径流式尿素合成塔与轴流式尿素合成塔的性能分析和比较

分析了轴流式尿素合成塔和径流式尿素合成塔的结构特征;指出了轴流式尿素合成塔的缺点和径流式尿素合成塔的优点。典型用户的使用效果表明：实施将轴流式尿素合成塔改为径流式尿素合成塔的技术改造,可使CO2转化率提高2%～3%;改造实施1年后进行大修检测,没有发现因塔型转化而引起的尿素合成塔衬里腐蚀的现象。     

预合成塔未装催化剂情况下的合成系统稳定运行总结

在甲醇合成装置中,预合成塔分布器设计不合理造成运行阻力过大,进出口压差高达0.4MPa,预合成塔催化剂活性严重降低,合成气在预合成塔内参加反应的数量降低,合成反应主要集中在合成塔内。因预合成塔床层阻力问题,造成合成回路循环量降低,使合成气在主合成塔内反应的时间延长,造成合成塔温度超温,严重影响催化剂寿命。为降低合成塔运行时床层温度,消除预合成塔催化剂床层阻力,卸出预合成塔内旧催化剂,只保留合成塔催化剂。并调节合成系统各工艺参数,有效避免合成塔超温。     

合成塔废热锅炉检修的保护措施

阐述了合成塔废热锅炉产生裂纹的原因,对检修合成塔废热锅炉时合成塔催化剂的保护步骤及检修过程进行了介绍。     

Casale新型高效合成塔板的应用

针对沧州大化尿素装置合成塔运行现状,分析了尿素合成反应及合成塔板对尿素合成的影响,介绍了Casale新型高效合成塔板的设计开发思路及在沧州大化尿素合成塔上的具体应用,并验证了新型高效塔板良好的技术及经济效果。     

甲醇合成塔压差增大的原因分析及技术改造应用

介绍了益达公司焦炉煤气制甲醇的工艺流程和甲醇合成塔的压差变化情况。针对甲醇合成塔进出口压差增大、总碳转化率明显下降的问题,从合成塔内部构造进行了分析,认为甲醇合成塔进出口压差增大主要由支撑瓷球间隙小、催化剂之间接触紧密、催化剂粉化严重等原因引起。在合成塔催化剂更换期间,通过改变合成塔支撑瓷球和合成催化剂的规格及合成催化剂的装填方法等,使合成塔压差降低至0.203 MPa、总碳转化率提高至98.15%。     

180 kt/a氨合成塔的设计与应用

论述了氨合成塔的设计原则,介绍了国内国昌公司NC型、安淳公司ⅢJD型18万t/a氨合成塔以及国外卡萨利公司、托普索公司18万t/a氨合成塔的内件结构特点、工艺流程和生产使用情况;结合生产实际应用数据,对4种氨合成塔进行了综合比较。结果表明,从合成系统氨净值比较,国内水平与国外尚存一定差距,国外托普索合成塔优于卡萨利合成塔的指标。     

合成塔的腐蚀与检验分析

本文结合合成塔生产工艺的特点,介绍了合成塔的主要腐蚀形式和腐蚀机理,详细论述了合成塔的检测检修方法,加强腐蚀监测、检测。     

尿素合成塔腐蚀情况与原因分析

文章叙述了2＃尿素合成塔的腐蚀情况，分析了合成塔腐蚀的原因，提出了防止合成塔腐蚀的措施。     

甲醇合成塔上升管焊缝缺陷修复研究

甲醇合成装置生产中的核心设备即为甲醇合成塔,其中的上升管更是重中之重。甲醇合成塔的上升管可能会因为焊缝问题而对反应过程产生影响,最终的反应结果往往不尽如人意。对此,首先提出了甲醇合成塔的结构和选材特征;其次,分析了造成甲醇合成塔上升管焊缝缺陷问题的主要原因;最后,研究了甲醇合成塔上升管缺陷问题的修复和养护方法。     

径流式尿素合成塔的发明与应用

分析了第1代尿素合成塔——轴流型尿素合成塔存在严重返混问题的原因以及返混造成的后果;论述了第2代尿素合成塔——径流式尿素合成塔的结构形式、工艺特点和生产运行数据;阐明了用径流式塔板改造轴流型尿素合成塔在塔型改造和节能减排方面的优势。     

提高尿塔转化率的技术发展趋势

通过总结传统塔板尿塔转化率的变化规律,分析气室型塔板在各厂的运行情况,几种等温型内件的特点,以及新近推出的径流式塔板的转化率,认为尿塔提高转化率,发展趋势有二:一种是等温合成塔;一种是将塔内物料由传统的轴向流动,改为径向流动.     

Experimental study of a reverse flow catalytic converter for a dual fuel engine

Theperformance of a reverse flow catalytic converter for a methane/diesel dual fuel engine, a monolith honeycomb converter with palladium catalyst washcoat, was evaluated under steady and transient engine conditions. The reverse flow converter provided superior performance (that is, higher conversion of pollutants) for several steady engine operations, compared with unidirectional flow operation. For transient operation following a step change in engine operating conditions, reverse flow is better than unidirectional flow when the change in engine operation results in a reduction in exhaust gas temperature. For an increasing exhaust gas temperature, reverse flow decreased the rate of increase of reactor temperature. The reverse flow converter was tested using the transient Japanese 6‐Mode tests. Reverse flow operation gave higher conversions than unidirectional flow for this test, with a switch time of 5 s giving the best results.     

MM430变频器在窑尾喂料系统中的应用

介绍了西门子MicroMaster430变频器在水泥回转窑窑尾喂料系统中的应用,利用冲板流量计、流量积算仪与MM430变频器的内置PID、BiCo实现了在来料不稳定的情况下仍能给回转窑提供稳定的入窑料流量。     

顶底复吹转炉内气液两相流行为的数值模拟

利用可压缩模型描述了四孔喷头顶吹超音速射流行为,并与前人实测结果对比验证了模拟结果. 通过耦合VOF和Lagrange模型对纯顶吹、顶底复吹炼转炉内熔池运动进行描述,并对炉底喷嘴数量、布置进行优化. 结果表明,在纯顶吹条件下,熔池的混均时间为523 s,炉底区域钢液流动微弱. 加入底吹氩气后,底部钢液速度增大,熔池混均时间为99 s. 炉底采用3个喷嘴的熔池混合效率要好于2个或4个的情况. 底吹喷嘴距离炉底轴心在0.3D~0.4D区间内最佳,且应偏近于0.4D区域.     

等温变换装置运行总结

针对传统变换炉在运行中存在的不足,开发了等温变换炉.介绍了等温变换炉的结构、特点及开发等温变换炉的意义,总结了等温变换炉的运行效果.用1台等温变换炉代替原多段绝热变换炉,简化了变换工艺流程、操作、设备,减少了热量损失,可多副产饱和蒸汽,实现了变换系统的准零汽耗.     

Simulation of Thermal and Flow Characteristics for Optimum Design of an Automotive Catalytic Converter

In the present work, the effect of a flow maldistribution on the thermal and conversion response of a monolithic catalytic converter is investigated. To achieve this goal, a combined chemical reaction and multidimensional fluid dynamic mathematical model has been developed. The present results show that flow uniformity within the monolith brick has a significant impact on light-off performance of the catalytic converter. In the case of lower flow uniformity, large portions of the monolith remain cold due to locally concentrated high velocities, and CO and HC are unconverted during the warm-up period, which leads to retardation of light-off. It has also been found that the heat-up pattern of the monolith is similar to the flow distribution profile in the early stage of the reaction. It may be concluded that flow maldistribution can cause a significant retardation of the light-off and, hence, can eventually worsen the conversion efficiency of an automotive catalytic converter.     

三段串联绝热轴向氨合成塔的模拟计算和设计优化

提出三段轴向氨合成反应器的数学模型和设计优化方法，对三段轴向氨合成反应器进行模拟计算。同时计算了操作压力分别为１５７８，１５０，１００，７．５ＭＰａ时，在三段串联绝热轴向反应器中满足日产１０００ｔ氨所需的最少催化剂用量。     

全径向流型凯洛格氨合成塔的数学模拟分析及其操作条件优化

建立了全径向型凯洛格（Kellog）氨合成塔（托普索S一200内件）的一维均相数学模型,并以实际运行的生产工艺数据为条件,应用龙格一库塔法求解微分方程组,确定在线使用的A110—1催化剂的活性校正系数;以此为基础,应用该数学模型,对全径向型的凯洛格氨合成塔（托普索S一200内件）的操作条件进行优化;结果表明,一维均相数学模型及其计算程序可为全径向型凯洛格氨合成塔的操作和优化提供参考,对提高氨合成塔生产能力具有积极意义。     

Simulation of Thermal and Flow Characteristics for Optimum Design of an Automotive Catalytic Converter

In the present work, the effect of a flow maldistribution on the thermal and conversion response of a monolithic catalytic converter is investigated. To achieve this goal, a combined chemical reaction and multidimensional fluid dynamic mathematical model has been developed. The present results show that flow uniformity within the monolith brick has a significant impact on light-off performance of the catalytic converter. In the case of lower flow uniformity, large portions of the monolith remain cold due to locally concentrated high velocities, and CO and HC are unconverted during the warm-up period, which leads to retardation of light-off. It has also been found that the heat-up pattern of the monolith is similar to the flow distribution profile in the early stage of the reaction. It may be concluded that flow maldistribution can cause a significant retardation of the light-off and, hence, can eventually worsen the conversion efficiency of an automotive catalytic converter.     

Transient simulation of a catalytic converter for a dual fuel engine

An experimental and modelling study was performed for a catalytic converter attached to a natural gas/diesel dual fuel engine. The catalytic converter was a ceramic monolith honeycomb substrate coated with a washcoat of catalyst. A multiple segmented design of converter was used. This paper describes the application of a one‐dimensional finite element model for the transient and steady state operation of this converter. The model is a single channel model. The laminar flow was approximated using a dispersed plug flow model. The chemical kinetics were simulated using LHHW type expressions. Comparison of simulated results are made with experimental results for heating and cooling cycles that resulted from speed and load changes on the engine. These comparisons showed a maximum difference between experimental and predicted emission levels of about 10%.