Cleanliness of Ti-bearing Al-killed ultra-low-carbon steel during different heating processes

During the production of Ti-bearing Al-killed ultra-low-carbon(ULC) steel, two different heating processes were used when the converter tapping temperature or the molten steel temperature in the Ruhrstahl–Heraeus(RH) process was low: heating by Al addition during the RH decarburization process and final deoxidation at the end of the RH decarburization process(process-Ⅰ), and increasing the oxygen content at the end of RH decarburization, heating and final deoxidation by one-time Al addition(process-Ⅱ). Temperature increases of 10°C by different processes were studied; the results showed that the two heating processes could achieve the same heating effect. The T.[O] content in the slab and the refining process was better controlled by process-Ⅰ than by process-Ⅱ. Statistical analysis of inclusions showed that the numbers of inclusions in the slab obtained by process-Ⅰ were substantially less than those in the slab obtained by process-Ⅱ. For process-Ⅰ, the Al_2O_3 inclusions produced by Al added to induce heating were substantially removed at the end of decarburization. The amounts of inclusions were substantially greater for process-Ⅱ than for process-Ⅰ at different refining stages because of the higher dissolved oxygen concentration in process-Ⅱ. Industrial test results showed that process-Ⅰ was more beneficial for improving the cleanliness of molten steel.

Process Reengineering of Cold Chain Logistics of Agricultural Products Based on Low-carbon Economy

Through the process analysis of cold chain logistics of agricultural products,we find that cold chain logistics of agricultural products contradict the development model of low-carbon economy to some extent.We apply the development idea of low-carbon economy,introduce the thirdparty logistics companies,establish distribution center of cold chain logistics of agricultural products,and strengthen information sharing,to reengineer the process of cold chain logistics of agricultural products in China.The results show that applying low-carbon economy to process reengineering of cold chain logistics of agricultural products,has advantages of increasing added value of products,promoting scale merit and abating lag,plays a role in promoting emission reduction,high efficiency and environmental protection in the process of cold chain logistics of agricultural products in China.

Controlled Rolling and Cooling Process for Low Carbon Cold Forging Steel

Effect of controlled rolling and cooling process on the mechanical properties of low carbon cold forging steel was investigated for different processing parameters of a laboratory hot rolling mill. The results show that the specimens with fast cooling after hot rolling exhibit very good mechanical properties, and the improvement of the mechanical properties can be attributed mainly to the ferrite-grain refinement. The mechanical properties increase with decreasing final cooling temperature within the range from 670 ℃ to 570 ℃ due to the finer interlamellar spacing of pearlite colony. The specimen with fast cooling after low temperature rolling shows the highest values of the mechanical properties. The effect of the ferrite grain size on the mechanical properties was greater than that of pearlite morphology in the present study. The mechanical properties of specimens by controlled rolling and cooling process without thermal treatment were greatly superior to that of the same specimens by the conventional rolling, and their tensile strength reached 490 MPa grade even in the case of low temperature rolling without controlled rolling. It might be expected to realize the substitution medium-carbon by low-carbon for 490 MPa grade cold forging steel with controlled rolling and cooling process.

Nitrogen removal for low-carbon wastewater in reversed A^2/O process by regulation technology

Full scale experimental study on nitrogen removal for low-carbon wastewater was conducted in reversed A2/O process in Jiguanshi waste water treatment plant in Chongqing,in order to aid the operation and maintenance of similar WWTP. When the proposed measures,such as using 0.1% (volume fraction of wastewater) landfill leachate,shortening HRT by 2/3 in the primary sedimentation tank and controlling DO at 0.5 mg/L in the 3rd section of aerobic zone,are applied,15% of the carbon source can be complemented,the favorable property of activated sludge is achieved,and the nitrogen removal effect is significantly improved. The effluent NH3-N is 2 mg/L and the removal rate is 90%. The effluent TN is 17 mg/L and the removal rate is 54%. The up-to-standard discharge of the effluent is achieved. And after the optimization,the unit electricity consumption also reaches 0.21 kW/h and saves 20%.

Grain refinement of low carbon steel produced by CSP process

In comparison with conventional production for hot strips, compact strip production (CSP) brings about some new micro-structural phenomena. Investigations were carried out to clarify the grain refinement mechanism of low carbon steel strips produced by the EAF-CSP process. Samples, obtained from the same rolling stock during continuous rolling, were examined through SEM, TEM and XEDS. Thin slabs have a dominant columnar structure and the spacing of the secondary dendrite arms ranges from 90 to -125 μm. The average grain sizes for the central area of the samples from the 1st to 6th pass are 41.6, 25.2, 21.4, 20.2, 13.1, 6.7 μm, respectively. Large number of nanometer oxide and sulfide have been found in the low carbon steel produced by the CSP process. The grain refinement mechanism can be summarized as follows: finer solidification structure of the thin slab; austenite recrystalliza-tion at higher temperature and stain accumulation at lower temperature caused by the great reduction of single rolling pass during continuous rolling; nano-scaled precipitates of sulfide and oxide which drag grain boundaries of austenite or ferrite to prevent the grain coarsening.

Deformation Behavior of Ultra-low Carbon Steel in Ferrite Region during Warm Processing

The hot deformation experiments of ultra-low carbon steel in ferrite range were carried out in a hot simulator in order to research hot deformation behaviors of ultra-low carbon steel in ferrite range at low temperature. The results show that the influences of deformation parameters on flow stress are different to those in austenitic deformation. The deformation characteristic parameters were calculated for ultra-low carbon steel in ferrite region. The flow stress equation for ultra-low carbon steel in ferritic deformation at low temperature was obtained.

Effects of Quenching Process on Microstructure and Mechanical Properties of Low Carbon Nb-Ti Microalloyed Steel

The low carbon Nb-Ti mieroalloyed tested steel was prepared by the process of vacuum induction furnace smelting, forging and hot rolling. The new steel aims to meet the demand of high strength, high toughness and high plasticity for building facilities. The effects of quenching process on microstructure and mechanical properties of tested steel were investigated. The results showed that prior austenite grain size, phase type and precipitation behavior of （ Nb, Ti） （ C, N） play important roles in mechanical properties of the steel. Through modified appropriately, the model of austenite grain growth during heating and holding is d^5.7778 = 5. 6478^5.7778 ＋ 7.04 × 10^22t^1.6136 exp（- 427. 15 ×10^3 /（RT））. The grain growth activation energy is Qg = 427. 15 kJ. During quenching, the microscopic structures are mainly martensite and lath bainite which contains lots of lath substructure and dislocations. The content of phases, fine and coarsening （ Nb, Ti ） （ C, N ） precipitated changes during different quenching temperatures and holding time. Finally compared with the hardness value, the best quenching process can be obtained that heating temperature and holding time are 900 ℃ and 50 mins, respectively.

Mechanical and corrosion properties of low-carbon steel prepared by friction stir processing

Low-carbon steel plates were successfully subjected to normal friction stir processing(NFSP) in air and submerged friction stir processing(SFSP) under water, and the microstructure, mechanical properties, and corrosion behavior of the NFSP and SFSP samples were investigated. Phase transformation and dynamic recrystallization resulted in fine-grained ferrite and martensite in the processed zone. The SFSP samples had smaller ferrites(5.1 μm), finer martensite laths(557 nm), and more uniform distribution of martensite compared to the NFSP samples. Compared to the base material(BM), the microhardness of the NFSP and SFSP samples increased by 19.8% and 27.1%, respectively because of the combined strengthening effects of grain refinement, phase transformation, and dislocation. The ultimate tensile strengths(UTSs) of the NFSP and SFSP samples increased by 27.1% and 38.7%, respectively. Grain refinement and martensite transformation also improved the electrochemical corrosion properties of the low-carbon steel. Overall, the SFSP samples had better mechanical properties and electrochemical corrosion resistance than the NFSP samples.

Optimum process of RH-MFB refining for ultra-low carbon steel

A mathematical model was established and applied to simulate thedecarburization of RH-MFB process in Pansteel Company. Study of theeffects of w_[C]0, w_[O]0, Ar flowrate, evaluation rate the MFB lanceblowing parameters on the decarburization process was car- Ried out.The results showed that this model could give the quantitativeunderstanding of the process, especially the behavior of MFB Lanceblowing. This model has realized the optimum process of RH-MFBrefining for ultra-low carbon steels in Pansteel.

Research on the Low-carbon-high-value Agriculture Technology in the Comprehensive Improvement of Intra-county Environment Pollution——Taking the Development of Cultivation and Breeding Industry in the Ecological Cyclic Agricultural Garden in Shaoshan Irri

The comprehensive improvement strategy of intra-county environment pollution in the city and countryside was searched.By the research method which combined the microscopic view,the macroscopic view with the dynamic perspective,the seriousness of rural water quality,soil and atmospheric pollution in Xiangxiang,Xiangtan and the surrounding areas in Shaoshan irrigated area was revealed.The control measure which was 'four-dimensional pollution in the city and countryside'—— low-carbon-high-value agriculture and the technology innovation was proposed.The low-carbon-high-value technology innovation industrialization demonstration in three parts which included the pre-production,mid-production and post-production deep-processing of cultivation and breeding industry in the ecological cyclic agricultural garden in Shaoshan irrigated area was the driving force.We tried to propel the low-carbon ecological cultivation and breeding industry which included the paddy rice,grass,tree,medicinal herbs and pig,cow,chick,duck,fish.We wanted to relieve the structural unbalance of previous cultivation and breeding industry,'cheap grain hurting the farmers' and the short-leg problem of social-economic-ecological benefit.The results showed that the low-carbon-high-value agricultural system was a poly-generation technology system which promoted the multi-level and grading utilization,saved the energy,reduced the consumption and cleaned the production based on the ecology.

生命周期评价方法在制革领域的应用研究现状分析

皮革工业是我国具有国际竞争优势的传统轻工支柱产业,其绿色低碳转型升级已是必然趋势。生命周期评价(Life Cycle Assessment,LCA)作为一种系统性、综合性的评价方法,可用于量化制革过程的资源环境影响。文章简要回顾了LCA方法的发展历程、标准流程与理论框架,重点总结了LCA方法在制革领域应用的研究现状及其对制革减污降碳的指导作用,以及现存的问题和解决方案。结合作者在皮革产品碳足迹核算标准方法研制与皮革化学品碳排因子数据库构建方面的研究与实践,核算形成皮革产品碳足迹数据库,并提出构建制革工艺LCA环境影响预测模型,希望赋能绿色低碳制革生产和皮革行业高质量发展。

Modeling of Microstructure Evolution and Mechanical Properties of Steel Plates Produced by Thermo-Mechanical Control Process and Its On-line Application

An integrated metallurgical model was developed to predict microstructure evolution and mechanical properties of low-carbon steel plates produced by TMCP. The metallurgical phenomena occurring during TMCP and mechanical properties were predicted for different process parameters. In the later passes full recrystallization becomes difficult to occur and higher residual strain remains in austenite after rolling. For the reasonable temperature and cooling schedule, yield strength of 30 mm plain carbon steel plate can reach 310 MPa. The first on-line application of prediction and control of microstructure and properties (PCMP) in the medium plate production was achieved. The predictions of the system are in good agreement with measurements.

中国铁矿石选矿技术发展与展望

铁矿石作为钢铁工业最为重要的原材料,是我国重要的战略性矿产资源之一。我国铁矿资源储量丰富,但97%以上属于贫矿,需要经过选矿富集后才能供给高炉炼铁。多年来,在我国选矿工作者的共同努力下,我国铁矿选矿技术得到长足进步和发展。通过回顾我国铁矿选矿技术的发展历程,综述单一弱磁选、单一浮选、重选—磁选—反浮选、磁化焙烧—磁选等主要选矿技术在我国铁矿选矿厂的应用,总结我国典型多金属共生型铁矿石如伴生稀土/萤石型铁矿石、伴生钛铁矿型铁矿石、伴生多金属硫化物型铁矿石和伴生硼铁矿型铁矿石的选矿现状,介绍影响我国铁矿选矿技术进步的关键设备如圆锥破碎机、高压辊磨机、半自磨机、立环脉动高梯度磁选机、高频振动细筛、搅拌磨机等,指出我国铁矿选矿未来要以“高效节能、低碳减排”为原则,以“优质优用、劣质能用”为战略,开发选冶联合工艺,研发大型高效设备,研制低温环保药剂,提高智能控制水平,加强资源综合利用。

电解锰行业清洁生产评价指标体系研究与应用

清洁生产评价指标体系研究对行业深入推进清洁生产具有重要意义,提出了适用于一般工业行业的“源头控制-过程减排-末端治理-循环利用”全过程清洁生产评价框架模型;构建了由生产工艺及装备等9个一级指标、45个二级指标组成的电解锰行业清洁生产评价指标体系,采用专家咨询-层次分析法确定各指标权重,其中电解锰渣无害化处理率和直流电耗指标的权重分别为0.092和0.050,反映出行业清洁生产的重点和关键点。对3家典型企业的清洁生产水平评价结果表明,案例企业对标Ⅰ级基准得分为40.78~77.26,与清洁生产Ⅰ级水平有差距,指标体系能有效反映电解锰企业的清洁生产水平。结合企业1实际情况,从生产工艺及装备等方面提出10项针对性的清洁生产改造措施建议,为企业推进清洁生产提供参考,也可为行业绿色低碳政策制定提供依据。

石墨掺杂刨花板低碳制备工艺及性能

木材等植物原料具有较低的导热性能,在刨花板热压过程中,热传递效率较低,不利于实现“双碳”目标。引入石墨这种导热性能优异的材料,并探讨了石墨添加量(1%,3%,5%)、石墨粒径(45,11,6.5μm)配比(1∶1∶1,0.5∶1∶1.5,1.5∶1∶0.5)以及热压温度(150,170,190℃)对刨花板物理力学性能和剖面密度分布的影响,探究了热压时板坯内部温度和蒸汽压力的变化。结果表明,刨花板的静曲强度、弹性模量、内结合强度和板面握钉力受石墨添加量的影响较大,而24 h吸水厚度膨胀率主要受石墨粒径配比影响。随着石墨添加量(1%~5%)的增加,刨花板的内结合强度、弹性模量、静曲强度、24 h吸水厚度膨胀率和板面握钉力呈下降趋势。当石墨粒径配比为1∶1∶1时,刨花板的吸水厚度膨胀率最小。提高热压温度可促进刨花板性能的提升,在固定石墨粒径配比(1∶1∶1)和添加量(1%)的条件下,不同热压温度下石墨的引入均能提升热压过程中板坯内部的温度和蒸汽压力,尤其是在较低热压温度下,石墨的影响更为显著。同时,石墨还可以提高刨花板的导热系数,进一步优化了热压效率。经综合考量,较佳的石墨添加工艺为石墨添加量1%、石墨粒径配比1∶1∶1和热压温度150℃。

大型炼化一体化过程全流程低碳运行分析与决策优化综述

石化工业是国民经济支柱产业,也是高能耗高排放行业。面向双碳背景下传统石化行业低碳化、智能化转型需求,针对碳排与工艺耦合机理复杂的炼化一体化全流程碳足迹表征精度低问题、耦合互联多装置生产流程碳排异常环节难追溯问题以及实际工业环境下全流程优化方案不收敛问题,本文以大型炼化一体化全流程为研究对象,描述了利用过程机理、工业大数据和人工智能技术,研究炼化一体化全流程碳足迹建模理论、全流程碳排异常环节溯源理论以及全流程装置分布式协同决策优化理论,实现炼化一体化全流程低碳优化。在为流程工业碳足迹建模、溯源和优化提供方法的同时,也为实际炼化一体化企业高效、低碳、智能生产提供指导建议。

城镇净水厂提标改造的主要问题及对策

城镇净水厂作为城市基础设施的重要组成部分,提供人们日常生活所需用水。由于部分水厂建成年代久远,净水工艺落后,难以处理水源中出现的新兴污染物,特别是《生活饮用水卫生标准》(GB5749-2022)发布实施,对于出厂水水质提出了更高要求。为优化处理工艺,提高运行管理成效,保障人民群众饮用水安全达标,已成为净水厂当前面临的重要任务。

论纺织印染废水低碳治理

纺织印染行业是废水及污染物排放量最大的工业行业之一,同时也是能源密集及碳排放高的行业;废水低碳治理已成为纺织印染行业可持续发展的重要路径。在分析印染废水处理工艺温室气体排放特征的基础上,提出依据染化料助剂推定的碳排放潜势概念;针对纺织印染废水处理工艺复杂及水质时变性大的问题,建立了基于碳氮物料平衡的废水处理工艺碳排放精准核算方法。面向废水低碳处理运行需求,总结了纺织印染废水低碳治理技术进展及发展方向。

富产化学品的绿色高效石油碱催化新技术

近年来,碱催化技术和原油直接制化学品技术越来越受到人们的关注。本文报道中国海洋石油集团有限公司开发的原油直接催化转化制化学品(DPC)碱催化技术,包括催化剂性能、工业试验效果、碱催化技术与分子筛酸催化技术的比较以及碱催化反应特点、反应机理等。DPC碱催化技术开发的关键是在发现可大幅减少焦炭和干气产率的催化新材料基础上,合成制备出高水热稳定性的介孔材料及具有高碱活性稳定性的碱催化剂,并开发出配套的反应-再生新工艺。处理劣质重油原料时,DPC技术比延迟焦化技术和催化裂化(FCC)技术更具优势,而与处理常压渣油或减压渣油的加氢处理工艺,即常压渣油加氢脱硫(ARDS)或减压渣油加氢脱硫(VRDS)技术相比,DPC技术也具有更多的优势。DPC技术在大幅降低干气和焦炭产率的同时,还能大幅提高化学品收率,是目前唯一适用于原油、蜡油、常压渣油、减压渣油、油砂沥青等各类原料的新技术。经初步证实,DPC碱催化技术遵循负碳离子反应机理,几乎不发生氢转移和芳烃缩合反应,但也表现出一定的裂解和异构化反应能力,是当前对用分子筛固体酸催化处理重油技术的颠覆性技术,可以取代延迟焦化、FCC、ARDS或VRDS工艺,为原油直接制化学品提供理论与技术指导、支撑与引领。

过程管理视角下的我国城市低碳经济建设水平诊断研究

低碳城市建设是长期性的系统工程,低碳经济则是其重要抓手。为准确把握我国低碳经济建设现状,文章基于过程管理视角构建了低碳经济建设水平诊断指标体系,动态系统地诊断了我国城市低碳经济建设水平。研究对我国36个重点城市的低碳经济建设成效开展分析后发现:(1)我国样本城市低碳经济建设水平较高,其中上海、南京、天津和重庆在城市低碳经济建设中表现较好。(2)空间分布上,东部沿海与长江经济带城市得分较高,而中西部城市得分则相对较低,城市低碳经济建设水平受其实际经济发展水平影响,且具有明显的空间溢出效应。(3)就环节得分而言,实施环节得分最高,其他环节各城市得分差异较大。研究为我国城市如何提升低碳经济建设水平提供了理论依据与针对性的政策建议,对促进我国低碳城市建设具有重要借鉴意义。