Effect of Low pH on Forming Process of Desulfurization Gypsum Composite Boards Strengthened by Melamine-formaldehyde Resin

Through exploring the effects of low pH on the composite system of desulfurization gypsum(DG)enhanced by melamine-formaldehyde resin(MF),it is found that the inducing of sulfate-ion,in contrast to chloride and oxalate ions,favors the longitudinal growth of the crystalline form of the hydration product,which was relatively simple and had the highest length to width(L/D)ratio.At the same time,MF can also improve L/D ratio of gypsum hydration products,which favors the formation of hydrated whiskers.Finally,in a composite system composed of hemihydrate gypsum,MF,and glass fibers,when dilute sulfuric acid was used to regulate pH=3-4,the tight binding formed among the components of the composite system compared to pH=5-6.The hydration product of gypsum adheres tightly to glass fiber surface and produces a good cross-linking and binding effect with MF.The flexural strength,compressive strength,elastic modulus,and water absorption of the desulphurized gypsum composite board is 22.7 MPa,39.8 MPa,5608 MPa,and 1.8%,respectively.

某有色冶炼企业环集烟气脱硫技术改造研究

某有色冶炼企业现有环集烟气脱硫装置一套,处理熔炼环集烟气等,采用石灰石-石膏法脱硫工艺,副产石膏。该脱硫装置运行良好,脱硫效率较高,开工率较高,脱硫尾气能够达标排放,存在的问题是石膏渣去向,废水量偏大。本次铜冶炼工艺改造后,吹炼环集烟气并入冶炼工艺烟气进烟气制酸系统,环集烟气脱硫系统处理熔炼环集烟气、沉降电炉环集烟气、阳极炉环集烟气和阳极炉工艺烟气。脱硫效率≥80%。脱硫尾气排放符合《铜、镍、钴工业污染物排放标准》(GB25467-2010)修改单中规定的特别排放限值标准,满足排放要求,不仅可以解决废气的环境污染问题,而且每年可为公司节省一定的废水处理成本。

Mathematical Modeling of the Vacuum Circulation Refining Process of Molten Steel

The available studies in the literature on mathematical modeling of the vacuum circulation (RH) refining process of molten steel have briefly been reviewed. The latest advances obtained by the author with his research group have been summarized. On the basis of the mass and momentum balances in the system, a new mathematical model for decarburization and degassing during the RH and RH KTB refining processes of molten steel was proposed and developed. The refining roles of the three reaction sites, i.e. the up snorkel zone, the droplet group and steel bath in the vacuum vessel, were considered in the model. It was assumed that the mass transfer of reactive components in the molten steel is the rate control step of the refining reactions. And the friction losses and drags of flows in the snorkels and vacuum vessel were all counted. The model was applied to the refining of molten steel in a multifunction RH degasser of 90 t capacity. The decarburization and degassing processes in the degasser under the RH and RH KTB operating conditions were modeled and analyzed using this model. Besides, proceeded from the two resistance mass transfer theory and the mass balance of sulphur in the system, a kinetic model for the desulphurization by powder injection and blowing in the RH refining of molten steel was developed. Modeling and predictions of the process of injecting and blowing the lime based powder flux under assumed operating modes with the different initial contents of sulphur and amounts of powder injected and blown in a RH degasser of 300 t capacity were carried out using the model. It was demonstrated that for the RH and RH KTB refining processes, and the desulphurization by powder injection and blowing in the RH refining, the results predicted by the models were all in good agreement respectively with data from industrial experiments and practice. These models may be expected to offer some useful information and a reliable basis for determining and optimizing the technologies of the RH and RH KTB refining and desulphurization by powder injection and blowing in the RH refining and for controlling the processes.

基于不确定性补偿的湿法脱硫系统二氧化硫超低排放控制

为了吸纳新能源,燃煤机组需要灵活运行,而由此引起的多变工作环境会导致湿法脱硫过程产生显著的非线性和不确定性,同时脱硫过程的时延特性也会增加控制难度。为了实现脱硫过程更快速灵敏的控制,提出一种基于变频改造的脱硫控制策略,并基于该策略,通过现场试验获得动态特性模型。同时,为了良好地处理不确定性,实现控制过程中的不确定性补偿,提出一种针对时延对象的更新高斯过程模型预测控制方法,并通过参数分析与仿真试验证明了该方法的可行性。最后,通过现场实际应用,验证了所提控制策略与控制方法的有效性。

烟气脱硫技术应用于电解铝的研究进展

为促进电解铝行业绿色健康发展和环境保护提升,综述了目前国内外电解烟气脱硫研究现状,从理论及工艺优缺点等方面进行了分析研究,并提出了电解铝烟气脱硫治理技术未来研究的建议,以期为电解烟气治理技术发展提供思路与借鉴。

我国铝土矿脱硫除铁研究现状及发展趋势

铝土矿中的硫和铁是影响氧化铝生产的重要杂质,为了更好地从铝土矿中脱硫、除铁,针对我国优质铝土矿资源严重短缺、对外依存度高,以及高硫高铁铝土矿选矿工艺技术中存在的问题,从我国铝土矿资源储量分布特点以及铝土矿脱硫、除铁方法两方面概述了铝土矿选矿的研究现状,对不同脱硫除铁工艺进行了介绍和综合分析,并从加大铝土矿选矿技术研究投入力度等方面进行了展望,探讨了未来高硫高铁铝土矿脱硫除铁的研究方向。

基于不确定性补偿的脱硫系统超低排放控制

为了弥补燃煤机组灵活运行条件下,脱硫系统本身的大时延、不确定性对脱硫过程的影响加剧问题,本文提出了一种基于变频浆液循环泵的脱硫控制策略,以提供更加及时的控制作用。同时,为了处理脱硫系统宽负荷运行时的时延特性和不确定性,提出了一种针对时延对象的更新高斯过程模型预测控制方法,并通过参数分析与仿真实验展示了该方法的性能。研究表明,本控制方案可以有效提高脱硫控制效率,从而降低能耗。

Central composite design for optimization and formulation of desulphurization of iron ore concentrate using atmospheric leaching process

Owing to the negative effects of sulphur in iron ore on steelmaking process and environment, a tank leaching process was performed in atmospheric conditions to remove the sulphur from the iron ore concentrate and simultaneously to transform sulphide minerals into useful by-products. To achieve desirable sulphur removal rate and efficiency, central composite design was adopted as a response surface methodology for the optimization and evaluation of the process. A full-quadratic polynomial equation between the sulphur removal and the studied parameters was established to assess the behaviour of sulphur removal as a function of the factors and to predict the results in various conditions. The optimum conditions were obtained based on the variance tests and response surface plots, from which the optimized ranges for each factor resulting in the best response （corresponding to the highest percentage of desulphurization） could be then achieved. The results show that most desirable conditions are atmospheric leaching in 1.39 mol/dm3 nitric acid and 0.88 mol/dm3 sulphuric acid for 47 h. The designed process under the optimized desulphurization conditions was applied to a real iron ore concentrate. More than 75% of the total sulphur was removed via the leaching process. In addition to the desulphurization, the conversion of sulphide-bearing minerals into useful by-products, extraction of valuable metals, and executing the process under atmospheric conditions are the other advantages of the proposed method.

产品精制装置胺液发泡的工艺调整及应对措施

某公司1.38 Mt/a产品精制装置液化气脱硫、脱硫醇系统受胺液发泡困扰,造成装置纤维膜接触器压差上涨、装置碱渣排放量增加、下游气体分馏装置原料带液、MTBE装置催化剂失活等方面影响。大检修期间,通过对液化气脱硫塔改造,开工后液化气脱硫塔采取塔下界位控制、降低贫胺液进料量、降低脱硫醇罐界位、降低碱液循环量等工艺调整措施,液化气带胺液量大幅降低,液化气水洗水质量、气体分馏装置原料液化气带液、MTBE装置催化剂失活等影响大幅改善。

倾动炉烟气双氧水脱硫工艺应用优化

江西铜业股份有限公司贵溪冶炼厂倾动炉的冶炼烟气经降温和除尘后,采用双氧水脱硫工艺脱除SO2达标排放。实际运行中存在文丘里塔和脱硫塔液位不稳定、脱硫效率低、工业用水量大等现象。为缓解乃至消除上述现象,对原有工艺进行优化和技术改进,增加了气液分离塔和气体分配器,采用了脱硫塔循环泵变频控制模式,优化了双氧水添加方式,改进了循环管道实现脱硫塔循环液串并联控制。通过以上工艺优化和技术改进,提高了双氧水利用率,降低了工业用水量、用电量以及稀酸、废酸排放量。

渝东南茅口组气井脱硫阻垢装置及工艺研究

渝东南茅口组气井生产管柱、流程管线及设备中均出现了不同程度的结垢情况,导致产量大幅度下降,设备维修频繁且困难,极大地影响了茅口组气井的正常平稳生产。通过对垢样、采出水样及入井药剂化验分析可知,现有工艺中碱性脱硫剂与高含Ca^(2+)、Mg^(2+)、HCO^(-)_(3)及CO^(2-)_(3)的地层水反应会产生大量碳酸盐类垢质。此研究中首先对渝东南茅口组气井的结垢机理进行了分析;然后设计了规模、成本适用于边远单井的脱硫防垢装置及配套工艺;最后将其应用于现场单井生产。实验结果表明,此脱硫阻垢工艺遏制了垢物的形成、扩散、累积,同时使脱硫效果得到了大幅提升。

循环流化床脱硫工艺在热回收焦炉烟气治理的运用

热回收焦炉烟气成分复杂,含有机物多、颗粒物高、SO3高、湿度大,湿法脱硫系统出现了排放口普遍蓝烟严重,且颗粒物排放不能稳定达到超低排放要求的问题。循环流化床脱硫工艺的运用,解决了湿法脱硫系统运行过程中的问题,在治理热回收焦炉烟气上存具有一定的指导意义。

石油和天然气生物脱硫技术分析和展望

综述了石油和天然气生物脱硫工艺应用的最新进展,对石油和天然气生物脱硫的原理、使用的微生物种类和工艺设计进行了比较和分析,并展望了生物脱硫技术在石油和天然气工业可能的发展与应用。通过对比分析,阐述了石油、天然气和其他原料生物脱硫机理的不同和联系,以及各种工艺目前存在的问题和可能的解决方法。边远地区、低含硫油气藏的开采和微生物脱硫能力的提高及其工艺的改善,将促使生物除硫技术在石油和天然气开发中广泛应用。

RH精炼过程深脱硫的试验研究

实验室钢液真空脱硫试验表明 ,组成为 6 5 %～ 85 %石灰和 1 5 %～ 35 %萤石的粉剂 ,粒度为 5mm以下 ,加入量在 3～ 8kg/t的条件下 ,可使初始硫含量为 0 0 0 35 %～ 0 0 0 6 5 %的钢液脱硫至 0 0 0 2 0 %以下 ,脱硫时间为 1 0～1 5min ,脱硫率在 6 0 %～ 80 %。 30 0tRH现场对管线钢的深脱硫试验表明 ,钢液平均初始硫含量为 0 0 0 30 %时 ,自转炉出钢至RH处理结束的脱硫效率平均可达到 4 6 7% ;RH处理结束钢水的平均硫含量为 0 0 0 1 6 %。

湿式氨法烟气脱硫中气溶胶的形成特性研究

气溶胶的形成是湿式氨法烟气脱硫过程存在的主要问题,通过测试分析氨法脱硫前后细颗粒的浓度与粒径分布、颗粒形态及其组成的变化特性,探讨了氨法脱硫中气溶胶的形成机理,并考察了影响气溶胶颗粒形成的主要因素。结果表明:氨水挥发逸出的气态NH3与烟气中SO2发生气相反应是气溶胶形成的主要原因,气溶胶含(NH4)2SO4、(NH4)2SO3、NH4HSO3等组分,粒径集中在0.07～0.70μm范围内,氨法脱硫系统对其难以有效脱除;氨水脱硫液温度及其浓度、烟气中SO2浓度、液气比等对气溶胶形成具有重要影响,形成量随氨水脱硫液及烟气中SO2浓度升高而增多,在保持NH3:SO2化学计量比不变的情况下,随液气比增大,气溶胶颗粒形成量减少。最后,对气溶胶颗粒的控制措施提出了建议。

双循环流化床半干法烟气悬浮脱硫技术研究与工程实践

文中论述一种双循环流化床烟气半干法悬浮脱硫装置 ,并完成了小型工业中试、工业示范。工程实践表明 :该工艺脱硫效率可达 92 % 。

低碳经济形势下烧结烟气脱硫技术的发展

对现行主流脱硫工艺石灰/石灰石-石膏法存在的问题进行了讨论,分析了"低碳经济"形势下可行的烧结烟气脱硫技术,指出湿法中氨法、干法中活性焦法有望成为低碳经济形势下烧结烟气脱硫的发展方向。

络合铁法脱H2S技术研究进展

分析了络合铁法脱除H2S机理和pH、羟基化程度、溶解氧浓度等因素对脱硫过程的影响;总结了络合铁脱硫液中可溶性铁盐、配体、自由基清除剂、硫颗粒改性剂、缓蚀剂等配方成分的作用;介绍了目前国内外主要的络合铁脱硫工艺LO-CAT工艺、SulFerox工艺、Sulfint工艺、DDS工艺、改良络合铁法脱硫工艺,并作了简要评价;指出络合铁法脱H2S技术存在的主要难题是配体降解、副盐累积、Fe2+再生缓慢、硫堵。开发高硫容脱硫剂配方、高传质效率脱硫设备、优化流程及装置配置是络合铁法脱H2S技术未来发展的方向。

脱硫废水深度降氟机理及工艺优化的试验研究

在静态试验装置中,通过化学沉淀与混凝法相结合的二次除氟工艺处理电厂高浓度含氟脱硫废水,采用正交试验研究了多因素操作条件对脱硫废水除氟效率的综合影响.结果表明:氯化钙除氟性能优于氢氧化钙,最佳钙氟摩尔比n(Ca)/n(F)=1∶1.3;添加硫酸铝、氯化铁等混凝剂可明显改善药剂的除氟性能,确定了最佳n(Al)/n(F)=1.5、最佳n(Fe)/n(F)=0.3;在pH=5～6的弱酸性条件、温度约为30℃、转速约为500r/min、添加聚丙烯酰胺(PAM)质量分数约为0.1%的情况下,除氟效率高达95%以上;影响脱硫废水除氟效率的因素由主到次依次为:CaCl2>Al2(SO4)3>PAM>FeCl3>pH>温度>搅拌转速.

燃煤锅炉湿法脱硫烟气中颗粒物排放特征

选择北京市典型燃煤锅炉进行研究,结果表明:烟气中可凝结颗粒物在总颗粒物中占有较高比例,供热燃煤锅炉总颗粒物排放水平明显高于电厂燃煤锅炉;颗粒物中水溶性离子含量较高,供热燃煤锅炉硫酸根比例尤其显著;烟气总颗粒物中存在大量不稳定的易被氧化的组分;同为燃煤源,不同的烟气净化工艺排放的PM2.5组分特征差异明显;现有标准和技术规范存在不足,无法满足全面、准确监测污染源排放总颗粒物的实际需要。建议建立总颗粒物、可凝结颗粒物的监测技术规范,全面测算燃煤锅炉硫、氮化合物排放情况,科学评估脱硫及脱硝效率。