Coke Plant Research Articles

Analysis of metal(loid) pollution and possibilities of electrokinetic phytoremediation of abandoned coking plant soil

In this study, the spatial distribution of eight metal(loid)s in the soil of an abandoned coking plant in Shanxi, China, was mapped, and the ecological and health risks of the coking plant were assessed. The results showed that the soil Pb content of the coking plant greatly exceeded the background value, and Hg, Cd and Pb were the most polluting factors contributing to the considerable ecological risk level. There was also a non-carcinogenic risk in the coking plant, in which oral intake was the main pathway, and As, Pb and Cr were the main contributors. As the main contributor to ecological risk and non-carcinogenic risks and the most polluting metal, Pb was selected as a priority pollutant in the coking plant. Based on the detected concentration of Pb in the coking plant soil and in consideration of phytostabilization, ryegrass, alfalfa and castor were employed to study the phytoremediation and electrokinetic-enhanced phytoremediation effect in a series of Pb-contaminated soils (0, 100, 200, 300 and 400 mg/kg). It was found that the underground parts of alfalfa and castor had stronger Pb enrichment ability, and their biomass and Pb absorption capacity were improved in electrokinetic remediation methods. The Pb absorption capacities of the tested plants and the promotion efficiencies of electrokinetic-enhanced phytoremediation followed the order castor > ryegrass > alfalfa. Under the optimal electrical conditions, the remediation efficiency of castor was increased by 106 %, 83 %, 51 % and 48 % in 100, 200, 300, and 400 mg/kg Pb-contaminated soils, respectively.

Saving of Coke Oven Gas by Reduction of Smoke Pushing of Recovery Type Coke Plant

For stable oven operation and prolongation of the coke oven life, it is important to remove excess carbon formation on the coke oven wall. It is considered that the carbon formation rate is influenced by the gas components generated during carbonation, the gas velocity and oven wall temperature are not uniformly maintained, as a result of smoke pushing. The smoke pushing is not favourable for the good health of the coke oven battery. In this paper, the smoke pushing can be rectified by proper maintenance of the gas path. Energy consumption and economic growth are interwoven, and rising energy levels always represent rising energy consumption. Coke is a reducing agent and a load-handling tool in blast furnaces. By this rectification, the coke oven gas flow was reduced from 17600Nm3/hrs to 17300Nm3/hrs without any extra manpower cost. The experimental set-up implementation of this modern proposal in a coke plant will make coke more extra energy efficient with no other extra costs.

Use of tyrosinase-inorganic salt hybrid nanoflowers and tyrosinase-MOF hybrid composites for elimination of phenolic pollutants from industrial wastewaters

Removal of phenolic pollutants from industrial wastewaters is always an important practical problem. Use of enzymes for dephenolization provides a green solution. In this work, enzymatic methods were developed by employing mushroom tyrosinase immobilized as enzyme-Cu3(PO4)2 hybrid nanoflowers and enzyme-metal organic framework (i.e., ZIF-8 and HKUST-1) hybrid composites, which were shown to be superior to processes mediated by tyrosinase immobilized on other supports in both dephenolization efficiency and reusability. Comparatively, tyrosinase@Cu3(PO4)2 and tyrosinase@HKUST-1 were better than tyrosinase@ZIF-8 in both specific activity and dephenolization efficiency. Typical phenolic pollutants, including 3 monophenols (phenol, p-cresol, p-chlorophenol) and 3 bisphenols (BPA, BPB, BPF), can be completely eliminated within 0.5–4 h. The dephenolization order was discussed based on the enzyme's substrate specificity. The operability and reusability of these hybrid biocomposites were highly improved by entrapping into alginate gels or by incorporating with modified magnetic Fe3O4 nanoparticles. Particularly, the magnetic biocatalyst was prepared via a facile one-pot/one-step de novo synthetic strategy, optimized by using response surface methodology (RSM). The as-prepared magnetic tyrosinase@mHKUST-1 retained a high dephenolization efficiency of 81% after 10 cycles and was effective for continuous dephenolization for at least 24 h. These hybrid biocomposites were also successfully applied to treatment of real industrial wastewater from a coke plant.

Enhanced Bioremediation of Aged Polycyclic Aromatic Hydrocarbons in Soil Using Immobilized Microbial Consortia Combined with Strengthening Remediation Strategies.

Microbial biodegradation is considered as one of the most effective strategies for the remediation of soil contaminated with polycyclic aromatic hydrocarbons (PAHs). To improve the degradation efficiency of PAHs, PAH-degrading consortia combined with strengthening remediation strategies was used in this study. The PAH biodegrading performance of seven bacterial consortia constructed by different ratios of Mycobacterium gilvum MI, Mycobacterium sp. ZL7 and Rhodococcus rhodochrous Q3 was evaluated in an aqueous system containing phenanthrene, pyrene, benzo[a]pyrene and benzo[b]fluoranthene. Bacterial consortium H6 (Q3:ZL7:MI = 1:2:2) performed a high degrading efficiency of 59% in 8 days. The H6 was subsequently screened to explore its potential ability and performance to degrade aged PAHs in soils from a coking plant and the effects of strengthening strategies on the aged PAH degradation, including the addition of glucose or sodium dodecyl benzene sulfonate (SDBS) individually or as a mixture along immobilization of the inoculant on biochar. The highest degradation efficiencies, which were 15% and 60% for low-molecular-weight (LMW) PAHs and high-molecular-weight (HMW) PAHs, respectively, were observed in the treatment using immobilized microbial consortium H6 combined with the addition of glucose and SDBS after 24 days incubation. This study provides new insights and guidance for future remediation of aged PAH contaminated soils.

Isolation of Diaphorobacter sp. LW2 capable of degrading Phenanthrene and its migration mediated by Pythium ultimum

ABSTRACT Phenanthrene, one of the polycyclic aromatic hydrocarbons, is stubborn and persistent and exists widely in petroleum-contaminated soil. Filamentous fungi are good assistants to bacterial transport, by hyphae passing through soil pores and reaching further positions. An isolated bacterial strain, from the contaminated soil of the coking plant, was identified as Diaphorobacter and named LW2, which could use phenanthrene as the only carbon source and energy for its growth. LW2 could degrade phenanthrene in a wide range of pH, temperature and initial concentration. When pH was 6 and 10, the removal rate of phenanthrene was 38.59% and 76.44%, respectively, and the removal rate of phenanthrene was 68.25% at 15 ℃. And LW2 could degrade 86.64% phenanthrene when the initial concentration was 100 mg L−1. The detection of DI-N-octyl phthalate, phthalic acid and p-hydroxybenzoic acid revealed that the strain LW2 metabolised phenanthrene through the phthalic acid pathway. Meanwhile, swimming and swarming test results suggested that LW2 was motile. The auxiliary effect of Pythium ultimum on LW2 migration was assessed. In the presence of Pythium ultimum, LW2 could migrate within the range of centimters by its mycelium, which was also observed by fluorescence microscopy. Meanwhile, the degradation ability of LW2 after the migration was also explored. The results proved that the migration process had no significant effect on its degradation ability, and LW2 still showed good phenanthrene metabolism ability. This study provides more possibilities for the bioremediation of phenanthrene-contaminated soil by screening the degradation bacteria and testing the effect of fungi on its migration.

Рішення щодо реконструкції систем аспірації коксо-сортувалень.

The paper summarizes the information on the operation of existing coke sorting aspiration systems at coke plants. It is shown that, according to the data of instrumental measurements carried out at operating coke plants, the actual emissions of dispersed particles from the exhaust pipes of coke sorting plants require the development of measures to reduce the emissions of suspended solids into the atmosphere. At the same time, almost all coke plants at coke sorting plants with wet coke quenching have aspiration systems with one-stage cleaning in wet dust collectors, which is justified by the relatively low initial dust content of the aspiration air. At the same time, at coke sorting plants, after dry coke quenching, the dust content of the aspiration air is much higher and reaches 10 g/m3. Given the high dust content, aspiration systems at such enterprises provide for a two-stage purification - in dry cyclones of the first stage of purification and in wet dust collectors of the second stage. Conclusions are drawn on the efficiency of coke dust collection processes in various dust collectors, and a justification for the use of dry methods of aspiration air purification in coke sorting systems is provided. A new concept of an aspiration system with a dry dust collection method is presented and recommendations for the modernization of existing systems are developed. The basic technical requirements for the use of dry cleaning of aspiration air of coke sorting plants in bag and pocket filters (for sieving and transporting wet quenching coke) are presented. Recommendations for reducing the possible relative humidity of aspiration air in coke sorting systems (during sieving and transporting wet quenching coke) have been developed. The design features of aspiration units with a dry method of aspiration air purification for wet coke quenching paths are presented. Keywords: coke production, coke dispersal facilities, coke sorting plant, aspiration system, dust removal unit, pollutant emissions. Corresponding author: T.F. Trembach, e-mail: ozos@giprokoks.com

Wastewater treatment in coke plants in the aspect of a circular economy

Wastewater treatment in coke plants in the aspect of a circular economy

Effect of Club cell secretory proteins on the association of tobacco smoke and PAH co-exposure with lung function decline: A longitudinal observation of Chinese coke oven workers.

Exposure to polycyclic aromatic hydrocarbons (PAH) and tobacco smoke is associated with epithelial damage and reduced lung function. Club cell secretory protein (CC16) is a known biomarker for lung epithelial cells. However, the potential relationships between PAH and tobacco smoke exposure, CC16 levels, and reduced lung function remain unclear. This longitudinal study aimed to explore the potential role of CC16 in the association of tobacco smoke and PAH co-exposure with lung function. We enrolled 313 workers from a coking plant in China in 2014 and followed them up in 2019. The concentrations of PAH and nicotine metabolites in urine were determined using high-performance liquid chromatography (HPLC) with a fluorescence detector and HPLC-tandem mass spectrometry, respectively. The plasma CC16 concentration was determined using an enzyme-linked immunosorbent assay. An analysis of the generalized estimating equation showed that each 1-unit increase in log-transformation of the last tertile of trans-3'-hydroxycotinine (3HC) was associated with a 3.30ng/ml decrease in CC16. Restricted cubic spline analysis revealed a significant nonlinear dose-effect association between cotinine (COT) and CC16 (Pnonlinear=0.018). In the low- CC16 subgroup, we found a significant association between total nicotine metabolites and forced vital capacity (FVC%) (β: 1.45, 95% CI: 2.87, -0.03), and the associations of nicotine (NIC), COT, and 3HC with FVC% were all of marginal significance. High levels of total hydroxyl polycyclic aromatic hydrocarbons (ΣOH-PAH) and NIC in the urine had an interactive effect on the decline of CC16 (P<0.05). Cross-lagged panel analysis indicated that the decrease in CC16 preceded the decrease in FVC%. CC16 mediated the association between elevated nicotine metabolites and decreased FVC% in the low- CC16 subgroup. CC16 plays an essential role in the association of PAH and tobacco smoke exposure with reduced lung function. Coke oven workers with low plasma CC16 levels are more likely to experience decreased lung function after tobacco smoke exposure.

Оцінка утворення осаду, сумісності та ставлення до розчинників вбирних олив у аспекті експлуатаційних властивостей.

Currently, coke plants are experiencing a shortage of absorbent oil for capturing benzene hydrocarbons. This forces the companies to limit the capacity of regeneration units, which leads to an increase in oil density. At the same time, the content of substances insoluble in toluene increases in the oil, which creates a complex multicomponent dispersed system. In the case of replenishment of the circulation cycle with light fresh foreign-made oils, which are artificial mixtures of fractions obtained during the distillation of coal tar, there is a risk of precipitation as a result of flocculation of dispersed particles. There is a need to assess the probability of precipitation of the absorbing oil using additional methods. In this paper, evidence of the colloidal structure of the absorbent oil is reviewed, showing its tendency to flocculate when aliphatic solvents and other reagents are added. The ability to form a heterogeneous blot of a mixture of oils and their solvents was evaluated according to the method available in the literature. This method was applied to mixtures of fresh foreignmade absorbent oil and polymers from the benzene department. The results showed the absence of heterogeneous blot formation using this method. An assessment of the spreading area of equivalent drops by volume showed that the deterioration of the properties of fresh oil occurs already at the introduction of 8% of polymers of the benzene department. A mixture of crude benzene components with working absorbent oil forms a heterogeneous spot when 60 % o-xylene is added. This makes it possible to calculate the flocculation coefficient and quantify the effectiveness of measures to improve the quality of recycled oil. The data obtained are consistent with the list of solvents available in the literature that cause and do not cause flocculation of dispersed particles in tar and its fractions. Keywords: washing oil, precipitation, dispersed substances, solvents, flocculation, coagulation. Corresponding author: Artem L. Bannikov, e-mail: artiksmartik@gmail.com

Удосконалення приладу для визначення показника питомого електричного опору коксу .

The two-probe method is the most acceptable for an objective assessment of the resistivity of coke, as it allows obtaining a representative sample with minimal time and labor. However, the standards developed on the basis of this method are characterized by large values of random errors, difficulties in taking them into account and eliminating the influence of transient electrical resistances between the electrodes and the coke powder sample due to the inability to ensure the stability of the bulk mass of its column at constant pressure. Elimination of the influence of transient resistances on the measurement result was ensured by improving the pressing unit and the design of the two-probe matrix, as well as replacing the potentiometer, milliammeter, voltmeter, rheostat and battery with a modern measuring unit. DSTU 8831:2019 was developed and put into effect, which makes it possible to obtain the most reliable results of the coke resistivity. To determine the value of the absolute total error, a series of measurements were made on industrial coke from two leading coke plants in Ukraine and laboratory coke produced in the experimental coke oven of the SE "UKHIN" with electric heating. The obtained results show that the values of the resistivity determined from the same sample but at different size classes differ significantly. The requirement to limit the content of the prepared analytical sample to a class of less than 0.05 mm is substantiated. In several cases, the resistivity of samples with the same volatile yield differs significantly, which confirms the thesis that the resistivity of coke is related to its readiness. The confidence interval of the measured resistivity values is significantly lower than its limit value provided by the standard. This makes it possible to use the improved device in studies of the resistivity of coke. Keywords: hard coal coke, resistivity, determination method, measurement error, coke readiness. Corresponding author I.V. Shulga, e-mail: ko@ukhin.org.ua

Optimised coker unit design integrating heat exchange network and exergy analysis

Two approaches are applied for reducing energy consumption in an actual delayed coking plant converting vacuum residue into lighter and higher value hydrocarbon products. Pinch analysis is applied with a view to optimising the pinch temperature approach and structure of the existing seven heat exchangers' network. This resulted in about 27% reduction of the total annual cost corresponding to an annual saving of about US$1.9 million. Exergy analysis is also conducted on other main process plant equipment which revealed a possible annual saving of US$0.75 million through generation of medium pressure steam in the blowdown tower.

Coke price prediction approach based on dense GRU and opposition-based learning salp swarm algorithm

Coke price prediction is critical for smart coking plants to make sensible production plan. The prediction of coke price fluctuations is a time-series problem, and gated recurrent unit (GRU) performs well on dealing with it. Meanwhile, densely connected GRU can improve the information flow of time-series data, but its key parameters are sensitive. Therefore, a novel coke price prediction method, named DGOLSCPP, is proposed using dense GRU (DGRU) and opposition-based learning salp swarm algorithm (OLSSA). Firstly, a model with two layers stacked DGRU is constructed for capturing deeper features. Secondly, OLSSA is proposed by introducing opposition-based learning, following and stochastic walk operation for enhancing searching ability. Finally, OLSSA is employed to adjust the key parameters of DGRU for winning the accurate predictive results. Experimental results on two real-world coke price datasets from a certain smart coking plant suggest DGOLSCPP outperforms other competitive methods.

Утилізація коксового дрібняку і шламу брикетуванням із зв’язуючою речовиною.

The article is devoted to the issues of rational use of secondary carbon-containing solid products of coke production: coke sludge, dust from aspiration units and coke fines. These issues are particularly relevant in the context of a widespread deterioration in the raw material base and, in particular, a shortage of coking coal, which leads to a deterioration in both coke yield and quality. This state of the coal raw material base is expected to continue for a long time. Therefore, for coke plants, the problem of waste-free, rational utilisation of small products of blast furnace coke production is of particular relevance. The article presents the results of studies of coke fines and argues the main directions of their qualified use. The technologies and schemes of design solutions for the qualified utilisation of solid fines of coke products and their transformation into highly liquid marketable products are considered. A review of modern methods of "cold" briquetting using water-soluble binders such as lignosulfonate, molasses, starch, liquid glass, ureaformaldehyde resin, etc. was carried out. The possibility of replacing up to 15 % of the main binding materials with coke production products: coal tar, polymers of the benzene department, and tar from a biochemical plant was established. It is shown that the addition of acidic resin worsens the strength of coke oven briquettes and cannot be recommended for use. The time and temperature of heat treatment of briquettes were determined experimentally: 15 min and 300 °C, respectively. A basic technological scheme for the production of 5-10 mm class from coke fines and coke briquettes for ferroalloy and blast furnaces is proposed. A technological scheme for the production of coke briquettes and a new apparatus for their heat treatment are proposed. The basic technological requirements for the quality of carbon reducing agents are formulated. Keywords: coke fines, coke sludge, charge, binder, coke briquette, heat treatment. Corresponding author D.V. Miroshnichenko, e-mail: dvmir79@gmail.com

Експериментальне дослідження залежності питомого електричного опору коксу від кінцевої температури

The dependence of the resistivity on the final coking temperature was studied on cokes obtained from the charge of one of the leading coke plants in Ukraine in a laboratory furnace designed by SE "UKHIN" with electric heating. The increase in the final temperature naturally contributes to an increase in coke readiness and the degree of orderliness of its structure. This is manifested in an increase in coke strength (increased resistance to grinding forces and post-reaction strength, reduced abrasion), increased coke density and porosity, reduced reactivity, volatile substance yield and specific electrical resistance. The increase in the final temperature contributes to the deepening of thermochemical polycondensation processes of coke formation, which causes the loss of additional low-molecular weight products, resulting in a slight decrease in the yield of gross coke and its sulphur content with a simultaneous increase in ash content. The previously theoretically substantiated hypothesis about the exponential nature of the dependence of the decrease in the specific electric coke with an increase in the final coking temperature was experimentally confirmed. Processing of the obtained experimental data made it possible to determine the numerical characteristics of this dependence, which makes it possible to determine the rational level of final coking temperatures when producing coke for various applications. In particular, to produce coke with a resistivity not exceeding 0.1 ohm∙cm, the final coking temperature should not be less than 957 oC. This is in line with the practice of coke production. To produce blast furnace coke with a lower resistivity, a higher temperature is required, while to produce ferroalloy coke with a higher resistivity, on the contrary, a lower temperature level is sufficient. Keywords: coal coke, electrical resistivity, final coking temperature, coke readiness, blast furnace coke, ferroalloy coke. Corresponding author I.V. Shulga, e-mail: ko@ukhin.org.ua

Technogenic magnetic particles in topsoil: Characteristic features for different emission sources

Variations in mineralogical composition, grain size internal structure and stoichiometry of technogenic magnetic particles (TMPs) deposited in topsoil may provide crucial information necessary to trace main pollution sources and recognize various technological processes. The aim of the study was to characterize, by means of magnetic parameters and Mössbauer spectra, the TMPs from non-ferrous metallurgy, cement, coke, glass production as well as long range transport (LRT) and compare the obtained data with previous results focused on iron mining and metallurgy. This research shows that only certain pollution sources (e.g. mainly iron mining, iron metallurgy, LRT and partly glass production) can be successfully distinguished by the applied parameters. The main features characteristic for TMPs produced by Fe-mining are: high values of concentration-dependent magnetic parameters, low values of coercivity, significant contribution from coarse MD (multi-domain) grains and a relatively high stoichiometry of magnetite. The most discriminative feature for TMPs generated by the glass industry is the abundance of goethite in the topsoil samples, which is confirmed by magnetic and Mössbauer techniques. The TMPs released by the Ni-Cu smelter and the Pb-Zn waste exhibit significant differences in the Mössbauer parameters, indicating different stoichiometry of magnetite for each group. Such variations are due to replacement of Fe by other elements at tetrahedral sites in the case of TMPs released from the Ni-Cu smelter. TMPs characteristic for the LRT emissions contain higher amount of finer fraction of low-stoichiometry magnetite (mostly single-domain SD particles) than those originating from other sources. The TMPs accumulated in the topsoils around the coking plants cannot be clearly discriminated by the applied methodology due to strong influence of the local pollution sources. Magnetic studies of the TMPs generated by cement production are complicated, since their properties mainly depend on individual technology (e.g. additives) used by the local cement plants.

Association of Polycyclic Aromatic Hydrocarbons exposure with sleep quality among coking plant workers

Objective: To explore the relationship between polycyclic aromatic hydrocarbons (PAHs) exposure and sleep quality in workers from a coking plant. Methods: From April to June 2019. Selected 632 employed workers in the coking plant of a large state-owned enterprise in Shanxi Province as the exposed group, and 477 employed workers in the water-pump plant belonged to the same enterprise as the control group. We used self-designed questionnaires to collect the basic information of subjects. We measured the concentrations of 12 PAHs in the peripheral blood of workers using gas chromatography-mass spectrometry (GC-MS) ; Pittsburgh Sleep Quality Index (PSQI) was used to evaluate the sleep quality of workers; The relationship between plasma PAHs concentration and sleep quality was analyzed using multiple linear regression model, restricted cubic spline (RCS) regression and logistic regression. Results: The concentration of 12 polycyclic aromatic hydrocarbons in the peripheral blood of the exposure group was (2.36±1.46) ng/ml, which was significantly higher than that of the control group (2.19±1.21) ng/ml. The detection rate of sleep disorder in the exposure group (18.0%) was higher than that in the control group (16.8%) , which was manifested by the significantly increased scores in subjective sleep quality, sleep latency, sleep disorders, daytime dysfunction, and PSQI. Multiple linear regression analysis showed that the PSQI score of workers in the high exposure group decreased by 0.80 (95% CI: -1.40~-0.19) points compared with the low exposure group, with a statistically significant difference (P<0.05) . RCS analysis showed a non-linear dose-response relationship of PSQI score with PAHs cumulative exposure (plasma PAHs concentration multiplied by length of service) . The results of logistic regression showed that compared with the low level group, the risk of somnipathy in the middle level group of PAHs cumulative exposure decreased by 44%, among which the risk of sleep disorder in the drinkers decreased by 40%, while the risk of somnipathy in the high level group increased by 96% compared with the low level group. Stratified analysis of alcohol drinking habit showed non-significant difference in PSQI score with low, medium, and high levels of PAHs cumulative exposure in non-drinkers (P>0.05) , and that the PSQI score was significantly increased in alcohol drinkers with high level of PAHs cumulative exposure compared to those with low and medium levels of PAHs cumulative exposure. Conclusion: The workers in the coking plant had high levels of PAHs in plasma and poor sleep quality, Higher level of PAHs cumulative exposure (>1396.56ng/ml) is a risk factor of poor sleep quality.

Analysis of the Impact of the Coke Manufacturing Process on the Service Life of Siliceous Refractory

In the manufacture of steel and foundry coke, there are a series of circumstances inherent to the process which can affect the life of the refractory material with which the ovens of the batteries are built. This article will deal with the impact of aspects such as sticky ovens and hard pushes on the refractory. For this purpose, data will be obtained from a Didier design coke plant built in the 1970s. In particular, the data comes from two batteries or groups of ovens over a period of two years. Of the types of refractories of which coke batteries are composed, we will only deal with silica material. This is the type of refractory with which the combustion and coking chambers of the ovens are almost exclusively built. Its characteristics and behavior make silica a major player in the service life of a coke battery. Therefore, any aspect of the process that is susceptible to damage during this refractory will have a great impact on the life of the coke manufacturing equipment. The results show that hard pushes and especially sticky ovens damage the silica refractory of the furnaces. Therefore, the proper management of production, focused in minimizing these effects, can contribute to reduce the maintenance cost and prolong the service life of the coke ovens.

Spatial distribution, source identification, and human health risk assessment of PAHs and their derivatives in soils nearby the coke plants

The coking industry can generate large amounts of polycyclic aromatic hydrocarbons (PAHs) and their derivatives, which may negatively impact the environment and human health. In this study, soils nearby a typical coking plant were sampled to assess the impact of coke production on the surrounding residential areas and human health. The mean concentration of PAHs and their derivatives in residential area soils nearby the coke plant was 4270 ng/g dw, which was 1 order of magnitude higher than that observed in areas far from the coke plant and approximately 4 times lower than that revealed the coke plant. In addition, the results showed that coking processing area was the most contaminant area of the coke plant (mean: 74.4 μg/g dw), where was also the main source of pollutants in residential areas. In terms of vertical soils in coking plant, the maximum levels of chemicals (mean: 205 μg/g dw) were presented at the leakage of underground pipelines, where were much higher than those in surface soils, and decreased with the increase of depth. The analysis of variance (ANOVA) results showed obvious differences in the concentrations of 6-nitrochrysene between the plant, residential areas and control areas. Meanwhile, 6-nitrochrysene had potential cancer risk (CR) for human in the coking site. Thus, 6-nitrochrysene was the most noteworthy PAH derivatives. Furthermore, the CR (mean: 5.94 × 10−5) and toxic equivalent quantities (TEQs) (mean: 14.8 μg·TEQ/g) of PAHs and their derivatives was assessed in this study. This finding suggested that PAHs and their derivatives especially those extremely toxic chemicals (Nitro-PAHs (NPAHs) and Br/Cl-PAHs (XPAHs)) might pose a potential health risk to residents nearby the coke plant. The current study provides further insights into the pollution characteristics of PAHs and their derivatives in coke plants and potential risks to the workers and surrounding residents.

The Effectiveness of the Implementation of Research Results in a Technological Scheme of Water Purification

Abstract The paper proposes technical solutions for the use of the reagent method of water preparation at coke plants in order to bring it to a quality suitable for use in the circulating water supply system of the PJSC Kharkiv Coke Plan. It is proposed to dilute phenolic water in a biochemical installation in a mixer before purification and to purify water with a flocculant. The paper recommends dosing the flocculant solution automatically using a preparation station. Additional purification of the clarified water is carried out using a filtration unit with a filter media from a layer of quartz sand. The economic effect from the implementation of the technical measures is achieved not only due to the reduction in fresh water consumption by 60 540 m3/year and the cessation of the discharge of phenolic water into the city sewer network, but also the replacement of the reagent with a more efficient one and a decrease in its consumption. It has been found that the introduction of the technical solutions for the circulating water supply system is economically and environmentally justifiable.

Effect of Normalization Methods on Accuracy of Estimating Low- and High-Molecular Weight PAHs Distribution in the Soils of a Coking Plant

Mapping spatial distribution of soil contaminants at contaminated sites is the basis of risk assessment. Hotspots can cause strongly skewed distribution of the raw contaminant concentrations in soil, and consequently can require suitable normalization prior to interpolation. In this study, three normalization methods including normal score, Johnson, and Box-Cox transformation were performed on the concentrations of two low-molecular weight (LMW) PAHs (i.e., acenaphthene (Ace) and naphthalene (Nap)) and two high-molecular weight (HMW) PAHs (i.e., benzo(a)pyrene (BaP) and benzo(b)fluoranthene (BbF)) in soils of a typical coking plant in North China. The estimating accuracy of soil LMW and HMW PAHs distribution using ordinary kriging with different normalization methods was compared. The results showed that all transformed data passed the Kolmogorov-Smirnov test, indicating that all three data transformation methods achieved normality of raw data. Compared to Box-Cox-ordinary kriging, normal score-, and Johnson-ordinary kriging had higher estimating accuracy of the four soil PAHs distribution. In cross-validation, smaller root-mean-square error (RMSE) and mean error (ME) values were observed for normal score-ordinary kriging for both LMW and HMW PAHs compared to Johnson- and Box-Cox-ordinary kriging. Thus, normal score transformation is suitable for alleviating the impact of hotspots on estimating accuracy of the four selected soil PAHs distribution at this coking plant. The findings can provide insights into reducing uncertainty in spatial interpolation at PAHs-contaminated sites.