Coke Production Research Articles

Enhanced Hydrolysis of Carbonyl Sulfide in Coking Oven Gas Utilizing an Efficient Ca-Ba-γ-Al2O3 Catalyst

China possesses a substantial capacity for coke production, resulting in the annual generation of over 100 billion standard cubic meters of the by-product coke oven gas. The comprehensive utilization of this gas has emerged as a matter of significant concern within the coking industry. The removal of carbonyl sulfide (COS) from coke oven gas is crucial for enhancing gas quality, mitigating equipment corrosion, minimizing environmental pollution, elevating the quality of recovered products, and fostering the production of high-quality steel. A novel Ca-Ba-γ-Al2O3 catalyst has been devised, employing γ-Al2O3 as the catalyst matrix and integrating calcium hydroxide (Ca(OH)2) alongside barium hydroxide octahydrate (Ba(OH)2·8H2O) as the alkaline activating components. The impact of various factors, including reaction temperature, humidity, and the number of activating components loaded, on the hydrolysis efficiency of COS has been meticulously investigated. Furthermore, the catalytic reaction mechanism has been elucidated utilizing advanced characterization techniques such as X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) analysis. The outcomes of this research reveal that, under optimal conditions of a reaction temperature of 55 °C and a humidity of 56%, the Ca-Ba-γ-Al2O3 catalyst achieves a remarkable COS hydrolysis efficiency of 95.22%.

A novel grey seasonal model with time power for energy prediction

The fluctuation of seasonal time series has attracted considerable attention. However, the complexity of socio-economic development and the variability of influencing factors make accurate predictions of seasonal time series more difficult. A new discrete grey seasonal model, namely DGSTPM(1,1), is established, which employs the time power term based on the cultural algorithm to effectively deal with the time sequences characterized by nonlinear tendency and periodic fluctuations. Firstly, the operating mechanism of the DGSTPM(1,1) model is expounded by combining the time power item with the traditional grey seasonal model to enhance the forecasting capability. Then, the optimal time power index of the model can be determined by incorporating the cultural algorithm. Subsequently, several properties are thoroughly discussed to illustrate the superiority and uniformity of the new model. Finally, two energy-related cases with different data features and sample sizes are applied to identify the efficacy and robustness of the DGSTPM(1,1) model, referring to monthly crude oil production in the United States and quarterly coke production in China. Based on the various error criteria, SPA and DM tests, the results indicate that the DGSTPM(1,1) outperforms its competitors both in simulation and prediction phases, including DGSTM(1,1), SGM(1,1), SDTGM, FTGM, SARIMA, LSSVM, BPNN, and LSTM models. Meanwhile, the new model can effectively address seasonal time series with nonlinear characteristics owing to its dynamic time power item with the support of the cultural algorithm.

Safety evaluation of deformed coke drum with nested stress at cold spot

In this article, the strain limit criterion and classical strength theories are used to evaluate the strength at the cold spot with nested effect of the deformed coke drum. First, the geometric model of the cold spot with nested effect before and after the deformation of the drum wall is established in the selected area, and the nested stress at the cold spot is calculated. Then, according to the calculated stress–strain results, the stress analysis of the drum wall at the cold spot is carried out. The results show that the coke drum yields during the cooling stage according to the strain limit criterion. According to classical strength theories, coke drum yields during the coke production and cooling stages. Finally, the paths are selected to calculate the equivalent stress–strain, and the stress–strain curves along the paths are plotted. By comparing the results of stress and strain evaluation, three evaluation methods are compared and studied.

Assessment of the contamination by carbonaceous anthropogenic particulates and polycyclic aromatic hydrocarbons (PAHs) concentration in recreational areas of an estuary heavily industrialized in Northern Spain

The commercial management of coal and its by-products has the potential to negatively impact natural coastal environments. The coal conversion processes and coke production are sources of polycyclic aromatic hydrocarbons (PAHs) emissions that also contribute to the pollution of those aquatic environments. This research assesses the contamination by carbonaceous anthropogenic particles and by polycyclic aromatic hydrocarbons of some recreational sites (Arañón, Peña del Caballo and San Balandrán area) located in the Avilés' estuary, an area in Northern Spain that has been heavily industrialized since the 1950s. The results obtained indicate a low concentration of solid organic anthropogenic particles in the intertidal sediments of the recreational sites in the estuary, probably due to the protective measures set in place at the facilities managing bulk coal and coke, which prevents the dispersion of coal dust (and other materials) as well as the eventual failure into the estuary. The characteristics of 16 priority pollutants PAHs analyzed in two recreational sites of the estuary (San Balandrán area), their distribution by aromatic ring number together with their diagnostic ratios demonstrate a pyrogenic nature with a main source from processes of coal and coke conversion (including combustion) in the facilities around the estuary. Some contribution of PAHs derived from petroleum cannot be ruled out. This contamination by PAHS is constant and sustained over time. The majority of the considered PAHs are well above the Spanish Generic Reference Level, (GRL) established for “protection of ecosystems with aquatic organisms”, and only a few of them are notably above the corresponding Spanish GRL established for “other uses of land”, which should include lands for recreational activities. The analysis of the potential toxicity risk of PAHs for human health and the organisms of the aquatic ecosystem suggests a relatively low toxicity risk to very high toxicity risk in the San Balandrán environment according to the concentration and distribution trend of PAHs identified in this area. This trend is dependent on the coastal dynamics and the protection level of the site, which also affect the distribution of the anthropogenic carbonaceous particulates in the same way.

A semi-industrial investigation about the use of iron-steel production by-products in reactive coke production

This study investigates the utilization of by-products from iron-steel integrated plants in the production of reactive coke. Various by-products were evaluated, and blast furnace flue dust with high iron (Fe) content was incorporated into the coal blend through the briquetting of highly volatile coal. The blend consisted of 10 % briquette coal comprise 1 % blast furnace flue dust. The addition of blast furnace flue dust with briquettes aimed to mitigate the reduction in coke strength caused by increased reactivity. Reactive coke was successfully produced through the evaluation of blast furnace flue dust, a by-product of iron and steel plants. The resulting reactive coke exhibited a reactivity value approximately 20 % higher than coke produced without the addition of blast furnace flue dust while maintaining its strength. By re-evaluating blast furnace flue dust as a by-product of the iron and steel process, the reactivity of coke increased without compromising its strength.

Kinetic insights into heavy crude oil upgrading in supercritical water

Heavy crude oil upgrading in a supercritical water environment is a promising technology owing to diverse advantages such as heteroatom removal, high yields of low molecular weight fractions, and inhibition of coke production. In order to increase the performance of this process, some challenges need to be overcome by researching the reaction mechanisms and developing proper numerical models. Therefore, the kinetic studies reported in the literature for hydrothermal upgrading of heavy crude oil under supercritical water conditions and their results were systematically analyzed and discussed to achieve a better understanding of the diverse approaches considered to determine the distribution of reaction products and limitations. Additionally, fundamental aspects of the kinetic models, including experimental considerations and numerical methodologies applied for kinetic parameter estimation, are reviewed to obtain representative information about the reactant system that can be subsequently integrated into reactor design models or reservoir simulations.

Study on the establishment of air pollutant and carbon emission inventory and collaborative emission reduction potential of China's coking industry from 2012 to 2022

Coking industry is usually regarded as a high pollution and high energy consumption industry. China is accelerating its efforts to reduce pollution and carbon emissions in the industrial sector, which has received little attention as the world's largest producer of coke. Therefore, in this study, the trend of air pollution and carbon emissions in China's coking industry and the path of coordinated emission reduction were studied. The results indicate that the average annual emissions of PM, SO2, NOx, VOCs, and CO2 in China's coking industry from 2012 to 2022 amount to 205.98, 69.47, 193.45, 599.80 Gg and 191.10 Tg, respectively. The main sources of PM, SO2, NOx, VOCs and CO2 in coking industry were coal preparation (51.5 %), charge and pushing (39.5 %), coke oven gas (99.8 %), byproduct recovery (47.0 %) and fuel combustion (87.5 %). The emissions from coking plants in central and southern Shanxi, eastern and southern Hebei, and central Shandong are the most concentrated. Ultra-low emission transformation and deep treatment of VOCs have greatly reduced pollutant emissions in key areas of air pollutant control, but the actual emission reduction effect of these measures has been weakened by the additional emissions caused by the increase of coke production in other non-key areas. The research on synergetic emission reduction path shows that there is a great synergistic benefit between air pollutants and CO2 emission reduction in coking industry. It is estimated that the APeq (air pollutants and carbon equivalent) of China's coking industry in 2025, 2028 and 2030 will decrease by 38.2 %, 63.5 % and 70.8 % respectively compared with 2022. With the continuous promotion of pollution reduction and carbon reduction measures, the emission reduction potential of China's coking industry will gradually shift from key areas to non-key areas.

A comprehensive thermodynamic analysis of hydrogen and synthesis gas production from steam reforming of propionic acid: Effect of O2 addition and CaO as CO2 sorbent

A thermodynamic analysis was performed for the production of synthesis gas and hydrogen gas from steam reforming of propionic acid, one of the constituents of the bio-oil, using ASPEN Plus v8.8. The aim of the study was to perform a global analysis on steam reforming of propionic acid focusing on several parameters such as steam-to-propionic acid ratio, reaction temperature, addition of O2 in the feed stream and presence of CaO as a CO2 sorbent in the reaction environment. The results showed that higher amounts of steam/propionic acid ratio resulted in higher H2 and CO2 yields. It was also observed that high H2O/PA molar ratios led to reduced coke production as WGS reaction was favored with excess steam, causing CO in the reaction mixture to be consumed through the WGS reaction rather than the Boudouard reaction. Addition of O2 in the reaction environment was observed to negatively affect yield of H2. Yet, coke formation was deprived and increasing the O2 amount in the feed stream decreased the energy required for the process. Furthermore, the presence of CaO enhanced H2 yield and energy requirements of the process compared to conventional steam reforming process. 100 % yield of H2 production with a heat generation of −83.4 MJ/kmol of PA and almost zero formation of CO2, CO, CH4 and coke is achieved at 600 °C for sorption enhanced steam reforming of propionic acid.

Application of life cycle assessment (LCA) to analyze the environmental loads of heavy machinery components

The heavy machinery used in mining and mineral processing generates significant environmental burdens that cause global warming and also negatively affect human health. This is caused by the use of large amounts of energy by these machines, including the amount of process heat, which generates negative environmental changes. As part of sustainable development, it is necessary to look for more friendly solutions, e.g., life cycle assessment (LCA). Therefore, the objective was to analyse the main environmental loads that arise during the extraction and processing of the component materials used in mining machines. In this case, the subject of the research was a reduction gear with a high utilisation rate in excavators and forklifts used in mining. The environmental impact criteria taken into account in the analysis were ozone depletion, human toxicity, and eutrophication. The analysis was carried out using the OpenLCA programme with the ecoinvent database. The results of the analysis showed that in the extraction and processing phase of the reduction gear materials, the main environmental loads arise for selected criteria arise, among others: during coke production, oil and gas extraction, natural gas transport, and hard coal exploitation. The results of the analysis may contribute to the sustainable development of machines in the mining industry and may be useful in the production of new mining machines in order to eliminate their negative impact throughout their life cycle.

Kinetic modeling of methane dehydroaromatization over Mo/ZSM-5 catalysts

We propose a novel kinetic model for the methane dehydroaromatization (MDA) reaction over the Mo/ZSM-5 catalyst to express the practical behavior of the catalytic reaction. Unlike existing MDA kinetic models, we introduced a deactivation model involving carbon deposit formation to simulate the more realistic behavior of the MDA reaction. The proposed kinetic model integrated the “apparent kinetic model,” which focuses on detectable components, and the “micro-kinetic model,” which incorporates the acidic properties and active sites of the catalyst. To validate this model, we conducted fixed-bed experiments across a wide range of operating conditions, including temperature, gas velocity, and metal loading. Compared with experimental data, our model predictions exhibited a remarkable error of 5 %. Specifically, by leveraging the relationship between the deactivation behavior and carbon deposit formation, the model accurately predicted the CH4 conversion rates, component yields, and coke production throughout the reaction. This model sheds light on catalytic behavior during carbon deposit generation under diverse operating conditions, contributing to a comprehensive understanding of the MDA reaction mechanism. The developed kinetic model can be applied to estimate reactor performance across various scenarios. By providing a kinetic model that incorporates information regarding the catalytic properties of Mo/ZSM-5 and the apparent gas concentration, our study offers a potent tool for estimating practical reactor performance and advancing MDA catalyst development.

Recent Trends in Tailoring External Acidity in Zeolites for Catalysis.

Zeolites are crystalline aluminosilicates with well-defined microporous structures that have found several applications in catalysis. In recent years, great effort has been devoted to defining strategies aimed at tuning structural and acidity properties to improve the catalytic performance of zeolites. Depending on the zeolitic structure, the acid sites located inside the crystals catalyze reactions by exploiting the internal channel shape-selectivity. In contrast, strong acid sites located on the external surface do not offer the possibility to control the size of molecules involved in the reactions. This aspect generally leads to a loss of selectivity toward desired products and to the uncontrolled production of coke. Passivating surface acidity is a promising way to overcome deactivation issues and to enhance the catalytic performance of zeolites. This Mini-Review aims to provide, for the first time, a complete overview of the techniques employed in recent years to neutralize strong external acid sites. Both chemical and liquid vapor deposition of silicates have been widely employed to passivate the external surface acidity of zeolites. In recent years, the epitaxial growth of layers of aluminum-free zeolite, e.g., silicalite-1, over the surface of the acidic zeolite has been proposed as a new approach to neutralize strong external acid sites controlling diffusional phenomena. NH3-TPD, FT-IR, SEM-EDX, and other techniques have been used to provide information about the level of control of the external strong acidity of passivated zeolites. In this Mini-Review, both passivation treatments and characterization techniques are compared and advantages and disadvantages deeply discussed to elucidate the effect of passivation procedures on physical features and especially the catalytic behavior.

Enhanced dehydroaromatization of methane with methanol on Mo-ZSM-5/ZSM-11 intergrown zeolite materials

Methane dehydroaromatization (MDA) represents an appealing route for the direct utilization of abundant methane resources. Currently, the major challenge of MDA reaction lies in the rapid catalyst deactivation via coke formation, hindering large-scale industrialization of the process. Herein we report an enhanced conversion route of MDA in the presence of methanol on Mo-based zeolite materials. Compared to regular ZSM-5, ZSM-11, and their mechanically mixed counterparts, Mo embedded in ZSM-5/ZSM-11 intergrown matrix exhibits higher methane conversion (16.0%) and aromatics selectivity (62.5%) while limiting coke production to 12.1% under the co-feeding of methane and methanol (nCH4/nCH3OH = 30). If no methanol addition, coke selectivity is up to 45.1% in MDA reaction. Additionally, hydrogen enriched syngas (nH2/nCO = 6) was obtained as a co-product of the methane and methanol co-aromatization. NH3-adsorbed 1H MAS NMR, Co2+ titrated UV-vis and Raman spectroscopy characterizations reveal that a proper amount of Brönsted acid sites and the binuclear Mo anchored on the Al pairs at the intersection cavity may account for the superior reaction performance of the intergrown zeolites. A catalytic mechanism was also proposed via 13CH3OH isotopic labeling tracer and in-situ13C solid-state NMR studies. Methanol is first decomposed into CO/H2, while CO is hydrogenated to CH4 and converted into CO2 via the water-gas shift reaction. Alternatively, methanol is converted into CO/CO2 through formate intermediates. Subsequently, CO2 reduces coke deposition via the reverse Boudart reaction, which improves the catalytic performance.

Electric dehydration of coal tar – a by-product of coke production for blast furnace smelting

Electric dehydration of coal tar – a by-product of coke production for blast furnace smelting

Insight into interaction among soil microbial community, soil metabolomics and enzyme activity after long-term PAH stress

The problem of soil polycyclic aromatic hydrocarbon (PAH) pollution in coking plant sites has been widely studied in recent years, but there is a lack of research on the correlation between soil microorganisms, soil metabolomics, and soil properties. Thus, in this study, the long-term impact of coke combustion on soil microbial community structure, enzyme activities, and metabolic pathways within a former coking plant site was investigated. Soil samples were collected from both the coking production area (CA group) and office area (OLA group), approximately 0 to 20 cm in depth. Compared with OLA group, elevated levels of 16 PAHs in the list of USA EPA were detected by gas chromatography-mass spectrometry in the CA group. Several dominant microorganisms, such as Altererythrobacter, Lysobacter, and Sulfurifustis, were identified by 16 s ribosomal DNA sequencing in the CA group. The fatty acid biosynthesis pathway exhibited specific inhibition, while the phenylalanine metabolic pathway was promoted in response to PAH stress. Long-term PAH exposure led to the inhibition of soil urease activity. The co-occurrence network of microorganisms revealed intricate patterns of co-metabolism and co-adaptation within complex bacterial communities, facilitating their adaptation to and decomposition of soil-borne PAHs. This research could provide valuable insights into the community characteristics and metabolic mechanisms of microorganisms inhabiting PAH-polluted soil within coking plant sites. The findings enhance our understanding of the indigenous soil microbiome and its intricate network dynamics under the persistent stress of PAHs, contributing to a more comprehensive knowledge of soil ecosystems in such environments.

Modernization of Coke Production at Magnitogorsk Iron and Steel Works (MMK)

Modernization of Coke Production at Magnitogorsk Iron and Steel Works (MMK)

Emerging trends in hydrogen and synfuel generation: a state-of-the-art review.

The current work investigated emerging fields for generating and consuming hydrogen and synthetic Fischer-Tropsch (FT) fuels, especially from detrimental greenhouse gases, CO2 and CH4. Technologies for syngas generation ranging from partial oxidation, auto-thermal, dry, photothermal and wet or steam reforming of methane were adequately reviewed alongside biomass valorisation for hydrogen generation, water electrolysis and climate challenges due to methane flaring, production, storage, transportation, challenges and opportunities in CO2 and CH4 utilisation. Under the same conditions, dry reforming produces more coke than steam reforming. However, combining the two techniques produces syngas with a high H2/CO ratio, which is suitable for producing long-chain hydrocarbons. Although the steam methane reforming (SMR) process has been industrialised, it is well known to consume significant energy. However, coke production via catalytic methane decomposition, the prime hindrance to large-scale implementation of these techniques for hydrogen production, could be addressed by coupling CO with CO2 conversion to alter the H2/CO ratio of syngas, increasing the reaction temperatures in dry reforming, or increasing the steam content fed in steam reforming. Optimised hydrogen production and generation of green fuels from CO2 and CH4 can be achieved by implementing these strategies.

Electrical Resistance as an Aggregate Characteristic of Coke Properties for Electrochemical and Coke Production

Electrical Resistance as an Aggregate Characteristic of Coke Properties for Electrochemical and Coke Production

Comparison of Bio-Coke and Traditional Coke Production with Regard to the Technological Aspects and Carbon Footprint Considerations

In a world facing the challenges of climate change, it is imperative to prioritize the search for sustainable technical solutions. This study focuses on evaluating the environmental impact of using bio-coke compared to traditional metallurgical coke, employing Life Cycle Assessment (LCA) as the evaluation tool. Bio-coke, produced from a blend of coking coals enriched with biomass, offers greater environmental potential than traditional coke due to a reduced share of non-renewable raw materials. The steel and coking industries are significant contributors to carbon dioxide emissions. LCA provides a comprehensive assessment of the environmental impact of bio-based additives, considering raw material deliveries, the coking process, application in metallurgy, and product end-of-life disposal. The analysis results indicate that the use of biomass additives leads to lower greenhouse gas emissions compared to coke production without bio-additives. Given the urgency of addressing global warming and the increasing demand for sustainable energy sources, this study’s findings can advocate for bio-coke as a more environmentally friendly alternative to traditional coke in the steel industry.

Synthesis of HZSM-5@activated carbon for improving aromatic production from catalytic pyrolysis of biomass

HZSM-5 widely used for the catalytic pyrolysis of biomass exhibits the drawbacks of high diffusion resistance and large coke production. To effectively enhance the catalytic efficiency and alleviate the coke deposition, a novel promising catalyst, HZSM-5 coated activated carbon (HZSM-5@AC), was prepared for the first time for in-line upgrading the pyrolysis products of soybean straw. Various catalysts including HZSM-5, activated carbon, and the HZSM-5@AC catalysts with different HZSM-5 to activated carbon mass ratios were characterized. The results showed that the HZSM-5 was successfully coated on the surface of activated carbon and the addition of activated carbon introduced a mesoporous structure and more acidic sites to the catalyst. The catalytic performance on the biomass conversion showed that the catalyst with HZSM-5-to-activated carbon mass ratio of 18:5 (18HZSM-5@5AC) had the highest catalytic efficiency on the conversion of biomass into aromatics with a selectivity of 99.5%, including 75.68% of benzene, toluene, and xylenes (BTX) with a yield of 74.68 mg/g. Moreover, a possible pathway for HZSM-5@AC catalyzed biomass pyrolysis was proposed through analyzing the conversion of model compounds. The catalyst cycling experiments demonstrated the higher stability of HZSM-5@AC than the parent HZSM-5 and activated carbon. TG, FTIR, Raman and SEM showed that the spent HZSM-5@AC was hardly structurally changed with a low coke yield of 0.08%. However, the spent HZSM-5 was partly structurally deactivated by large aromatic ring systems with a coke yield of 3.74%. SEM results also showed that a large amount of polymerized material encapsulated the surface of the spent HZSM-5.

The employment of domain adaptation strategy for improving the applicability of neural network-based coke quality prediction for smart cokemaking process

Precise coke quality prediction is essential for coke production process optimization to achieve the reduction in energy consumption and CO2 emissions, thus moving toward carbon neutrality in the coking industry. However, the complexity of coal molecular structures and the chemical reactions in the cokemaking process pose significant challenges to the applicability of existing coke quality prediction models. Based on the recently widely employed Artificial Neural Network (ANN) method, this study is the first to introduce domain adaptation strategies for improving the applicability of ANN in predicting coke quality including Coke Strength after Reaction (CSR) and Coke Reactivity Index (CRI). 649 Chinese coal samples with properties including Mad, Ad, Vdaf, St,d, G, X and Y along with coke quality were collected. They were initially categorized into source and target domains characterized by different distributions. Subsequently, two scenarios were independently evaluated based on coal samples in the target domain, which either lacked any information or contained partial information of actual coke quality. The results suggested that the proposed approach can significantly enhance the predictive performance for coal samples across various distributions. Moreover, a comprehensive investigation was also conducted to determine key factors influencing the effectiveness of coke quality prediction with this approach.