Modelling the modified claus process reaction furnace and the implications on plant design and recovery

The calculation of product composition, flow rate and temperature of the modified Claus process reaction furnace is typically done by assuming either thermodynamic equilibrium or by empirical methods fitted to plant data. This paper extensively reviews the literature on the Claus reaction furnace and compares equilibrium and empirical results of the predicted concentrations of the key components: hydrogen (H₂), carbon monoxide (CO), carbonyl sulphide (COS) and carbon disulphide (CS₂). The implication of the reaction furnace model on the overall plant design and sulphur recovery is subsequently presented. It is well known that results of equilibrium calculations do not match plant data taken both before and after the waste heat boiler (WHB). Moreover, even though results of empirical methods do not match plant data taken before the WHB, one empirical method provides the best fit of highly scattered data taken after the WHB and provides a conservative plant design and estimates of sulphur recovery and emissions.     

The fate of methane in a claus plant reaction furnace

Experimental kinetic data are reported for key side reactions occurring in the front end [i. e. the reaction furnace (RF) and the waste heat boiler (WHB)] of modified Claus plants used for sulfur recovery from the sour gases evolved in the treatment of natural gas. An extensive experimental study was conducted in a high temperature tubular reactor system for two important homogenous gas‐phase reactions. Firstly, experiments were carried out to study the oxidation of hydrogen sulfide and methane mixtures in the presence of oxygen. Secondly, the reaction between methane and sulfur dioxide was investigated experimentally. These results showed that methane was much less competitive for oxygen than hydrogen sulfide. Hence, in a partially oxidizing environment of a RF, data showed that methane reacted significantly with other major sulfur containing species, as secondary reactions, to form COS and especially CS². This is highly problematic from an environmental point of view.     

合成氨二段转化废热锅炉失效分析

综述合成氨二段转化废热锅炉失效历程分析，废热锅炉列管穿孔、管板泄漏及水压试验泄漏的原因，提出解决对策。     

SIMULATING VARIOUS SCHEMES OF THE CLAUS PROCESS

An interactive program based on the Gibbs free energy minimization and the FLOWTRAN system analysis was written to simulate various schemes of the Claus process. Dew point calculation and feedback control loops were provided. Certain species are treated as inerts in units like condensers, reheaters, and the waste heat boiler, Simulation of the Claus process air demand and simulation of two Claus plants (including a commercial one) were presented and the results analyzed.     

Thermal Decomposition Of Carbonyl Sulfide At Temperatures Encountered In The Front End Of Modified Claus Plants

Understanding the kinetics of the formation and consumption of COS and CS₂ in the front end of the modified Claus process will be a significant step towards reducing the environmental impact of these plants. Specifically, homogeneous intrinsic rate expressions are needed for engineering design and simulation, which will lead to new, optimized ways of operating these plants. Hence, a high-temperature kinetic study of the COS decomposition reaction was carried out. Experiments were performed with inlet COS compositions in the range of 0.20-2.33 mol%, with pressures at 101-150 kPa and temperatures at 800-1100°C; these conditions cover the conditions typically encountered in the front end of the modified Claus process. The experimental results showed that COS conversion is dependent on the inlet concentration of COS, which contrasts with previously reported higher temperature studies. Finally, the COS decomposition kinetics were modeled as the sum of two reactions, which provided a satisfactory representation of experimental data.     

Thermal Decomposition Of Carbonyl Sulfide At Temperatures Encountered In The Front End Of Modified Claus Plants

Understanding the kinetics of the formation and consumption of COS and CS₂ in the front end of the modified Claus process will be a significant step towards reducing the environmental impact of these plants. Specifically, homogeneous intrinsic rate expressions are needed for engineering design and simulation, which will lead to new, optimized ways of operating these plants. Hence, a high-temperature kinetic study of the COS decomposition reaction was carried out. Experiments were performed with inlet COS compositions in the range of 0.20–2.33 mol%, with pressures at 101–150 kPa and temperatures at 800–1100°C; these conditions cover the conditions typically encountered in the front end of the modified Claus process. The experimental results showed that COS conversion is dependent on the inlet concentration of COS, which contrasts with previously reported higher temperature studies. Finally, the COS decomposition kinetics were modeled as the sum of two reactions, which provided a satisfactory representation of experimental data.     

大型粉煤气化炉及废锅系统整体动力效应分析

大型煤粉气化炉及废热锅炉通过导管连接成一整体,且气化炉底部裙座固定,在废热锅炉侧采用恒力弹簧吊架吊挂支撑,如采用“常规设计”无法进行承压外壳的强度计算。建立了气化炉与废热锅炉系统的整体计算模型,采用应力分析计算方法进行系统整体动力效应计算,确定了各种载荷工况下的系统整体变形、力和力矩,为准确计算各关键部件的强度,保证气化炉和废热锅炉系统整体的安全奠定了基础。     

普光气田克劳斯反应炉废热锅炉陶瓷套管技术改造

介绍了中石化普光气田天然气净化厂12套硫磺回收单元克劳斯反应炉废热锅炉的结构及内衬施工过程.废热锅炉除陶瓷套管及刚玉浇注料外全部国产化.在试车烘炉中废热锅炉第一段入口端陶瓷套管大面积开裂,后采用进口材料和国产材料2套修复方案加以处理.实践证明,采用国产锆刚玉陶瓷套管及刚玉浇注料修复后废热锅炉运行稳定.目前废热锅炉已运行4年时间,预计使用寿命可超过6年.     

转化废热锅炉泄漏原因及处理

阐述锦西天然气化工有限责任公司合成氨装置在运行过程中转化废热锅炉工艺侧泄漏情况,分析泄漏原因,提出维持运行期间的工艺注意事项及停车检修的工艺处理方法.     

低温Claus尾气加氢催化剂浅析

介绍了4种低温Claus尾气加氢催化剂的性能指标和研究进展。与普通催化剂相比,使用该低温催化剂可使加氢反应器的入口温度在224～240℃运行,取消在线燃烧炉和废热锅炉,Claus尾气流量可减少10%～15%,装置总投资可降低约18%,总操作费用可减少20%左右。并且装置工艺流程得到优化,操作性和稳定性提高。目前,该低温催化剂已在国内多套硫磺回收装置中得到推广应用。     

水泥窑余热锅炉清灰方式选择

介绍了烟气中灰尘对余热锅炉的主要危害,水泥窑窑头和窑尾积灰特性,以及选择合理的清灰方式对余热锅炉正常运行的重要性。重点分析比较了余热锅炉的几种常用清灰方式及其效果,提出窑头利用沉降除尘、窑尾利用机械振打锅炉管束能达到良好的清灰效果,可提高余热锅炉的热效率。     

蒸发管外置式废热锅炉

蒸发管外置式废热锅炉由沸腾层热管废热回收器和烟道废热回收器组成，在一套55kL／a硫铁矿制酸系统中首次投入使用。该废热锅炉结构简单，投资省(仅60万元)，无露点腐蚀，不会因少数热管损坏而停车，所产蒸汽量达1L／1，蒸汽压力1．0～2．5MPa。目前锅炉已稳定运行1年多，各项指标均达到设计要求。     

干法熄焦装置余热锅炉"三管"的腐蚀及防护

介绍了干法熄焦装置余热锅炉的过热器管、蒸发器管和省煤器管腐蚀爆漏的原因及防护措施。     

浅析冶炼烟气制酸废热锅炉设计要点

介绍了冶炼烟气制酸废热锅炉的结构及设计要点。根据冶炼烟气尘含量高且烟尘粘结性强、烟气腐蚀性强及烟气波动性大的特性,废热锅炉设计时有针对性地对锅炉进行热工计算及结构选型,采用垂直烟道纵横向冲刷型锅炉并合理选择运行参数、加强振打除灰,以确保锅炉在恶劣工况下的适应性和安全性。     

二段转化废热锅炉炉管腐蚀的探讨

对合成氨新工艺二段转化炉后废热锅炉炉管运行情况进行分析，指出在运行过程中，因磷酸在钠在特定的环境中，在高温条件下，转化为焦磷酸钠或六偏磷酸钠，使炉水变为酸性，造成炉管酸性腐蚀。     

催化裂化余热锅炉系统火【用】分析

利用炯分析方法对催化裂化余热锅炉进行了综合炯效率分析,分析了余热锅炉系统在运行中的炯效率表达式;并且用此方法进行了实例计算与分析,得出了余热锅炉在实际运行中有效能利用情况,对余热锅炉炯效率的影响因素进行了定性分析,确定了炯损失的关键环节为排烟炯损失和温差传热炯损失;通过针对性的优化方案对余热锅炉进行改造,若使其排烟温度降至150oC时,余热锅炉系统炯效率将提高10．4％。     

重整装置余热锅炉节能改造

为了回收重整加热炉系统烟气余热,多生产中压蒸汽,同时提高设备的运行的可靠性,消除安全隐患,对余热炉的烟筒、风机、炉管、保温材料等进行了改造和维修,改造后中压蒸汽产量有了较大幅度提高,同时增加了设备运行可靠性和运转周期,减少了安全隐患和维修费用。     

一种新型废热锅炉的结构设计

介绍了一种湿法脱硫制酸装置中新型废热锅炉的工艺参数和整体结构,结合实际生产运行中设备可能发生的失效模式,着重阐述了废热锅炉管板、管板与换热管连接形式及耐热防护等重要结构部件的设计和改进.     

水泥余热发电AQC余热锅炉改造可行性研究

本文针对早期水泥窑余热发电项目设计偏保守,发电量偏低的问题做了技术分析,并从理论角度指出通过窑头AQC锅炉本体的简单改造,即增加部分管箱的换热管排数,就可以起到锅炉扩容,提高发电量的目的。尽管此类改造尚存不确定因素,但为当前水泥企业指明了一条降本增效、节能减排的新途径。     

造气废热锅炉改造小结

以造气火管式废热锅炉的改造为主线,对火管式废热锅炉存在的火管变形扭曲、热应力无法消除、露点腐蚀、焊接工艺、水侧的氧腐蚀和垢下腐蚀问题进行了剖析。提出了改进意见,即热水加热器管间距由32mm扩至50mm、软水加热器及套管式过热器最上端增加防腐护瓦、设计1台专用制贫气锅炉、改进材质等,并对改造后的套管式锅炉结构特点及其使用效果进行了介绍。