Proton NMR studies on concentrated aqueous sulfuric acid solutions and Nafion-H

Sulfuric acid containing limited amounts of water, H₂SO_4.nH₂O with 0.23≤n≤4, has been studied by ¹H broad-line NMR at 4 K and MAS NMR at room temperature. The broad-line NMR spectra indicate the formation of H₃O⁺ and HSO₄ ^- ions. H₂SO_4.2H₂O is correctly written as H₃O⁺HSO₄ ^-.H₂O. The results are compared with the Nafion- H/water system. This revised version was published online in July 2006 with corrections to the Cover Date.     

板式浓硫酸冷却器的应用

在硫酸装置扩能时 (由 2 0 kt/ a改为 4 0 kt/ a) ,选用板式浓硫酸冷却器 (32 m2 )代替原铸铁排管冷却器。使用中发现管路直径偏小 ( 10 8m m) ,水质差结垢严重 ,硫酸泵扬量选择偏小等问题。提出改进措施     

13C MAS NMR mechanistic study of the initial stages of propane activation over H-ZSM-5 zeolite

¹³C MAS NMR study of the early stages of propane 2-¹³C activation was performed over H-ZSM-5 catalysts with various content of protonic and aprotonic sites. The reaction mechanism was tested by addition of various probe-molecules (C₃H₆, C₆H₆, H₂, H₂O and CO). The results on tracing the fate of ¹³C label during this experiments conclude to a monofunctional mechanism involving propane protonation on the strong Brønsted sites of H-ZSM-5 and the formation of carbonium ion type transition states, which further evolve in four different ways leading to ¹³C scrambling in propane, cracking, dehydrogenation and disproportionation.     

叔丁醇常压羰基化合成三甲基乙酸

以甲酸为CO来源,常压下浓硫酸催化将叔丁醇羰基化得到三甲基乙酸。考察了醇酸配比、硫酸用量、反应温度、反应时间对三甲基乙酸收率的影响。结果表明,反应最优工艺条件为:n(叔丁醇)∶n(甲酸)∶n(浓硫酸)摩尔比=1∶1.5∶6.6,反应温度为30℃,反应时间为180 m in,三甲基乙酸的平均收率高达75.04%。     

带阳极保护不锈钢管道在热浓硫酸介质中的应用

介绍 10 0 0 t/ d硫磺制酸装置中热浓硫酸管道使用材料的方案比较 ,确定在干吸工序全面使用带阳极保护的不锈钢浓硫酸管道 ,说明其原理、应用及注意事项     

硫铁矿制酸装置生产优质液体SO_3联产发烟硫酸及精制硫酸

阐述用硫铁矿制酸装置生产液体SO_3联产w(H_2SO_4)115%的发烟硫酸及精制硫酸的产品方案设计、生产工艺过程以及在生产过程中遇到的问题及其解决办法。在硫铁矿制酸装置上成功生产3种产品,使产品售价平均达800元/t以上,大大提高了硫酸企业的市场竞争力。     

浓硫酸清净乙炔工艺运行总结

介绍了浓硫酸清净乙炔工艺的运行情况、控制要点及针对运行过程中出现的清净塔温度上升、中和塔换碱频繁、废酸处理困难等问题采取的相应解决措施。认为浓硫酸清净乙炔工艺与次氯酸钠清净乙炔工艺相比,具有成本低、节水、电石渣易处理等优点。     

利用浓硫酸和富铁矿渣制备聚合硫酸铁的研究

研究以富铁矿渣和浓硫酸为原料,采用低温焙烧制取絮凝剂聚合硫酸铁(PFS)的方法,考察了焙烧温度、浓硫酸用量对铁浸出率的影响。通过一系列的絮凝沉降实验,研究了产品用量、浓度、pH对絮凝沉降效果的影响规律。实验结果表明:最佳焙烧温度为180℃,最佳浓硫酸用量为0.46mL/g。在产品的性能研究中,当产品用量为4mL/L时,不仅絮凝效果显著,而且上清液透光度高,沉淀物体积小。     

乙炔硫酸清净中硫酸单耗的影响因素

分析了100万t/a聚氯乙烯装置乙炔硫酸清净中硫酸单耗的影响因素,提出了解决措施,达到了节能降耗的目的。     

阳极保护浓硫酸冷却器的设计与运行

为了提高浓酸冷却效果 ,用 3台阳极保护浓硫酸冷却器 ,代替铸铁排管冷却器。介绍阳极保护浓硫酸冷却的设计参数 ,选用泵前流程的原因 ,重点讨论冷却水路的设计方案。通过热量衡算与 1年的运行表明 :采用先并后串的冷却水路 ,并增设 1台凉水塔 ,可以满足干燥酸、一吸酸、二吸酸的冷却要求 ,而且阳极保护浓硫酸冷却器恒电位仪运行正常。     

浓硫酸清净技术在PVC生产中的应用

介绍了浓硫酸清净新技术在电石法PVC生产中的运行情况,并和次氯酸钠清净技术作了比较,指出该技术更加符合节能减排发展思路。     

氯乙烯合成原料气浓硫酸脱水工艺运行总结

介绍了用于合成氯乙烯的乙炔和氯化氢采用浓硫酸脱水净化的工艺流程、技术特点和运行情况,原料气组成分析结果显示浓硫酸脱水效果优于传统混合脱水工艺。     

环己烷羧酸亚硝化的反应动力学模型

由环己烷羧酸与亚硝基硫酸的亚硝化反应制取己内酰胺是一个重要的工业反应过程.实验证实了该过程伴有环己烷羧酸与三氧化硫作用的平行副反应以及己内酰胺与亚硝基硫酸作用的串联副反应，由此提出了亚硝化过程的反应动力学模型.在假定各主、副反应之间没有交互影响的基础上，通过分析-综合实验方法间接地确定了模型参数.该模型能够很好地解释工业亚硝化过程的控制参数，并为工业亚硝化过程的进一步优化提供了理论依据.     

耐98%硫酸的无溶剂自流平重防腐地坪涂料及其施工

通过选用特殊改性环氧树脂和固化剂,制备防腐性能优异的无溶剂重防腐自流平地坪涂料,尤其是具有耐浓硫酸腐蚀的功能,同时也简要介绍了该产品配方组成,物化性能以及在地坪施工应用。     

In situ 13C MAS NMR Study on the Mechanism of Butane Isomerization Over Catalysts with Different Acid Strength

Reaction mechanism of skeletal isomerization of n-butane over sulfated zirconia (SZ), Cs_2.5H_0.5PW¹²O₄₀ (Cs_2.5) and H-form mordenite (H-MOR) catalysts was studied using ₁₃C MAS NMR with ₁₃C-labeled n-butane. The isomerization of n-butane over SZ type catalysts proceeds predominantly via a monomolecular mechanism below 333 K and gradually changes to a bimolecular alkylation-β-scission mechanism as the reaction temperature is increased to 423 K. Iron promoter in SZ catalyst facilitates the bimolecular process. The n-butane isomerization over Cs_2.5 also proceeds mainly via a monomolecular mechanism below 373 K. The bimolecular mechanism becomes significant as the reaction temperature is increased to 423 K. On both SZ and Cs_2.5 catalysts hydrogen inhibits the isomerization reaction, in particular the bimolecular process. In contrast, the n-butane isomerization over H-MOR with relatively moderate acid strength proceeds mainly via a bimolecular mechanism at 473 K. The kinetics of n-butane isomerization on SZ below 333 K and Cs_2.5 below 373 K are well represented by the Langmuir–Hinshelwood equation for a reversible first order surface reaction, further supporting that a monomolecular mechanism proceeds primarily on SZ and Cs_2.5 catalysts at early reaction stage. All results suggest that the stronger the acidity of the catalyst the lower the reaction temperature of n-butane isomerization and the more contribution of the monomolecular mechanism. The overall mechanism of 1−₁₃C-n-butane reaction on SZ, Cs_2.5 and H-MOR catalysts including ₁₃C scrambling and butane isomerization is proposed.     

自动反洗表面过滤器在硫酸装置稀硫酸过滤上的应用

硫酸净化工序斜板沉降器出来的污酸用自动反洗表面过滤器进行清污分离,介绍处理工艺流程及主要设备。每年可以回用硫酸1400t（折标酸）,年经济效益约为86．19万元。     

酸性镀锡液中游离硫酸的测定

本文提出了一种酸性镀锡液中游离硫酸含量的测量方法。阐述了该方法的原理,该方法准确度高,可满足生产的需要。     

Regeneration of activated carbon after contact with sulfuric acid solution

This study deal's with the feasible use of a commercial activated carbon in the uptake of H₂SO₄ from aqueous solution and with the regeneration of the spent product. Thermogravimetry TG and FT‐IR spectroscopy are used in the analysis of samples. The activated carbon is a very effective material for the uptake of H₂SO₄. Using a 9.0 mol dm⁻³ H₂SO₄ solution, the mass increase is 37.8 wt%. From the sample obtained, the H₂SO₄ can be removed largely either by heating at 250 °C for 2 h in a N₂ atmosphere or by washing thoroughly with distilled water for 24 h. The mass loss in both cases amounts to 33.6 wt%. The FT‐IR spectroscopy results indicate that the surface chemistry of the carbon is not affected, noticeably, at least, after its contact with the H₂SO₄ solution. The behavior of H₂SO₄ toward carbon is compared with that of HNO₃. © 2000 Society of Chemical Industry     

硫酸行业“十三五”发展思路

介绍我国硫酸行业"十二五"期间取得的成绩,分析行业当前发展面临的问题,提出"十三五"期间我国硫酸行业科技、环保、节能、转型升级、淘汰落后产能等方面的发展方向和主要任务。"十三五"期间,行业应优化存量,严控增量,"十三五"末硫酸产能应控制在1.4亿t/a左右,淘汰落后产能1 000万t,全行业年平均产能利用率达到80%。进一步优化产业布局,促进科技创新,拓宽硫资源来源,推广热能回收技术,加大"三废"治理力度,切实提高硫酸行业清洁生产水平。     

应用六西格玛方法减少氯气干燥中消耗的浓硫酸

介绍了在离子膜法烧碱生产装置中,如何利用六西格玛的理论方法,将离子膜法烧碱生产氯气处理过程中浓硫酸消耗由21.15 kg/t降至18.5 kg/t,且不影响干燥氯气品质。