载二氧化硫活性炭微波辐照解吸研究

本文研究了微波辐照不同操作条件 (微波功率、载气流量、饱和活性炭量、再生时间、再生次数 )对活性炭再生的影响 ,并提出了最优操作工况 ,同时对后续研究的重点提出了建议 ,并对解吸机理进行了探讨。     

微波外场中的硫酸钙碳热还原

采用微波加热介质技术,研究了煤粉作为还原剂的硫酸钙碳热还原反应。结果显示,在碳与硫物质的量比为0.6、反应温度为1 200 ℃、反应时间为10 min条件下,硫酸钙的分解率可达98.53%。二氧化硅作为助熔剂,促进了固相反应。试验中掺入石墨粉,降低了反应温度,并进一步缩短了反应时间。微波场中硫酸钙的反应速率高于普通碳热还原反应。     

二氧化硫还原喷雾干燥制碱式硫酸铬

详细描述了一种碱式硫酸铬制法，重铬酸钠溶液与二氧化硫气体在还原塔内进行氧化还原反应，经调整碱度后用离心雾化式喷雾干燥机干燥，得到优质碱式硫酸铬。     

二氧化硫催化还原为单质硫的研究进展

介绍了以H₂、CO、NH₃、炭及烃类物质为还原剂将SO₂催化还原为单质硫的研究进展，指出以CO和C₂H₄为还原剂的研究将更有实际意义。     

催化还原二氧化硫为单质硫的研究进展

催化还原二氧化硫为单质硫不仅可消除二氧化硫污染,而且可得到有价值的单质硫。本文对分别以炭、氢气、甲烷、一氧化碳等为还原剂将二氧化硫还原为单质硫的催化剂、反应过程及催化机理做了详细阐述;分析了各种还原剂还原二氧化硫的优缺点,指出炭热还原二氧化硫和直接利用烟气中一氧化碳还原二氧化硫是未来发展的重要方向。     

氟磷灰石碳热还原过程及动力学研究

为探明电炉法黄磷的反应历程,采用纯物质模拟电炉法黄磷生产,并使用HSC热力学软件、X射线衍射(XRD)、扫描电子显微镜(SEM)等分析方法对该过程进行辅助研究。HSC和XRD分析结果表明氟磷灰石碳热还原反应历程如下:Ca_5(PO_4)_3F优先与SiO_2发生脱氟反应生成Ca_3(PO_4)_2,而Ca_3(PO_4)_2又被碳还原产生CaO,并结合SiO_2形成钙硅酸盐,而F最终以SiF_4(g)的形式排出体系;动力学分析结果表明氟磷灰石的碳热还原反应是一个变级反应,反应级数随温度升高而降低,反应速率随温度升高而增大,随时间增大而降低,其反应活化能为188.96 kJ×mol~(-1),表明是一个高能耗反应;渣相SEM分析结果表明随着温度的升高,体系的液相逐渐增多,物质扩散加快,导致反应速率增大,这与动力学分析结果相一致。     

载二氧化硫活性炭微波辐照解吸研究

研究了微波辐照不同操作条件(微波功率、载气流量、饱和活性炭量、再生时间、再生次数)对活性炭再生的影响,并提出了最优操作工况,同时对后续研究的重点提出了建议,最后对解吸机理进行了探讨。     

碳热还原法制备氮化铝反应机制的研究进展

本文综述了碳热还原反应制备AlN的各种反应机制,并进行了评述,详述了气-固反应机制和固-固反应机制的特点、实验证据及存在的不足.认为Al2O3蒸发分解零级反应与固相扩散反应共存的机理能较好地解释目前的实验现象,但仍需进行完善.     

还原光度法测定大气中的二氧化硫试验研究

近年来二氧化硫对环境及人类的危害越来越严重,对其监测已成为保护大气环境的重要方面。文章采用还原分光光度法对大气中的二氧化硫进行了测定。方法简便灵敏,精密度高,线性关系达0．999。将该法用于大气中二氧化硫的测定,可获得满意的结果。     

碳热还原氮化法制备碳氮化钛粉末

以物质的量比为1∶2.5的TiO_2粉和活性炭粉为原料,于N2气氛下采用碳热还原氮化法在不同的合成温度(分别为1500℃、1600℃、1650℃、1700℃、1750℃,N2压力固定为0.1MPa)和N2压力(分别为0.05MPa、0.1MPa、0.15MPa、0.2MPa,温度1700℃)下保温3h合成了碳氮化钛粉末。研究结果表明提高合成温度和降低N2压力有利于合成碳含量高的碳氮化钛粉末;在N2压力为0.1MPa的条件下,于1700℃保温3h热处理后,可以获得平均粒径为2μm的碳氮化钛粉末。     

催化还原烟气中SO2到单质硫的研究进展

综述了烟气中催化还原SO₂到单质硫的研究进展，着重介绍了无氧及含氧体系下以H₂和CO为还原剂，将SO₂还原为单质硫的主要研究成果，主要包括各种催化剂的组成、性能和催化机理，并对催化还原脱硫的研发趋向作了展望。     

冶炼烟气中SO2催化还原为元素S的研究进展

冶炼烟气中SO2催化还原为元素S是利用适当的还原剂将烟道气中的SO2选择性地催化还原成单质硫,这种方法的最终产物是固态单质硫,无废水废渣排放。因此,把烟气中的SO2选择性的还原为单质硫将是一种既具有经济效益又具有社会效益的适合我国国情的烟气脱硫方法。本文综述了目前将烟气中SO2催化还原为元素硫进行回收的主要方法,分析了每种方法的优缺点,并提出烟气中SO2直接还原脱硫技术所存在的问题和发展趋势。     

Conversion of SO2 into elemental sulfur by using the RF plasma technique

This study demonstrates a new approach for converting SO₂ into elemental sulfur by adding CH₄ in a radio-frequency (RF) plasma reactor. With the applied power (P) of the RF reactor specified at 90 W and operating pressure set at 4000 N/m², it was found that as the CH₄/SO₂ ratio (R) was increased from 0.3 to 1.0, most sulfur-containing products were in the form of elemental sulfur. While R was increased from 1 to 2, the content of elemental sulfur was decreased significantly, but CS₂ was increased dramatically. While R was increased from 2 to 3, both elemental sulfur and CS₂ contents became quite comparable. Nevertheless, it was found that both H₂ and CO (that is, syngas) were the main nonsulfur-containing products under all testing conditions. These results indicate that the use of the RF plasma technique was not only beneficial to convert SO₂, but also was able to convert CH₄ into useful materials. For R = 0 (that is, no CH₄ was introduced), it was found that the SO₂ conversion (i.e., η) = 0.084, indicating that the RF plasma process was inadequate to convert pure SO₂ without adding CH₄ as a reducing agent. While R was increased to 2, it was found that η was improved significantly to 0.968 accompanied with η = 0.999. But as R was increased from 2 to 3, both η and η were slightly decreased. Both η and η also were sensitive to the applied power (P). As P was increased from 15 W to 90 W at R = 2, it was found that both η and η were increased dramatically from 0.247 and 0.320 to 0.968 and 0.999, respectively. But as P was increased from 90 W to 120 W, the increase on both η and η became very limited. Based on these, this study suggests that the operating condition of R = 2 and P = 90 W would be the most appropriate combination for SO₂ conversion. © 2004 American Institute of Chemical Engineers AIChE J, 50: 524–529, 2004     

由二氧化硫生产元素硫

WorleyParsons创新性二氧化硫还原工艺可有效地从二氧化硫气体中回收硫,能够处理矿石沸腾炉、冶炼和燃煤电厂排放气以减少硫排放量。该新工艺是对几种成熟工艺的创新性组合:CH4与硫蒸气反应生成CS2, CS2随后催化水解生成H2S,H2S与SO2进行Claus反应生成硫。主要优点是较低的燃料消耗、较少的排放量、较好的产品硫质量和较高的操作稳定性。     

用转化气催化还原二氧化硫生产元素硫

研究了一种在反应器-转化器将天然气转化为含一氧化碳和氢气的转化气、在催化反应器中用甲烷转化产物将二氧化硫还原为元素硫的工艺。高温转化器(1 100～1 300℃)中天然气流量为150～180 m~3／h,转化气ψ(CO H_2)达30％～40％;催化反应器中氧化铝催化剂分3层装载,进气流量为:SO_2 65～100 m~3／h,N_2 215～230 m~3／h,烟道气440～660m~3／h;ψ(SO_2)为9％～12％。试验结果表明,当催化反应器进气温度维持在415～505℃时, 二氧化硫和甲烷转化产物之间的反应使催化剂温度上升至700～770℃,大多数二氧化硫在第一催化剂床被还原, 该过程在1 500～2 000 h~(-1)的高空速下进行;该工艺二氧化硫的转化率为75％～85％,其中55％～65％转化成元素硫,15％～25％转化为硫化氢和CO_S。     

Analytical procedure for the determination of trace carbon impurity in elemental sulfur

An analytical procedure has been developed for determining trace levels of carbon in elemental sulfur based on the standard combustion technique and incorporating gas chromatographic (GC) analysis of the products. Laboratory testing has shown a relative error of 5 ppmw or 5%, whichever is greater, in the results of the analysis for carbon contents of 50 ppmw and above and detection threshold of 15 ppmw carbon, along with good reproducibility.     

Selective catalytic reduction of sulfur dioxide with hydrogen to elemental sulfur over Co---Mo/Al2O3

The selective reduction of sulfur dioxide with hydrogen to elemental sulfur was studied over Co---Mo/Al₂O₃. When the feed conditions were properly optimized (SO₂/H₂ mole RATIO = 1:3), a sulfur yield of about 80% was achieved at temperatures around 300°C. The temperature is the lowest that has been reported so far for any catalyst for this reaction. The catalytic activity remained high and stable after presulfiding with 10% H₂S in hydrogen. Little influence on the catalytic activity was observed if the water content in the feed was kept below 11 vol.-%. The overall reaction consisted of two individual steps occurring on two different sites; sulfur dioxide was first hydrogenated to hydrogen sulfide on the metal sulfide phase, then followed by the Claus reaction of hydrogen sulfide with sulfur dioxide to produce elemental sulfur on the acidic sites of the alumina support.     

SO_2改性活性炭催化PS降解对氯苯酚的研究

采用SO_2高温焙烧法对活性炭进行了掺硫改性,并以掺硫活性炭(ACS)为催化剂,研究了对氯苯酚(4-CP)在ACS活化过硫酸盐(ACS/PS)体系中的降解规律和机理。结果表明,ACS比表面积有所降低,同时表面掺杂的含硫官能团以砜基和噻吩基为主。ACS的催化活性有明显提升,尤其在酸性环境和较高反应温度时。在反应温度为55℃时,反应210 min,ACS/PS体系4-CP几乎完全降解,相对改性前提高30.9%。基于中间产物测定数据,初步推断了4-CP在ACS/PS体系中的降解机理和过程。     

催化还原脱除SO2研究的进展

烟气中的ＳＯ２的催化还原脱除过程受到还原剂和催化剂的双重影响,目前对这二者的研究相当广泛,尤其是对催化剂的研究取得了较大的进展。在研究过程中,人们探讨了其可能的机理,并对水蒸气等因素的影响作了研究。但大部分研究仅限于无氧尾气中ＳＯ２的脱除。本文将就这一过程研究的进展加以评述。