Breakthrough analysis for CO2 removal by activated hydrotalcite and soda ash

Carbon dioxide sorption rate parameters and sorption capacities on two different regenerable sorbents, namely hydrotalcite and activated trona, were investigated in a fixed bed flow adsorber, in the temperature range of 400–527 °C and 80–152 °C, respectively. Hydrotalcite, which was activated at 550 °C, was shown to give total and breakthrough CO₂ sorption capacities as high as 1.16 and 0.70 mmol/g, respectively, at 452 °C, in the absence of water vapor. In the presence of excess water vapor, the total CO₂ sorption capacity was not affected much, however a decrease in the breakthrough capacity and on the sorption rate constant was observed, especially at lower temperatures. In the presence of water vapor, activated trona was shown to give comparable total and breakthrough CO₂ sorption capacities, at much lower temperatures (T < 100 °C). The deactivation model gave good predictions of the CO₂ breakthrough curves and it was successfully used for the evaluation of the adsorption and the deactivation rate constants.     

Study on the reaction mechanism of SO2 hydrogenation over Mo-based catalyst

Mo-based catalysts are widely used for the SO₂ hydrogenation process. However, the detailed reaction mechanism is still unclear and some details should be further supplemented. In this article, the SO₂ hydrogenation processes over the Mo-based catalyst were systematically studied. Several technologies including temperature-programmed experiments, isotope-tracing experiment, fourier transform infrared spectroscopy, and switching experiment were adopted to investigate the reaction steps. The results indicated that during the SO₂ hydrogenation process there were three reaction processes containing six steps: First SO₂ would adsorb on the active sites, which could start at relatively low temperature. Then the adsorbed SO₂ would react with H₂ and gradually form elemental sulfur that could be strongly anchored with S atoms of the MoS₂ surface. Afterward, the sulfur further reacted with H₂ to generate H₂S. Alongside with the consumption of S atoms, the sulfur would be reduced and the active sites was recovered, thus starting the next reaction cycle.     

对隔膜和离子膜碱同时生产时盐水系统SO2-4问题的探讨

分析从6 万t/a隔膜碱和2 万t/a离子膜碱变为隔膜碱和离子膜碱各4 万t/a产品结构的盐水系统中的SO2-4平衡问题,提出降低盐水系统中的S O2- 4的合理措施.     

比值分析仪在硫磺回收中的应用

在硫磺回收装置中设置硫比值分析仪可有效提高硫回收率,降低SO2排放量,同时也可以达到节能减排、保护环境的目的。本文阐述了比值分析仪在硫磺回收工艺中的重要性,同时介绍了880NSL型比值分析仪的原理和在某硫磺回收装置的应用。     

The influence of temperature and the concentration of MNSO4 on the simultaneous absorption and reaction of mixtures of SO2 and O2

We have studied the simultaneous absorption of gaseous mixtures of SO₂ and O₂ in solutions of MnSO₄ up to 0.75 mol/L and at temperatures between 10 and 40°C. The reactor used was operated continuously for the gas phase and batchwise for the liquid. The liquid phase was saturated in SO₂ at the first sampling after one hour. The absorption of O₂ was the controlling step in the process, with reaction order of 0 and 1 for SO₂ and O₂, respectively, and a fast reaction regime for MnSO₄ at concentrations of more than 0.025 mol/L. As far as manganese is concerned, our results show that the reaction order varies according to its concentration and we have obtained an equation which relates the kinetic constant to temperature and the concentration of the catalyst.     

SO2-Na2S-H2O体系热力学分析

利用Na<,2>S溶液吸收SO<,2>是湿法烟气脱硫中具有良好应用前景的新方法.为了能更好地利用Na<,2>S溶液进行烟气深度脱硫,文中通过热力学计算,对Na<,2>S溶液吸收SO<,2>烟气所构成的SO<,2>-Na<,2>S-H<,2>O体系中气液固三相组成与pH值的关系进行了分析.结果表明,pH值大于6时,SO<...     

Metal sorption with extractant-impregnated macroporous resins. 2. Chemical reaction and particle diffusion kinetics

The rates of the sorption of zinc ions from aqueous sulfate solutions with di(2-ethylhexyl)phosphoric acid-impregnated Amberlite XAD macroporous resins were measured in finite bath by a batch-contact time method. The sorption process was initially found to be controlled by a combined chemical reaction and particle diffusion process using a provable modified shrinking-core model. A more rigorous model based on Fick's law was then developed to elucidate the sorption mechanism, and a procedure was suggested to simultaneously determine the reaction rate constant and effective particle diffusivity.     

液相中H2S与SO2反应动力学研究

在鼓泡反应器中研究了二氧化硫和硫化氢在三种不同pH值溶液,即水溶液、盐酸-柠檬酸钠缓冲溶液和碳酸钠-碳酸氢钠缓冲溶液中的反应行为.结果表明,液相中两者的反应主要是发生在硫化氢分子和亚硫酸氢根离子之间.在对实验数据分析的基础上,得出了三种液相溶液中的统一反应速率方程为r=kcH2SC0.5HSO3-,k=1.531×104exp(-2139—T)其中,反应活化能为17.78kJ·mol-1.     

A Comprehensive Kinetic Study of the Reaction of SO2 with CaO by the Random Pore Model

The kinetics of the reaction between CaO and SO₂ was studied by the random pore model, to accurately consider the porous structure of the solid reactant. The inherent reaction rate constants and rate dependency with respect to the SO₂ concentration were determined from the initial slopes of the conversion‐time profiles obtained by thermogravimetry. A power law concentration dependency was applied and then the first‐order kinetics was verified. The product layer diffusivity was evaluated from the comparison of whole experimental conversion‐time profiles with the model predictions.     

近年来广州市二氧化硫的变化特征

近年来,广州市环境管理部门针对二氧化硫污染问题,采取了一系列的防治措施。为了评价这些措施的效果,以2003～2008年SO2监测数据为基础,对广州市二氧化硫浓度的变化趋势及其原因进行了分析。结果表明,广州市环境空气中SO2年日平均浓度呈显著下降趋势。冬季浓度较高,夏季浓度较低。     

S1000-11型SO_2鼓风机提高参数的分析与应用

介绍了S1 0 0 0 1 1型SO2 鼓风机改型增容的分析与应用。通过综合改变该风机转子的结构参数 ,实现了扩容增产的目的 ,并在大型硫酸厂试用成功。     

NOx、SO2液相反应研究进展--一种同时脱硫脱氮的新思路

从烟气脱硫脱氮的角度讨论了NOχ与SO2在液相中的一系列反应,包括NO、SO2溶于水与SO3^2-、HSO3^-水溶液间的反应,更为重要的是通过研究SO2^-与HSO3^2-反应制备羟胺二磺酸盐、硫酸羟胺的过程,即生产尼龙66的中间体己内酰胺的必备原料,提出了一种有意义的脱硫脱氮新思路：利用NOχ的氧化性与SO2的还原性在水溶液中构造一自催化自氧化还原反应,并得到有用的工业原料硫酸羟胺。     

工艺参数对硫化碱转化及二氧化硫释放的影响研究

基于煤粉还原芒硝法生产硫化碱的碱回收锅炉技术,研究了不同工艺参数对硫化碱转化率及二氧化硫释放率的影响。结果表明,反应温度为1 200 ℃、煤粉粒径为550~830 μm、停留时间为8~10 min为较优参数,在此条件下硫化碱转化率可达93.67%,继续提高反应温度或增加停留时间对提升硫化碱转化率效果有限;芒硝与煤粉质量比应控制在1∶（1.05~1.15）,可达到较高的硫化碱转化率和较低煤耗;在有氧气氛下,二氧化硫主要由硫化碱氧化生成,由硫化碱氧化生成的二氧化硫量远大于煤的热解和氧化生成的二氧化硫量,因此可通过控制反应区的氧浓度来降低二氧化硫生成量;随着反应温度升高,二氧化硫释放时间提前,但过高的反应温度会加剧硫化碱氧化,从而增加二氧化硫生成量。     

烟气分析法测试燃煤SO_2释出量的研究

为了有效控制SO2的排放量,有必要研究不同温度下燃煤排放SO2含量的测试方法。介绍了烟气分析法用于测试燃煤可释出SO2含量时的试验方法,其中包括间歇式烟气分析法和连续式烟气分析法。通过分析烟气分析法的精确度及重现性,分析该方法的优缺点,并验证其可行性。结果表明:烟气分析法的精确度和重现性不佳,但是可以及时反映燃煤排放SO2的真实情况。因此在完善测试装置后,烟气分析法作为燃煤SO2的测试方法值得进一步深入研究。     

Synthesis and characterization of BaAl2Si2O8 using mechanically activated precursor mixtures containing coal fly ash

BaAl₂Si₂O₈ (BAS) was synthesized by solid state reaction, using coal fly ash [CFA, containing (in wt.%) 75–78% silico-aluminous glassy phase, 14.6% mullite, 5.2% quartz, 1.9% magnetite, plus other minor phases] as main raw material. A BaCO₃–CFA–Al₂O₃ powder mixture of stoichiometric BAS composition was mechanically activated in an attrition mill for up to 12 h and then sintered at 900–1300 °C. The monoclinic BAS phase (Celsian) was desired because it has better mechanical and thermal properties than the hexagonal BAS polymorph (Hexacelsian), but this tends to form first, remaining frequently metastably at low temperatures; besides, the Hexacelsian to Celsian conversion is sluggish and difficult to occur. The reaction rate, the apparent density and the mechanical properties of the synthesized materials increased with increasing milling time and sintering temperature. The mineralizing effect caused by some of the CFA impurities produced Hexacelsian to Celsian conversions higher than those previously reported for mechanically activated BAS materials.     

Scrubbing of SO2 with trona solution in a spray drier

Effect of operating variables on the scrubbing efficiency of SO₂ in a spray drier was investigated using trona (Na₂ CO₃ · NaHCO₃ · 2H₂ O) solutions of different compositions. Results indicated that for a Na/S mole ratio of two (stoichiometric ratio) about 80% of the SO₂ was removed. For higher Na/S ratios, SO₂ removal efficiency increased by up to 100%. Increased SO₂ concentration in the feed gas and decreased outlet temperature caused an increase in the overall conversion. At low temperatures and low SO₂ concentration, the reaction takes place mainly between SO₂ and Na₂ CO₃ As the temperature is increased, decomposition of NaHCO₃ to Na₂ CO₃ and sorption reactions take place simultaneously.     

基于酸度系数(pKa)模型的胺法SO2捕集过程多目标效能分析

筛选高SO₂吸收容量、低解吸能耗的吸收剂是提高胺基烟气SO₂捕集工艺应用潜力的重要途径。本研究采用SMD连续溶剂化模型和密度泛函理论在M05-2X/6-31G*基组水平上预测了5种有机二胺类物质的pK_a,基于预测的pK_a建立起吸收剂对SO₂吸收容量和解吸反应热的数学模型,以探讨有机二胺-酸-水三元体系吸收剂捕集SO₂过程中的效能关系。结果表明,数学模型符合工程精度要求。二胺的SO₂吸收容量和脱质子反应焓都随pK_a增大而增加,筛选有机胺吸收剂展现出对SO₂吸收容量和反应焓的多目标矛盾性特征;量化了5种二胺的SO₂循环吸收容量和解吸反应热的数值关系,在相同SO₂循环容量条件下,5种二胺中羟乙基哌嗪（HEP）的解吸热最小,HEP为有机二胺-酸-水三元体系中的一种潜力二胺类吸收剂。     

基于MDEA的烟气SO2捕集过程工艺参数和能量集成分析

有机胺吸收法是一种高效环保型烟气脱硫技术,而从系统工程的角度对烟气SO₂捕集工艺的分析、优化和能耗评估尚未有详细报道。对N-甲基二乙醇胺（MDEA）为吸收剂的烟气SO₂捕集过程工艺进行研究,考察了MDEA浓度、温度、SO₂解吸率对捕集效果的影响规律。结果显示,MDEA溶液浓度为30%（质量）、烟气温度不高于45℃、回流贫液温度不高于41℃时,SO₂吸收效果较好;增加SO₂解吸率是以降低解吸气中SO₂纯度和增大再沸器负荷为代价,水分汽化是再生能耗增高的主要原因。针对吸收剂再生过程能耗大的问题,采用热泵辅助精馏对解吸过程进行能量集成,吸收剂再生能耗可降低47%,年度总费用（TAC）可降低9.93%。本研究对有机胺体系的SO₂捕集系统工业化应用具有重要的指导作用。     

磺化装置SO2转化塔的数据分析及热量利用的途径

参照意大利BALLESTRA公司的磺化装置SO2转化塔的设计数据,介绍了磺化工艺中SO2转化为SO3的反应过程及反应热的传递方式,通过对转化塔操作参数的分析,提出利用这部分热能途径,以达到优化操作的目的.