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The large-scale coke oven is a developing trend in coking technology, and the influence of the industrial coke oven size on the quality of metallurgical coke needs to be revealed. Under the same raw coals and blending ratios, metallurgical cokes were obtained from top-loading coke ovens with carbonization chamber heights of 6 and 7 m, respectively. The macroscopic quality and microstructure of the refined metallurgical cokes were comprehensively tested. The results showed that the conventional cold and thermal strength indexes of Coke-7m were better than those of Coke-6m. The comprehensive thermal strength at multiple temperatures further showed that the thermal strength advantage of Coke-7m was mainly manifested at low temperatures (1050 and 1100 °C) or a high temperature (1300 °C), where the solution-loss reaction mode of coke tended to be the "uniform reaction model" or "unreacted core model". At medium temperatures, the solution-loss reaction mode tended to be the "gradient reaction model", which had a greater destructive effect on the thermal strength of coke. At this time, the thermal strengths of the two cokes were close. Microstructure characterization revealed that industrial coke oven size mainly affected the carbon structure of coke but had little effect on pore structure. The advantage of Coke-7m regarding carbon structure is an important reason for its superior macroscopic quality compared to Coke-6m. [ABSTRACT FROM AUTHOR]

The prediction of coking duration is critical during operation of commercial coke oven batteries; however, it is still far from accurately predict since it has to rely on experience-based estimation. To address this problem, we proposed a machine learning-based approach, and presented a general practice and theoretical framework for predicting coking duration accurately and efficiently. Three types of neutral networks, including the multi-layer perceptron (MLP) model, the radial basis function (RBF) model, and the long short-term memory (LSTM) model, were tested and evaluated in terms of predicting accuracy, training and predicting time. On this basis, a novel two-stream joint MLP-RBF neural network was proposed. All the networks were trained and tested with onsite-collected datasets. In the modeling, the potential relationships between variables are deeply learnt automatically. The results show that the innovative joint network inherits advantages from both sides and exhibits the lowest prediction error, 2.79% (MAPE) or 4.26% (RMSPE), and is recommended as the most appropriate for practical application. This work not only presents an efficient approach for predicting coking duration, but also examines the extent to which the machine learning technology can be employed during the digital transformation of traditional industries. [ABSTRACT FROM AUTHOR]

Selection of the hydraulic drive and automation system for opening and closing the coke discharge doors of the quenching car is considered. The goal is to determine the best equipment for the hydraulic drive and the best pumping station mounted in the locomotive so as to ensure effective discharge of the quenched coke on the sorting ramp, at the required rate and with uniform coke distribution over the length of the ramp. Components are proposed for the hydraulic drive that opens and closes the coke discharge doors of the quenching car. Hydraulic cylinders with built-in sensors for monitoring the position and speed of the moving components (the cylinder rods and connectors) are employed. In the hydraulic drive, the operation of the hydraulic cylinders is regulated by means of distributors with proportional control. The use of hydraulic drive systems and hydraulic automation in coke production ensures efficient operation of the equipment—in particular, uniform distribution of the quenched coke over the sorting ramp. Design features proposed for the hydraulic pumping station in the locomotive ensure effective opening and closing of the coke discharge doors in the quenching car on the basis of hydraulic accumulators and auxiliary equipment. [ABSTRACT FROM AUTHOR]

3-D numerical simulations based on diffusion combustion technology were employed to optimize the multi-stage air/gas supply system in a coke oven battery with 7.1 m coking chambers. In the heating flues, the Eddy-Dissipation Concept (EDC) model and the ideal gas model were utilized to numerically investigate diffusion combustion. What is more, the radiation between the flue gas and the silicon brick was calculated using the Discrete Ordinates (DO) model. After validating the reliability of the model with field-measured data, insights into the temperature field and gas flow in the heating flue, and heat flux distribution over the heating wall were obtained. To characterize the vertical heating uniformity, an index of the standard deviation of the heat flux over the vertical heating walls was proposed. By optimizing the multi-stage air/gas supply design of heating flues, the vertical heating uniformity was improved by 60% according to the index values. The approach developed in this work can be a useful tool for the design of large-capacity coke oven batteries at different scales. [ABSTRACT FROM AUTHOR]

The basic components of a furnace for laboratory coking are considered. The problems encountered in organizing laboratory coking are discussed. Among the features of coking, particular attention is paid to the poor thermal conductivity of the coal charge, which sets limits on the design. Photographs of coke samples obtained in two different furnaces are presented: one furnace has bottom heat supply, while the other has bilateral heat supply. The structure of the coke samples is considered. The coke produced with bottom heat supply has characteristics such as cauliflowers, tar lines, particles of finger and palm type, and also longitudinal and transverse cracks. Such elements are also seen in industrial coke. The coke produced with bilateral heat supply takes the shape of the coking chamber. It consists of many structural elements with sharp corners. The geometry of the coke cake may reflect the specifics of the heat and mass transfer. Accordingly, in designing the furnace for laboratory coking, it is important to produce coke whose geometry resembles that of industrial coke. [ABSTRACT FROM AUTHOR]

One- and two-dimensional models are employed to determine how the heating wall temperature of a furnace chamber within a coke battery affects the coke quality. The half-width b of the chamber is considered as a secondary factor. One- and two-dimensional thermal models of coking permit the prediction of coke quality. The results are verified by means of production data for Moscow Coke and Gas Plant (Moskoks). The optimal coking temperatures are determined on the basis of the one- and two-dimensional models of the coke oven. [ABSTRACT FROM AUTHOR]

In this study, the energy view of an oven of a 70-oven coke battery in an iron and steel plant was evaluated based on operating parameters and recommendations for improving efficiency were made. A mass and energy balance per coking period (p) was created for a coke oven. It was found that during each coking period, 51.2% of the energy input was used as coking heat. It is predicted that approximately 6.91% of the input energy can be recovered from flue gas into the combustion air. By recovering the heat from the flue gas into the combustion air, the efficiency of the coke oven can be increased to 58.11%. The heat of the coke oven gas can be recovered and converted into usable form, which accounts for 6.53% of the total energy input. With the dry quenching process, it is possible to recover around 24% of the energy used from coke. Improved oven insulation, heat recovery from coke and flue gases, and the dry quenching process can recover energy worth more than 25.19 GJ/p. The energy efficiency of the furnace was predicted to rise to 82.11% with coke dry quenching and to more than 88.64% with coke gas heat recovery and insulation upgrades. The potential economic savings are $2578, equivalent to a reduction in CO₂ emissions of 2.45 tons per coking period. The financial equivalent of emissions reductions from carbon trading could be $233 per coking period. Through the processes of dry coke quenching, coke gas (CG), and flue gas heat recovery and thermal insulation improvements of the coke battery, the total amount of recoverable energy can exceed 617,294 GJ/year.

The influence of the thermal conductivity of silica bricks on the coking process as an important component of the coking and combustion chambers is still unclear. A multi-chamber coupling mathematical model of a coke oven is developed to investigate the energy-saving effect of using high thermal conductivity silica bricks in the coke oven. The model is validated using measured temperatures of coal and flue gas bed in a coke oven in operation for a coking cycle. Temperature variation and its distribution in the coking chamber, combustion chamber, and heating wall are simulated for the coke oven using silica bricks with different thermal conductivities. The obtained results showed that compared with the use of common silica bricks, coking time of one cycle can be reduced by ∼60 min, with a decreased consumption of fuel gas by ∼4.9%. The enhancement of heat transfer from the flue gas to the heating wall and the heating wall to coal using silicon bricks with high thermal conductivity can effectively shorten not only the temperature difference between the two sides of the heating wall but also reduce the mean flue temperature of the flue gas by ∼24.5 °C.

The aim of this paper is to quantify the amounts of volatile organic compounds (VOCs) emitted from a coke oven in a steel plant in Taiwan and estimate the emission factors of VOCs using an innovative sampling technique. The identification of VOCs emissions was referred to in the AP-42 report issued by the USEPA and the field measurement data of fugitive emissions. VOCs were sampled using a self-designed closed sampling system. A total of six emission points, including quenching emissions, charge lid emissions, combustion stack emissions, door emissions, charging emissions, and coke pushing emissions, were identified in the coking process after comparing with the report of AP-42, and the emission factor of VOCs was 0.030 kg/ton-coke. It showed that the emission factor of VOCs via field measurement was approximately 56% of that reported by Taiwan EPA. Therefore, VOCs emissions estimated by the Taiwan EPA would be highly overestimated than those from the coke oven in the site. [ABSTRACT FROM AUTHOR]

Industrial emissions are a serious environmental problem worldwide due to particulates and toxic gases. This study aims to generate an activity-specific emission inventory and estimate emissions dispersion extent in the vicinity of the coastal industrial village by simulating the existing coke oven and pellet plant emissions using the steady-state plume model. Continuous air quality monitoring results were compared with the predicted consequential emissions for the year 2018-19. The maximum ground-level concentrations of particulate and gases within the modeling simulation domain were observed at 9005 m away from the center. They were predicted to be 116.39 µg.m-3, 79.14 µg.m-3, 52.97 µg.m-3, and 211.86 µg.m-3. Data analysis showed that air mass transport from the project to the receptor sites resulted in ambient air concentrations higher than those observed in the other sites. Overall predicted results obtained from AERMOD Cloud simulations were shown to have less bias than the measured results. They recommended considering it as appropriate for the prediction of annual average concentration. [ABSTRACT FROM AUTHOR]

On the basis of the thermal balance in the heating wall and coking chamber, a general mathematical model is obtained for the temperature distribution at the walls of the heating channels. The model indicates that heat liberation due to combustion of the heating gas predominates over ~37% of the heating-channel height from the hearth (the first interval). In the second (upper) interval, heat transfer of the nonreacting gas–air mixture with the combustion products and the coal charge (through the coke-oven wall) is dominant. The temperature curve described by these equations determines the configuration of the temperature field in the heating channel. To even out this curve by decreasing the maximum temperature in the first interval and increasing the low temperature in the second, inert gas or steam may be supplied to the lower part of the heating channel, but diverted away from the section above 37% of the channel height. In the present work, the expediency of assessing the reproducibility of temperature measurements in the walls of industrial coke ovens by the telemetric method is established. To estimate the influence of the reagent mixing on the combustion rate and hence on the temperature distribution over the height of the heating channel, investigation of the composition of the gas–air mixture at various distances from the hearth is proposed. [ABSTRACT FROM AUTHOR]

It is of great interest to determine the uniformity of heating in coke ovens. Current measurement methods are described. The deficiencies preventing their use for the regulation of coke heating are discussed. A new method is proposed on the basis of telemetric equipment determining the temperature over the height of the heating channels. This method is simple to use: within a single shift, the temperature distribution over the height of all the heating channels in several walls may be assessed. The pace of the measurements is increased because the equipment does not need special cooling before repeated use. In industrial conditions, this method is used to measure the wall temperature of the heating channels in coke ovens. These experimental results are compared with the theoretical equations proposed in the previous part of this research. The results confirm the proposed mechanism of the process, which is fully consistent with the industrial temperature distribution over the height of the heating channel (except for the hearth temperature). In addition, the results emphasize that the general model must take correct account of the composition of the heating medium (a gas–air mixture)—primarily its air excess. [ABSTRACT FROM AUTHOR]

In view of the formation process of nitrogen oxide in the vertical flue of coke oven, a three-dimensional steady-state mathematical model of heat transfer, mass transfer and combustion process was established, and the numerical method was used to solve the problem. The effects of exhaust gas circulation ratio, preheating temperature of blast furnace gas and air and the blending ratio of coke oven gas on the NOX generation characteristics were studied. The above parameters were further optimized to the model that was applied to 6-m coke oven of Ansteel. The results show that the numerical simulation results are in good agreement with theoretical combustion temperature and the NOX emission data of 6-m coke oven in Ansteel. Through the optimization scheme, the preheating temperature of gas and air is the most significant one, followed by ratio of exhaust gas circulation and coke oven gas blending. The optimized model is applied to 6 m coke oven of Ansteel, and the average content of NOX in the exhaust gas is reduced from 364 to 228 mg/m3, with good effect. [ABSTRACT FROM AUTHOR]

The aim of this paper is to quantify the amounts of volatile organic compounds (VOCs) emitted from a coke oven in a steel plant in Taiwan and estimate the emission factors of VOCs using an innovative sampling technique. The identification of VOCs emissions was referred to in the AP-42 report issued by the USEPA and the field measurement data of fugitive emissions. VOCs were sampled using a self-designed closed sampling system. A total of six emission points, including quenching emissions, charge lid emissions, combustion stack emissions, door emissions, charging emissions, and coke pushing emissions, were identified in the coking process after comparing with the report of AP-42, and the emission factor of VOCs was 0.030 kg/ton-coke. It showed that the emission factor of VOCs via field measurement was approximately 56% of that reported by Taiwan EPA. Therefore, VOCs emissions estimated by the Taiwan EPA would be highly overestimated than those from the coke oven in the site.

Uniform coke heating within coke ovens is of great importance. The temperature difference along the axis of the coke cake increases with increase in oven length and height and may reach 300°C or more, depending on the coke-battery design and technological factors. The introduction of control devices is a well-established approach to more uniform heating of the coke cake, in combination with methods of temperature calculation at the wall of the heating channel. However, this approach depends on information determined experimentally. That introduces more error in determining the temperature distribution over the channel height. Accordingly, attempts are made in the present work to describe the combustion of the heating gas on the basis of the minimum number of simply and reliably measurable factors. A three-parameter equation is obtained. Its structure is universal in terms of the set of factors. Adopting that equation as a model, the action of various factors on the temperature distribution over the height of the heating channel may be studied. [ABSTRACT FROM AUTHOR]

Technological factors affecting the quality of coal tar are considered. Recommendations are made to improve tar quality. The influence of technological factors on the tar's content of quinoline-insoluble components is analyzed. [ABSTRACT FROM AUTHOR]

Cokemaking is an important unit operation in an integrated steel plant as coke quality has a strong influence on blast furnace performance. A two-dimensional (2D) model coupling physico-chemical phenomena inside combustion and coking chambers of a coke oven has been presented. It was implemented using the computational fluid dynamics software Ansys Fluent and was solved by a serial decoupling approach to improve convergence and to reduce computational time. The model predictions for gas temperatures inside the combustion chamber and the effect of coal moisture content on evolution of coke bed temperatures are in reasonable agreement with published experimental data. The computational time required for the 2D model is six times lower than that for a corresponding three-dimensional model. This model is useful for model-based optimization of cokemaking and for designing coke ovens with reduced computational burden. [ABSTRACT FROM AUTHOR]

The effective control of coke oven flue temperature is discussed in this paper. A predictive control method based on orthogonal neural network for coke oven flue temperature is proposed. Firstly, the orthogonal neural network has good fitting ability, global optimisation ability, generalisation ability and fast training speed, which is suitable for the modelling of coke oven heating process. Then, the nonlinear system of coke oven is transformed into a time-varying linear model by linearisation method, and generalised predictive control algorithm can be introduced. In order to improve the performance of the generalised predictive control algorithm, this paper adopts the stair-like generalised predictive control algorithm. The algorithm cannot only avoid the on-line solution of the inverse matrix, greatly reducing the amount of calculation, but also improve the robustness and anti-interference ability. At the same time, some correction strategies are adopted to reduce the computational complexity of the model. Finally, according to the actual working conditions, three case studies under normal working condition, the change of setting temperature and under random disturbance are performed out. Compared with the comparative control method, the simulation results show that the proposed control method is effective. [ABSTRACT FROM AUTHOR]

This article presents the results of studies that determine the changes in the phase composition and structure of dinas refractories under the operating conditions of coking coal. Their changes are attributed to differences in the temperatures and rates of dinas cooling/heating during the cyclic loading/unloading of coked materials, the conditions of refractory contact with an operating environment, and the degree and nature of mechanical loads in different masonry zones of coke ovens. The regularities and features of macro- and microstructural organizations in combination with the formation phase composition of dinas refractory in various zones of coke oven masonry have been noted. No critical changes in the integrity of dinas product materials relative to microstructure and phase composition have been revealed. Data have confirmed the further operational suitability of such products under testing conditions on the stand unit of pilot production. [ABSTRACT FROM AUTHOR]

The influence of the composition and preparation of the coal batch on the expansion pressure is a neglected aspect of coke production. A research coke oven is proposed for establishing the optimal composition of tamped and loose batch and determining the expansion pressure. This coke oven yields values of the expansion pressure for both loose batch and tamped batch. [ABSTRACT FROM AUTHOR]

In the combustion process of a coke oven, it is crucial to evaluate the operating state to ensure control performance for the stabilization of the coke oven temperature. This paper presents an assessment method for a coke oven operating state based on the analysis of the mechanism. A coke oven, which is an integrator, is categorized into serial subsystems, which include two coking chambers and one combustion chamber. First, the raw gas temperature of every coking chamber is extracted online and is combined with the qualitative trend analysis that yields the feature point of the raw gas temperature. Subsequently, fuzzy method is presented to describe the uncertainty and evaluate the heat level of each subsystem. Finally, a comprehensive assessment of the operating state of the coke oven is performed by combining the weighted contribution of all subsystems, which is expressed by information entropy. Simulations and experiments demonstrate the validity of the method. [ABSTRACT FROM AUTHOR]

The studies conducted on one of the coke batteries showed that as the pressure of the charge spreads, the amount of throughput of raw coke gas in the heating system of the oven increases, which indirectly confirms the relationship between the pressure of the load and the deflection of the heating wall. [ABSTRACT FROM AUTHOR]

The device for removing and installing coke-oven doors is considered. Improving its hydraulic equipment ensures effective coke-oven operation in coke discharge and decreases the environmental impact. The performance of its hydraulic system and pump unit is assessed. New hydraulic-drive systems are proposed for the pump unit and individual mechanisms in the device. [ABSTRACT FROM AUTHOR]

Real-time performance assessment is one of the main methods to guarantee the steady operation of production during the combustion process of a coke oven. In this study, a real-time assessment method is proposed for this combustion process based on the analytic hierarchy process (AHP) and intuitionistic multiplicative preference relation. Relevant scholars, senior engineers, and elite workers participated in this project to build the AHP model with three aspects (i.e. safety, stability, and economic benefit) and perform pairwise comparisons of criteria and sub-criteria through group decisions. To support real-time, the pairwise comparisons of alternatives were realized by an automatedmethod using measurement values. This comprehensive assessment method demonstrates ability to provide real-time performance evaluation for the combustion process. An experiment was conducted to evaluate the effectiveness and viability of the proposed method. [ABSTRACT FROM AUTHOR]

The article presents a study on the measures adopted in an existing coke plant in order to reduce levels of benzo(a)pyrene dispersed in the environment surrounding the facility. The area has been affected by significant levels of pollution from polycyclic aromatic compounds due to the fugitive emissions from the coke oven, which did not comply with the most recent regulation. A monitoring programme was therefore launched in order to support a framework for intervention. Several problems with the battery made it necessary to implement a novel system to collect and abate fugitive emissions during the operations. The monitoring of the fugitive emissions from the coke oven, before, during and after the implementation of the system, has shown a drop of the visible emission time at charging below 30 s, matched by the return of pollution from benzo(a)pyrene in the area below the legal limits (1 ng/Nm3). When compared to the installation costs, these results suggest that the proposed solution can be replicated in other existing by-product coke plants. [ABSTRACT FROM AUTHOR]

The present study explored the feasibility of using graphite electrodes for the electrochemical oxidation of cyanide, thiocyanate, phenol and aniline with hydrogen peroxide. The dosing effects of hydrogen peroxide and current density were examined in the pre-treated coke oven wastewater. It was found that 0.025 M hydrogen peroxide and 13.63 mA/cm2 of current density were more favorable for the removal of 100%, 90%, 71% and 40% cyanide, thiocyanate, phenol and aniline respectively. The increased removal of phenol in the coke oven wastewater was attributed to the pre-treatment of wastewater. Initially, 28% phenol was converted to phenolate ion by air stripping process, which increased the removal rate of phenol by the electro-oxidation process as the removal of phenolate is quite easy compared to phenol. The advanced oxidation process degrades the more toxic cyanide into less toxic intermediate cyanate ions (CNO-), which further cut down into nontoxic end products such as N2, HCO3 and CO2. The experimental results show that the primary mechanisms in the oxidation of cyanide and phenol are mediated electro-oxidation by hydroxyl radicals and hypochlorite ions. The operating cost under the optimized conditions for the removal of 100% cyanide and 71% phenol was estimated to be 616.95 INR/m³. [ABSTRACT FROM AUTHOR]

The chemical composition of atmospheric particulate (PM10) in the Friuli Venezia Giulia (FVG) region (NE Italy) has been characterized for the first time with the help of exploratory data analysis (EDA) techniques (uni-, bi-, and multivariated, i.e., principal components analysis), molecular and elemental diagnostic ratios, and seasonal trends. Despite that the available analytical data was limited to the parameters routinely analyzed on PM10 by ARPA FVG (11 elements and 16 PAH congeners), the large number of samples and of measured chemical parameters, together with the applied techniques of data analysis, allowed us to extract useful latent information from the dataset, resulting in a greater knowledge of both regional and local features. Specifically, we succeeded in matching data patterns to the known pollution sources of some sampling stations, both industrial (two secondary fusion steelworks and one coke oven) and urban (traffic and domestic heating), and in defining the mainly urban or mainly industrial feature of some questionable sampling stations. This is of paramount importance to check for possible industrial inputs in urban stations, allowing policymakers to implement the most appropriate response. [ABSTRACT FROM AUTHOR]