfide, sulfur dioxide, and benzothiophene, respectively, the abundance of hydrogen results in the recreation of hydrogen sulfide. Consequently, the presence of hydrogen in the simulated syngas is the main factor that determines the low conversion rate of hydrogen sulfide. Conversion of hydrogen sulfide into various sulfur compounds might be problematic in the context of syngas purification and the application of the right technique for sulfur removal.

Systematic Assessment of Visible-Light-Driven Microspherical V2O5 Photocatalyst for the Removal of Hazardous Organosulfur Compounds from Diesel

The organosulfur compounds present in liquid fuels are hazardous for health, asset, and the environment. The photocatalytic desulfurization technique works at ordinary conditions and removes the requirement of hydrogen, as it is an expensive gas, highly explosive, with a broader flammability range and is declared the most hazardous gas within a petroleum refinery, with respect to flammability. The projected work is based on the synthesis of V2O5 microspheres for photocatalytic oxidation for the straight-run diesel (SRD) and diesel oil blend (DOB). The physicochemical properties of V2O5 microspheres were examined by FT-IR, Raman, UV-vis DRS, SEM, and Photoluminescence evaluations. The as-synthesized photocatalyst presented a trivial unit size, a narrow bandgap, appropriate light-capturing capability, and sufficient active sites. The desulfurization study discovered that the anticipated technique is substantial in desulfurizing DOB up to 37% in 180 min using methanol as an interfacing agent. Furthermore, the outcome of employing a range of polar interfacing solvents was examined, and the 2-ethoxyethanol elevated the desulfurization degree up to 51.3%. However, the anticipated technology is constrained for its application in sulfur removal from SRD. Additionally, the mechanism for a photocatalytic reaction was seen in strong agreement with pseudo-first-order kinetics. The investigated photocatalyst exhibited a compromised recyclability and regeneration tendency.