料面喷吹蒸汽对烧结矿产质量和CO排放的影响

 随着钢铁行业烧结烟气污染物超低排放标准的持续收紧,烧结料面喷吹技术以其节能减排提质的潜在优势成为新的研究热点,被广泛认为是当前具有一定综合减排效果的烧结过程控制技术。为探究料面喷吹蒸汽的最优工艺制度,查明蒸汽喷吹影响烧结过程的作用机理,以期实现其工业化应用,采用某钢铁厂的烧结原料,研究了蒸汽喷吹总量、喷吹流量及开始喷吹时刻对烧结矿产质量指标及CO排放的影响。结果表明,在50 kg 级烧结杯原料条件下,料面喷吹蒸汽最佳试验条件应为烧结点火8 min后连续喷15 min,喷吹流量为0.02 m3/min,喷吹总量为180 g;此时,较基准相比,垂直烧结速度和利用系数稍有降低,成品率和转鼓强度分别提高0.60%和1.94%,固体能耗降低1.15 kg/t,达到最优值,烧结烟气CO浓度降低10.91%;表明喷吹蒸汽的进入使得被其他混匀矿包裹燃料中的碳元素充分反应,发挥高温反应的效果显著,进而提高成品率和转鼓强度;同时适宜蒸汽的加入参与到烧结高温带反应,有利于H₂O与C和O₂反应,将还原性气氛的CO转化为CO₂,进而降低CO排放和烧结固体能耗。综合来看,在合理的喷吹制度下,料面喷吹蒸汽可起到烧结过程CO减排和改善烧结矿产质量指标的双重效果。     

烧结料面喷吹蒸汽对烧结矿质量和CO排放影响研究

近年来,烧结料面喷吹技术成为研究的热点,期望通过喷吹介质达到烧结节能减排改质的效果。前人研究了烧结料面喷吹天然气、焦炉煤气、氧气、烧结大烟道和环冷机废气等介质对烧结矿产、质量的影响。本文重点研究了烧结料面喷吹蒸汽对烧结矿质量和CO排放的影响,通过在烧结杯试验中对烧结废气成分和料层温度进行测试的手段评价了喷吹蒸汽的效果。研究表明烧结料面适宜的蒸汽喷吹可起到CO减排和改善烧结矿质量的综合效果。     

烟气循环烧结工艺中富氧和焦炉煤气喷吹的优化

利用铁矿石烟气循环烧结的静态工艺模型,研究了富氧、焦炉煤气喷吹及其组合使用对铁矿石烟气循环烧结工艺的固体燃料消耗和污染物排放的影响.结果表明:基准烟气循环烧结工艺中,焦粉单耗为44.284 kg/t,CO_2、SO_2和烟气排放量分别为339.123、1.306和2 060.478 kg/t;采用富氧率为7.0%优化工艺,焦粉单耗减少了0.64%,CO_2、SO_2和烟气排放量分别减少了8.86%、10.34%和20.37%;采用焦炉煤气喷吹量为0.5%优化工艺,焦粉单耗减少了8.69%,CO_2、SO_2和烟气排放量分别减少了3.06%、2.3%和2.74%;采用富氧率为7.0%,焦炉煤气喷吹比例为0.5%的综合工艺,焦粉单耗减少了9.59%,CO_2、SO_2和烟气排放量分别减少了11.84%、9.57%和22.65%.     

烧结烟气CO的产生及治理途径——源头及过程控制技术

烧结烟气CO的减排越来越受到重视,从源头和过程减少CO的排放,对烧结清洁生产意义重大.本文从低碳烧结技术和烧结过程燃料燃烧调控技术入手,总结从源头和烧结过程减少CO排放的方法.结果 表明:超厚料层烧结技术、富氢能源利用技术等可以从源头减少CO的生成,而燃料粒度及分布的控制技术、蒸汽喷吹技术、富氧改变燃烧介质技术和烟气循...     

分层供热富氢烧结关键技术探索与研究

 中国提出2030年碳达峰、2060年碳中和的“双碳”战略以缓解温室效应带来的环境问题。钢铁是仅次于火电的国内第二碳排放大户,作为钢铁行业中的核心环节,烧结工序的碳减排已是必然趋势。常规烧结工艺中,料层中固体颗粒燃料难准确满足“自蓄热效应”要求的“上多下少”的分布要求,导致料层内部供热不均、成矿质量差、能效低下,且易出现微观局部还原性气氛,对烧结成矿和烟气中CO增多造成负面影响,制约了烧结节能减碳水平的提升。对此,作者研究了燃料形态、燃料分布对烧结的影响规律,提出了“分层供热富氢烧结”理念,阐述了厚料层烧结条件下料层上、中、下各层不同的气固组合供热方法,即顶层依靠富氧点火耦合固体燃料供热、上中层依靠富氢燃气喷加耦合固体燃料供热,下层依靠水蒸气喷加耦合固体燃料供热,同时探明了对应该方法的分层供热低碳烧结机理,详细阐述了富氧点火耦合固体燃料顶层供热、富氢燃气喷加耦合固体燃料中上层供热、水蒸气喷加耦合固体燃料下层供热等关键技术及其技术效果,并对应用上述技术可能出现的烧结过湿层恶化问题提出了解决办法。通过这些技术的集成应用,可以大幅降低烧结工序能耗,减少烧结工序碳消耗、碳排放及其他污染物排放,并改善烧结矿质量。     

不同蒸汽喷吹条件下烧结烟气的NOx和SO2排放规律

为降低烟气中NO_x和SO₂的排放质量浓度，提高固体燃料的燃烧效率，本文基于某钢铁厂的烧结原料开展50 kg级烧结杯试验，研究向烧结料面喷吹蒸汽条件下喷吹总量、喷吹流量及开始喷吹时间等因素对烧结过程NO_x和SO₂排放的影响。结果表明：点火8 min后向料面连续喷吹蒸汽15 min,当喷吹流量为0.02 m³/min时，烧结烟气中NO_x和SO₂排放质量浓度分别降低11.75%、13.25%,并且烧结矿的产、质量指标亦有优化。蒸汽的加入有利于固体燃料分子键的断裂，加速固体燃料挥发分中HCN和NH₃的析出进程，同时增强了烧结料层的局部还原性气氛，进而促进烧结过程NO的异相还原反应，降低了NO_x的排放质量浓度；向料面喷吹蒸汽会使过湿层增厚，使SO₂在过湿层中逐渐被吸收，当过湿层消失时，SO₂瞬间释放不充分，从而降低其排放质量浓度，并且延迟其排放峰值。本文研究...     

脱硫剂喷吹耦合活性焦技术降低烧结烟气SO2

烧结生产作业过程中会产生大量二氧化硫(SO₂)、氮氧化物(NO_x)和粉尘等大气污染物，是钢铁污染物排放的主要来源。某钢厂435 m²烧结机采用逆流式活性焦一体化脱除工艺进行污染物减排，减排设备长期运行出现老化，造成SO₂浓度超过减排系统所能承受的最大值，减排后烟气中SO₂浓度超标，且对活性焦脱硝能力产生了不利影响。为减轻活性焦减排压力，在烧结大烟道处设置脱硫剂喷吹减排系统，形成了“过程减排”和“末端治理”相结合的烟气污染物减排技术。实际应用结果表明，喷吹脱硫剂后活性焦入口烟气SO₂浓度由853.78 mg/m³降低至668.76 mg/m³,达到了活性焦脱硫脱硝工艺正常运行的工艺条件，有效解决了SO₂浓度超负荷的问题。活性焦入口处粉尘浓度由25.48 mg/m³上升至31.39 mg/m³,烟气中粉尘增加量的不明显，减排工艺的脱硫脱硝效果未受到负面...     

燃气喷吹耦合热风循环烧结的热风罩内数值模拟与结构优化

热风烧结耦合燃气喷吹技术是在热风罩内同时进行热风循环烧结和燃气喷吹的一种新型强化烧结技术，该技术能提高烧结矿产质量、降低烧结固体燃料消耗和污染物排放量。当流场均匀性较低时，喷出的燃气易富集、着火和逃逸，严重影响运行安全。为此，本文利用Fluent软件对某烧结厂500 m²烧结机热风罩内流场进行仿真模拟，结果表明：热风进入罩内后偏向于一侧料面，并在进气口下方产生回流死区使得外界空气进入罩内阻碍喷出的燃气进入料面，导致喷吹管附近燃气富集；通过优化罩内结构，使得进入料面的最大风速由6.42 m/s降低至2.72 m/s,料面风速方差由2.70降低至0.25,喷嘴出口区域和料面的最大燃气质量分数分别由1.82%和0.98%降低至1.30%和0.53%,相比原结构分别降低了57.63%、90.74%、28.57%和45.92%;优化后侧部漏风平均风速由1.17 m/s降低至0.22 m/s,相比原结构降低了81.2%,保证了燃气喷吹耦合热风循环烧结系统的安全高效稳定运行。     

全氧高炉风口喷吹烧结烟气的冶炼特征

摘要：建立了高炉或氧气高炉喷吹烧结烟气的数学模型,实现对烧结烟气利用与处理的目的。模拟结果显示：当烧结烟气喷吹温度为1250℃,全氧高炉的炉缸与炉身处各循环200m3/t炉顶煤气时,烧结烟气喷吹量每增加100m3/t,高炉理论燃烧温度降低约134℃,直接还原度增大0.02。随着烧结烟气喷吹量的增加,煤比逐渐增大,炉顶煤气中氮气含量逐渐增大,SO2浓度逐渐降低。当烧结烟气喷吹量达到894m3/t时,炉顶煤气中的SO2质量浓度为214.28mg/m3,与普通高炉相比,降低约1.48mg/m3;氮氧化物质量浓度为45.42mg/m3,低于普通高炉约6.36mg/m3。     

烧结料面喷蒸汽试验及效果分析

为强化对烧结烟气的综合治理,在控制污染物排放的同时,保证烧结生产的顺利进行,进行了烧结表面喷蒸汽试验。通过分析烧结矿质量和生产过程指标来研究喷吹水蒸气的影响;通过测量烟气成分和流量来分析烟气中CO、NOx、SO2的变化;通过总结试验数据,改进工艺,为烧结生产实现降低污染物排放提供了技术指导。     

Development and commercial application of Baosteel sintering flue gas recirculating process

Because of the low temperature,large waste gas volume,high pollutant content,and complicated compositions,waste heat recovery and emission gas treatment of sintering flue gas have always presented a challenge in the steel industry,and this issue has attracted widespread attention both locally and abroad. Recently,based on the first domestic pilot plant and demonstration project,Baosteel has performed a series of innovative research and development investigations on its sintering flue gas recirculating( SFGR) process,in which the system design and optimization,dioxin-related contaminant source suppression,ore matching structure optimization,wear-resistant design of cycling fans and pipelines,high-efficiency dust removal equipment,system control and stable operation strategy,flue gas mixing and switching control,circular hood sealing,oxygen content conditioning,recirculation sintering system process control,and model development have been studied,and a complete set of equipment and technology for the SFGR process has been initially developed. The investigation results suggest that the SFGR process can not only significantly reduce exhaust gas volume and pollutant emissions but also recover low-temperature waste heat and reduce the energy consumption of sintering; therefore,the overall technologies possess great value in energy savings,pollution emission reduction,and sintering ore quality / yield improvement.     

晋南钢铁高炉喷吹富氢气体工业化实践

 钢铁工业是中国制造业中碳排放量最高的行业,碳排放占全国碳排放总量的15%左右。高炉是钢铁工业碳消耗量最大的工序,碳消耗占钢铁流程总碳消耗的70%以上,减少高炉冶炼碳消耗是降低钢铁工业碳排放的最有效措施。高炉喷吹富氢气体不但可以提高冶炼效率,减少污染物排放,而且可以减少焦炭或煤粉消耗,从源头上降低高炉冶炼碳消耗,从而减少碳排放。以山西晋南钢铁两座1 860 m3高炉风口喷吹富氢气体工业化生产数据为例,详细研究了高炉喷吹富氢气体对燃料比、风口理论燃烧温度、炉腹煤气量、H₂利用率以及CO₂排放量的影响。结果表明,喷吹富氢气体可以显著降低高炉固体燃料消耗,在吨铁富氢气体喷吹量为65 m3条件下,富氢气体与固体燃料的置换比为0.49 kg/m3;风口喷吹富氢气体降低了风口理论燃烧温度,吨铁每喷吹1 m3富氢气体,风口理论燃烧温度降低约1.5 ℃,高炉鼓风量和炉腹煤气量都少量降低;喷吹富氢气体以后,炉内H₂的利用率平均为37.3%,CO的利用率约为43.2%;吨铁CO₂排放量可以降低80 kg左右,高炉CO₂排放降低了5.6%,取得了较好的经济、环境和减污降碳效果。     

Research and industrial testing of dioxin emission reduction technology in the sintering process

Based on an analysis of the chlorine elements in each component of the sintering mixture,industrial tests of the use of dioxin reduction techniques in the sintering process were found to reduce the chlorine sources and inhibit the formation of dioxins.The dioxin reduction effect obtained in the industrial experiment was better than that in the sintering pot experiment,but their patterns were consistent.When urea is used as an inhibitor,the dioxins can be significantly reduced.When a 0.02％ratio of urea was added,a maximum dioxin emission reduction of 79％was obtained.Reducing the chlorine sources also had an obvious dioxin reduction effect,enabling a 69.49％reduction.In addition,when these two technologies were applied simultaneously,a significant emission reduction rate of 92.23％ was achieved.The concentration of dioxins in flue gas dropped to 0.2421 ng TEQ/m3 before desulfurization,which meets the emission standard for dioxins in the final exhaust gas.     

烟气循环烧结过程料层温度及NOx排放模拟模型

 为了研究烟气循环条件影响料层的热状态及减排机理,依据烟气循环烧结过程主要反应的热力学和动力学、气-固传热规律以及气体流体力学,建立了烟气循环烧结料层温度及NO_x排放的数值模拟模型。试验验证结果表明,模型计算的料层温度、气体组分(O₂、CO、NO)等与试验检测值吻合较好,料层温度及NO排放浓度相对误差在±5%以内;根据模拟模型分析可知,烟气循环烧结中影响NO排放的主要因素是烟气循环中O₂和CO浓度,随着O₂浓度的降低和CO浓度的上升,燃料氮氧化反应速率明显下降,NO-CO还原反应速率升高,烟气中NO平均排放浓度降低。     

Flue gas recirculation in iron ore sintering process

Flue gas recirculation has been introduced into iron ore sintering process to reduce pollutant emissions. Compared with the conventional process, the sintering indices reduce gradually with decreasing O₂ content in the recirculating gas. With sufficient O₂, the principle on the use of flue gas recirculation is proposed. The heat loss caused by the decrease in O₂ content is compensated by 250°C gas and 0.5%CO. The flame and heat transfer fronts of the sintering bed coincide using mixed gases of no more than 6%CO₂ and 8%H₂O (g). A novel technology of 35.5% flue gas recirculation ratio is proposed with qualified sintering indices.     

Influence of O2 Content in Circulating Flue Gas on Iron Ore Sintering

 Circulating flue gas can reduce the emission of flue gas, and furthermore, it can reuse the waste heat effectively in the sintering process. Compared with conventional sintering, O2 that gets through the sintering bed decreases because of substituting circulating gas for air. The influences of O2 content on sintering process are studied through simulating the flue gas circulation sintering with artificial gas. It shows that, with the reducing of O2 content in circulating gas, the combustion speed of fuel decreases and incomplete combustion degree increases, which makes the flame front fall behind the heat front and reduces the heat utilization efficiency of fuel. The ultimate result is that the temperature of sintering bed decreases and the liquid phase reduces. In addition, the reducing atmosphere is strengthened because of flue gas circulation, which makes the magnetite increase yet calcium ferrite reduce gradually. Because the content of calcium ferrite with good strength reduces, the sinter yield and tumble strength decrease. To ensure the sinter index, the favorable O2 content of circulating flue gas is no less than 15%.     

烧结过程二噁英减排技术研究与工业试验

在完成烧结混合料中各组分氯元素分析的基础上,通过工业试验,分别对降低氯源以及阻滞生成这两种烧结过程中的二噁英减排技术进行了验证。工业试验的二噁英减排效果优于烧结锅试验,但规律一致。以尿素为阻滞剂时,二噁英减排效果显著,但存在最优配比。当尿素添加配比达到0.02%时,减排效果最佳,可达79%;降低氯源也具有明显的二噁英减排作用,减排率可达69.49%;同时采取两种技术,减排效果更加显著,减排率达92.23%,脱硫前烟气中二噁英浓度降至0.2421 ng TEQ/m^3,已可满足最终排放废气中二噁英的排放标准。     

活性焦法烧结烟气脱硝率影响因素解析

 为了明确活性焦在烧结烟气净化系统循环使用过程中脱硝性能变化及影响烧结烟气脱硝率的主要工艺参数,提高活性焦法烧结烟气净化效率,通过红外光谱分析和模拟试验研究循环使用中活性焦性能变化及其对脱硝率的影响,并通过生产数据统计分析明确影响活性焦法烧结烟气脱硝率的主要工艺参数及其影响规律。结果表明,经循环使用,活性焦表面酚基和醌基数量增加,对NO吸附量降低,导致活性焦前期脱硝率下降,而氨气预吸附处理可大幅提高其前期脱硝率;随脱硝段高度位置下降,脱硝率经历100%、迅速降低、缓慢升高直至平衡等阶段。其次,脱硝率与氨氮比、O₂体积分数、NO_x质量浓度、解析温度呈正相关,与H₂O体积分数、SO₂质量浓度、烟气流量、活性炭床温度呈负相关,其中,氨氮比、O₂体积分数和NO_x质量浓度对脱硝率影响最大,工艺参数优化过程中应着重关注。