大气中二次无机气溶胶的形成反应和清除方法

综述了雾霾发生期间大气气溶胶的化学组成、性质和溯源研究进展。从无机化学视角分析了二次无机气溶胶的形成反应和形成过程,认为大气中含有的二氧化硫和一氧化氮在光照射、氧气、水分和催化剂存在下发生氧化反应和水合反应生成含有硫酸、硝酸和亚硝基硫酸的酸雾,然后与大气中含有的氨、钙、铝和铁的化合物反应生成无机复盐;当大气温度和湿度变化时就析出含大量结晶水的无机复盐,成为灰霾的主要组分,无机复盐结晶体积膨胀导致太阳光的散射;还提出了清除二次无机气溶胶的途径和方法。建议加强重金属对雾霾形成催化作用的研究;建议加强对环境友好的光催化清除雾霾方法的研究。     

硫酸工业的近期发展动向——如何减少废气对大气的污染

硫酸工业的近期发展,带来了大量的二氧化硫和硫酸的小液滴对于这个工业区域的大气污染。老厂放出来的废气中,有3000ppm的二氧化硫和600毫克/米~3的硫酸。美国一台新硫酸设备所产生的废气,其中二氧化硫最高含量在500ppm以内,而其他工业国已减少到了100ppm以下。一种减少废气中二氧化硫含量的有效方法,是使用双接触系统,高效分离液滴,必要时还可用吸收二氧化硫的溶剂,作最后废气的处理。     

明胶中二氧化硫测定装置标准化的建议

<正> 一、序言由于二氧化硫是一种较强的还原性物质,在明胶中含量太高时,明胶作为一种食品添加剂,在胶囊、食品的加工生产和贮存过程中会发生化学变化,使染料和色素退色,影响质量;另外,二氧化硫又作为照相明胶生产胶片的活性微量杂质的添加物之一,经常用来调整明胶的照相性能。因此,随着明胶作为一种加工助剂日益广泛地应用于许多工业领域,对明胶中二氧化硫的含量提出了越来越严格的要求,各行业也都制定了各自不同的行业标准.这样就要求明胶生产厂家在明胶的半成品生产和明胶成品的配胶过程中,对二     

氟里昂生产中失效催化剂的初步处理

目前国内都采用五氯化锑作为催化剂生产氟里昂产品。由于原料内所含微量水分、微量二氧化硫及微量有机杂质的累积影响,五氯化锑使用一段时间后即失效。国内过去对失效催化剂的处理未予重视,习惯都排放在河流或地沟内。因此有大量的酸雾、高浓     

利用硫酸尾气制液体二氧化硫和硫铵生产小结

遵照伟大领袖毛主席“综合利用很重要,要注意”的指示,在厂党委领导下,在兄弟单位配合下,我厂综合利用硫酸尾气低浓度二氧化硫制造液体二氧化硫和液体硫铵工程,在一九七五年底胜利建成。经过二年多的试车生产实践,各项主要指标均达到予期的效果。这是贯彻毛主席光辉指示的又一丰硕成果。 我厂硫酸生产(原料分为:株冶炼锌废气、硫磺、硫精砂三个系统)过程中,每小时排空～16万标米~3/时废气。废气含0.3～0.5％SO_2。这些低浓度二氧化硫未综合利用以前,不仅浪费了国家大量硫的资源,而且污染了大气,严重的危害了职工居民的健     

超提纯精馏—塔中存料作用

Buiten于1960年提出了当塔中存料作用可略去时除去微量α>1之杂质之间歇精馏计算方法。1964年Wilcox又提出了关于存料作用可忽略时之超提纯间歇精馏的计算方法,两者的基本公式实际上即作者在1957年所提出的。对于存料作用可忽略时除去微量杂     

用二氧化硫富集湘常硼矿的探讨

本法是用二氧化硫(包括焙烧气和含二氧化硫的工业废气)处理含碳酸盐为主要杂质的硼镁矿,使矿中固相杂质进入气相和液相,从而富集硼矿。在常温常压下,将二氧化硫按所需用量加入到矿中,在搅拌的情况下,二氧化硫与矿粉作用,矿中的碳酸盐(主要是碳酸钙)转化为溶解度很大的亚硫酸氢盐,并逸出二氧化碳气体。反应结束后,立即将亚硫酸氢盐溶液与溶解度极小的硼镁矿分离,滤渣即     

换网器的基本原理

Ⅰ.滑板式换网器为了确保挤出产品的质量,当有杂质在挤出机中存留时,就应该把它除掉。使用具有这种清除作用的过滤器不断收集带入的杂质时,过滤网之前的压力就会增高,最终必须采用更换过滤器网组的方法加以解决。如果没有换网器的话,这种更换将是一种既费     

浅谈酸雨

酸雨即“酸性降水”,通常以PH值的大小作为判别标准,PH值小于5.6时的降水即为酸雨(如雨、雾、雪、雹)。其产生决定于两个重要因素:一是酸性物质(如硫酸、硝酸、盐酸)的来源及其在大气中浓度的大小;二是降水酸化的过程及其形成的条件。大气中硫酸及其前体物二氧化硫(SO_2)主要由石化燃料燃烧产生;硝酸及其前体物氮氧化物(NO_x)主要由汽车尾气和煤、油燃烧产生;盐酸的天然发生源有火山喷发、海盐等,人为发生源主要是含氯产品的工业(氯碱、聚氯乙烯生产等)。降水酸化的主要酸性物质是硫酸(包括硫酸盐),其次是硝酸(包括硝酸     

硫酸污水处理情况报告

前言 硫酸污水处理,系水洗流程生产硫酸的关键问题之一,我厂硫酸车间第一期工程年产硫酸八万吨,采用三文一器流程,每小时排出污水量80米~3左右,呈酸性反应,含有砷、氟、二氧化硫及硫铁矿渣等有毒杂质,为了对人民健康及农作物负责起见,必须予以处理,使达到卫生标准后再排入江中。 1959年春,全国水洗流程硫酸会议后,成立了污水处理试验研究小组,开展这方面的试验研究工作。在上级领导大力支持和七、八个兄弟单位的配合与帮助下,从1959年9月开始,到1962年九月结束,前后进行了三年左右(其中曾有间断),做了无数次较有系统的试验研究,初步解决了硫酸污水处理问题。     

Electrogenerative formation of ferric ions in a sulfur dioxide–sulfuric acid solution; Graphite catalysed sulfur dioxide oxidation

The electrogenerative oxidation of ferrous ions in 3m sulfuric acid, containing sulfur dioxide and subsequent sulfur dioxide oxidation, were studied in connection with potential regenerable sulfur dioxide remediation processes. The presence of sulfur dioxide in the feed stream did not affect cell performance. Oxidation of sulfur dioxide in the electrogenerative reactor took place when high ferrous to ferric ion conversions were obtained. Low cost graphite and iron ions served as an effective mediating system for promoting electron transfer to sulfur dioxide in strong acid solutions. In contrast, the homogenous reaction between iron(iii) and sulfur dioxide is relatively slow. In a separate batch reactor, the heterogeneous iron(iii) and sulfur dioxide reaction was found to be graphite catalysed, accounting for sulfur dioxide conversion observed in the electrogenerative reactor. Ferrous ion presence should be minimized, because it inhibits the desired catalysed reaction.     

硫磺流化法还原钛白石膏工艺模拟研究

利用硫磺、碳等还原硫酸法钛白粉生产副产物钛白石膏是处理钛白石膏堆放问题的方法之一。针对硫磺在回转窑分解钛白石膏制硫酸和氧化钙的过程存在时间长、硫磺用量大、硫化钙产量不高等问题,提出了以钛白石膏为原料利用酸浸法去除铁杂质后,利用硫磺为还原剂将石膏在气固竖式反应器中煅烧生成硫化钙和二氧化硫,前者再与硫酸钙煅烧制得氧化钙和二氧化硫,得到的氧化钙可以中和废酸和废水,产生的二氧化硫用来制硫酸的方法。先利用反应热力学计算软件HSC分析确定实验方案,分别在流态化实验（800 ℃,保温40 min）和煅烧实验（1 100℃,保温1.5 h）后得到硫化钙转化率与氧化钙纯度均达到90%左右。再利用Aspen软件模拟了工艺流程,模拟出二氧化硫体积分数可达12.09%,满足制硫酸的需求。硫酸生产成本估算为263.9元/t,具有较大的市场前景。     

淤浆反应器中SO_2的催化氧化

研究了常温常压下淤浆反应器中SO_2催化氧化反应,通过改变反应物的进口浓度和测定小颗粒床层平均氧化反应速率(此时传质阻力最小),间接验证了假定的反应机理:氧在活性炭活性位上的吸附为速率控制步骤,本征反应速率相对于颗粒表面的溶氧浓度为一级,而与此浓度范围内的SO_2浓度无关,通过改变催化剂的用量、粒径及反应温度,测定了各模型参数.     

Using vanadium catalysts for the oxidation of hydrogen chloride with molecular oxygen

Regeneration of chlorine by oxidation of hydrogen chloride is an important problem in the production of chloroorganic products. The known catalysts for this reaction are insufficiently active and typically not stable enough, while data on the use of V catalysts for this process are absent. Here we report on our study of the stability and catalytic activity of the industrial sulfuric acid production sulfate-promoted vanadium catalyst IK-1-6 in the process of oxidation of hydrogen chloride with molecular oxygen. Under conditions of low conversion (less than 15%) with the reaction in the external diffusion region, the catalyst activity attained 660 g/(kg cat h) at 400°C, and the mass loss rate of the catalyst was (due to the formation of volatile vanadyl chloride) 4.6 % per hour, based on vanadium. Under high conversion conditions (over 60%), the vanadyl chloride formed in the top layer of the catalyst was hydrolyzed and precipitated on subsequent layers as the conversion of the reaction mixture increased, leading to a redistribution of vanadium over the catalyst bed height and hindering its removal form the reactor. The stable operation of the catalyst can be ensured by intermittently changing the flow direction of the reactant gas in the catalytic reactor or using an array of several reactors connected in series, intermittently changing their places in the inlet-outlet chain. Our results show that the industrial sulfate-promoted vanadium catalysts for the oxidation of sulfur dioxide are more active and stable than all known catalysts of the Deacon process (except for ruthenium catalysts) and could be used for catalytic oxidation of hydrogen chloride.     

The electrochemical oxidation of aqueous sulfur dioxide: A critical review of work with respect to the hybrid sulfur cycle

Literature regarding the mechanism of the electrochemical oxidation of aqueous sulfur dioxide to sulfuric acid has been critically evaluated to provide a detailed understanding of the reaction under various applied conditions. This reaction is of high relevance to the hybrid sulfur cycle for large scale hydrogen production, as well as other industrial applications such as flue gas desulfurisation. Widespread disagreement in the literature and non-reproducible behaviour of the electrochemical oxidation reaction has been found in this review to often be a result of poorly defined electrode preconditioning procedures. It has also been found that the mechanistic pathway of the oxidation reaction is heavily influenced by the electrode material, solution pH and the applied anodic potential. These factors are thought to influence adsorption and the reductive formation of sulfur species at low potentials.     

黏土钒矿直接常压活化酸浸提钒热力学分析

目前黏土钒矿直接酸浸的试验以及基础性研究较少,为了进一步推动此类问题的研究进展,本项研究采用试验结合热力学计算的方法,通过试验得到了最佳浸出剂结果,运用热力学计算诠释了活化浸出钒过程的热力学行为以及其机理,同时进一步分析了不同硫元素的总量对酸浸液中各组分的影响,为从酸浸液中提钒工艺进行了溶液化学分析。结果表明：二氧化锰有能力将低价钒氧化至高价钒,从而提升钒的浸出率,升高温度对浸出率的提高以及二氧化锰的氧化均会造成不利影响,但是会抑制杂质的浸出,对杂质分离起到积极影响。硫酸的用量一方面会影响浸出过程的pH,同时会影响酸浸液中各组分的含量,低硫的酸浸体系与高硫体系中钒的离子形态存在差异。低硫体系中铁杂质的溶解度会小于高硫体系,有利于提钒过程中杂质的分离。通过分析浸出过程中溶液组分的变化,可以为后续提钒工序提供理论依据。     

排球挂钩用铝合金基材阳极氧化处理及耐蚀性研究

使用铝合金挂钩对装入网兜的排球进行悬挂和管理,具有取用方便、节约空间、美观等优点。使用硫酸阳极氧化技术对排球挂钩用5005铝合金基材进行了处理,并对阳极氧化膜的性能进行了研究。结果表明:阳极氧化膜主要由铝、氧、硫、碳元素构成,其中铝和氧的总质量分数超过80%,少量的硫来自硫酸。经过硫酸阳极氧化处理后,铝合金表面形成高硬度和高熔点的a-Al2O3和y-Al2O3,大大提高了铝合金的硬度。阳极氧化膜由高电阻的阻拦层和多孔层构成,可以有效地分散和降低自腐蚀电流密度,大大提高铝合金基材的耐蚀性。     

A double wall reactor for supercritical water oxidation: Experimental results on corrosive sulfur mustard simulant oxidation

The corrosion of reactor is one of the obstacles that inhibiting the development of supercritical water oxidation (SCWO) into a viable industrial process. A concentric vertical double wall reactor has been developed in which SCWO reaction takes place inside an inner tube (titanium grade 2, non-porous) whereas pressure resistance is ensured by a Hastelloy C-276 external vessel, to handle high-risk wastes resulting from munitions demilitarization. Experimental results concerning the oxidation of a mixture of thiodiglycol [TDG, (HOC₂H₄)₂S] and hydrochloric acid [HCl], which is used as a sulfur mustard stimulant, confirmed the ability of the reactor to treat corrosive wastes. High destruction rates based on total organic carbon were achieved (>99%) without production of chars or undesired gases such as carbon monoxide and methane. The carbon-containing product was carbon dioxide. Sulfur and chloride were totally recovered in the aqueous effluent as sulfuric acid and hydrochloric acid. No corrosion was noticed in the reactor. The titanium tube shielded the pressure vessel from corrosion.     

OXIDATION OF SULFUR DIOXIDE IN DIFFERENT TYPES OF THREE PHASE REACTORS

Five different types of three-phase reactors are compared with each other by using oxidation of sulfur dioxide on activated carbon. The kinetic measurements were carried out by changing concentrations of sulfur dioxide from 0.04 to 0.17% (volume) and those of oxygen from 2 to 21%. The reaction rate was 0.2 order with respect to sulfur dioxide and 0.5 order with respect to oxygen. The catalytic effectiveness factor and intraparticle diffusivity were evaluated by changing particle sizes of activated carbon from 0.03 to 1.6 mm. Resistances of gas-liquid, liquid-solid mass transfer and intraparticle diffusion were estimated for individual reactors. The optimum reactor was dependent on operating conditions such as gas flow rates, rotating speeds and particle sizes.     

Kinetic studies on the reactions involved in the hot gas desulfurization using a regenerable iron oxide sorbent—II: Reactions of iron sulfide with oxygen and sulfur dioxide

In the hot gas desulfurization process using iron oxide sorbent, the regeneration of the sulfided iron oxide sorbent consists of two reactions: the oxidation of iron sulfide with air, and its reaction with the sulfur dioxide formed during the air oxidation. This part describes the kinetic studies on the reactions of iron sulfide (formed by the reactions of Fe₂O₃ with H₂CO mixture and subsequendy with H₂S) with oxygen and sulfur dioxide. The experimental and analysis procedures used are similar to those outlined in Part I of this paper.The activation energies for the oxygen and the sulfur dioxide reactions are found to be 15.63 and 17.5 kcal/mol, respectively. Notably, the product oxides formed in the two cases are different. With air, the reaction is fast and the final product is Fe₂O₃, whereas with SO₂, the major product is Fe₃O₄, which slowly oxidizes to Fe₂O₃ in a secondary step. Also, in the latter reaction elemental sulfur is formed.