Desulfurization Method Research Articles

Improvement of desulfurization efficiency of Al-rich ladle furnace refining slag with an aqueous carbonation method by hydrothermal or ultrasound pretreatment.

Ladle furnace (LF) slag is a type of steel slag, which has limited applications due to its high S content. Aqueous carbonation is a prospective method for desulfurization of the LF slag. However, the Al-rich LF raw slag has very low desulfurization efficiency with carbonation method. This study investigated the improvement of desulfurization efficiency of the Al-rich LF slag with carbonation method by hydrothermal (HP) or ultrasound pretreatment (UP). The results showed that C3AHX was formed in pretreated slags because of C12A7 hydration, which could remove part of S. After carbonation, most of the C3AHX in pretreated slags produced crystalline CaCO3 bonded by amorphous Al(OH)3 (the other reaction product) in 10min. In the carbonation process, S removal was mainly determined by carbonation efficiency. The S content was reduced to about 0.40% for the pretreated slags from 1.04% in the raw slag. By contrast, the S content was reduced to only 0.93% for slag without pretreatment under the same carbonation conditions. The possible reason of the improvement of desulfurization efficiency by HP or UP was the formation of thin plate-like C3AHx, which increased the surface area available for carbonation reaction. The UP slag presented slightly lower S content than the HP slag because high ultrasound energy increased the reactivity of Ca2SiO4.

Green and efficient sulfur dioxide removal using hydrogen peroxide in rotating packed bed reactor: Modeling and experimental study

In order to reduce SO2 emissions and achieve green utilization of sulfur resources, a desulfurization method of SO2 removal using hydrogen peroxide (H2O2) in rotating packed bed (RPB) is proposed. It can not only achieve the efficient removal of SO2, but also lead to the effective utilization of sulfur resources. A mathematic model was first developed to describe the reaction and mass transfer process between H2O2 and SO2 in RPB. The influences of different operating conditions including RPB rotating speed, H2O2 mass fraction, gas–liquid volumetric flow rate ratio, gas flux, and inlet SO2 concentration on desulfurization performance were studied. Under the optimized conditions, it turned out that the desulfurization efficiency was above 99% and the outlet SO2 concentration was ultra-low, below 35 mg/m3. The validity of the model was confirmed by the fact that most of the predicted desulfurization efficiency agreed well with the experimental result with a deviation within 5%. The height of mass transfer unit HTU for RPB is calculated to be 1.60–2.07 cm, which is one order of magnitude lower than that of conventional reactors, indicating the investment of the desulfurization reactor can be greatly reduced by using RPB.

Modeling of catalytic adsorptive desulfurization in a cyclic process

Catalytic adsorptive desulfurization (CADS) recently received attention due to its integrated nature in reaching ultra-low sulfur content fuel. In this study, a mathematical model is used to simulate catalytic adsorptive behavior for a model fuel of toluene with 300 ppm di-benzothiophene over TiO2/SBA-15 catalyst. The results showed that near 100% sulfur removal can be obtained for the model fuel and negligible heat is released in the reactor. Cyclic temperature swing adsorption is studied and after one cycle, the process reached to steady state condition. The effect of addition of methanol in regeneration of adsorbent is also investigated and the results showed that injection of methanol would add some benefits into the process of desulfurization in terms of late breakthrough happening and reduction in di-benzothiophene concentration in the bed. A comparison between catalytic adsorptive (CADS), oxidative-adsorption (OADS) and adsorption desulfurization (ADS) methods is also conducted and the results showed that the first process provides a higher adsorption capacity.

Ionic liquids for the removal of sulfur and nitrogen compounds in fuels: a review

Air pollution is partly due to the emission of toxic sulfur and nitrogen oxides during fuel combustion. Therefore, these compounds should be removed from fuels. For that, ionic liquids have been recently developed to extract sulfur and nitrogen compounds from petroleum and fuels. Ionic liquids can extract S- and N-containing compounds either simultaneously or selectively. Ionic liquids usage appears better than classical desulfurization and denitrogenation processes due to the efficiency and selectivity of ionic liquids. Here we review methods for desulfurization and denitrogenation with focus on extraction by ionic liquids, and their regeneration and recycling. We also discuss limitations of ionic liquids, such as environmental biodegradation, bioaccumulation and corrosivity.

Selection of ionic liquid for extraction processes: Special case study of extractive desulfurization

Selecting of appropriate ionic liquids (ILs) as extracting agents is a key to ensuring an extraction process. Therefore, this study illustrates a systematic method for an extractive desulfurization (EDS) process to select the most promising ILs. The proposed method combines: 1) COSMO-RS calculation of the mutual solubility of ILs and fuel oil, and the capacity of ILs for the S-compounds, 2) experimental investigation of the prescreened ILs for their desulfurization ability, 3) and Aspen Plus simulation of developing a new insight into the industrial application of EDS. Based on the obtained results, [C1pyr][H2PO4] and [C1pyr][HSO4] having small mutual solubility with fuel oil, high extraction capacity for S-compounds and high desulfurization efficiency are selected as two promising ILs. Considering the qualification of the low sulfur content standard and real industrial applications, [C1pyr][H2PO4] is recognized as the most favorable solvent for the EDS process. The proposed method initiating from micro-level to experimental stage and finally to industrial stage can preferably be extended over a variety of extraction application for selection of the promising ILs.

Iron Recovery from Residue of Lateritic Nickel Leaching Industry

HPAL (High-Pressure Acid Leaching) is one of the important technologies for extracting nickel and cobalt from nickel laterite ore. In the next few years, some plants using this technology will be operated in Indonesia. The production will be estimated to be 543,000 tons per year by 2025. On the other hand, HPAL will produce more than 26 million tonnes of residue, and it requires good management. The residue utilization for certain industrial raw materials is one of the solutions. To determine the potential utilization residue, the characteristic of the residue must be elaborated through some methods. The characterization is carried out based on mineralogical and chemical properties. The feed used in the HPAL process dominates with magnetite and goethite with 41,15 % Fe and 1,35 % Ni content. The residue of HPAL contains Fe and significant Sulphur content, silica, aluminium and calcium. The quantity of Sulphur must be decreased by the desulfurization method then followed by the reduction process. The analysis shows that HPAL residue is still required additional processing for reducing the Sulphur content. The residue utilization trial still needs to be done to determine the quality of the iron-making products produced produced.

Influence of UV Radiation on the Process of Noncatalytic Oxidation of Dibenzothiophene in Dibenzothiophensulphone by the Oxygen in Air

Oxidation of dibenzothiophene (DBT) is used as the model reaction in studying the process of catalytic oxidative desulfurization of diesel fuel. The method of oxidative desulfurization includes the stage of oxidation of thiophene compounds contained in the fuel into the corresponding thiophenesulfones, followed by their extraction from the reaction mixture with a polar liquid. In this paper, we study the oxidation reaction of DBT into DBT sulfone in a solution in octane, with atmospheric oxygen in the presence of benzaldehyde at room temperature and irradiation of the reaction mixture with ultraviolet (UV) light. It is shown that in this case a DBT conversion of 97 to 98% can be achieved without using a catalyst. It is also found that UV irradiation of the reaction mixture can be carried out periodically (in pulses of a duration of 1 min), which makes it possible to exclude overhearing reaction mixture.

Thermoadsorption Demetallization of Heavy Oil Residues

The high content of metal- and sulfur-containing compounds in the composition of heavy oil residues leads to negative impacts during their processing, the use of catalysts and equipment. To solve this problem, various methods of demetallization and deasphalting are proposed. The article provides information on various methods of demetallization, desulfurization and coking of heavy oil residues. The disadvantages of the considered methods are shown, and a thermal adsorption processing method is proposed as an effective method of demetallization and desulfurization. The results of demetallization and desulfurization of vacuum residue from the Pavlodar Petrochemical Plant (Kazakhstan) using various adsorbents: serpentine, zeolite modified with wollastonite and coke, kaolin clay with coke are presented. The maximum degree of demetallization of 81‒94% with respect to vanadium and nickel is observed when using kaolin clay modified with coke as an adsorbent and during the process at 400 °C for 4 h. The maximum degree of desulfurization 39.6% is observed during the process using zeolite modified with wollastonite and coke at 400 °C for 3 h. After demetallization and desulfurization, the vacuum residue was subjected to a coking process to produce coke with improved performance and yield. Coke with good yield (32%) and low values of ash and mass fraction of total moisture is obtained by vacuum residue coking after demetallization with kaolin clay modified with coke.

Novel product-adjustable technology using Wellman-Lord method coupled with sodium-alkali for SO2 removal and regeneration from smelting gas

A product-adjustable method for desulfurization and regeneration was proposed in this study. Two stages of SO2 absorption combined the sodium-alkali and Wellman-Lord methods. The products could be recycled as valuable pure SO2, H2SO4, or Na2SO3. The absorption characteristic and the regenerative behavior with Na2SO3 solution were investigated. The influences of various temperatures, oxygen concentration, and absorbent concentration in SO2 removal were studied respectively. Na2SO3 exhibited SO2 removal efficiency higher than 99% and maintained it with the temperature range of 25–60 °C. Oxidation of Na2SO3 harmed its absorption ability. Ascorbic acid realized good oxidation inhibition effect with concentration less than 0.1%. The utilization rate of Na2SO3 remained nearly 100% at different concentrations. Meanwhile, desorption of saturated absorbent (mainly NaHSO3) was studied. The desorption proportion rose with the increasing concentration of HSO3- while slightly changing with desorption temperature. Ascorbic acid could raise SO2 regeneration concentration higher than 2.5%. Part of NaHSO3 could be regenerated to release high-concentration SO2 and fully used in further absorption. The system showed good regeneration performance for at least 4 rounds and stabilized then. Therefore, the improved regeneration technology realized the reuse of Na2SO3 and the recycling of pure SO2.

Deep desulfurization of sintering flue gas in iron and steel works based on low-temperature oxidation

AbstractThe deep desulfurization method of sintering flue gas based on the low-temperature oxidation method is studied. Based on the analysis of the main principle of deep desulfurization of sintering flue gas, a deep desulfurization system of sintering flue gas is constructed, which is composed of an absorption washing unit and a washing solution treatment unit. Sodium hydroxide solution is used as the desulfurizing absorbent to mix with the sintering flue gas entering the reaction tower. Sulfur dioxide in the sintering flue gas reacts with sodium hydroxide to generate sodium sulfite, and sodium sulfite is oxidized to produce sodium sulfate; ozone is produced by ozone generator, nitrogen oxide compounds are oxidized by ozone to generate oxyacid, which is easy to be removed by sodium hydroxide washing solution, and the detergent is the same as that used to remove sulfur dioxide and dust. The experimental results show that the highest desulfurization rate and denitrification rate of the proposed method are 90% and over 22%, and the reaction efficiency and economy are significantly better than that of the comparative method, which shows that the method is reasonable and effective.

Effect of magnesium injection process on hot metal desulfurization

To solve the technical problems of hot metal desulfurization by injecting magnesium particulate, a new method of hot metal desulfurization by bottom-blowing magnesium vapor combined with mechanical agitation was put forward. The effects of three different desulfurization processes on the desulfurization efficiency were studied in view of thermodynamics and kinetics. It was found that the utilization efficiency of magnesium can reach 82.6% and desulfurization efficiency can reach 86.2% during the first 4 min using the method of magnesium vapor injection combined with mechanical agitation. The gasification of magnesium powder leads to significant splashing and magnesium losses in the process of magnesium powder injection, resulting in a low utilization efficiency of magnesium of 51.8% and a low desulfurization efficiency of 55.76%. Activation energy for a first-order kinetic relationship between magnesium powder and sulfur was measured from the experiments, which was 142.82 kJ/mol in the temperature range of 1573–1723 K. The activation energy of the reaction between magnesium vapor and sulfur was around 54.8–65.0 kJ/mol in the temperature range of 1573–1723 K, which indicates that the desulfurization with magnesium vapor proceeds relatively easier than the desulfurization with magnesium powder.

Desulfurization Performance of Choline Chloride-Based Deep Eutectic Solvents in the Presence of Graphene Oxide

Extractive catalytic oxidative desulfurization (ECODS) is the one of the recent methods used in fuel desulfurization which involved the use of catalyst in the oxidative desulfurization of diesel fuel. This study is aimed to test the effectiveness of synthesized choline chloride (ChCl) based deep eutectic solvent (DES) in fuel desulfurization via ECODS method, with the presence of graphene oxide (GO) as catalyst and hydrogen peroxide (H2O2) as oxidant. In this study, 16 DESs based on choline chloride were synthesized using glycerol (GLY), ethylene glycol (EG), tetraethylene glycol (TEG) and polyethylene glycol (PEG). The characterization of the synthesized DES was carried out via Fourier transform infrared spectroscopy (FTIR) analysis, density, and viscosity determination. According to the screening result, ChCl-PEG (1:4) was found to be the most effective DES for desulfurization using ECODS method, with a removal of up to 47.4% of sulfur containing compounds in model oil in just 10 min per cycle after the optimization of the reaction parameters, and up to 95% desulfurization efficiency could be achieved by six cycles of desulfurization. It is found that the addition of GO as catalyst does not increase the desulfurization performance drastically; hence, future studies for the desulfurization performance of DESs made up from ChCl and PEG and its derivatives can be done simply by using extraction desulfurization (EDS) method instead of ECODS method, for cost reduction purpose and easier regulation of DES waste into environment.

An Integrated Process of Reductive Desulfurization by Sodium Borohydride and Its Electroreduction Regeneration in Ionic Liquid

In this study, a novel desulfurization method was developed by introducing ionic liquid (IL) into the integrated process of reductive desulfurization by NaBH4 and its regeneration via NaBO2 electroreduction, where ILs play a dual role of electrolyte and extracting agent. Under the conditions of -2.4 V forward pulse voltage, 0.6 V reverse pulse voltage, 0.6 s forward pulse time, 0.4 s reverse pulse time, 0.8 s turn-off time, 80 min electrolytic time, 4/1 IL/oil volume ratio, sulfur removal reached more than 95% for model fuel oil. Therefore, the novel integrated process of reductive desulfurization by NaBH4 and its electroreduction regeneration in IL is feasible and promising.

Sources and Markets of Limestone Flour in Poland

Limestone flour is used in a variety of industrial sectors such as power and heat generation, glass-making, paper-making, the construction industry and construction materials manufacturing, the production of agriculture, plastics and rubber goods, as well as coal mining, and environmental protection. This paper aims to characterize and interpret the limestone flour supply and demand trends in the main applications in Poland in the last decade. In order to track the changes of domestic consumption for this commodity, its major users have been surveyed along with analyses of data from the Statistics Poland (GUS). The results showed that during 2009–2018 the coal-fired power plants became the biggest customer of limestone flour utilized as a sorbent in the wet flue gas desulfurization method (FGD). This method has been implemented in the vast majority of Polish power plants. It is estimated that in the last decade the total annual production capacity of limestone flour at the milling plants in Poland increased by 1.5 million tons, to around 6.0 million tons. In the forthcoming years, this is expected to continue to increase despite EU restrictions on fossil fuel use (especially hard coal and lignite). Other promising areas of future growth are: for limestone flour of medium quality—the construction materials manufacturing and the construction industry itself, for limestone flour of the highest quality—the glass industry, while for fine-grained limestone flour of high-quality—the plastics and rubber industries. In terms of resource security, it is worth noting that Poland is a country rich in limestone deposits. However, only some of them, that is, limestone rock varieties of the Jurassic and Devonian ages from the Kielce vicinity in central Poland are suitable for the production of high-quality limestone flour for the needs of the mentioned industries. The paper analyses the potential of the limestone flour production from the available limestone rock deposits with respect to the current and future needs of the domestic market in Poland.

Variation of Sulfur Content in Coking Coal as Function of Its Particle Size

To understand quality of coking coal possessing different particle sizes, coal samples from Gao Yang (GY) and Shui Yu (SY) mines were systematically studied. The samples had wide particle size variations with six distinct ranges. The main emphasis was placed on analyzing sulfur and coke contents as function of particle sizes. X-ray photoelectron spectroscopy (XPS) was used to analyze sulfur content as well as its chemical state. Sulfur coordination and group geometry was analyzed by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) was applied to characterize surface morphology. Sieving of the coal samples increased ash and sulfur contents in all fractions. Organic sulfur was mostly present as thiophene for all particle size ranges. Macromolecular structure of coal was almost the same for all samples. Changes in total sulfur content of different coal fractions were mainly caused by the variations in inorganic sulfur concentrations because organic sulfur content remained almost constant. Understanding particle size distribution in different coals is important for selecting and optimizing appropriate desulfurization methods.

Oil relations between China and Russia- Electrochemical Behavior of organic sulfur compounds

The man purpose of this paper is that the demonstration fuel electrochemical hydrogenation desulfurization method is feasible. First, many sulfur compounds in fuels are summarized as thiophene, which is a typical representative of materials. Then, analyze and judge the reaction mechanism of thiophene electrochemical hydrogenation desulfurization. Furthermore, typical of this oil in the thiophene sulfur compounds the reaction mechanism, by analogy, that the electrochemical hydrogenation of oil desulfurization method is feasible.

Pt nanoparticles encapsulated on V2O5 nanosheets carriers as efficient catalysts for promoted aerobic oxidative desulfurization performance

Platinum group metals (PGMs) usually exhibit promising aerobic catalytic abilities, providing a green and feasible oxidative desulfurization method. However, often, the PGM nanoparticles (NPs) get leached, and the catalysts are deactivated. In this work, Pt NPs with particle sizes of approximately 4–5 nm were encapsulated effectively and uniformly on the surface of vanadium pentoxide (V2O5) nanosheets (with thicknesses of approximately six atomic layers) through strong metal-support interactions. The synthesized catalysts promote catalytic aerobic oxidation reactions, realizing deep desulfurization (99.1%, < 5 μg g−1) under atmospheric pressure and 110 °C reaction temperature. Remarkable degrees of sulfur removal could be achieved for oils with different initial S-concentrations and substrates. Additionally, the as-prepared catalysts could be recycled for reuse at least seven times.

Desulfurization and Denitrification of Ship Exhaust Gas with Low Temperature Plasma

In order to reduce the emission of pollutants such as sulfur oxides and nitrogen oxides in ship exhaust gas, the principles and experimental methods of desulfurization and denitrification with low temperature plasma with dielectric barrier discharge were introduced in this study. The impacts of reactor voltage and reactor frequency of low temperature plasma, humidity and oxygen content of ship exhaust gas on the efficacy of desulfurization and denitrification were also explored by experiments in this study. It was revealed that the low temperature plasma technology could desulfurize and denitrify the ship exhaust gas better. The efficacy of desulfurization and denitrification would be increased when the voltage increases. At a voltage of 20 kV, the removal rates of NO and SO2 reached 59% and 52% respectively. When the reactor voltage was maintained at 15 kV, the removal rates of NO and SO2 would rise at the beginning and decrease later with increase of the frequency. The highest removal rates of NO and SO2 were 55% and 42% respectively when the frequency was 10 kHz. The efficacy of desulfurization and denitrification can be affected by humidity and oxygen content of the ship exhaust gas. Researches in this study provided a crucial reference for the application of low temperature plasma technology in the desulfurization and denitrification of ship exhaust gas.

Analysis of hot metal desulfurization methods efficiency during titanomagnetite processing

To make high-quality steel, it is necessary to ensure low sulfur content in the hot metal entering a steelmaking shop. The task to obtain low sulfur metal can be solved either during blast furnace smelting or its ladle desulfurization immediately after tapping out of blast furnace. Under conditions of JSC EVRAZ NTMK, the ladle desulfurization of vanadium hot metal is not applied, since it leads to a loss of vanadium. Is explained by the fat, that calcium oxide forms with V2O5 a strong calcium vanadate (3СаО·V2O5), which makes the process of vanadium recovery during further slag processing more complicated. Therefore the ladle desulfurization is accomplished after devanadation of hot metal. After the devanadation the semi-product has ions of oxygen, which makes it impossible to arrange an effective desulfurization and males it necessary to smelt the hot metal with limited sulfur content. The factors, effecting the process of hot metal desulfurization in a blast furnace, including slag basicity, MgO content in it, temperature of smelting products and slag viscosity, are presented. Dependence of distribution coefficient of sulfur on slag basicity has been shown. Research goal is pig iron desulphurization efficiency estimation by means of MgO increasing in slag. Data analysis findings about smelting products composition over 500 tappings for each of two investigated JSC EVRAZ NTMK blast furnaces have been reported. The aim of the study was comparison of hot metal desulphurization efficiency due to both slag basicity increase and MgO increase in slag. Results of data analysis on smelting products composition of over 500 heats for each of two investigated JSC EVRAZ NTMK blast furnaces have been presented. It was established that a sulfur content decrease in hot metal is achieved more effectively by MgO increase in slag. It has been shown that MgO has better desulfurizing properties, and with an increase of its content in the blast furnace slag, the overall technology for running the blast furnace process improves. It was recommended to increase the consumption of materials containing MgO while maintaining basicity at a constant level. Such a technology will allow to decrease sulfur content in hot metal, as well as will result in the process stabilization providing other conditions being equal.

A study of the desulfurization selectivity of a reductive and extractive desulfurization process with sodium borohydride in polyethylene glycol

The selectivity of a facile reductive and extractive desulfurization process was studied. In this desulfurization method, polyethylene glycol was used as the extractant, and sodium borohydride was used as the reductant. Several different simulated fuels were prepared by dissolving thiophenic sulfides, methylbenzene and hexylene in octane. The results showed that methylbenzene and olefins had different effects on different sulfur compounds during this desulfurization process. The extraction and reduction mechanisms were also explained. Four factors could affect the desulfurization performance: (1) intermolecular hydrogen bonding: (a) active O bonding with aromatic H or (b) S bonding with H atoms in hydroxide radicals, (2) “like-dissolves-like” interactions between polyethylene glycol and thiophenic sulfides, (3) the methyl steric hindrance effect and the electron density of sulfur atoms, and (4) the combination of S atoms with produced nickel boride to form active desulfurization centres. The desulfurization reaction path was also deduced according to the GC/MS results.