Ambient PM2.5 samples were collected in Laiwu, a small industrial city in China known for steel production, to measure and evaluate the mass concentrations of PM2.5 and the inorganic water-soluble ions (IWS ions). The highest PM2.5 value recorded was 251.28 mu g/m(3), which occurred during winter and was lower than other major Chinese cities. The spatial distribution showed that the center of the city, which is connected to the downtown area, was heavily polluted (170 mu g/m(3) higher) compared to the suburbs. With the exception of winter, the weight of PM2.5 was dominated by IWS ions, with three secondary ions (NO3-, SO42-, and NH4+) accounting for more than 70% of the total ions in mass. This percentage is higher than that of big cities. An increase in sulfur oxidation ratios (SOR), nitrogen oxidation rate (NOR), and anion equivalent/cation equivalent (AE/CE) indicated that the atmosphere in Laiwu was more oxidized than other big cities. The ion analysis revealed that PM2.5 was highly correlated with NO3-, SO42-, and NH4+. The principal component analysis indicated that district heating during winter and industrial output and secondary transformation during summer were the major sources of the water-soluble ions. The backward trajectory study identified the north of Shandong Province as the likely source-area that affected air quality in Laiwu.

回顾了《钢铁行业产能置换实施办法》政策出台的背景,汇总了该办法施行以来涉及的新建、退出和压减产能数据,分析了各地区涉及的产能占比分布、新建项目装备特点和退出产能去向特点,从政府、行业、企业3个层面阐述了产能置换对钢铁行业高质量发展的推动意义.

钢铁工业全球化具有资源、技术、市场和人才全球化4个特征.中国钢铁工业在践行"一带一路"倡议上,已在铁矿资源获取、国际工程承包和钢材消费市场开发方面取得突破.计算了中国钢铁相关企业跨国指数,总结了钢铁工业国际产能合作现状,并给出合作成功案例的4个特点.对钢铁工业国际产能合作涉及的风险因素进行识别和影响分析,从相关政府部门和"走出去"企业层面分别给出合作建议,最后对钢铁工业国际产能合作进行展望.

Poor N2 selectivity and low SO2-tolerant are dominated weaknesses for low-temperature selective catalytic reduction of NO with NH3 (NH3-SCR) catalysts, which must be overcome for practical applications. Herein, a Mn-Fe mixed catalyst supported on active carbon (Mn-Fe/AC) for low-temperature NH3-SCR of NO was prepared, and the influence of SO2 on this process was also studied. Both iron and sulfur dioxide exhibited a dual-acting over Mn-Fe/AC catalyst for NH3-SCR of NO. Sulfur dioxide had two effects when SO2 was introduced in the feed gas under SCR conditions, including inhibiting the low temperature activity of the catalysts and improving N2 selectivity which exceeded 90% during the whole testing temperature. The introduction of SO2 could promote the formation of NH2NO which was the main intermediate and then decomposed into N2. Fe species in Mn-Fe/AC catalyst could improve N2 selectivity. In the presence of SO2, it showed considerable SO2 resistance compared to Mn/AC catalyst. On the one hand, iron species improved the selectivity through forming new active sites promoting the formation of NH2NO and suppressing the free NO3- generation. On the other hand, iron existing in Mn-Fe/AC catalyst could decrease the amount of sulfur species adsorbent and SO2 oxidation, thereby exhibiting better SO2 resistance.

In this paper, the combustion behavior of low rank coal and its product after hydrothermal carbonization with paper sludge hydrochar were studied. The Raman technique was used to compare the structural differences between raw coal and the product. Thermogravimetric analysis was employed to conduct experiments of single sample and their mixtures with different proportions at a heating rate of 20 °C/min, the activation energy of chemical reactions was calculated. The results showed that upgraded product had higher carbon ordering degree than raw coal and the ignition temperature and burnout temperature of the product were advanced. Compared with raw coal, the combustion characteristic parameters C and S of the product were higher, indicating that its combustibility was better. As for the mixture, when the paper sludge hydrochar ratio was not more than 10%, the mixed fuel combustion curve was still similar to coal curve. After the paper sludge hydrochar ratio exceeded 10%, the activation energy of the mixed combustion reaction of paper sludge hydrochar and upgraded coal was lower than that of raw coal and paper sludge hydrochar. These results indicated that the mixture of upgraded coal and paper sludge hydrochar as mixed fuel was a better option.

The development of catalysts with high NH3-SCR activity in the presence of SO2 was urgent for non-electric industries to control NOx emission at low temperature. Herein, a series of Sm-doping MnFeOx catalysts were synthesized through a typical PEG-assisted co-precipitation method and applied for low-temperature NH3-SCR process. SmMnFe-0.1 catalyst significantly broadened the activation temperature window and yielded almost 100% NO conversion from 75 to 200 oC, moreover, the NO removal efficiency could still maintain at about 90% in the presence of SO2 and H2O. The characterization results confirmed that Sm could optimize the dispersity of active components and enlarge the surface area of catalyst. Furthermore, strong interaction among active ions facilitated more oxygen vacancies and accelerated NO oxidation to NO2, further cooperating with abundant adsorbed NH3, leading to cause 'Fast SCR' reaction. Both catalysts were dominated by the E-R mechanism desipte MnFeOx catalyst also obeyed the L-H pathway. Particularly, the intense redox cycles between Sm and Mn inhibited the electron transferring from SO2 to Mn ions, and induced that Fe species serving as sacrificial sites along with Sm to preferentially react with SO2, resulting in an enhanced SO2 tolerance, and the possible mechanism model was proposed.

提高铁水碳饱和度,减弱侧壁炭砖侵蚀,实现炉缸长寿对高炉炼铁具有重要意义.利用静态法系统地研究了高炉系统中进入炉缸铁水的碳源的渗碳性能,并计算了表观反应速率常数K.研究结果表明,不同碳源的渗碳性能由强到弱为:NMA炭砖＞碳棒＞煤粉＞焦炭＞9RDN炭砖.碳源的渗碳性能随其石墨化程度的升高而降低.碳源中的灰分会极大影响其渗碳性能,但以团聚大颗粒形式存在的灰分并不能减弱其渗碳能力,同时Al2O3可明显降低碳源的渗碳速率.9RDN炭砖的渗碳性能低,预示着其可适应更加复杂的炉况条件.煤粉和焦炭渗碳性能偏差,煤粉以及炉料下行过程形成的焦粉进入炉缸会降低死料柱空隙度,造成炉缸不活跃,使得炉况波动频繁,并不利于死料柱渗碳和侧壁保护层的稳定.因此,要适当提升入炉焦炭粒度,增大风量,减弱未燃煤粉及焦粉对炉缸侧壁炭砖长寿的负面影响.

随着供给侧结构性改革的持续深入,中国钢铁产业布局发生了一些积极变化.全球钢铁布局特征可分为资源依托型、市场临近型及沿海港口型3种主流类型.从高质量发展的角度,客观审视目前中国钢铁工业的布局调整,分析中国钢铁布局的历史沿革、动态变化、存在的问题,对钢铁布局过程中其与工艺流程结构、区域容量和兼并重组的关系进行研究.最后,从钢铁产业发展的大趋势、大战略出发,建议加大"北钢南运"步伐,努力将粗钢产量不平衡指数控制在4以下,可一定程度上解决"北钢南运"的历史问题,助力钢铁工业高质量发展.

为了寻找新的高炉可喷吹物代替价格昂贵的无烟煤,将不同配比的烟煤与烧结烟气脱硫脱硝过程产生的活性炭粉进行混合.通过测量不同配比混煤的爆炸性和着火点,以评价其安全性,利用热重分析仪分析其燃烧性.结果表明,活性炭粉可以代替部分无烟煤进行高炉喷吹,此外,烟煤具有强爆炸性,而活性炭粉没有爆炸性,二者混合物中,当活性炭粉质量分数大于40％时没有爆炸性.烟煤的燃烧性优于活性炭粉,二者混合后会发生反协同效应,混煤燃烧性能相较于单煤变差,且混煤燃烧性能随着活性炭粉比例的增加而变差.

高炉喷吹煤粉是目前高炉冶炼降低焦比最为有效的措施之一,然而高炉喷吹煤粉种类繁多,为了保持较高的煤/焦置换比和降低高炉冶炼喷吹成本,需要对喷吹煤种进行合理的选择和搭配.以国外某钢厂提供的12种煤粉为原料,系统进行了其作为高炉喷吹煤粉所关注的基础性能和工艺性能分析,根据测试结果对不同煤粉进行高炉喷吹的综合性能进行了研究,为钢厂高炉喷吹煤粉的优化选择提供指导.研究结果表明,提供的12种煤粉中4号为高变质无烟煤,6号、7号和12号为高变质贫瘦煤,5号、10号和11号为低变质贫瘦煤,1号、2号、3号、8号和9号为低变质烟煤.相比于国内高炉喷吹用的煤粉,该钢厂提供的12种煤粉具有较低的灰分和硫含量,进行高炉喷吹能够降低渣量和入炉硫负荷;同时,所选煤粉的喷流性、流动性较高,灰熔融温度较高,低变质烟煤具有强爆炸性,不能单独作为高炉喷吹使用;不同煤粉的可磨性和燃烧性能差异较大,成为限制其应用于高炉喷吹生产的关键.结合不同煤粉高炉喷吹综合性能评价指标的计算结果,优选8号、10号、11号和12号煤粉作为高炉喷吹煤粉使用.考虑不同煤粉的采购成本,12号煤粉用于高炉喷吹降低冶炼的成本最为显著.

A novel anti-Pb poisoning Sm and Fe co-doped Mn-Ce/AC catalyst was prepared by impregnation method for low-temperature NH3-SCR of NO reaction. Maintaining the excellent low-temperature activity of Mn-Ce/AC catalyst, Sm and Fe co-doping remarkably enhanced the catalyst's Pb-resistance with NO conversion up to 77%. Sm and Fe co-doped poisoning-catalysts exhibited large specific surface area and pore volume, and the crystallinity of the MnOx and CeOx reduced. The redox properties and surface acidity of the lead poisoned SmFeMnCe/AC catalyst were effectively retained, which could promote NO oxidation and NH3 activation, further benefiting the SCR reaction. In situ DRTFTS results indicated that the low-temperature NH3-SCR mechanism of all poisoned catalysts followed both L-H mechanism and E-R mechanism, and the L-H mechanism was dominated. On the one hand, the extraordinary lead resistance of Sm weakened the damage of lead species on the physicochemical properties of the catalyst; on the other hand, the high oxidation properties and surface acidity of Fe enhanced the catalytic activity of the poisoned catalyst. Finally, a possible synergistic mechanism model of Sm and Fe co-doping on Mn-Ce/AC catalyst against Pb-poisoning was proposed.

Highly accurate prediction of converter molten steel end temperature is important foundation of realizing intelligent smelting in converter procedure. Single model prediction of converter end temperature has problems such as weak generalization ability and difficulty in increasing accuracy. To tackle these problems, this review proposes a modeling method based on Bayesian formula that dynamically integrate multiple models with different features. First, various data patterns and features are explored using different modeling methods and respective prediction model for converter molten steel end temperature is constructed. Then, the value range of the objective is discretized and the confidence levels of the prediction results from different models are computed based on Bayesian formula. Last, the prediction values of different models are weighted according to their confidence level and a comprehensive prediction result is obtained. Testing and comparison are carried out on the integration model and the three single models (support vector regression, random forest, and BP neural network) using actual production data. Results show that the integration model based on Bayesian formula can further increase the prediction accuracy effectively on top of single model prediction accuracy.

Due to the accumulation of heavy metal compounds produced by the sintering process in steel industry, the catalysts used for low-temperature selective catalytic reduction of NO with NH3 (NH3-SCR) might be seriously deactivated. In this work, the deactivation effect of PbCl2, Pb(NO3)(2), and PbSO4 on Mn-Ce activated carbon supported catalyst for low-temperature NH3-SCR of NO was investigated and compared. Poisoned catalysts were provided by impregnating fresh catalysts with Pb(NO3)(2), PbSO4 and PbCl2 aqueous solutions, respectively. Deactivation could be observed on the poisoned samples, and the deactivation degree was following PbCl2 > PbSO4 > Pb(NO3)(2). The catalytic activities of all samples were tested, and the physicochemical properties of fresh and poisoned catalysts were assessed. PbCl2 caused the most severe deactivation of the catalyst, owing to its poor redox property and surface acidity. Cl-could also react with Mn active sites to form -O-Mn-Cl bonds, resulting in additional acid sites, although these newly generated sites were not reactive in NH3-SCR reaction process. PbSO4 exhibited moderate poisoning effect due to the addition of SO42-, which created new Bronsted acid sites, facilitating the NH3 adsorption and NO reduction. Pb(NO3)(2) had the least poisoning impact on the catalyst due to the NO3-, promoting the NH3 activation. The in situ DRIFTS results revealed that NH3-SCR reaction over all samples was governed by Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanism, and did not change due to the lead poisoning. Finally, a possible mechanistic model for different lead salts poisoning over Mn-Ce/AC catalyst was proposed.(C) 2022 Elsevier Inc. All rights reserved.

Aiming at the crane scheduling problem for uncertainty tasks in multi-crane scheduling situation, this article proposes a deep reinforcement learning-based crane scheduling modeling method that is not dependent on mathematical planning and has certain generality. First, the crane scheduling process is integrated into deep reinforcement learning framework in which the orbit space of the crane and the transportation task is environmental information and crane is the intelligent agent. Second, the interactive mode between reinforcement learning algorithm and environment is adjusted to adapt to the combined learning of multi-crane scheduling model. Last, the crane scheduling model for uncertainty tasks is constructed by optimizing reward discount factor, learning rate, and reward function intensive mode. Testing of the model is carried out based on practical crane scheduling in one steelmaking workshop. Scheduling proposal is generated and all crane tasks are completed within the planned time, which verifies the feasibility of this model. Results show that compared with manual scheduling plan, the scheduling proposal based on the new model reduces total task completion time by 11.52%, time of collision of crane routes decreases by 57.14%, and negative crane transportation distance shortens by 55.26%. The high efficiency of the scheduling model is therefore verified.

To clarify the low-temperature NH3-SCR performance of Mn-Ce/zeolite catalysts and the specific promotion influence between Mn-Ce active components and zeolite supports, Mn-Ce/zeolite catalysts were synthesized using Mn-Ce mix oxides loading on several kinds of zeolites (ZSM-5 zeolite, Beta zeolite, X zeolite and Y zeolite) by impregnation method. The results indicated that Mn-Ce/X catalyst had high NO conversion of nearly 100% at 150 ? and the excellent SO2 resistance at different temperature. The Mn-Ce/ZSM-5 and Mn-Ce/Beta catalysts had NO conversion of about 100% at 275 ? while the Mn-Ce/Y catalyst had the lowest NO conversion. Additionally, Mn-Ce/X catalyst had higher relative ratio of Mn4+ and Ce3+ species, more Bronsted acid sites and better reducibility than that of other three catalysts, which could promote NH3-SCR activity. Moreover, the Bronsted acid sites and the Lewis acid sites on Mn-Ce/X catalyst were more stable at low-temperature. Besides, the SCR reaction of Mn-Ce/ZSM-5, Mn-Ce/Beta and Mn-Ce/X catalysts mainly followed Langmuir-Hinshelwood (L-H) mechanism at lower temperature and Eley-Rideal (E-R) mechanism at higher temperature. Furthermore, Mn-Ce/X catalyst had better adsorption ability of nitrate and nitrite species as well, which could enhance NH3-SCR reaction process

Zinc salts and SO2 would cause Mn-Ce/AC catalyst poisoning, reducing the service life of the catalyst. In this study, the effects of Nb2O5 on the tolerance of ZnCl2 and SO2 over Mn-Ce/AC catalyst were studied by the characterization results of BET, SEM, XRD, H-2-TPR, NH3-TPD, TG and XPS. It indicated that doping Nb2O5 could effectively enhance the SCR performance and N-2 selectivity of Zn-Mn-Ce/AC catalyst. Meanwhile, Nb2O5 could significantly improve the SO2 poisoning resistance of Zn-Mn-Ce/AC catalyst when sulfur dioxide was added into the reaction system. Nb2O5 could react with SO2 in a preferential way to restrain the sulfuration of manganese and cerium oxides on the catalyst. More importantly, Nb2O5 reacted with SO2 to form Nb sulfate and then formed a new acidic site on the Zn-Mn-Ce/AC catalyst surface, which promoted the adsorption of NH3 and inhibited the adsorption of SO2, then restricted the reaction between NH3 and SO2 and hindered the formation of ammonium sulfate channels.

Different crystal phases of MnO2 were synthesized and tested for NH3–SCR of NO and NH3 oxidation performances during 50–120 °C. Among those catalysts, α-MnO2 showed the most superior SCR performance for NOx conversion and N2 selectivity, and NH3 species on its surface were active to react with the oxygen, while NH2 species were also easily oxidized by the oxygen. For β-MnO2, NH3 (ads, B) species and part of NH3 (ads, L) species on its surface were active to react with oxygen, while NH3 (ads, L) species adsorbed at Lewis sites showed low reactive with O2, thereby producing less N2O and low NO conversion. γ-MnO2 showed the similar NOx conversion rates and N2O amount generated from the NH3 oxidation comparing to α-MnO2, while yielding much more N2O generation ratios from SCR reactions conditions. Besides, NH3 (ads, L), NH3 (ads, B), NO32− and NH2 species adsorbed on γ-MnO2 surface had high reactivity and could all be consumed by oxygen rapidly. And the N2O formation of δ-MnO2 mainly generated from SCR reactions conditions in the temperature range of 50–120 °C, while the adsorbed NH3 (ads, L) species were hard to react with O2.

我国钢铁工业巨大的产能规模、以煤为主的能源结构、以高炉-转炉为主的冶炼流程导致其面临巨大的减碳压力,是国家兑现"碳达峰碳中和"承诺的主战场之一.通过对我国钢铁工业的发展现状与趋势分析、基于工序的我国钢铁工业碳排放分析、典型钢铁冶炼低碳技术分析、我国钢铁工业低碳发展路径浅析等全面梳理了我国钢铁工业的碳排放现状,并为我国钢铁工业低碳技术的研发提出了若干建议,以期为我国钢铁工业"碳中和"愿景的如期实现提供参考.

The nonisothermal thermogravimetric analysis was implemented for gasification of sawdust char (SD-char), wheat straw char (WS-char), rice husk char (RH-char), bamboo char (BB-char) and anthracite coal (AC) in the presence of CO2. The dependence of activation energy upon conversion for different biochars and AC was obtained by the integral isoconversional nonlinear (NL-INT) method which is a model-free method. Based on the activation energy values from the NL-INT method, a model-fitting method called random pore model (RPM) was used to estimate the kinetic parameters including the preexponential factor and pore structure parameter from the experimental data. The results are shown that the gasification reactivity of different samples from high to low can be sorted as that of WS-char, SD-char, BB-char, RH-char and AC. In the early stage of gasification, the activation energy values of biochars increase generally with an increase in the conversion degree, whereas the value of AC decreases. Thereafter, the activation energy values remain almost unchanged when the conversion is up to some extent. When the conversion degree varies between about 0.3 and 0.9, these carbon materials can be sorted in the order of average activation energy from low to high as WS-char, SD-char, AC, RH-char and BB-char, respectively, 134.3, 143.8, 168.5, 184.8 and 193.0 kJ/mol. It is shown that a complex multistep mechanism occurs in the initial stage of gasification, while a single-step gasification mechanism exists in the rest of the gasification process. The RPM is suitable for describing the gasification of biomass chars and AC except the initial gasification. Additionally, it is found that the kinetic compensation effect (KCE) still exists in the gasification reactions of biochars and AC. However, the AC deviates markedly from the KCE curve. This may be caused by the similarity of carbonaceous structure of biochars and the difference in reactivity between biochars and AC.

The catalytic graphitization process of coke carbon with iron was investigated in the temperature range of 1100 degrees C-1500 degrees C using X-ray diffraction, scanning electron microcopy, high-resolution transmission electron microscopy (HRTEM). The evolution of micro-crystal graphite lattice fringes was carefully analyzed by image processing of the HRTEM micrographs. A strong catalytic effect of iron on graphitization was observed at temperature above 1200 degrees C with an obvious increase of carbon structural orders. Iron was found to promote the decrease of d(002) value and increase of Lc values of the turbostratic carbon, while the d(002) value of the newly formed graphitic carbon is quite below that of the commercial graphite when it just forms at 1200 degrees C. The melting point of iron particles were decreased due to the significant carbon dissolution into iron, leading to the melting and aggregation of iron. The lattice fringe length and the stacking number of micro-crystal graphite were found to increase obviously, while no clear change of crystal orientation was observed. This indicates that the growth of micro-crystal graphite was along its original orientation. The carbon dissolution - graphite precipitation mechanism can be used to explain the catalytic graphitization process very well.