Coking industry is a potential source of heavy metals(HMs)pollution.However,its impacts to the groundwater of surrounding residential areas have not been well understood.This study investigated the pollution character...Coking industry is a potential source of heavy metals(HMs)pollution.However,its impacts to the groundwater of surrounding residential areas have not been well understood.This study investigated the pollution characteristics and health risks of HMs in groundwater nearby a typical coking plant.Nine HMs including Fe,Zn,Mo,As,Cu,Ni,Cr,Pb and Cd were analyzed.The average concentration of total HMswas higher in the nearby area(244.27μg/L)than that of remote area away the coking plant(89.15μg/L).The spatial distribution of pollution indices including heavy metal pollution index(HPI),Nemerow index(NI)and contamination degree(CD),all demonstrated higher values at the nearby residential areas,suggesting coking activity could significantly impact the HMs distribution characteristics.Four sources of HMs were identified by Positive Matrix Factorization(PMF)model,which indicated coal washing and coking emission were the dominant sources,accounted for 40.4%,and 31.0%,respectively.Oral ingestionwas found to be the dominant exposure pathway with higher exposure dose to children than adults.Hazard quotient(HQ)values were below 1.0,suggesting negligible non-carcinogenic health risks,while potential carcinogenic risks were from Pb and Ni with cancer risk(CR)values>10−6.Monte Carlo simulation matched well with the calculated results with HMs concentrations to be the most sensitive parameters.This study provides insights into understanding how the industrial coking activities can impact the HMs pollution characteristics in groundwater,thus facilitating the implement of HMs regulation in coking industries.展开更多
This work proposed a strategy to improve the caking index of polyethylene terephthalate(PET)waste,in which low-temperature pyrolysis treatment(LTPT)was used to depolymerize PET waste.The mechanism of G modification wa...This work proposed a strategy to improve the caking index of polyethylene terephthalate(PET)waste,in which low-temperature pyrolysis treatment(LTPT)was used to depolymerize PET waste.The mechanism of G modification was revealed combining thermogravimetric(TG)analysis,Fourier transform infrared spectroscopy,pyrolysis-gas chromatography with mass spectrometric detection,and solid-state 13C nuclear magnetic resonance spectroscopy.Furthermore,crucible coking experiments were also conducted using industrial coal mixture and treated PET with the optimum G(PET300)or raw PET to evaluate the applicability of PET waste in coal-blending coking.According to characterization results of coke reactivity(CR),coke strength after reaction(CSR)indices,TG-related curves,pore volumes,and Raman spectra of the resultant cokes,LTPT could greatly increase the G of PET,and the optimum temperature was 300℃.Specifically,compared with the coke obtained from the blend with PET,the CR of the coke produced from the blend with PET300 decreased by 4.9%,whereas the CSR of the increased by 7.4%,suggesting that LTPT could increase the proportion of PET used for coal-blending coking.The improvement in G is attributed to the changes in C-O/C=O ratio,aliphatic H and aromaticity caused by LTPT.展开更多
The fractionating tower bottom in fluid catalytic cracking Unit (FCCU) is highly susceptible to coking due to the interplay of complex external operating conditions and internal physical properties. Consequently, quan...The fractionating tower bottom in fluid catalytic cracking Unit (FCCU) is highly susceptible to coking due to the interplay of complex external operating conditions and internal physical properties. Consequently, quantitative risk assessment (QRA) and predictive maintenance (PdM) are essential to effectively manage coking risks influenced by multiple factors. However, the inherent uncertainties of the coking process, combined with the mixed-frequency nature of distributed control systems (DCS) and laboratory information management systems (LIMS) data, present significant challenges for the application of data-driven methods and their practical implementation in industrial environments. This study proposes a hierarchical framework that integrates deep learning and fuzzy logic inference, leveraging data and domain knowledge to monitor the coking condition and inform prescriptive maintenance planning. The framework proposes the multi-layer fuzzy inference system to construct the coking risk index, utilizes multi-label methods to select the optimal feature dataset across the reactor-regenerator and fractionation system using coking risk factors as label space, and designs the parallel encoder-integrated decoder architecture to address mixed-frequency data disparities and enhance adaptation capabilities through extracting the operation state and physical properties information. Additionally, triple attention mechanisms, whether in parallel or temporal modules, adaptively aggregate input information and enhance intrinsic interpretability to support the disposal decision-making. Applied in the 2.8 million tons FCCU under long-period complex operating conditions, enabling precise coking risk management at the fractionating tower bottom.展开更多
Coking wastewater,characterized by high biological toxicity,poses significant challenges for traditional biological treatment methods.This study developed a novel in-situ immobilized photocatalytic-algae-bacteria cons...Coking wastewater,characterized by high biological toxicity,poses significant challenges for traditional biological treatment methods.This study developed a novel in-situ immobilized photocatalytic-algae-bacteria consortia(P-ABC)system using a polyether polyurethane sponge as a carrier,aiming to enhance biological treatment efficiency for actual coking wastewater.Results showed a 16.8%increase in algal density(up to 1.51×10^(5) cells/mL)in the P-ABC system compared to non-coupled controls,with significantly improved microbial metabolic activity,confirming the carrier's exceptional biocompatibility.Compared to standalone algae-bacteria consortia systems,the P-ABC system achieved higher removal efficiencies for chemical oxygen demand(COD_(Cr),19.8%),total organic carbon(TOC,21.2%),and total nitrogen(TN,30.4%).These findings validate the system's potential for improving stable and efficient treatment of industrial wastewater.Furthermore,this study offers insights into bio-enhanced treatment technologies and provides a reference pathway for integrating advanced oxidation and biological processes.展开更多
Polystyrene(PS)waste was depolymerized using a low-temperature pyrolysis treatment(LTPT)to increase its caking index.The mechanism of caking index modification was revealed by using Fourier transform infrared spectros...Polystyrene(PS)waste was depolymerized using a low-temperature pyrolysis treatment(LTPT)to increase its caking index.The mechanism of caking index modification was revealed by using Fourier transform infrared spectroscopy,thermogravimetric(TG)analysis,pyrolysis-gas chromatography with mass spectrometric detection,and solid-state^(13)C nuclear magnetic resonance spectroscopy.The crucible coal-blending coking tests were carried out using an industrial coal mixture and the treated-PS with the highest caking index(PS300)or raw PS.Some properties of the resultant cokes were also analyzed.It was demonstrated that the caking index of PS dramatically increased by LTPT;however,exceeding 300℃ did not yield any benefit.The caking index increased due to the formation of the caking components,whose molecules are medium in size,caused by LTPT.Additionally,the coke reactivity index of the coke obtained from the mixture containing PS300 decreased by 5.1%relative to that of the coke made from the mixture with PS and the coke strength after reaction index of the former increased by 7.3% compared with that of the latter,suggesting that the ratio of depolymerized PS used for coal-blending coking could increase relative to that of PS.展开更多
If assortment priee parity of Clase coking coal and its qtalty price danrcnee is nonreasonable, it deren't gulde in Anprotrig tbe quallry metaliurgical coking coal and may be influence theeconomic benefit of me...If assortment priee parity of Clase coking coal and its qtalty price danrcnee is nonreasonable, it deren't gulde in Anprotrig tbe quallry metaliurgical coking coal and may be influence theeconomic benefit of metallurgical enterprises. This paper propose the principles and mathematicmodel for determination aseortment party of clean cokingcoal and its quality difference of ash content in clean coking coal in order to urge wasbenes into producing superior clean coking cleal whichis under condition of consideration both interest waskeries and interest metallurgicai industry. It canbe used as a method in theory to make price strategies under condition of socialism maket economicfor washeries of clean coking coal展开更多
The maximum possibility of utilizing the Indian coking coals and inferior grade coking coal for producing metallurgical coke through non-recovery stamp charging tech_nology was investigated. Indian indigenous coals co...The maximum possibility of utilizing the Indian coking coals and inferior grade coking coal for producing metallurgical coke through non-recovery stamp charging tech_nology was investigated. Indian indigenous coals contained low percent of vitrinite （〈50%） and higher content of ash （〉15%） compared to imported coking coal. Therefore, the selection of appropriate proportion of different types of coals was a major challenge for coke makers. Coal blend selection criterion based on a single coefficient, named as composite coking potential （CCP）, was developed. The use of increased proportion of semi-soft coal （crucible swelling number of 2.5） and high ash （≥15%） indigenous coal in the range of 20%- 35% and 20%-65% respectively in the blends resulted in good quality of coke. Plant data of a non recovery coke oven were used for developing and validating the model. The results showed that the coke strength after reaction （CSR） varied in the range of 63.7%-67.7% and the M40 value was between 81.8 and 89.3 in both the cases.展开更多
A full-scale plant using anaerobic, anoxic and oxic processes （A1/A2/O）, along with a pilot-scale membrane bioreactor （MBR）, nanofiltration （NF） and reverse osmosis （RO） integrated system developed by Shanghai...A full-scale plant using anaerobic, anoxic and oxic processes （A1/A2/O）, along with a pilot-scale membrane bioreactor （MBR）, nanofiltration （NF） and reverse osmosis （RO） integrated system developed by Shanghai Baosteel Chemical Co. Ltd., was investigated to treat coking wastewater for industrial reuse over a period of one year. The removals reached 82.5% （COD）, 89.6% （BOD）, 99.8% （ammonium nitrogen）, 99.9% （phenol）, 44.6% （total cyanide （T-CN））, 99.7% （thiocyanide （SCN-）） and 8.9% （fluoride）, during the A1/A2/O biological treatment stage, and all parameters were further reduced by over 96.0%, except for fluoride （86.4%）, in the final discharge effluent from the currently operating plant. The pilot-scale MBR process reduced the turbidity to less than 0.65 NTU, and most of the toxic organic compounds were degraded or intercepted by the A1/A2/O followed MBR processes. In addition, parameters including COD, T-CN, total nitrogen, fluoride, chloride ion, hardness and conductivity were significantly reduced by the NF-RO system to a level suitable for industrial reuse, with a total water production ratio of 70.7%. However, the concentrates from the NF and RO units were highly polluted and should be disposed of properly or further treated before being discharged.展开更多
The optimal condition for a one-step process removing organic compounds from coking wastewater by simultaneously synthesized organobentonite as a pretreatment was investigated.Results showed that sorption of organic c...The optimal condition for a one-step process removing organic compounds from coking wastewater by simultaneously synthesized organobentonite as a pretreatment was investigated.Results showed that sorption of organic compounds by organobentonite was positively correlated to the cation surfactant exchange on the bentonite and the octanol-water partition coefficient（Kow） of the solutes.With 0.75 g/L bentonite and 180 mg/L（60% of bentonite cation exchange capacity） cetyltrimethylammonium bromide,the removal efficiencies of the 16 polycyclic aromatic hydrocarbon（PAHs） specified by the US Environmental Protection Agency in coking wastewater except naphthalene were more than 90%,and that of benzo（a）pyrene was 99.5%.At the same time,the removal efficiencies of CODCr,NH3-N,volatile phenols,colour and turbidity were 28.6%,13.2%,8.9%,55% and 84.3%,respectively,and the ratio of BOD5/CODCr increased from 0.31 to 0.41.These results indicated that the one-step process had high removal efficiency for toxic and refractory hydrophobic organic compounds,and could improve the biodegradability of the coking wastewater.Therefore it could be a promising technology for the pretreatment of toxic and refractory organic wastewater.展开更多
An adaptive state feedback predictive control （SFPC） scheme and an expert control scheme are presented and applied to the temperature control of a 1200 kt·a^-1 delayed coking furnace, which is the key equipment...An adaptive state feedback predictive control （SFPC） scheme and an expert control scheme are presented and applied to the temperature control of a 1200 kt·a^-1 delayed coking furnace, which is the key equipment for the delayed coking process. Adaptive SFPC is used to improve the performance of temperature control in normal operation. A simplified nonlinear model on the basis of first principles of the furnace is developed to obtain a state space model by linearization. Taking advantage of the nonlinear model, an online model adapting method is presented to accommodate the dynamic change of process characteristics because of tube coking and load changes. To compensate the large inverse response of outlet temperature resulting from the sudden increase of injected steam of a particular velocity to tubes, a monitoring method and an expert control scheme based on heat balance calculation are proposed. Industrial implementation shows the effectiveness and feasibility of the proposed control strategy.展开更多
Shenmu(SM)subbituminous coal without caking property was treated by low-temperature rapid pyrolysis(LTRP)to modify its caking and coking properties.The treated samples were characterized by Fourier transform infrared ...Shenmu(SM)subbituminous coal without caking property was treated by low-temperature rapid pyrolysis(LTRP)to modify its caking and coking properties.The treated samples were characterized by Fourier transform infrared spectrometry,vitrinite reflectance,and X-ray diffraction to determine the modification mechanism.Moreover,caking index(G)and coking indices(mechanical strength,coke reactivity,and coke strength after reaction)were employed to evaluate caking and coking properties,respectively.The results showed that SM coal was gradually upgraded with increasing processing temperature.Furthermore,the G values for the treated samples were significantly higher than that for SM coal,and G reached the maximum value at 450℃,implying the modification of caking property and the existence of an optimum temperature(450℃).Additionally,laboratory coking determinations showed that LTRP increased the mechanical strength of coke and coke strength after reaction and decreased coke reactivity when the treated coals were used in the coal blends instead of raw SM coal.Overall,LTRP treatment is effective to improve the caking and coking properties of SM coal.A mechanism was proposed for the modification.Suitable upgrading degree with suitable molecular masses and some releasable hydrogen-rich donor species present within the coal,which dominate the development of caking property,is important.展开更多
The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur,high-quality coal resources,and sulfur removal from high-sulfur coal is the most important issue.This paper re...The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur,high-quality coal resources,and sulfur removal from high-sulfur coal is the most important issue.This paper reviews the speciation,forms and distribution of sulfur in coal,the sulfur removal from raw coal,the thermal transformation of sulfur during coal pyrolysis,and the sulfur regulation during coal-blending coking of high organic-sulfur coals.It was suggested that the proper characterization of sulfur in coal cannot be obtained only by either chemical method or instrumental characterization,which raises the need of a combination of current or newly adopted characterization methods.Different from the removal of inorganic sulfur from coal,the organic sulfur can only be partly removed by chemical technologies;and the coal structure and property,particularly high-sulfur coking coals which have caking ability,may be altered and affected by the pretreatment processes.Based on the interactions among the sulfur radicals,sulfur-containing and hydrogen-containing fragments during coal pyrolysis and the reactions with minerals or nascent char,regulating the sulfur transformation behavior in the process of thermal conversion is the most effective way to utilize high organic-sulfur coals in the coke-making industry.An in-situ regulation approach of sulfur transformation during coal-blending coking has been suggested.That is,the high volatile coals with an appropriate releasing temperature range of CH4 overlapping well with that of H2 S from high organic-sulfur coals is blended with high organic-sulfur coals,and the C–S/C–C bonds in some sulfur forms are catalytically broken and immediately hydrogenated by the hydrogencontaining radicals generated from high volatile coals.Wherein,the effect of mass transfer on sulfur regulation during the coking process should be considered for the larger-scale coking tests through optimizing the ratios of different coals in the coal blend.展开更多
Carbon dioxide and methane are two main greenhouse gases which are contributed to serious global warming.Fortunately,dry reforming of methane(DRM),a very important reaction developed decades ago,can convert these two ...Carbon dioxide and methane are two main greenhouse gases which are contributed to serious global warming.Fortunately,dry reforming of methane(DRM),a very important reaction developed decades ago,can convert these two major greenhouse gases into value-added syngas or hydrogen.The main problem retarding its industrialization is the seriously coking formation upon the nickel-based catalysts.Herein,a series of confined indium-nickel(In-Ni)intermetallic alloy nanocatalysts(In_(x)Ni@SiO_(2))have been prepared and displayed superior coking resistance for DRM reaction.The sample containing 0.5 wt.%of In loading(In_(0.5)Ni@SiO_(2))shows the best balance of carbon deposition resistance and DRM reactivity even after 430 h long term stability test.The boosted carbon resistance can be ascribed to the confinement of core–shell structure and to the transfer of electrons from Indium to Nickel in In-Ni intermetallic alloys due to the smaller electronegativity of In.Both the silica shell and the increase of electron cloud density on metallic Ni can weaken the ability of Ni to activate C–H bond and decrease the deep cracking process of methane.The reaction over the confined InNi intermetallic alloy nanocatalyst was conformed to the Langmuir-Hinshelwood(L-H)mechanism revealed by in situ diffuse reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS).This work provides a guidance to design high performance coking resistance catalysts for methane dry reforming to efficiently utilize these two main greenhouse gases.展开更多
Coking wastewater has caused serious health risk in coal-producing areas of China, however its toxic effects have not been well understood. The genotoxicity induced by coking wastewater on mice in vivo and its possibl...Coking wastewater has caused serious health risk in coal-producing areas of China, however its toxic effects have not been well understood. The genotoxicity induced by coking wastewater on mice in vivo and its possible oxidative mechanisms were investigated via observing the induction of micronuclei in polychromatic erythrocytes of mouse bone marrow, and subsequently determining the antioxidative enzyme activities （superoxide dismutase Cu, Zn-SOD, Se-dependent glutathione peroxidase, and catalase）, thiobarbituric acid reactive substance contents and protein carbonyl levels in brains and livers of mice. Results showed that the tested coking wastewater caused a significant increase of micronucleus frequencies in a concentration-dependent manner. Also, the sample increased lipid peroxidation and protein oxidation levels, which was accompanied by changes in antioxidative status. Interestingly, pre-treatment with an antioxidant （vitamin C） led to a statistical reduction in the micronucleus frequency caused by coking wastewater. This implies that coking wastewater induces evident genetic damage in mammalian cells, and exposure to polluted areas might pose a potential genotoxic risk to human beings; in the process, oxidative stress played a crucial role.展开更多
The dynamic change of microbial community during sludge acclimation from aerobic to anaerobic in a MBR for coking wastewater treatment was revealed by Illumina Miseq sequencing in this study. The diversity of both Bac...The dynamic change of microbial community during sludge acclimation from aerobic to anaerobic in a MBR for coking wastewater treatment was revealed by Illumina Miseq sequencing in this study. The diversity of both Bacteria and Archaea showed an increase–decrease trajectory during acclimation, and exhibited the highest at the domestication interim. Ignavibacteria changed from a tiny minority（less than 1%） to the dominant bacterial group（54.0%） along with acclimation. The relative abundance of Betaproteobacteria kept relatively steady, as in this class some species increased coupled with some other species decreased during acclimation. The dominant Archaea shifted from Halobacteria in initial aerobic sludge to Methanobacteria in the acclimated anaerobic sludge. The dominant bacterial and archaeal groups in different acclimation stages were indigenous microorganisms in the initial sludge, though some of them were very rare. This study supported that the species in＂rare biosphere＂ might eventually become dominant in response to environmental change.展开更多
A laboratory-scale anaerobic sequencing batch reactor (ASBR) was used to pretreat coking wastewater. Inoculated anaerobic granular biomass was acclimated for 225 d to the coking wastewater, and then the biochemical me...A laboratory-scale anaerobic sequencing batch reactor (ASBR) was used to pretreat coking wastewater. Inoculated anaerobic granular biomass was acclimated for 225 d to the coking wastewater, and then the biochemical methane potential (BMP)of the coking wastewater in the acclimated granular biomass was measured. At the same time, some fundamental technological factors, such as the filling time and the reacting time ratio (tf/tr), the mixing intensity and the intermittent mixing mode, that affect anaerobic pretreatment of coking wastewater with ASBR, were evaluated through orthogonal tests. The COD removal efficiency reached 38％～50％ in the stable operation period with the organic loading rate of 0.37～0.54 kg COD/(m3.d) at the optimum conditions of tf/tr, the mixing intensity and the intermittent mixing mode. In addition, the biodegradability of coking wastewater distinctly increased after the pretreatment using ASBR. At the end of the experiment, the microorganism forms on the granulated sludge in the ASBR were observed using SEM (scanning electron microscope) and fluoroscope. The results showed that the dominant microorganism on the granular sludge was Methanosaeta instead of Methanosarcina dominated on the inoculated sludge.展开更多
The influence of barium addition to a Ni/Al2O3 catalyst on the reaction intermediates formed,the activity,resistance of the catalyst to coking,and properties of the coke formed after acetic acid steam reforming were i...The influence of barium addition to a Ni/Al2O3 catalyst on the reaction intermediates formed,the activity,resistance of the catalyst to coking,and properties of the coke formed after acetic acid steam reforming were investigated in this study.The results showed the drastic effects of barium addition on the physicochemical properties and performances of the catalyst.The solid-phase reaction between alumina and BaO formed BaAl2O4,which re-constructed the alumina structure,resulting in a decrease in the specific surface area and an increase in the resistance of metallic Ni to sintering.The addition of barium was also beneficial for enhancing the catalytic activity,resulting from the changed catalytic reaction network.The in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study of the acetic acid steam reforming indicated that barium could effectively suppress the accumulation of the reaction intermediates of carbonyl,formate,and C=C functional groups on the catalyst surface,attributed to its relatively high ability to cause the gasification of these species.In addition,coking was considerably more significant over the Ba-Ni/Al2O3 catalyst.Moreover,the Ba-Ni/Al2O3 catalyst was more stable than the Ni/Al2O3catalyst,owing to the distinct forms of coke formed (carbon nanotube form over the Ba-Ni/Al2O3 catalyst,and the amorphous form over the Ni/Al2O3 catalyst).展开更多
A recombinant human androgen receptor yeast assay was applied to investigate the occurrence of antiandrogens as well as the mechanism for their removal during gray wastewater and coking wastewater treatment. The membr...A recombinant human androgen receptor yeast assay was applied to investigate the occurrence of antiandrogens as well as the mechanism for their removal during gray wastewater and coking wastewater treatment. The membrane reactor（MBR） system for gray wastewater treatment could remove 88.0% of antiandrogenic activity exerted by weakly polar extracts and 97.3% of that by moderately strong polar extracts, but only 32.5%of that contributed by strong polar extracts. Biodegradation by microorganisms in the MBR contributed to 95.9% of the total removal. After the treatment, the concentration of antiandrogenic activity in the effluent was still 1.05 μg flutamide equivalence（FEQ）/L, 36.2%of which was due to strong polar extracts. In the anaerobic reactor, anoxic reactor, and membrane reactor system for coking wastewater treatment, the antiandrogenic activity of raw coking wastewater was 78.6 mg FEQ/L, and the effluent of the treatment system had only 0.34 mg FEQ/L. The antiandrogenic activity mainly existed in the medium strong polar and strong polar extracts. Biodegradation by microorganisms contributed to at least 89.2%of the total antiandrogenic activity removal in the system. Biodegradation was the main removal mechanism of antiandrogenic activity in both the wastewater treatment systems.展开更多
Coking wastewater（CW） contains toxic and macromolecular substances that inhibit biological treatment. The refractory compounds remaining in biologically treated coking wastewater（BTCW） provide chemical oxygen dem...Coking wastewater（CW） contains toxic and macromolecular substances that inhibit biological treatment. The refractory compounds remaining in biologically treated coking wastewater（BTCW） provide chemical oxygen demand（COD） and color levels that make it unacceptable for reuse or disposal. Gas-phase pulsed corona discharge（PCD） utilizing mostly hydroxyl radicals and ozone as oxidants was applied to both raw coking wastewater（RCW） and BTCW wastewater as a supplemental treatment. The energy efficiency of COD,phenol, thiocyanate and cyanide degradation by PCD was the subject of the research. The cost-effective removal of intermediate oxidation products with addition of lime was also studied. The energy efficiency of oxidation was inversely proportional to the pulse repetition frequency： lower frequency allows more effective utilization of ozone at longer treatment times. Oxidative treatment of RCW showed the removal of phenol and thiocyanate at 800 pulses per second from 611 to 227 mg/L and from 348 to 86 mg/L, respectively, at 42 k Wh/m^3 delivered energy, with substantial improvement in the BOD5/COD ratio（from 0.14 to 0.43）.The COD and color of BTCW were removed by 30% and 93%, respectively, at 20 k Wh/m^3,showing energy efficiency for the PCD treatment exceeding that of conventional ozonation by a factor of 3–4. Application of lime appeared to be an effective supplement to the PCD treatment of RCW, degrading COD by about 28% at an energy input of 28 k Wh/m3 and the lime dose of 3.0 kg/m^3. The improvement of RCW treatability is attributed to the degradation of toxic substances and fragmentation of macromolecular compounds.展开更多
Electrochemical removal of ammonia is a new and effective method in coking wastewater.The reaction mechanism of ammonia removal was proved by stable polarization curve in this paper.First,the supposing of reaction ste...Electrochemical removal of ammonia is a new and effective method in coking wastewater.The reaction mechanism of ammonia removal was proved by stable polarization curve in this paper.First,the supposing of reaction steps of the electrode were proposed.And then reaction parameter of the electrode was measured by Tafel curve.Finally,the reaction mechanism was determined by quasi-equilibrium approach.The results showed that Cl2+H2O→HOCl+H++Cl was the rate-determining step,the calculated apparent transfer coefficient was uniform to the experimental value.展开更多
基金supported by the National Key Research and Development Program of China(No.2019YFC1804501)the National Natural Science Foundation of China(Nos.42122056 and U1901210)+2 种基金Guangdong Basic and Applied Basic Research Foundation(No.2021B1515020063)the Key Research and Development Program of Guangdong Province(No.2021B1111380003)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Z032).
文摘Coking industry is a potential source of heavy metals(HMs)pollution.However,its impacts to the groundwater of surrounding residential areas have not been well understood.This study investigated the pollution characteristics and health risks of HMs in groundwater nearby a typical coking plant.Nine HMs including Fe,Zn,Mo,As,Cu,Ni,Cr,Pb and Cd were analyzed.The average concentration of total HMswas higher in the nearby area(244.27μg/L)than that of remote area away the coking plant(89.15μg/L).The spatial distribution of pollution indices including heavy metal pollution index(HPI),Nemerow index(NI)and contamination degree(CD),all demonstrated higher values at the nearby residential areas,suggesting coking activity could significantly impact the HMs distribution characteristics.Four sources of HMs were identified by Positive Matrix Factorization(PMF)model,which indicated coal washing and coking emission were the dominant sources,accounted for 40.4%,and 31.0%,respectively.Oral ingestionwas found to be the dominant exposure pathway with higher exposure dose to children than adults.Hazard quotient(HQ)values were below 1.0,suggesting negligible non-carcinogenic health risks,while potential carcinogenic risks were from Pb and Ni with cancer risk(CR)values>10−6.Monte Carlo simulation matched well with the calculated results with HMs concentrations to be the most sensitive parameters.This study provides insights into understanding how the industrial coking activities can impact the HMs pollution characteristics in groundwater,thus facilitating the implement of HMs regulation in coking industries.
基金supported by the National Natural Science Foundation of China(22308006,22278001)the Natural Science Foundation of Anhui Provincial Education Department(KJ2021A0407).
文摘This work proposed a strategy to improve the caking index of polyethylene terephthalate(PET)waste,in which low-temperature pyrolysis treatment(LTPT)was used to depolymerize PET waste.The mechanism of G modification was revealed combining thermogravimetric(TG)analysis,Fourier transform infrared spectroscopy,pyrolysis-gas chromatography with mass spectrometric detection,and solid-state 13C nuclear magnetic resonance spectroscopy.Furthermore,crucible coking experiments were also conducted using industrial coal mixture and treated PET with the optimum G(PET300)or raw PET to evaluate the applicability of PET waste in coal-blending coking.According to characterization results of coke reactivity(CR),coke strength after reaction(CSR)indices,TG-related curves,pore volumes,and Raman spectra of the resultant cokes,LTPT could greatly increase the G of PET,and the optimum temperature was 300℃.Specifically,compared with the coke obtained from the blend with PET,the CR of the coke produced from the blend with PET300 decreased by 4.9%,whereas the CSR of the increased by 7.4%,suggesting that LTPT could increase the proportion of PET used for coal-blending coking.The improvement in G is attributed to the changes in C-O/C=O ratio,aliphatic H and aromaticity caused by LTPT.
基金financially supported by the Innovative Research Group Project of the National Natural Science Foundation of China (22021004)Sinopec Major Science and Technology Projects (321123-1)
文摘The fractionating tower bottom in fluid catalytic cracking Unit (FCCU) is highly susceptible to coking due to the interplay of complex external operating conditions and internal physical properties. Consequently, quantitative risk assessment (QRA) and predictive maintenance (PdM) are essential to effectively manage coking risks influenced by multiple factors. However, the inherent uncertainties of the coking process, combined with the mixed-frequency nature of distributed control systems (DCS) and laboratory information management systems (LIMS) data, present significant challenges for the application of data-driven methods and their practical implementation in industrial environments. This study proposes a hierarchical framework that integrates deep learning and fuzzy logic inference, leveraging data and domain knowledge to monitor the coking condition and inform prescriptive maintenance planning. The framework proposes the multi-layer fuzzy inference system to construct the coking risk index, utilizes multi-label methods to select the optimal feature dataset across the reactor-regenerator and fractionation system using coking risk factors as label space, and designs the parallel encoder-integrated decoder architecture to address mixed-frequency data disparities and enhance adaptation capabilities through extracting the operation state and physical properties information. Additionally, triple attention mechanisms, whether in parallel or temporal modules, adaptively aggregate input information and enhance intrinsic interpretability to support the disposal decision-making. Applied in the 2.8 million tons FCCU under long-period complex operating conditions, enabling precise coking risk management at the fractionating tower bottom.
基金supported by the National Natural Science Foundation of China(No.22076113)Shaanxi Province Key R&D Program Project(No.2020NY-235)。
文摘Coking wastewater,characterized by high biological toxicity,poses significant challenges for traditional biological treatment methods.This study developed a novel in-situ immobilized photocatalytic-algae-bacteria consortia(P-ABC)system using a polyether polyurethane sponge as a carrier,aiming to enhance biological treatment efficiency for actual coking wastewater.Results showed a 16.8%increase in algal density(up to 1.51×10^(5) cells/mL)in the P-ABC system compared to non-coupled controls,with significantly improved microbial metabolic activity,confirming the carrier's exceptional biocompatibility.Compared to standalone algae-bacteria consortia systems,the P-ABC system achieved higher removal efficiencies for chemical oxygen demand(COD_(Cr),19.8%),total organic carbon(TOC,21.2%),and total nitrogen(TN,30.4%).These findings validate the system's potential for improving stable and efficient treatment of industrial wastewater.Furthermore,this study offers insights into bio-enhanced treatment technologies and provides a reference pathway for integrating advanced oxidation and biological processes.
基金supported by the National Natural Science Foundation of China(22308006 and 22278001)the Natural Science Foundation of Anhui Provincial Education Department(KJ2021A0407).
文摘Polystyrene(PS)waste was depolymerized using a low-temperature pyrolysis treatment(LTPT)to increase its caking index.The mechanism of caking index modification was revealed by using Fourier transform infrared spectroscopy,thermogravimetric(TG)analysis,pyrolysis-gas chromatography with mass spectrometric detection,and solid-state^(13)C nuclear magnetic resonance spectroscopy.The crucible coal-blending coking tests were carried out using an industrial coal mixture and the treated-PS with the highest caking index(PS300)or raw PS.Some properties of the resultant cokes were also analyzed.It was demonstrated that the caking index of PS dramatically increased by LTPT;however,exceeding 300℃ did not yield any benefit.The caking index increased due to the formation of the caking components,whose molecules are medium in size,caused by LTPT.Additionally,the coke reactivity index of the coke obtained from the mixture containing PS300 decreased by 5.1%relative to that of the coke made from the mixture with PS and the coke strength after reaction index of the former increased by 7.3% compared with that of the latter,suggesting that the ratio of depolymerized PS used for coal-blending coking could increase relative to that of PS.
文摘If assortment priee parity of Clase coking coal and its qtalty price danrcnee is nonreasonable, it deren't gulde in Anprotrig tbe quallry metaliurgical coking coal and may be influence theeconomic benefit of metallurgical enterprises. This paper propose the principles and mathematicmodel for determination aseortment party of clean cokingcoal and its quality difference of ash content in clean coking coal in order to urge wasbenes into producing superior clean coking cleal whichis under condition of consideration both interest waskeries and interest metallurgicai industry. It canbe used as a method in theory to make price strategies under condition of socialism maket economicfor washeries of clean coking coal
文摘The maximum possibility of utilizing the Indian coking coals and inferior grade coking coal for producing metallurgical coke through non-recovery stamp charging tech_nology was investigated. Indian indigenous coals contained low percent of vitrinite （〈50%） and higher content of ash （〉15%） compared to imported coking coal. Therefore, the selection of appropriate proportion of different types of coals was a major challenge for coke makers. Coal blend selection criterion based on a single coefficient, named as composite coking potential （CCP）, was developed. The use of increased proportion of semi-soft coal （crucible swelling number of 2.5） and high ash （≥15%） indigenous coal in the range of 20%- 35% and 20%-65% respectively in the blends resulted in good quality of coke. Plant data of a non recovery coke oven were used for developing and validating the model. The results showed that the coke strength after reaction （CSR） varied in the range of 63.7%-67.7% and the M40 value was between 81.8 and 89.3 in both the cases.
文摘A full-scale plant using anaerobic, anoxic and oxic processes （A1/A2/O）, along with a pilot-scale membrane bioreactor （MBR）, nanofiltration （NF） and reverse osmosis （RO） integrated system developed by Shanghai Baosteel Chemical Co. Ltd., was investigated to treat coking wastewater for industrial reuse over a period of one year. The removals reached 82.5% （COD）, 89.6% （BOD）, 99.8% （ammonium nitrogen）, 99.9% （phenol）, 44.6% （total cyanide （T-CN））, 99.7% （thiocyanide （SCN-）） and 8.9% （fluoride）, during the A1/A2/O biological treatment stage, and all parameters were further reduced by over 96.0%, except for fluoride （86.4%）, in the final discharge effluent from the currently operating plant. The pilot-scale MBR process reduced the turbidity to less than 0.65 NTU, and most of the toxic organic compounds were degraded or intercepted by the A1/A2/O followed MBR processes. In addition, parameters including COD, T-CN, total nitrogen, fluoride, chloride ion, hardness and conductivity were significantly reduced by the NF-RO system to a level suitable for industrial reuse, with a total water production ratio of 70.7%. However, the concentrates from the NF and RO units were highly polluted and should be disposed of properly or further treated before being discharged.
基金supported by the National Natural Science Foundation of China (No. 20890111)
文摘The optimal condition for a one-step process removing organic compounds from coking wastewater by simultaneously synthesized organobentonite as a pretreatment was investigated.Results showed that sorption of organic compounds by organobentonite was positively correlated to the cation surfactant exchange on the bentonite and the octanol-water partition coefficient（Kow） of the solutes.With 0.75 g/L bentonite and 180 mg/L（60% of bentonite cation exchange capacity） cetyltrimethylammonium bromide,the removal efficiencies of the 16 polycyclic aromatic hydrocarbon（PAHs） specified by the US Environmental Protection Agency in coking wastewater except naphthalene were more than 90%,and that of benzo（a）pyrene was 99.5%.At the same time,the removal efficiencies of CODCr,NH3-N,volatile phenols,colour and turbidity were 28.6%,13.2%,8.9%,55% and 84.3%,respectively,and the ratio of BOD5/CODCr increased from 0.31 to 0.41.These results indicated that the one-step process had high removal efficiency for toxic and refractory hydrophobic organic compounds,and could improve the biodegradability of the coking wastewater.Therefore it could be a promising technology for the pretreatment of toxic and refractory organic wastewater.
基金the State Key Development Program for Basic Research of China(2002CB312200)the National High Technology Research and Development Program of China(2007AA04Z193)
文摘An adaptive state feedback predictive control （SFPC） scheme and an expert control scheme are presented and applied to the temperature control of a 1200 kt·a^-1 delayed coking furnace, which is the key equipment for the delayed coking process. Adaptive SFPC is used to improve the performance of temperature control in normal operation. A simplified nonlinear model on the basis of first principles of the furnace is developed to obtain a state space model by linearization. Taking advantage of the nonlinear model, an online model adapting method is presented to accommodate the dynamic change of process characteristics because of tube coking and load changes. To compensate the large inverse response of outlet temperature resulting from the sudden increase of injected steam of a particular velocity to tubes, a monitoring method and an expert control scheme based on heat balance calculation are proposed. Industrial implementation shows the effectiveness and feasibility of the proposed control strategy.
基金The authors are grateful to the National Natural Science Foundation of China(No.21776002)Natural Science Foundation of Anhui Provincial Education Department(Nos.KJ2016A097 and KJ2017A056)+1 种基金Innovation Project of Overseas People of Anhui Province,Student Research Training Program of Anhui Province(201810360190)Youth Natural Science Foundation of Anhui University of Technology(No.QZ201806)for financial support.
文摘Shenmu(SM)subbituminous coal without caking property was treated by low-temperature rapid pyrolysis(LTRP)to modify its caking and coking properties.The treated samples were characterized by Fourier transform infrared spectrometry,vitrinite reflectance,and X-ray diffraction to determine the modification mechanism.Moreover,caking index(G)and coking indices(mechanical strength,coke reactivity,and coke strength after reaction)were employed to evaluate caking and coking properties,respectively.The results showed that SM coal was gradually upgraded with increasing processing temperature.Furthermore,the G values for the treated samples were significantly higher than that for SM coal,and G reached the maximum value at 450℃,implying the modification of caking property and the existence of an optimum temperature(450℃).Additionally,laboratory coking determinations showed that LTRP increased the mechanical strength of coke and coke strength after reaction and decreased coke reactivity when the treated coals were used in the coal blends instead of raw SM coal.Overall,LTRP treatment is effective to improve the caking and coking properties of SM coal.A mechanism was proposed for the modification.Suitable upgrading degree with suitable molecular masses and some releasable hydrogen-rich donor species present within the coal,which dominate the development of caking property,is important.
基金financial support of National Natural Science Foundation of China(U1910201,21878208)Transformation of Scientific and Technological Achievements Programs of Higher Education Institutions in Shanxi(TSTAP)Shanxi Province Science Foundation for Key Program(201901D111001(ZD))。
文摘The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur,high-quality coal resources,and sulfur removal from high-sulfur coal is the most important issue.This paper reviews the speciation,forms and distribution of sulfur in coal,the sulfur removal from raw coal,the thermal transformation of sulfur during coal pyrolysis,and the sulfur regulation during coal-blending coking of high organic-sulfur coals.It was suggested that the proper characterization of sulfur in coal cannot be obtained only by either chemical method or instrumental characterization,which raises the need of a combination of current or newly adopted characterization methods.Different from the removal of inorganic sulfur from coal,the organic sulfur can only be partly removed by chemical technologies;and the coal structure and property,particularly high-sulfur coking coals which have caking ability,may be altered and affected by the pretreatment processes.Based on the interactions among the sulfur radicals,sulfur-containing and hydrogen-containing fragments during coal pyrolysis and the reactions with minerals or nascent char,regulating the sulfur transformation behavior in the process of thermal conversion is the most effective way to utilize high organic-sulfur coals in the coke-making industry.An in-situ regulation approach of sulfur transformation during coal-blending coking has been suggested.That is,the high volatile coals with an appropriate releasing temperature range of CH4 overlapping well with that of H2 S from high organic-sulfur coals is blended with high organic-sulfur coals,and the C–S/C–C bonds in some sulfur forms are catalytically broken and immediately hydrogenated by the hydrogencontaining radicals generated from high volatile coals.Wherein,the effect of mass transfer on sulfur regulation during the coking process should be considered for the larger-scale coking tests through optimizing the ratios of different coals in the coal blend.
基金supported by the National Natural Science Foundation of China(21976078 and 21773106)the National Key R&D Program of China(2016YFC0205900)+1 种基金the Natural Science Foundation of Jiangxi Province(20202ACB213001)National Engineering Laboratory for Mobile Source Emission Control Technology(NELMS2019A12)。
文摘Carbon dioxide and methane are two main greenhouse gases which are contributed to serious global warming.Fortunately,dry reforming of methane(DRM),a very important reaction developed decades ago,can convert these two major greenhouse gases into value-added syngas or hydrogen.The main problem retarding its industrialization is the seriously coking formation upon the nickel-based catalysts.Herein,a series of confined indium-nickel(In-Ni)intermetallic alloy nanocatalysts(In_(x)Ni@SiO_(2))have been prepared and displayed superior coking resistance for DRM reaction.The sample containing 0.5 wt.%of In loading(In_(0.5)Ni@SiO_(2))shows the best balance of carbon deposition resistance and DRM reactivity even after 430 h long term stability test.The boosted carbon resistance can be ascribed to the confinement of core–shell structure and to the transfer of electrons from Indium to Nickel in In-Ni intermetallic alloys due to the smaller electronegativity of In.Both the silica shell and the increase of electron cloud density on metallic Ni can weaken the ability of Ni to activate C–H bond and decrease the deep cracking process of methane.The reaction over the confined InNi intermetallic alloy nanocatalyst was conformed to the Langmuir-Hinshelwood(L-H)mechanism revealed by in situ diffuse reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS).This work provides a guidance to design high performance coking resistance catalysts for methane dry reforming to efficiently utilize these two main greenhouse gases.
基金supported by the National Natural Science Foundation of China (No.20977060)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20121401110003)+3 种基金the Project for Science and Technology Development of Shanxi Province(No.20120313009-2)the Natural Science Foundation of Shanxi Province(No.2012021008-1)the Research Project Supported by Shanxi Scholarship Council of China(No.2011-013,2012-009)the Program for the Top Young and Middle aged Innovative Talents of Higher Learning Institutions of Shanxi
文摘Coking wastewater has caused serious health risk in coal-producing areas of China, however its toxic effects have not been well understood. The genotoxicity induced by coking wastewater on mice in vivo and its possible oxidative mechanisms were investigated via observing the induction of micronuclei in polychromatic erythrocytes of mouse bone marrow, and subsequently determining the antioxidative enzyme activities （superoxide dismutase Cu, Zn-SOD, Se-dependent glutathione peroxidase, and catalase）, thiobarbituric acid reactive substance contents and protein carbonyl levels in brains and livers of mice. Results showed that the tested coking wastewater caused a significant increase of micronucleus frequencies in a concentration-dependent manner. Also, the sample increased lipid peroxidation and protein oxidation levels, which was accompanied by changes in antioxidative status. Interestingly, pre-treatment with an antioxidant （vitamin C） led to a statistical reduction in the micronucleus frequency caused by coking wastewater. This implies that coking wastewater induces evident genetic damage in mammalian cells, and exposure to polluted areas might pose a potential genotoxic risk to human beings; in the process, oxidative stress played a crucial role.
基金supported by the National Natural Science Foundation of China(No.51678334)
文摘The dynamic change of microbial community during sludge acclimation from aerobic to anaerobic in a MBR for coking wastewater treatment was revealed by Illumina Miseq sequencing in this study. The diversity of both Bacteria and Archaea showed an increase–decrease trajectory during acclimation, and exhibited the highest at the domestication interim. Ignavibacteria changed from a tiny minority（less than 1%） to the dominant bacterial group（54.0%） along with acclimation. The relative abundance of Betaproteobacteria kept relatively steady, as in this class some species increased coupled with some other species decreased during acclimation. The dominant Archaea shifted from Halobacteria in initial aerobic sludge to Methanobacteria in the acclimated anaerobic sludge. The dominant bacterial and archaeal groups in different acclimation stages were indigenous microorganisms in the initial sludge, though some of them were very rare. This study supported that the species in＂rare biosphere＂ might eventually become dominant in response to environmental change.
基金Project (No. 40272108) supported by the National Natural Science Foundation of China
文摘A laboratory-scale anaerobic sequencing batch reactor (ASBR) was used to pretreat coking wastewater. Inoculated anaerobic granular biomass was acclimated for 225 d to the coking wastewater, and then the biochemical methane potential (BMP)of the coking wastewater in the acclimated granular biomass was measured. At the same time, some fundamental technological factors, such as the filling time and the reacting time ratio (tf/tr), the mixing intensity and the intermittent mixing mode, that affect anaerobic pretreatment of coking wastewater with ASBR, were evaluated through orthogonal tests. The COD removal efficiency reached 38％～50％ in the stable operation period with the organic loading rate of 0.37～0.54 kg COD/(m3.d) at the optimum conditions of tf/tr, the mixing intensity and the intermittent mixing mode. In addition, the biodegradability of coking wastewater distinctly increased after the pretreatment using ASBR. At the end of the experiment, the microorganism forms on the granulated sludge in the ASBR were observed using SEM (scanning electron microscope) and fluoroscope. The results showed that the dominant microorganism on the granular sludge was Methanosaeta instead of Methanosarcina dominated on the inoculated sludge.
基金supported by the National Natural Science Foundation of China(No.51876080)the Strategic International Scientific and Technological Innovation Cooperation Special Funds of National Key Research and Development Program of China(No.2016YFE0204000)+3 种基金the Program for Taishan Scholars of Shandong Province Governmentthe Recruitment Program of Global Experts(Thousand Youth Talents Plan)the Natural Science Foundation of Shandong Province(ZR2017BB002)the Key Research and Development Program of Shandong Province(2018GSF116014)。
文摘The influence of barium addition to a Ni/Al2O3 catalyst on the reaction intermediates formed,the activity,resistance of the catalyst to coking,and properties of the coke formed after acetic acid steam reforming were investigated in this study.The results showed the drastic effects of barium addition on the physicochemical properties and performances of the catalyst.The solid-phase reaction between alumina and BaO formed BaAl2O4,which re-constructed the alumina structure,resulting in a decrease in the specific surface area and an increase in the resistance of metallic Ni to sintering.The addition of barium was also beneficial for enhancing the catalytic activity,resulting from the changed catalytic reaction network.The in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study of the acetic acid steam reforming indicated that barium could effectively suppress the accumulation of the reaction intermediates of carbonyl,formate,and C=C functional groups on the catalyst surface,attributed to its relatively high ability to cause the gasification of these species.In addition,coking was considerably more significant over the Ba-Ni/Al2O3 catalyst.Moreover,the Ba-Ni/Al2O3 catalyst was more stable than the Ni/Al2O3catalyst,owing to the distinct forms of coke formed (carbon nanotube form over the Ba-Ni/Al2O3 catalyst,and the amorphous form over the Ni/Al2O3 catalyst).
基金funded by the National High-Tech Research and Development Program (863 Program) of China (No. 2013AA062705-1)the National Natural Science Funds of China (No. 51308319)
文摘A recombinant human androgen receptor yeast assay was applied to investigate the occurrence of antiandrogens as well as the mechanism for their removal during gray wastewater and coking wastewater treatment. The membrane reactor（MBR） system for gray wastewater treatment could remove 88.0% of antiandrogenic activity exerted by weakly polar extracts and 97.3% of that by moderately strong polar extracts, but only 32.5%of that contributed by strong polar extracts. Biodegradation by microorganisms in the MBR contributed to 95.9% of the total removal. After the treatment, the concentration of antiandrogenic activity in the effluent was still 1.05 μg flutamide equivalence（FEQ）/L, 36.2%of which was due to strong polar extracts. In the anaerobic reactor, anoxic reactor, and membrane reactor system for coking wastewater treatment, the antiandrogenic activity of raw coking wastewater was 78.6 mg FEQ/L, and the effluent of the treatment system had only 0.34 mg FEQ/L. The antiandrogenic activity mainly existed in the medium strong polar and strong polar extracts. Biodegradation by microorganisms contributed to at least 89.2%of the total antiandrogenic activity removal in the system. Biodegradation was the main removal mechanism of antiandrogenic activity in both the wastewater treatment systems.
基金supported by the Special Foundation for Applied Science and Technology of Guangdong Province(No.2015B020235005)the National Natural Science Foundation of China(No.51278199)The PCD device was designed at Tomsk Polytechnic University within the framework of Tomsk Polytechnic University Competitiveness Enhancement Program grant
文摘Coking wastewater（CW） contains toxic and macromolecular substances that inhibit biological treatment. The refractory compounds remaining in biologically treated coking wastewater（BTCW） provide chemical oxygen demand（COD） and color levels that make it unacceptable for reuse or disposal. Gas-phase pulsed corona discharge（PCD） utilizing mostly hydroxyl radicals and ozone as oxidants was applied to both raw coking wastewater（RCW） and BTCW wastewater as a supplemental treatment. The energy efficiency of COD,phenol, thiocyanate and cyanide degradation by PCD was the subject of the research. The cost-effective removal of intermediate oxidation products with addition of lime was also studied. The energy efficiency of oxidation was inversely proportional to the pulse repetition frequency： lower frequency allows more effective utilization of ozone at longer treatment times. Oxidative treatment of RCW showed the removal of phenol and thiocyanate at 800 pulses per second from 611 to 227 mg/L and from 348 to 86 mg/L, respectively, at 42 k Wh/m^3 delivered energy, with substantial improvement in the BOD5/COD ratio（from 0.14 to 0.43）.The COD and color of BTCW were removed by 30% and 93%, respectively, at 20 k Wh/m^3,showing energy efficiency for the PCD treatment exceeding that of conventional ozonation by a factor of 3–4. Application of lime appeared to be an effective supplement to the PCD treatment of RCW, degrading COD by about 28% at an energy input of 28 k Wh/m3 and the lime dose of 3.0 kg/m^3. The improvement of RCW treatability is attributed to the degradation of toxic substances and fragmentation of macromolecular compounds.
基金Supported by the National Natural Science Foundation of China （20771080 20876104）
文摘Electrochemical removal of ammonia is a new and effective method in coking wastewater.The reaction mechanism of ammonia removal was proved by stable polarization curve in this paper.First,the supposing of reaction steps of the electrode were proposed.And then reaction parameter of the electrode was measured by Tafel curve.Finally,the reaction mechanism was determined by quasi-equilibrium approach.The results showed that Cl2+H2O→HOCl+H++Cl was the rate-determining step,the calculated apparent transfer coefficient was uniform to the experimental value.
