一段炉结炭触媒用于二段炉

在以气态烃为原料的合成氨生产中,用于烃类蒸汽转化的Z102触媒用量较大,价格也较昂贵。为此,保护好触媒,确保触媒正常使用十分必要。我厂以油田气为原料生产合成氨,一、二段炉均用Z102转化触媒,一次装填量为17.5吨。自投产以来,一段转化炉曾发生过两次触媒结炭事故。触媒结炭后表现在触媒床层阻力增加,炉管温度上涨并花白,出口残余甲烷超高,最高达18.5％,因而无法生产。结炭后曾     

二段转化炉触媒托筐塌裂原因分析及预防措施

二段转化炉触媒托筐塌裂原因分析及预防措施郑建文（黑龙江省大庆石油化工总厂炼油厂黑龙江省大庆市１６３７１１）二段转化炉是合成氨装置的关键设备之一，在一段炉内未被转化的大约９％的ＣＨ在此进一步转化。位于二段炉下部出口处的触媒托筐是二段炉的一个关键部件，它...     

全径向转化器顺利投产

转化器触媒层阻力大是当前影响硫酸增产的主要障碍之一。我车间继硫酸二、三系统转化器一、二段改成径向转化收到一定效果之后,学习了湛江化工厂的先进经验,对     

挖掘潜力 强化管理 延长二段炉触媒使用周期

结合日产450t/d合成氨生产装置二段转化炉触媒使用情况,阐述了影响二段炉触媒使用周期因素,并根据该触媒使用情况挖掘潜力,通过对工艺空气预热盘管改造,优化了二段炉运行参数,提高二段转化率,为延长二段炉触媒使用周期创造有利条件。     

提高常压中温变换触媒使用时间的总结

一、概况我厂造气车间共有十套常压变换炉,大致可分为两种流程,一种是轴向炉(并联式)流程(如图1),水煤气及蒸汽经并联的甲、乙变换炉,各有三层触媒,触媒厚度:一层700mm,二层500mm,三层800mm,共计28.28m~3。一般一层为 B104与 B106混装,二层为 B104,三层为 B106。用煤气冷激降低二层触媒温度,用蒸汽冷激降低三层触媒温度。另一种是径向炉(串联式)流程(如     

川化一段炉废热回收改造浅述

川化股份有限公司第二化肥厂日产1000t合成氨、1600t尿素装置是20世纪70年代从日本东洋工程公司(TEC)成套引进的第一套大化肥装置，其合成氨装置一段转化炉排放烟气量大、温度高(达230℃)，不仅浪费热能而且对周围环境造成一定污染。根据我国能源政策规定，大型加热炉排放烟气温度应控制在180℃以下，因此，一段转化炉废热回收十分必要。     

一段转化炉转化气温度自动调节

用天然气制合成氨的工艺中,需将甲烷转化成氢气,一段转化炉就是用来完成甲烷粗转化这道工序的.为了保证一段转化炉转化反应的正常进行,并达到予期的转化率,工艺上要求一段转化炉出口气体中甲烷含量低于11%.影响炉出口气体中甲烷含量的因素很多,如转化温度,天然气和蒸汽比值,生产负荷,原料气压力、触媒活性等.其中转化温度的波动     

小氮肥厂一段转化炉水气比控制系统

最大的合成氨产量和最低的原料、燃料消耗是氨肥生产所追求的目标,而合成氨产量、原料和燃料消耗主要反映在一段转化炉的转化效率上,影响一段转化炉转化效率的二个主要指标为入炉水蒸汽和天然气的比值及转化温度。由于小氮肥厂工艺原料的不稳定性,使水汽比参数对转化率的影响尤为突出。过低的水气比将产生析碳反映,永久损坏转化触媒,所以实际操作中水气比控制得很高,这样虽然保护了触媒,但大大增加了能源消耗,所以将水气比稳定地控制在某一恰当的给定值上,有着十分重要的节能意     

重油气化系统加压变换使用喷水调温

我厂加压变换操作压力为20公斤/厘米~2,原一、二、三层触媒温度用35公斤/厘米~2蒸汽调节。由于我厂蒸汽为过热蒸汽,温度高达350℃,而第三层触媒温度为450～470℃。由于蒸汽温度同触媒层温度差较小,调节效果不好,而蒸汽用量却很大。我厂加压变换流程是:汽气比为1.4左右,油煤气经加压变换初换热器及中间换热器预热后进加变炉第一、第二层使一氧化碳部分转化,经部分转化后的变换气进中间换热器管内,再进变换炉第三层。原变换炉内未考虑用冷凝水     

变换炉新型复合结构内衬

郾城县第二化肥厂用φ2300变换炉,工作压力(绝压)14.5公斤/厘米~2。触媒分三段,一、二段间和二、三段间用冷凝水冷激降温;原内衬为石棉板、保温砖、轻质耐火砖复合结构,内衬厚为235毫米;炉内触媒容积仅9.5米~3,生产能力受到限制。因内衬导热系数大,炉体壁温高,热损失多,触媒升温还原时间较长,生产中变换蒸汽用量大,触媒使用后期需开电加热器维持生产,浪费能源。又因炉壁温度高,长期使用不安全,并缩短炉子的使用寿命。为挖掘变换的生产能力和实现节能降耗,1984年改用硅酸铝耐火纤维毡和轻质火砖新型     

一段炉催化剂析炭及炉管的超温保护

从原料气质量、系统负荷、水碳比等方面分析了一段炉催化剂析炭的原因;论述了一段炉转化管超温的影响因素;提出了炉管降温措施和处理方法,总结了实施效果;指出避免催化剂析炭是控制一段炉转化管超温的重要措施。     

焦炉气催化部分氧化的数值模拟

利用F luent中标准κ-ε模型和多孔介质模型对焦炉气催化部分氧化转化炉进行模拟计算。整个反应床层分为氧化反应区和转化区,氧化反应区主要发生燃烧反应;转化区则装填催化剂,发生甲烷重整反应。通过模拟计算给出了转化炉内温度分布、压力分布、组分摩尔分数分布。转化炉出口的温度与气体摩尔分数与Aspen P lus软件模拟结果相吻合。表明CFD模拟结果是准确的,可用于焦炉气催化部分氧化转化炉的工艺和结构设计中。     

入口气体组成对天然气重整工作温度的影响

重整催化剂是影响重整制氢系统造价和寿命的重要因素。由于在所需重整温度下容易烧结积炭,廉价的Ni系催化剂在分布式中小型重整反应器中的应用受到了限制。为了使Ni系催化剂在不易发生烧结积炭的温度下工作,分析了在一定原料CH4空速和转化率下入口气体组成对重整工作温度的影响,并探讨了在原料气中导入循环气来改变重整入口气体组成的方法。结果表明：Ni系催化剂在导入一定组成和流量比的循环气与不导入循环气时相比,一定原料CH4空速和转化率下的重整工作温度大幅降低。据此,提出了一种用于燃料电池电站氢源系统的重整制氢工艺流程,其特征是将部分燃料电池阳极出口气作为循环气与原料气混合后导入重整反应器,使天然气重整工作温度大幅降低。     

Simulation of Secondary Reformer in Industrial Ammonia Plant

In order to develop a reactor design model for the secondary reformer in the industrial ammonia plant, the effectiveness factor and convection heat transfer coefficient between gas and catalyst surface have been studied. The temperature and composition of inlet gas to the catalyst bed are predicted using the kinetic equations of 32 radical reactions. The effect of oxygen content in air on the product synthesis gas composition and the ratio of synthesis gas to nitrogen have been studied. The effectiveness factor has been calculated with the assumption that the steam methane reforming reaction is first order in methane partial pressure. The catalyst shape is assumed to be spherical with an equivalent volumetric diameter. The temperature and composition profiles along the axial distance are predicted using a one‐dimensional heterogeneous catalytic reaction model. The temperatures of both gas and catalyst surface decreased with the axial distance from the top of the bed, while the reactions took place. The temperature difference between gas and catalyst surface also decreased along the axial distance. The predicted temperature and composition by the proposed simulation method have been verified with the data from the industrial plant.     

Modelling the complex interactions between reformer and reduction furnace in a midrex‐based iron plant

This article studies the complex mass and energy interactions between the reformer and the reduction furnace in an iron plant based on Midrex technology. The methodology consists in the development of rigorous first principle models for the reformer and the reduction furnace, in addition to models for auxiliary units such as heat recuperator, scrubber and compressor. In this regard, a one‐dimensional heterogeneous model for the catalyst tubes which takes into account the intraparticle mass transfer resistance was developed for the reformer unit, while the furnace was modelled with bottom‐firing configuration. As for the reduction furnace, the mathematical model was based on the concept of shrinking core model. The furnace was modelled as a moving bed reactor taking into consideration the effects of water gas shift reaction, steam reforming of methane and carburisation reactions. The model was first validated using data from a local iron/steel plant and was then simulated to determine key output variables such as bustle gas temperature, degree of metalisation, carbon content, ratio of hydrogen to carbon monoxide, reductants to oxidants ratio and required compression energy. The effects of key input parameters on the performance of the plant were studied. These parameters included recycle ratio, scrubber exit temperature, injected oxygen flow rate, flow rate of natural gas after reformer, to transition zone, to reformer and to cooling zone. Useful profiles were compiled to illustrate the results of the sensitivity analysis. These results may serve as guidelines for a further optimisation of the plant.     

川西北甲醇装置高能耗原因与对策

设计工况下开工锅炉不能停运,开工过程中燃料消耗和放空损失大是造成川西北甲醇装置天然气和锅炉水消耗上升的主要原因。通过调整蒸气系统操作参数,更换换热设备和甲醇合成触媒,改造转化炉燃料气流程,缩短合成触媒倒入合成新鲜气时间的整改措施,解决了运行和开工过程中天然气和锅炉水消耗高的问题。     

NC型1200mm氨合成塔内件特性及系统配置的优化设计

NC型12 0 0mm氨合成塔内件采用一轴二径绝热反应形式 :轴向冷激采用菱形分布器结构 ,两段径向采用鱼鳞筒或径向流分布器 ,使气流呈辐射状进入催化剂床层 ,路径缩短 ,床层阻力降低 ,特点是对三段催化剂床层进行冷激控制 ,使其在最佳温度范围内反应。在系统中采用气体分流进塔设计 :将水冷出口气体进氨分改为先进冷交 ;系统设置新鲜气氨冷器 ;对系统的主要辅助设备预留了较大的富裕量     

高浓度CO变换气制甲醇问题的探讨及催化剂选型

通过动力学模拟计算和实验研究,对高浓度CO变换气制甲醇工艺中,第一反应器反应深度控制、甲烷化副反应和催化剂选型等问题进行了讨论,结果表明:通过控制反应的水/气和催化剂装量均可达到控制反应深度的目的;降低床层的热点温度,增加水/气和空速均可抑止甲烷化副反应发生;选用强稳定性、抗水合性能和低温活性高的CO耐硫变换催化剂,可以满足高CO浓度变换气对催化剂性能的要求。     

Deactivation of a Ni-Based Reforming Catalyst During the Upgrading of the Producer Gas, from Simulated to Real Conditions

The deactivation of a nickel reforming catalyst during the upgrading of the producer gas obtained by gasification of lignocellulosic biomass was studied. The research involved several steps: the selective deactivation of the catalyst in a laboratory scale; the streaming of the catalyst with the producer gas of a downdraft and an oxygen/steam circulating fluidized bed (CFB) gasifier; and tests in a reformer placed in a slipstream of the CFB gasifier. The information obtained allowed to elucidate the catalyst deactivation mechanisms taking place during the reforming of the producer gas: physical deactivation by deposition of fine ashes, aerosol particulate or carbon; poisoning by H₂S and HCl present in the gas phase and thermal sintering because of the high operation temperatures required to avoid the chemical deactivation. These physical and chemical effects depended on the composition of the biomass fuel.     

QZ201/QZ202型二段炉转化催化剂的工业应用

以高温烧结氧化铝为载体,镍为活性组份,高熔点稀土氧化物为助剂制备的二段转化炉催化剂具有使用强度高,耐热性能好,转化活性稳定。床层阻力降低等特点。工业应用结果表明,该催化剂的综合性能达到国内同类催化剂的水平。