High-sulfur Petroleum Coke Research Articles

Sustainable Processing of Ultralow-Cost Petroleum Cokes Into Ultrastable Self-Doped Fe3C@CNT Catalysts for High-Efficiency HER.

Petroleum cokes are largely used as low-cost anodes in aluminum industries and general fuels in cement industries, where large amounts of CO2 are generated. To reduce CO2 release, it is challenging to develop green strategies for processing abundant petroleum cokes into high-value products, because there are abundant hetero-atoms in petroleum cokes. To overcome such issues, a sustainable electrochemical approach is proposed to convert ultralow-cost high sulfur petroleum coke and iron powders into high-efficiency catalysts for hydrogen evolution reaction (HER). During molten-salt electrolysis, raw petroleum cokes are converted into CNTs via heteroatom removal and the catalytic effect of Fe, forming Fe3C nanoparticles on the sulfur and nitrogen co-dopped carbon nanotubes (Fe3C@S, N-CNTs). The electrochemical reaction analysis using the continuum model suggested that the rate-determining step referred to the slow transport of mobile ions inside the porous cathode. Because the self-doped S and N atoms massively alleviated the energy barrier for H* absorption and H2 desorption (i.e., promoting HER kinetics), the as-prepared Fe3C@S, N-CNTs exhibited low overpotentials at 10mAcm-2 in acidic (96mV) and alkaline (106mV) solutions with ultralong-term duration (200h). This study offers a sustainable approach to convert ultralow-cost petroleum cokes into ultrastable catalysts for high-efficiency HER.

Effect of High Calcium and High Iron Coal on Ash Fusion Characteristics of Petroleum Coke during Cogasification.

Entrained flow gasification provides a more efficient utilization method for high-sulfur petroleum coke. The operation temperature of the entrained flow gasifier must be above the ash fusion temperature (AFT) of petroleum coke due to the liquid slag discharge. In this work, petroleum coke was blended with high-calcium coal and high-iron coal, respectively, under a reducing atmosphere, and the variations in AFTs were recorded by an ash fusion temperature analyzer. The influence of mineral transformations on the ash fusion characteristics of blended ash was analyzed by X-ray diffraction and FactSage. The results showed that both high calcium coal and high iron coal could efficiently reduce the AFTs of petroleum coke. When the ratio of high calcium coal and high iron coal reached 60 wt %, the corresponding flow temperature (FT) of mixed ash decreased to 1225 and 1312 °C, respectively. With the content of high calcium coal increasing, coulsonite (FeV2O4), vanadium trioxide (V2O3) and nickel (Ni) with high-melting points tended to decrease, causing the decrease of AFT for mixed ash. As high iron coal was added, Ni and V2O3 continuously kept decreasing. In particular, the percentage of FeV2O4 first increased and thereafter decreased with high iron coal above 40 wt %.

Valorization of a high-sulfur petroleum coke for energy and fuels through its co-processing with a forest waste, using concrete wastes for sulphur and carbon dioxide capture under mild conditions

Current work provided a comprehensive assessment on the pyrolysis, combustion and gasification of a high-sulfur pet coke (PEC) and its blends with a forest waste (FOP). The potential of waste concrete fractions to capture SO2 and CO2 emissions was explored. The experiments were conducted in a fixed bed system and a thermogravimetric-mass spectrometric unit. Thermal behavior, reactivity, conversion, synergy, structural and chemical characteristics of solid materials, quantitative analysis of products and heating value, chemical, mineralogical and fusibility analysis of ashes were studied as a function of temperature, blending ratio and sorbent/fuel ratio. Addition of sorbent at a ratio Ca/S = 2 resulted in a desulfurization extent of 76–81 % during combustion. Quarry dust sorbent captured up to 95.4 % of CO2 emitted below 700 °C. At 1000 °C H2 content was 64.8–72.9 % mol and syngas yield 1.1–1.8 m3/kg. The gasification performance of PEC was improved upon blending with FOP.

Process optimization, exergy analysis, and GHG emissions of ammonia production systems by gasification of high-sulfur petroleum coke with CO2 capture

High-sulfur petroleum coke is commonly used as a fuel because of its high carbon content and calorific value. Direct combustion of high-sulfur petroleum coke has the problem of emitting a lot of CO2 and sulfide. Gasification is an environmentally friendly way to utilize high-sulfur petroleum coke. Therefore, this study first established hydrogen production systems with CO2 capture through high-sulfur petroleum coke gasification. The hydrogen is then reacted with nitrogen from air separation unit for producing ammonia, which is easy to transport and store. After optimizing and analyzing the key parameters of the established models, exergy and life cycle GHG emissions analysis are carried out to evaluate the technical performance and environmental impact. In the system with an 85 % gasification conversion rate of petroleum coke, the ammonia production capacity, exergy efficiency, and GHG emissions are 2300 kmol/h, 45.39 %, and 1468 kg CO2-eq/t NH3. When the conversion rate is elevated by ten percentage points, the ammonia production and exergy efficiency are increased to 2664 kmol/h and 51.95 %, while the GHG emissions are only reduced by 85 kg CO2-eq/t NH3 since most of the CO2 produced by the system is captured. Improving the petroleum coke conversion rate can significantly increase the exergy efficiency of ammonia production system, but has little impact on reducing GHG emissions during the process.

Study on the Role of Additives in Calcination Desulfurization Process of High Sulfur Petroleum Coke

Due to the high sulfur content of high sulfur petroleum coke, sulfur-containing gas will be produced in the production process, reducing product quality and other problems, resulting in increased production costs and equipment corrosion. How to reduce the sulfur content of high sulfur petroleum coke is of great significance to improve the utilization rate of high sulfur petroleum coke and the sustainable development of related industries. In this paper, the desulfurization of high sulfur petroleum coke was carried out by using the additive-assisted high-temperature calcination method. It was found that the desulfurization effect of different kinds of desulfurization additives was different, among which MO1, MC2, MC1 desulfurization effect was better, and the desulfurization rate could reach 68%, 58%, 56%. After compounding the three desulfurizers, the desulfurization rate can be up to 75%, and then the influence of calcination temperature and time on the desulfurization rate was investigated. Finally, the physicochemical properties of petroleum coke before and after desulfurization were analyzed by X RD, FT-IR.

Deep Desulfurization of High-Sulfur Petroleum Coke via Alkali Catalytic Roasting Combined with Ultrasonic Oxidation.

The sulfur in petroleum coke is harmful to carbon products, underscoring the importance of desulfurization for high-sulfur petroleum coke. This paper proposes a method combining alkaline catalytic roasting with ultrasonic oxidation for the deep desulfurization of high-sulfur petroleum coke. The results show that the desulfurization rate reaches 88.99% and the sulfur content is reduced to 0.83 wt.% under a coke particle size of 96-75 μm, sodium-hydroxide-to-petroleum-coke ratio of 50%, roasting temperature of 700 °C, and holding time of 2 h. The alkali-calcined petroleum coke is ultrasonically oxidized and desulfurized in peracetic acid. The results show that, under a hydrogen peroxide content of 10%, hydrogen-peroxide-(liquid)-to-petroleum-coke (solid) ratio of 20 mL/g, acetic acid content of 5 mL, ultrasonic power of 300 W, reaction temperature of 60 °C, and reaction duration of 4 h, the sulfur content is reduced to 0.15 wt.% and the total desulfurization reaches 98.01%. Through a series of characterizations, the proposed desulfurization mechanism is verified. Alkali roasting effectively removes a significant portion of sulfur in petroleum coke. However, the elimination of certain sulfur compounds, such as the more complex thiophene, presents challenges. The thiophene content is subsequently removed via ultrasonic oxidation.

Synergistic effect mechanism of biomass ash-derived K-Ca-Si catalytic system on syngas production and reactivity characteristics of high-sulfur petroleum coke gasification

In this study, three typical biomass ash (BA) components, KCl, CaCO3 and SiO2, are selected as model compounds to construct BA-based key ternary component system for petroleum coke (PC) gasification. Gas product analysis was conducted using gas chromatography to study the influence of different catalysts on the gas product distribution, gas yield and carbon conversion of PC gasification, and clarify the synergistic effects of binary and ternary components in K-Ca-Si catalytic system. In addition, electron scanning microscopy (SEM) and Raman techniques are used to characterize the physicochemical structure of gasification semi-char to reveal the synergistic mechanism of K-Ca-Si system. The results show that the yield of different gases is ordered as H2 > CO > CO2 and the increment of H2 yield, CO yield, syngas yield and carbon conversion in K-Ca-Si catalytic system is 43.41 mmol/g, 26.67 mmol/g, 80.37 mmol/g and 0.49, compared with single PC gasification, respectively. By comparing the theoretical and actual value of gas yield and carbon conversion, it is found that there are synergistic catalytic effects for K-Ca-Si ternary catalyst, but Si will inhibit the activity of K and Ca. Coupled with SEM and Raman analysis, synergistic mechanism of ternary catalytic system can be revealed. KCl and CaCO3 reduce the graphitization degree of semi-char by reacting with carbon matrix, and CaCO3 can stimulate the pore structure development of semi-char, which accelerate reaction between KCl and carbon matrix to form intermediate active sites, thus favoring gasification reaction and exhibiting a synergistic effect. SiO2, on the other hand, will combine with KCl and CaCO3 to form inert silicates, resulting in the deactivation of KCl and CaCO3. It could be concluded that for high K-high Ca-low Si ternary catalytic system, KCl and CaCO3 would still show a synergistic effect due to higher CaCO3 content than SiO2.

In-situ Formation of Sulphur-Trapped Petroleum Coke via Thermal Cracking of Vacuum Residue: A Practical Approach to Reduce Environmental Pollution

Environmental regulations restrict the use of high-sulphur petroleum coke as a solid fuel due to the emission of a substantial amount of sulphur oxides (SOx) upon combustion. Therefore, the free sulphur present in petroleum coke needs to be reduced to achieve lower SOx emissions. This paper describes a novel and efficient method for the trapping of free sulphur in petroleum coke during its formation from vacuum residue in the presence of an additive. Among the various additives tested, calcium oxide (10 wt%) was found to be most effective for maximum trapping of free sulphur in petroleum coke. This sulphur-trapped petroleum coke reduces SO2 emissions by 67% upon combustion; hence, it can be used as a better fuel than regular high-sulphur petroleum coke. Thus, by replacing regular petroleum coke with this newly developed sulphur-trapped petroleum coke, environmental pollution can be reduced significantly.

Preparation of Carbon-Based Solid Acid Catalyst from High-Sulfur Petroleum Coke with Nitric Acid and Ball Milling, and a Computational Evaluation of Inherent Sulfur Conversion Pathways.

A series of petroleum coke (petcoke)-derived solid acid catalysts were prepared via nitric acid treatment with or without ball milling pretreatment. The inherent sulfur in petcoke was converted to sulfonic groups, which were active sites for the esterification of octanoic acid and methanol at 60 °C, with ester yields of 14-43%. More specifically, samples without ball milling treated at 120 °C for 3 h had a total acidity of 4.67 mmol/g, which was 1.6 times that of the samples treated at 80 °C, despite their -SO3H acidities being similar (~0.08 mmol/g). The samples treated for 24 h had higher -SO3H (0.10 mmol/g) and total acidity (5.25 mmol/g) but not increased catalytic activity. Ball milling increased the defects and exposed aromatic hydrogen groups on petcoke, which facilitated further acid oxidation (0.12 mmol -SO3H/g for both materials and total acidity of 5.18 mmol/g and 5.01 mmol/g for BP-N-3/120 and BP-N-8/90, respectively) and an increased ester yield. DFT calculations were used to analyze the pathways of sulfonic acid group formation, and the reaction pathway with NO2• was the most thermodynamically and kinetically favourable. The activities of the prepared catalysts were related to the number of -SO3H acid sites, the total acidity, and the oxygen content, with the latter two factors having a negative impact.

A novel route for preparing Gd2O2S:Eu3+ phosphor using high-sulfur petroleum coke as a sulfur source

A novel route for preparing Gd2O2S:Eu3+ phosphor using high-sulfur petroleum coke as a sulfur source

Development of chemical looping desulfurization method for high sulfur petroleum coke

High sulfur petroleum coke is an important by-product of petroleum industry, but it is hard to directly use due to the serious environmental pollution. The development of desulfurization technology has critical significance for the utilization of petroleum coke as resource, in which the thiophene represents the key difficulty in desulfurization. Here, by using a Fe2O3/Al2O3 composite as oxygen carrier, a chemical looping oxidation method was proposed to remove sulfur from petroleum coke for the first time. The Fe2O3/Al2O3 oxygen carrier could effectively oxidize the organic sulfur, and realized a removal efficiency of 63%. The used oxygen carrier exhibited a superparamagnetic property, and could be conveniently separated from the desulfurized petroleum coke. After air calcine, the oxidation ability of the oxygen carrier could be regenerated and used for another desulfurization cycle. Density functional theory calculations were conducted to elucidate the oxidation and evolution processes of thiophene by the oxygen carrier. The C-S bond in thiophene structure could be gradually destroyed by active oxygen, and transformed into sulfur dioxide after the desulfurization. The chemical looping oxidation provides a more convenient desulfurization method, which helps the resource utilization of high sulfur petroleum coke.

Synergism between lignite and high-sulfur petroleum coke in CO2 gasification

Abstract High-sulfur petroleum coke (PC) as solid waste has high treatment cost. Gasification technology can utilize PC and lignite for co-gasification. Organically combining the two is the key to expanding the adaptability of gasification raw materials. This work used thermal analysis technology to study the gasification reaction of PC and lignite systems in a CO2 atmosphere. The results show that the starting and end temperatures of the co-gasification of lignite/high-sulfur PC are lower than those of pure coke. The improved carbonization rate and gasification reaction index indicate that lignite improves the gasification performance. The gasification synergy factors are all greater than 1, indicating that the co-gasification process produces obvious synergism, and the synergism is more obvious in the gasification stage after 800°C. The lignite ash is gradually enriched on the surface of high-sulfur PC with the temperature increase, and the Ca and Fe elements have an obvious catalytic effect, but the catalytic effect has a saturation value. Ashes from lignite used as a multi-component gasification catalyst can increase the overall reactivity in the lignite/high-sulfur PC system, which can broaden the selection of gasification raw materials, and make efficient use of the resource characteristics of both.

Coal-based sulfur hybrid sorbent for removal of Hg0 from flue gas. Part 2. High organic sulfur coal

It is a win–win strategy to prepare mercury sorbents from low-cost high-sulfur raw materials. In part 1, mercury sorbents with excellent performance were prepared from high inorganic sulfur coal through KOH activation. However, this method does not work for high organic sulfur coal. In this work, a two-step preparation method is developed to prepare mercury sorbents from high organic sulfur coal. The first step is the co-pyrolysis/carbonization of Fe2O3 and coal, during which organic sulfur in coal is converted into FeSx. XPS shows that the percentage of Sx2–/S on the surface of the carbonized samples gradually increases from 5.4% to 22.2% with the m(Fe):m(So) ratio from 0:4 to 5:4. The second step is KOH activation, and it converts FeSx into various S species, including C-S, S0, S22− and S2−. Among the prepared mercury sorbents, LF+3Fe/4S-A (m(Fe):m(So) = 3:4) shows the best mercury removal performance, and its mercury removal efficiency remains above 84% for 120 min under N2+O2 at 120 °C. The Hg-TPDD and XPS results indicate that S*, including C-S, S0 and S22−, are the major active sites for mercury removal rather than Fe element, and HgS is the main existing form of mercury on the used sorbents. Besides LF coal, this two-step process is also applicable to other high organic sulfur coals (such as LL coal, WJZ coal, and SY coal) and high-sulfur petroleum coke.

Нефтяной кокс и его нецелевые фракции в производстве стабилизирующей добавки для щебеночномастичного асфальтобетона

The article provides a brief analysis of the current state of the problem of expanding the scope of qualified use of high-sulphur petroleum coke and its non-target fraction such as «coke breeze» as an effective compositematerial of a stabilizing additive to crushed stone mastic asphalt concrete with improved physical and mechanical characteristics, including increased resistance to rutting asphalt.

As2O3 removal from coal-fired flue gas by the carbon-based adsorbent: Effects of adsorption temperature and flue gas components

Gaseous As2O3 emitted from the coal-fired power plant is one of the most carcinogenic and harmful pollutants. In this work, the commercial activated carbon (AC), wood chip-based biomass coke (BC), and KOH activated high-sulfur petroleum coke (PC) were selected, and the effects of adsorption temperature and flue gas components on gaseous As2O3 removal of the carbon-based adsorbents were investigated. The results show that under the basic adsorption conditions, the As2O3 removal ability satisfies BC > PC > AC with the best arsenic removal ability of BC at 150 ℃. Increasing the adsorption temperature benefits the oxidation of As3+ to As5+ on the surface of the three carbon-based adsorbents. Oxygen-containing functional groups (C–O and O–C=O), Al2O3, K2S, and K2SO4 are the main active sites for As2O3 chemisorption. Overall, increasing adsorption temperature leads to the first increase and then decrease in arsenic removal ability of carbon-based adsorbents. Physical adsorption is the main reason for the change in their arsenic removal ability. The weakening degree of physical adsorption is higher than the promotion of chemisorption with increasing adsorption temperature. NO has inhibitory effects on the As2O3 removal by BC. Low concentration (<4000 ppm) SO2 can promote the As2O3 removal by BC due to the formation of SO42- and the increased content of oxygen-containing functional groups.

The Effects of Physical-Chemical Evolution of High-Sulfur Petroleum Coke on Hg0 Removal from Coal-Fired Flue Gas and Exploration of Its Micro-Scale Mechanism.

As the solid waste by-product from the delayed coking process, high-sulfur petroleum coke (HSPC), which is hardly used for green utilization, becomes a promising raw material for Hg0 removal from coal-fired flue gas. The effects of the physical–chemical evolution of HSPC on Hg0 removal are discussed. The improved micropores created by pyrolysis and KOH activation could lead to over 50% of Hg0 removal efficiency with the loss of inherent sulfur. Additional S-containing and Br-containing additives are usually introduced to enhance active surface functional groups for Hg0 oxidation, where the main product are HgS, HgBr, and HgBr2. The chemical–mechanical activation method can make additives well loaded on the surface for Hg0 removal. The DFT method is used to sufficiently explain the micro-scale reaction mechanism of Hg0 oxidation on the surface of revised-HSPC. ReaxFF is usually employed for the simulation of the pyrolysis of HSPC. However, the developed mesoporous structure would be a better choice for Hg0 removal in that the coupled influence of pore structure and functional groups plays a comprehensive role in both adsorption and oxidation of Hg0. Thus, the optimal porous structure should be further explored. On the other hand, both internal and surface sulfur in HSPC should be enhanced to be exposed to saving sulfur additives or obtaining higher Hg0 removal capacity. For it, controllable pyrolysis with different pyrolysis parameters and the chemical–mechanical activation method is recommended to both improve pore structure and increase functional groups for Hg0 removal. For simulation methods, ReaxFF and DFT theory are expected to explain the micro-scale mechanisms of controllable pyrolysis, the chemical–mechanical activation of HSPC, and further Hg0 removal. This review work aims to provide both experimental and simulational guidance to promote the development of industrial application of Hg0 adsorbent based on HSPC.

Parameter optimization and exergy efficiency analysis of petroleum coke-to-hydrogen by chemical looping water splitting process with CO2 capture and self-heating

The petroleum coke-to-hydrogen process is promising since the output of high-sulfur petroleum coke is increasing year by year, the pollution emissions of its combustion for power generation are serious, and the refinery needs a lot of hydrogen. Therefore, this study establishes the process model and conduct the parameter optimization of the petroleum coke direct chemical looping hydrogen production process. The optimized mass ratios of oxygen carrier (Fe2O3), steam, and air to petroleum coke are 12.71, 2.98, and 2.18; however, that are 12.71, 1.79–2.08, and 4.53–5.32 when the proportion of the reduced oxygen carrier entering steam reactor is reduced from 100% to 60–70%, which can be operated in a self-heating mode with air preheating temperature of 278.54–816.80 ℃. When the proportion is increased from 60% to 65.32% and 70%, the product exergy of hydrogen is increased from 454.58 MW to 494.92–530.36 MW with about 100% CO2 capture and the exergy efficiency is therefore increased from 59.56 to 60.75% to 62.32–63.59% and 62.65–63.91%. This paper also studies the sulfur distribution and existing forms of sulfides. Finally, this study found that the exergy efficiency of the chemical looping hydrogen process with the proportion of 65–70% is significantly higher than that of the hydrogen production process by petroleum coke gasification.

Interface engineering of quaternary ammonium phosphotungstate for efficient oxidative desulfurization of high-sulfur petroleum coke

Reducing the sulfur content in high-sulfur petroleum coke (HSPC) has become an urgent issue, however, remains a great challenge with the development of petroleum refining industry. Herein, a highly-efficient catalyst quaternary ammonium phosphotungstate ionic liquid [(C4H9)4N]3PW12O40 (C4@HPA) was initiated to activate H2O2, and the sulfur content of HSPC was remarkably decreased from 4.46 wt.% to 2.76 wt.% at a relatively mild temperature (70 oC), which is discernible below than 1400 oC in industry. The characterization results showed that only sulfate can be removed, while sulfoxide and sulfone were retained in petroleum coke. Moreover, the desulfurization activity of C4@HPA/H2O2 to thiophene sulfides decreases as follows: Thiophene > 2-Methylthiophene > 2,5-Dimethylthiophene > Dibenzothiophene > 4-Methyldibenzothiophene. It reveals that the sulfur of 4-MDBT is the most difficult to be removed. Therefore, this founding here may shine light on the understanding and construction of efficient catalyst for desulfurization of high-sulfur petroleum coke in industry.

Vacuum-assisted and alkali roasting for desulfurization of petroleum coke

A new vacuum-assisted alkali roasting desulfurization technology for petroleum coke is presented in this article. Deep desulfurization experiments were carried out on high-sulfur petroleum coke under argon and vacuum conditions. The results showed that vacuum was more favorable for the pyrolysis of organic sulfur in petroleum coke at high temperatures (>1400 °C) compared with argon. Vacuum-assisted alkali roasting desulfurization can reduced the sulfur content of petroleum coke to 0.18%, and the desulfurization rate can reached 98.54% at 1600 °C. The mechanism of sulfur removal in petroleum coke was preliminarily explored by Gauss, Multiwfn and VMD software, and the experimental samples were analyzed by Carbon–Sulfur Analyzer, XPS and SEM. The experimental results strongly verify the correctness of the simulation calculation. It is difficult to remove thiophene and sulfone in petroleum coke, but Vacuum-assisted alkali roasting can overcome this point, and greatly improve the desulfurization rate of petroleum coke.

Synergistic effects, gas evolution and ash interaction during isothermal steam co-gasification of biomass with high-sulfur petroleum coke

This work investigated the co-gasification behavior of rice straw (RS) and a high-sulfur petroleum coke (PC). An isothermal gasification experiment under a steam atmosphere was conducted on a self-designed thermogravimetry (TG) coupled with mass spectrometry (MS). The results indicate that the high sulfur content in PC seem to have no significant effect on co-gasification. RS showed obvious catalytic effect only after it was completely gasified into ash. Affected by the high concentration of steam, the main components of synthesis gas are H2 and CO2. The RS ash presents a violent melting state, and the lower RS addition ratio only shows a strong catalytic effect in the initial stage of the reaction. The high addition ratio makes the ash particles in the liquid phase contact and react well with the PC particles, and will not inhibit the gasification of the PC particles before the PC particles are completely wrapped.