Coke Oven Research Articles

Lab-scale Process Parameter Determination of a Two-stage DRI (direct reduced iron) Process Using Reformed COG (coke oven gas)

On the road to carbon neutrality, a great deal of attention is being paid to emerging technologies such as the DRI (direct reduced iron) process. This study proposes a two-stage DRI process using reformed COG (coke oven gas), and determined optimal process parameters. The reduction and carbonization of Carajás iron ore used in the field were examined by monitoring the weight loss of the samples, and EDS and XRD measurements with respect to the reaction temperature and operating time for different reducing environments. While the reduction of iron ore is completed in 60 min at 800oC regardless of the reducing environment, the carbonization of reduced iron is attainable only at 800oC with high hydrogen content in the reducing gas. Thus, a countercurrent scheme in the proposed DRI process is justified, in which COG containing high hydrogen content is flowed into the 2nd stage operated at 800oC and subsequently directed to the 1st stage operated at 600oC. The reduction of iron ore is initiated in the 1st stage for 60 min irrespective of the reducing environment, and the completion of the reduction and the following carbonization is fulfilled in the 2nd stage for 40 min under a high reducing environment. An equilibrium analysis supported that the cracking of CH4 in COG to graphite leads to the formation of CO from CO2 and the successive formation of Fe3C from reduced Fe. The carbonization of iron ore is possible only in the presence of CO2 . It also showed that too high or low reducing environments are not desirable to accomplish the DRI process. This study is expected to be provide an effective guideline for optimizing similar DRI processes.

PIG-A gene mutation as a mutagenicity biomarker among coke oven workers.

PIG-A gene mutations can be detected in humans, and PIG-A assays can potentially predict the risk of exposure to carcinogens. However, extensive, population-based studies to validate this are lacking. We studied a cohort of occupational coke oven workers with chronic high exposure to carcinogenic polycyclic aromatic hydrocarbons, which are well-studied genotoxins classified by the IARC as carcinogenic to humans. Peripheral blood erythrocytes of workers were assessed for gene mutations using a PIG-A assay, and chromosome damage using the cytokinesis-block micronucleus test with lymphocytes. Two sample populations from a non-industrialized city and new employees in industrial plants were selected as controls. We observed a significantly elevated PIG-A mutation frequency (MF) and increased frequencies of micronuclei (MN) and nuclear buds (NBUDs) in coke oven workers, compared with levels in the control groups. We found that the coke oven workers with different lengths of service had a relatively high mutation frequency. Overall, the study findings showed that occupational exposure of coke oven workers increases the genetic damage and the PIG-A MF could be a potential biomarker for risk assessment of carcinogen exposure.

Design and thermodynamic analysis of a novel structure utilizing coke oven gas for LNG and power cogeneration

Coke oven gas is a by-product of the process of producing coke from coal and contains valuable compounds such as hydrogen and methane. In this study, an improved process was proposed for co-generation of power and LNG from COG with low CO2 emissions and high energy and exergy efficiency. This proposed process includes: LNG Recovery Unit, Organic Rankin Cycle, and the power plant. The results of simulation showed that the exergy and energy efficiencies for this proposed process are 77.9% and 70.29%, respectively, which are considerably higher than other studies. It is found that the total exergy destruction of the proposed process is 4272.95 kW, and the power plant with 3118.1 kW exergy destruction has the largest share in total exergy destruction. Additionally, outcomes showed that ORC recovered 1205 kW of waste heat from compressor exhaust gases and produced 167.4 kW of power. Environmental analysis shows indirect carbon emissions for the proposed process is zero. The CO2 emissions for the total energy and electric power generation were 0.0034 kgCO2/MJ and 406 gCO2/kWhel, respectively which are lower than coal or natural gas power plants.

Decarbonizing ceramic industry: Technological routes and cost assessment

The ceramic industry is a primary contributor to carbon emissions, but its technological decarbonization routes remain underexamined. This article is one of the first to explore the decarbonization routes available to the ceramic industry in reducing carbon emissions and to assess the economic feasibility of these options. We considered 14 green technologies across four categories: energy substitution, energy efficiency improvement, material consumption reduction, and process improvement. We developed a methodological framework to evaluate the decarbonization potential and costs of these technologies through quantitative models and to construct a decarbonization route based on the evaluation results. Using Huida Group Co. Ltd., a world-leading ceramic manufacturer, as a case study, we identified technological decarbonization routes for the ceramic industry. Our findings showed that replacing coke oven gas with natural gas or green hydrogen results in the most significant carbon reduction. Considering the economic feasibility, energy efficiency improvement technologies, lightweight product design, and waste recycling are the most effective, reducing total emissions by 4.31%, 2.58%, and 1.83%, respectively, while also increasing profits. Clean energy and electrification are the most promising long-term decarbonization pathway. The use of green hydrogen in the firing process can reduce emissions by 30.10% with an added cost of 907.54CNY/t of products. This cost will be reduced to zero when the price of hydrogen is lower than 8.70 CNY/kgH2 and the price of carbon trading is higher than 500 CNY/tCO2. Finally, using an electric heater and microwave drying technique can reduce carbon emission by 6.09% and 12.23%, respectively, for producing one ton of ceramic products, when the emission factor of the power grid is 0.23 tCO2/MWh.

Hydrogen production from low pressure coke oven gas by vacuum pressure swing adsorption

Hydrogen is a major component of coke oven gas (COG) and can be used in gas-based direct reduction iron processes to help the steel industry achieve the carbon peaking and carbon neutrality goals. However, the high compression power consumption is the main drawback of the current PSA cycle since the COG needs to be compressed from atmospheric pressure to ∼18 bar to achieve a hydrogen production with purity >99.9% and recovery < 85%. Here in this study, we experimentally demonstrate by using a 4-bed 12-step lab-scale VPSA rig filled with activated carbon RB3 and can obtain a hydrogen product with a purity of 99.67% and a recovery of 91.97% at a feed pressure of only 5.17 bar. We then constructed a non-isothermal non-adiabatic VPSA model using our in-house code and validated the model against experimental breakthrough and VPSA cycles. Parametric optimization produced a H2 product of 99.995% purity and 92.29% recovery at a slightly increased adsorption pressure of 6 bar and a vacuum pressure of 0.02 bar with 10.21 mol.H2/kg.ads/hr productivity and 7.09 kJ/mole.H2 specific power. We also confirmed that light product purge at vacuum pressure can effectively improve the H2 purity and the gas flow direction of the pressure equalization step has a significant effect on the mass transfer front. Our research presents the success of low-pressure hydrogen production from COG, which will greatly accelerate the transformation of COG utilization and promote the decarbonization of the iron and steel industry.

Benchmark Dose Assessment for Coke Oven Emissions-Induced Mitochondrial DNA Copy Number Damage Effects*

ObjectiveThe study aimed to estimate the benchmark dose (BMD) of coke oven emissions (COEs) exposure based on mitochondrial damage with the mitochondrial DNA copy number (mtDNAcn) as a biomarker. MethodsA total of 782 subjects were recruited, including 238 controls and 544 exposed workers. The mtDNAcn of peripheral leukocytes was detected through the real-time fluorescence-based quantitative polymerase chain reaction. Three BMD approaches were used to calculate the BMD of COEs exposure based on the mitochondrial damage and its 95% confidence lower limit (BMDL). ResultsThe mtDNAcn of the exposure group was lower than that of the control group (0.60 ± 0.29 vs. 1.03 ± 0.31; P < 0.001). A dose–response relationship was shown between the mtDNAcn damage and COEs. Using the Benchmark Dose Software, the occupational exposure limits (OELs) for COEs exposure in males was 0.00190 mg/m3. The OELs for COEs exposure using the BBMD were 0.00170 mg/m3 for the total population, 0.00158 mg/m3 for males, and 0.00174 mg/m3 for females. In possible risk obtained from animal studies (PROAST), the OELs of the total population, males, and females were 0.00184, 0.00178, and 0.00192 mg/m3 respectively. ConclusionBased on our conservative estimate, the BMDL of mitochondrial damage caused by COEs is 0.002 mg/m3. This value will provide a benchmark for determining possible OELs.

Prioritizing the hydrogen pathways for fuel cell vehicles: Analysis of the life-cycle environmental impact, economic cost, and environmental efficiency

The deployment of fuel cell vehicles (FCVs) is very important for the decarbonization of the transportation sector. While the energy infrastructure is regarded as a critical factor for the deployment of FCVs, it is still unclear which hydrogen pathway of FCVs has the highest environmental efficiency and should be prioritized, thus restricting the development of related energy infrastructures. Therefore, 17 major hydrogen pathways of FCVs in China are designed in this study, and their environmental impacts, economic costs, and environmental efficiencies are evaluated and compared with those of the energy pathway for battery electric vehicles (BEVs). The results show that the pathways with electrolysis hydrogen from renewables have lower emissions and higher economic costs, which is contrary to the pathways with fossil-based hydrogen. Among the 17 pathways, the pathway with hydrogen from coke oven gas has the most life-cycle environmental efficiency and should be prioritized; however, it is still lower than that of the energy pathway for BEVs. As a higher share of renewables in the total electricity generation would lead to a higher environmental efficiency of hydrogen electrolysis, the hydrogen pathway with renewables could potentially be the most cost-efficient pathway with a decrease in the cost of renewables.

The Research on Waste Heat Utilization Technology of Coke Oven Gas in Ascension Pipe

The Research on Waste Heat Utilization Technology of Coke Oven Gas in Ascension Pipe

Simulation and 4E analysis of a novel multigeneration process based on carbon dioxide capture and utilization, water electrolyzer, and COG reforming

Current study presents a novel integrated process for cogeneration of methanol (37020 kg/h), heating (25730 kgLPS/h), oxygen (1000 kmol/h), and desalinated water (29.83 m3/h) from polluting resources, including flue gas and coke oven gas (COG). Concerning carbon dioxide (CO2) capture and utilization concept, COG reforming, and generating hydrogen from an electrolyzer, the newly designed configuration is available. The other subsystems of the proposed structure include seawater desalination unit, steam power plant, methanol production unit, and ammonia power plant. Thermodynamic outcomes demonstrate that the total energetic and exergetic efficiencies equal 58.71% and 69%, correspondingly. Also, the total destructed exergy is 135311 kW, where the COG steam reforming subsystem has the major share (29%). Subsequently, total CO2 emission, net CO2 emission, and the intensity of the CO2 emission of this configuration are respectively found at 32970 kg/h, −7395.71 kg/h, and −0.1998 kgCO2/kgMeOH. Based on the economic evaluation, the cost rate of yielded methanol equals 0.351 $/kg, which exhibits a significant decrease compared to other structures. Concerning the sensitivity study, it is found that enhancing the desorption column’s reflux ratio results in decreasing the total CO2 emission. In addition, increasing the feedwater of the electrolyzer, due to the rise in the CO2 conversion, is one of the important factors in growing the total energetic efficiency and methanol production, as well as decreasing the net CO2 emission of the process.

Simulation and 4E analysis of a novel coke oven gas-fed combined power, methanol, and oxygen production system: Application of solid oxide fuel cell and methanol synthesis unit

To address an innovative trigeneration process using coke oven gas as the input fuel, a novel heat integration process based on a solid oxide fuel cell is designed and discussed in the current research. Since the coke oven gas is a hydrogen-enriched fuel, its application in a solid oxide fuel cell power plant can improve sustainability and environmental indexes. The flue gas leaving the fuel cell subsystem is directed to a Kalina power cycle and an absorption power cycle for heat recovery, wherein additional power is available. Accordingly, the rejected flue gas is sent into a methanol synthesis unit for producing methanol. A part of generated electric power is delivered to a proton electrolyte membrane electrolyzer, where the water electrolysis process generates hydrogen and oxygen. Here, the generated hydrogen is delivered to the methanol synthesis unit. This system is simulated in the Aspen HYSYS software. To study the designed system, energy, exergy, environmental, and economic assessments are considered. In addition, a sensitivity study based on the main variables is performed. According to the results, the energy and exergy efficiencies of the whole structure are 34.69% and 88.885, respectively. In addition, the methanol production cost was 0.595 $/kg. The CO2 emission intensity is found to be 0.18 kgCO2/kgMeOH. So, the use of coke oven gas reduced the environmental threats considerably.

A byproduct gas distribution model for production users considering calorific value fluctuation and supply patterns in steel plants

Coke oven gas (COG), blast furnace gas (BFG) and linz-donawitz process gas (LDG) are three types of byproduct gases that serve as pivotal energy carriers in steel plants. Reasonable distribution of byproduct gases plays an important role in energy management and scheduling. However, it is difficult to achieve the goal of on-demand supply due to the changeable supply patterns, which usually hinder the efficient utilization of byproduct gases and cause the environmental pollution. Additionally, the influence of calorific value fluctuation on determining the distribution time periods is a research gap. To tackle this problem, a byproduct gas distribution model for production users considering calorific value fluctuation and supply patterns is proposed in this paper. The model was divided into three linear programming sub-models with flexible objective functions and constraints determined by different supply patterns and distribution strategies. Finally, to demonstrate the performance of the proposed model, a case study was conducted on a typical steel plant, and the results highlight the excellent accuracy of the model and ensures the gases are supplied to the users based on their demand.

Pages of the enterprise chronicle ‒ engineering solutions

The history of the Makeevka Metallurgical Plant is considered on the examples of the most important and striking technical decisions made by the engineers of the enterprise within the framework of the blast furnace, open-hearth and rolling industries. With regard to blast furnace production following developments are noted: enlarged assembly of blast furnaces and auxiliary units; the launch in 1929 of the largest blast furnace in the USSR with a volume of 842 m3, which served as a prototype for the design and construction of large furnaces at other enterprises; achievement of the best indicators in the country in terms of the useful volume utilization factor; launch in 1957 of blast furnace No. 5 with a volume of 1400 m3, the largest at that time in the USSR; realization of industrial use of coke oven gas in blast-furnace production. With regard to open-hearth production following achievements are noted: the first experience in the USSR in mastering a floor filling machine; the complex of solutions that ensured victory in the All-Union competition of metallurgists for the best quality and low cost of products; leadership in the development of chromium-magnesite domes and evaporative cooling of furnace elements; establishing of the world record for steel smelting at a 200-ton unit. In the field of rolling production, the development of the first Soviet blooming is noted. The current struc-ture of the plant is presented, which is currently based on the production of wire and long products on unique aggre-gates: a wire mill 150 and long products rolling mill 390. The role of the Donetsk National Technical University in the training of engineering personnel for the Makeevka Metallurgical Plant, from 1921 to the present, is noted

Investigation on the performance of a by-product hydrogen-fueled spark-ignition engine with Miller cycle under various lean conditions

The direct combustion of by-product hydrogen is a promising way for reducing costs and greenhouse emissions. Coke oven gas (COG) which is mainly composed of H2, CH4 and CO is a major source of by-product hydrogen that is suitable to be adopted by internal combustion engines. This paper investigated the COG combustion in a spark-ignition engine with Miller cycle. To get an overview of by-product hydrogen combustion properties, two kinds of COG compositions with the maximum and minimum hydrogen fractions were tested. The excess air ratio (λ) was raised from stoichiometric to the lean limit to explore the capability of COG on improving the engine performance under a common-driving speed of 1500 rpm and part load conditions. The test results indicated that the engine fueled by COG with higher hydrogen fractions could gain concentrated heat release period, extended lean burn limit, reduced HC and CO2 emissions, and enhanced working capability only at ultra-lean conditions. The properly increased λ availed improving engine efficiency and lowering HC emissions. The peak indicated thermal efficiency of 38.6% was acquired at the λ of 1.2, while the lowest HC emissions of only 32 ppm was gained at the λ of 1.4. Under ultra lean conditions, NO emission dropped to near zero, and CO from the by-product hydrogen-fueled engine was negligible for all tested ranges. An interesting trend of peak pressure correlated crank angle versus λ was also found in this study.

Energy-saving and emission-reduction potential of fuel cell heavy-duty trucks in China during the fuel life cycle.

Exploring alternative fuels and advanced vehicle technology is a crucial strategy for vehicle emission reduction. Fuel cell heavy-duty trucks (FC-HDTs) have a promising application prospect to alleviate the high energy consumption and emissions of road freight, but their environmental performance during the fuel life cycle should be further studied. This study is aimed at evaluating the fossil fuel consumption and GHG emissions of FC-HDTs in China using the updated GREET model. The results show that (1) comparing various hydrogen production pathways, it is found that the coke oven gas (COG) pathway can provide the best environmental performance, while the energy consumption and greenhouse gas (GHG) emissions of the coal gasification (CG) and grid power water electrolysis (GPWE) pathways will be significantly decreased in the future. (2) Among the involved vehicles in China, FC-HDT with GVWR18 has the greatest energy-saving and emission-reduction potential. (3) The application of carbon capture and storage (CCS) technology in hydrogen production is conducive to improving the emission-reduction effect of FC-HDT while increasing its energy consumption slightly. The key to achieving upstream carbon neutrality is to optimize the hydrogen production structure and electricity mix, along with adjusting the hydrogen production process and transportation mode. Furthermore, the fuel economy and payload of the FC-HDT affect its environmental performance, indicating the importance of improving the technology of the drivetrain, fuel cell, and hydrogen storage tank.

The effect of toluene trace admixtures on the plasma‐assisted oxygen trace removal from hydrogen‐rich gas mixtures in a surface dielectric barrier discharge reactor

AbstractA surface dielectric barrier discharge reactor was applied in the removal of oxygen traces from coke oven gas (COG), to which toluene was added as a model hydrocarbon contaminant. The adverse effect of toluene on O2 conversion was observed in a H2/N2/O2 mixture, while in synthetic COG consisting of H2, CH4, N2, CO, CO2, and O2, it remained unchanged. Online gas chromatography (GC) showed that the reactivity of toluene is mainly driven by H2/N2/O2. The accumulated residue was dissolved and analyzed by GC coupled with mass spectrometry. The identified reaction products suggest that toluene undergoes ring‐opening and functionalization.

A novel modeling strategy for the prediction on the concentration of H2 and CH4 in raw coke oven gas

A novel modeling strategy for the prediction on the concentration of H2 and CH4 in raw coke oven gas

Deposits in Coke Oven Gas Lines and Equipment at Coke Plants: A Review

Deposits in Coke Oven Gas Lines and Equipment at Coke Plants: A Review

Transient numerical simulation of heat recovery coke oven based on chemical percolation devolatilization model

ABSTRACT The actual coking engineering challenge is changed into a numerical simulation calculation problem due to the difficulty in monitoring the parameters of the heat recovery coke furnace. The release law of coal volatiles is calculated using the chemical percolation devolatilization (CPD) model in this study. To explore the distribution properties of the temperature field and flow field in the furnace as well as the burning condition of the surface of the coal cake, the user-defined function (UDF) is coupled with the porous medium model, and the transient condition simulation is carried out. The accuracy of the model is verified by comparing the temperature values at different times with the actual parameters. According to the calculations, the fuel burns more fully when the equivalency ratio is close to 1, and that the flame propagation speed increases with combustion temperature. When the bulk density is 1100 kg/m3 and the air input velocity is 13.3 m/s, the reaction lasts for 15 hours and the emission of volatiles is very minimal, resulting in a poor combustion reaction. The coal cake surface’s major temperature range is 1200 K to 1400 K after 30 hours of reaction time, which is beneficial to accelerate the maturation of coke. The coal cake surface’s temperature distribution at 45 and 60 hours is lower than that of the coke. Additionally, an increase in air and flame propagation velocity can strengthen furnace disturbance, enhance the temperature and velocity distribution uniformity, hasten coke ripening, and enhance coke quality.

Impact of carbon monoxide on performance and microbial community of extreme-thermophilic hydrogenotrophic methanation in horizontal rotary bioreactor

A novel horizontal rotary bioreactor was developed for upgrading biogas from coke oven gas at extreme-thermophilic condition. The introduction of CO decreased the outlet methane content from 80% to 50% due to insufficient H2. This hindrance was overcome by increasing the proportion of incoming hydrogen, coupled with a prolonged gas retention time from 24 to 72 h, leading to a restoration of methane content to 91.6%. Notably, CO and CO2 exhibited a competitive relationship to hydrogen, which was determined by their contents. The substitution of Methanothermobacter for Methanobacterium as the dominant genus was observed at 70 °C, with relative abundance exceeding 98%. Incorporation of CO increased bacteria diversity and fostered a syntrophic relationship between the bacterial community and M. thermautotrophicus. This study provides both theoretical basis and practical support for biogas upgrading from coke oven gas using a biofilm reactor, thus aiding its future industrialization prospects.

Impact of Hydrogenous Gas Injection on the Blast Furnace Process: A Numerical Investigation

Intensifying hydrogen use in the blast furnace is a key technology for significant coke and CO2 emissions reductions. The most straightforward approach is the implementation of high hydrogenous gas injection rates in the BF tuyeres. Yet this solution has not been widely implemented due to a lack of understanding of the impact on the furnace’s internal state. In this paper, a newly developed BF mathematical model is presented and validated on operation data. The model is next applied to investigate the effect of hydrogenous gas injection on the overall performance and internal state of the furnace. The current state of an industrial BF is used as a starting point, increasing the injection of coke oven gas, natural gas or pure H2 to the maximum where the limits for a safe and stable process are still obeyed. All three gases were found capable of significantly decreasing the coke rate, but only coke oven gas and pure H2 allowed for a significant reduction of the CO2 emissions. It was found that the indirect reduction of H2 is intensified by hydrogen enrichment partially at the expense of indirect reduction by CO. Furthermore, the water gas shift reaction is intensified at increased hydrogenous gas injection, affecting the CO and H2 utilization of the top gas. The study gives an insight into the feasibility of BF processes with high hydrogenous gases injection into the tuyeres and the resulting coke savings.