MICROWAVE INDUCED CONVERSION OF HYDROGEN SULFIDE

Abstract

The reaction of hydrogen sulfide with trona and calcium oxide in the presence of char started as soon as microwave energy was applied. However, with conventional heating, the reaction started only when the bed temperature reached approximately 540^°c. char absorbing microwave energy is rapidly heated to very high temperatures, enhancing the H₂S reaction with oxides contained in char or oxides added to char in the reaction. A 100% conversion of trona was achieved but the maximum conversion of calcium oxide was only 79%. The minimum content of char required to induce the reaction of H₂S with trona using microwave energy was 20% of char-trona mixture. When the trona content in the mixture of char-trona mixture was greater than 50%, an additional conversion of H₂S occurred to produce some amount of elemental sulfur that was deposited in the bed. This clearly demonstrates that char combined with microwave induces H₂S reaction with mineral oxides.     

逆流旋转填料床中络合铁法脱除气体中H2S

以逆流旋转填料床为脱硫设备,络合铁为脱硫剂,对模拟气中的H₂S进行了脱硫实验研究。考察了气/液流量比、超重力因子、气体流量、H₂S入口质量浓度对脱硫率的影响,并对比分析了逆流旋转填料床与错流旋转填料床的脱硫性能。结果表明,相比错流旋转填料床,逆流旋转填料床更适合于低硫尾气的精脱硫,脱硫率可达99%以上。与传统塔式脱硫技术相比,逆流旋转填料床络合铁法脱硫技术脱硫效率高、气/液流量比大、设备体积小,具有工业化应用潜力。     

ELECTROMAGNETIC ENHANCEMENT OF CHEMICAL REACTIONS (Devolatilization of Char and Coal)

Char in the microwave energy field may enhance chemical reactions by three different ways as described below: (1) directly react with elements in molecules when contacted, (2) create free radicals when the gas molecules contact char,and (3) provide heat to adjacent solid particles. To understand the interactions between char and microwave energy, we first investigated the microwave energy absorption by char and also by the mixture of char and coal at various apparent bed temperatures and various ratios of coal to char in the mixture.

The experimental results clearly demonstrated that pyrolysis products are excellent absorbents of the microwave energy. To enhance the pyrolysis rate of coal with the microwave energy, it was necessary to add char that increased energy absorption rate. Coal/char mixture pyrolysis started immediately when the microwave energy was applied. Also, microwave energy absorption rate increased to 73% of input power. When coal concentration in the coal/char mixture exceeded 50%, energy absorption rate decreased to 54% of input power. Without char, coal was not pyrolyzed with the microwave energy (550 W) applied for 60 minutes.     

ELECTROMAGNETIC ENHANCEMENT OF CHEMICAL REACTIONS (Devolatilization of Char and Coal)

Abstract

Char in the microwave energy field may enhance chemical reactions by three different ways as described below: (1) directly react with elements in molecules when contacted, (2) create free radicals when the gas molecules contact char,and (3) provide heat to adjacent solid particles. To understand the interactions between char and microwave energy, we first investigated the microwave energy absorption by char and also by the mixture of char and coal at various apparent bed temperatures and various ratios of coal to char in the mixture.

The experimental results clearly demonstrated that pyrolysis products are excellent absorbents of the microwave energy. To enhance the pyrolysis rate of coal with the microwave energy, it was necessary to add char that increased energy absorption rate. Coal/char mixture pyrolysis started immediately when the microwave energy was applied. Also, microwave energy absorption rate increased to 73% of input power. When coal concentration in the coal/char mixture exceeded 50%, energy absorption rate decreased to 54% of input power. Without char, coal was not pyrolyzed with the microwave energy (550 W) applied for 60 minutes.     

硫酸盐热化学反应蚀变天然气模拟

高H₂S天然气一般被认为是硫酸盐热化学还原反应(TSR)的结果。在高温高压不饱和水蒸气条件下对天然气与硫酸镁TSR反应进行了热模拟实验研究,确定了TSR反应途径,探讨了TSR可能的地质影响因素。结果表明,天然气与硫酸镁反应主要生成MgO、H₂S、CO₂及焦炭等产物,随着模拟温度升高,TSR转化率逐渐增大,天然气中总烃含量减少,CH₄比例逐渐增大,C₂H₆与C₃H₈ 含量呈递减趋势。干燥系数与CO₂含量呈明显的正相关关系,干燥系数与H₂S含量以及CO₂与H₂S含量之间正相关性低,这可能是由于TSR不同阶段主要控制因素不同导致的。地质条件下,高硫化氢天然气的形成与演变很可能受控于温度、碳链长度、金属离子、水和硫化氢含量这几种主要因素。     

KINETIC AND STRUCTURAL STUDIES OF CALCIUM-BASED SORBENTS FOR HIGH-TEMPERATURE COAL-GAS DESULFURIZATION

The absorption of H₂S by large particles of limestone, dolomitic limestone and dolomite (average mass-radius of 0·40 mm) was tested under simulated coal gases. Below the calcination temperature of CaCO₃ (about 900^°C under 1 bar of CO₂), complete conversion of the calcium carbonate to calcium sulfide can only be achieved with dolomite. Above the calcination temperature of CaCO₃, the conversion to CaS is complete for all three sorbents in about one hour when 10,000 ppm H₂S is present in the gas phase. Large particles of limestone thus appear to be a suitable sorbent for high-temperature coal-gas desulfurization (above about 900 ^°C). A mathematical model based on the kinetic information collected in this work predicts the desulfurization performance of a packed or moving bed of limestone particles. Finally, a low-temperature regeneration scheme for the spent sorbent (CaS) in which sulfur can be subsequently recovered as the element is suggested.     

硫化氢生成模拟实验研究

利用封闭体系的高压釜实验装置进行硫化氢生成的模拟实验已有报道,但硫化氢的生成量很少或很难检测到。因此研制了开放体系的石英管模拟方法,探讨了硫酸钙、硫磺、黄铁矿分别与正己烷反应生成硫化氢以及低成熟泥灰岩生烃模拟过程中硫化氢的生成特征。结果表明,硫酸钙与正己烷在高温下可以发生反应,但反应比较困难,且硫化氢的生成量较少;单质硫与正己烷在较低温度下即可发生反应,并可生成大量的硫化氢;黄铁矿与正己烷可以发生反应并生成大量的硫化氢,主要是黄铁矿高温分解形成的单质硫与烃类反应的结果。低成熟泥灰岩生烃模拟过程中能够生成大量的硫化氢与其含有较多的黄铁矿有关。硫化氢生成的成功模拟为其成因机理研究提供了重要的实验手段和依据。      

噻吩脱硫过程中钒氧化物晶格氧的作用

以γ-Al₂O₃、VO₂和V₂O₅为催化剂,在连续固定床微反装置上、500℃下,考察了噻吩在常压下的脱硫反应过程,并进行了噻吩原位吸附红外光谱、XPS光电子能谱、XRD等表征。结果表明,在催化裂化反应条件下,采用具有单纯L酸中心的催化剂时,噻吩脱硫反应的转化率很低;采用具有单纯氧化-还原中心的催化剂时,噻吩可被氧化成CO、CO₂及SO₂,但转化率也较低;采用既具有酸中心又具有氧化 还原中心的V₂O₅时,由于酸中心和氧化-还原中心的协同作用,噻吩脱硫反应的转化率最高,H₂S和SO₂的产率也最高。催化裂化反应条件下,噻吩可以被钒氧化物的晶格氧氧化,同时V₂O₅与VO₂失去部分晶格氧被还原为V₂O₃等低价态产物;由于V₂O₅比VO₂活泼晶格氧数目多,较易被还原,因此噻吩脱硫反应的SO₂产率更高。V₂O₅表面存在的L酸中心Vⁿ⁺－O－V为噻吩的初始吸附中心,L酸中心与临近的V=O双键的作用促进了噻吩的氧化。     

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��The reactions in combustion furnace are very complicated in Claus sulfur recovery process, but it is important for design and production to research these reactions. The reactions which produce H₂, CO. COS and CS₂ are discussed in this article. It is pointed out that H₂ and CO are mainly generated from the decomposition and reactions of H₂S and CO₂ in acid gas and the resultant is rough increased with the increasing of the H₂S content in acid gas and the temperature of furnace. COS is formed by the reaction between CO and elemental S. Once H₂S content in acid gas is over 70%, COS yield drops rapidly. CS₂ is formed by the reaction between CH₄ and elemental S. When the temperature of furnace increases to about 1300��, the generation of CS₂ is stopped.     

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??Through an appropriately simpllfied calculation model,the sulfur-making method of sour containing l5%??50% H₂S has been studied,and two main understandings have been obtained as fol-lowing:(1)the conventional divided-flow Claus Process can be used for the H₂S concentration of l5% ??25%,the direct-flow Claus Process may be used for the sour gas of 49% H₂S as its concentration lower limit in general,accordmg to the thermal stability of commonly used material of furnace wall,25%??45% H₂S is suitablely used for non-conventional divided-flow Claus Process;(2)the total conversion rate of H₂S of non-conventional Claus Process is lower than direct-flow process but higer than conventional divided-flow process.     

NiMoS加氢脱硫催化剂表面非化学计量硫物种动态平衡

加氢脱硫(HDS)催化剂NiMoS活性相表面非化学计量硫(S_x)物种的动态变化是HDS活性的决定因素。在HDS过程中,S_x物种处于动态平衡,且这一平衡与催化剂、H₂S分压及硫化温度相关。笔者采用程序升温的方法研究了催化剂载体、助剂Ni、硫化温度、H₂S分压对NiMoS催化剂表面S_x物种的影响。结果表明：催化剂载体对S_x物种的总量和还原性具有显著影响,Ni的引入显著促进S_x物种还原,提升HDS活性;硫化气相H₂S分压决定了催化剂表面S_x物种含量,气相中H₂S分压升高易使S_x物种增多,表面可利用NiMoS活性位减少,从而导致HDS活性降低。S_x物种含量与H₂S分压及硫化温度的关系符合热力学平衡及van′t Hoff等压方程,进一步将S_x物种含量与HDS反应速率系数进行关联,提出H₂S分压S_x物种含量HDS活性之间的定量关系。     

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��The equilibrium solubility of sour gas mixture of H₂S and CO₂ in MDEA aqueous solution (2.5kmol/m³),had been determined at 40�� and 100��.The scope of partial pressure of H₂S is 0.03��149.35 kPa and that of CO₂ is 1��416.85 kPa.A solubility isoline chart of the sour gas mixture of H₂S and CO₂ is shown in this paper also.     

GC-FID/MS技术应用于苯并噻吩催化裂化转化规律的研究

首次利用相对质量响应因子建立了GC-FID/MS技术分析裂化液体中硫化物的方法,并将其应用于苯并噻吩催化裂化转化规律的研究。结果表明,该方法的准确度较高,苯并噻吩催化裂化反应后的硫平衡均高达95%以上。在催化裂化条件下,纯苯并噻吩很难开环裂化脱硫,四氢萘的加入可明显促进苯并噻吩的转化,提高气体硫的摩尔选择性,并降低裂化汽油馏分段的硫含量。     

REACTION OF VISBREAKER BITUMENS WITH SULFUR

The utilization of sulfur in bituminous binders started many years ago: a number of roads were paved in U.S. with SA (sulfur-asphalt) mixtures. Literature reports that, when mixing sulfur and asphalt, H₂S evolution starts at temperatures higher than 150°C.

By using thermal analysis techniques, the present paper shows that H₂S evolution begins at about 130°C for most types of bitumens. Kinetics of reaction between sulfur and visbreaker bitumens were also studied: the reaction order with respect to sulfur is equal to 0.5 for the three visbreaker bitumens considered in this work.     

高含硫钻井液缓蚀剂的合成及性能研究

本文合成了抑制H₂S腐蚀的咪唑啉类缓蚀剂,并研究了它们的性能。正交试验表明,最佳合成条件是:反应温度:190～200℃;酸:胺(mol比)=1:1.05;反应时间以3～5小时为宜。根据以上条件合成的缓蚀剂,在含有3200mg/lH₂S的泥浆中,用量为0.2%时,抑制效果能达到80～90%,与碱式碳酸锌复配使用时,能提高缓蚀效率和降低碱式碳酸锌的用量,并发现缓蚀剂与CaO之间具有明显的协同效应。泥浆流变性能试验表明,缓蚀剂能提高泥浆的动切力和动塑比,对失水量影响不大。此外,利用X-射线衍射试验证明:(1)低碳钢在含H₂S的泥浆中,腐蚀产物的主要组成为Fe₉S₆;(2)H₂S会破坏FCLS的稳定性,分解出Fe²⁺,与H₂S反应生成面心立方的Fe₂S₄。     

钻井泥浆除硫剂的研究

本文介绍了一种无机锌盐化台物——川设6—1钻井液除硫剂,根据试验结果,论证了它对钻井液的除硫效率和对钻具的防腐效果;并与两种进口的钻井除硫剂进行了对比.现场试验结果表明:川设6—1除硫反应快、效率高、成本低,使钻井液中的硫化氢浓度很快降低到安全界限,从而防止了钻具和套管的硫化物应力腐蚀和失重腐蚀,大大延长了钻具的使用寿命,并避免了钻井操作人员的硫化氢危害.     

高含硫气藏物质平衡方程研究

高含硫气藏是一类特殊的气藏,其物质平衡方程与常规气藏相比存在着较大差别。常规气藏物质平衡方程没有考虑硫沉积现象,因此不能完整地描述高含硫气藏的开发动态。从气藏物质平衡基本原理出发,在考虑硫沉积的基础上,分别针对定容、封闭和水驱气藏的情况,进行了完整地推导,得到了高含硫气藏的物质平衡方程。     

非含硫金属盐对稠油水热裂解生成硫化氢影响实验

高含硫稠油注蒸汽开采过程中,稠油、水蒸气和岩石基质间将发生水热裂解和硫酸盐热化学还原反应,并产生H₂S。为排除硫酸盐热化学还原生成H₂S反应,研究了金属离子对高含硫稠油水热裂解反应生成H₂S的催化作用,开展了AlCl₃、MgCl₂、CaCl₂和ZnCl₂这4种不含硫金属盐与稠油的水热裂解反应实验。实验结果表明:在240~300℃范围内,Al³⁺、Mg²⁺、Ca²⁺、Zn²⁺对稠油水热裂解反应生成H₂S均有催化作用,且Al³⁺的催化效果最好;pH值越低水热裂解生成H₂S反应越强烈,这是因为金属盐溶液呈酸性使H⁺质子化作用加强,而且金属离子对水热裂解中间反应包括C-S键断裂、加氢脱硫、水气转换等反应有催化作用;在一定浓度范围内,金属盐浓度越高,溶液pH值就越低,且金属离子与反应物接触几率增加,对水热裂解催化效果越明显,生成的H₂S越多。     

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本文介绍了采用复合吸收剂净化天然气的试验结果,在现有三甘醇等脱水剂中添加单乙醇胺,在脱水的同时脱除H_2S,在保证净化气露点低于-21℃的条件下,使净化气中H_2S含量亦低于5mg/m～3。     

黄骅坳陷大港探区高含H_2S天然气地球化学特征及成因

渤海湾盆地继冀中坳陷晋县凹陷发现H_2S气藏后,在黄骅坳陷大港探区又发现了高含H_2S气藏,在煤成气气藏中发现如此高含量的H_2S和CO_2在国内还属首次,酸性气体的成因也引起国内学者的关注。通过气、岩有机地球化学参数的对比,认为该区高含量H_2S归因于TSR反应,揭示了煤成气区同样可以发生TSR,丰富了过去只在海相原油裂解气区发生TSR的地质认识;高含量有机或有机-无机混合的CO_2除了与碳酸盐岩的热变质、TSR有关外,与烃类气体属于煤成气有很大的关系。黄骅坳陷大港探区H_2S的富集受储层中的硫源丰富程度和地层温度的控制,高含H_2S天然气主要分布在石炭系—二叠系覆盖且埋深较大的中南部地区,如埕海、泊古—乌马营—王官屯等地区。研究成果对该区高含酸性天然气形成机制以及天然气下一步勘探部署工作都具有积极指导意义。