连续换热式氨触媒床轴向最佳温度的分布

通过数学模型和编制电算程序计算，作连续换热式氨合成塔内最佳温度Ｔｍ和最佳浓度ＹＮＨ３，ｍ沿触媒床高度ｌ分布的曲线Ｔｍ－ｌ和ＹＮＨ３，ｍ－ｌ比Ｔ－Ｙ图更能直接、明确地反映床层轴向实际温度和氨浓度与最佳温度和氨浓度之间的偏差分布规律。     

从纯碱厂蒸氨废液中回收CaCl2,NaCl的设想

从纯碱厂蒸氨废液中回收ＣａＣｌ＿２、ＮａＣｌ的设想徐学波南化（集团）公司连云港碱厂关键词氨碱法制碱，氯化钙，三废处理，综合利用氨碱法制碱的蒸氨废液是纯碱厂三废排放之一。年产６０万ｔ的纯碱厂每年排放蒸氨废液量在５００～６００万ｍ￣３，其中ＣａＣｌ＿２约...     

大型氨厂合成塔温度优化控制

氨合成塔作为合成氨装置中的关键设备之一，其床层温度的优化操作及控制品质对提高塔内氨转化率具有很大影响，本文从工艺角度对合成塔内的最佳温度分布进行分析后提出一种迅速有效的确定氨合成塔优化状态的简易算法，并采用计算机分级控制方式，实现了氨合成塔温度优化控制。     

网格法求解三套管氨合成塔催化床径向浓度和温度分布

在柱坐标系中建立了描述三套管氨合成塔催化床径向浓度和温度分布的数学模型.采用网格法计算了管间催化床不规则截面的浓度分布和温度分布.计算方法快速、有效.     

浅议蒸馏塔的内防腐

浅议蒸馏塔的内防腐姜宜松，姜斌，王和堂，范彩凤（大连化学工业公司碱厂大连ｌ１６０３２）主题词：蒸氨塔，防腐大化碱厂有蒸馏塔四台。每台直径为２．８ｍ，高４２．７ｍ，共３４圈。塔体分为蒸馏段和预热段。１￣＃～１６￣＃圈为蒸馏段，内有ｌｌ个菌帽和空圈组成。...     

氨合成反应器冷管效应的研究

以氨合成反应器为研究对象，以拟均相二维模型计算了床层温度和产物浓度分布，并与实测的轴向分布值比较，发现用二维模型计算时，催化剂的活性只有在比按一维模型测得的活性系数高时才能相互吻合。考察了催化床径向温度，浓度和速度分布，定量计算了“冷管效应”的大小，结果表明，由于冷管效应，氨合成塔中近40％的区域催化剂活性不能正常发挥。     

Φ600XF-ⅢJ型氨合成塔内件及其系统操作要点

介绍Φ６００ＸＦ－ⅢＪ型氨合成塔内件的特点。针对操作中出现热点位置下移的情况，提出解决办法和操作要点，以调节触媒床层温度分布尽可能靠近“最佳曲线”，提高氨产量，最大地发掘该内件的潜力。     

硝磷酸氨法净化生产磷酸二氢铵工艺研究

针对硫酸法湿法磷酸生产磷酸二氢铵副产磷石膏的问题，基于硝酸法冷冻母液深度脱硝后的净化液，采用氨中和工艺生产工业级磷酸二氢铵，系统研究了反应温度、磷酸浓度、反应时间、搅拌速率、pH、杂质离子浓度等因素对于氨中和工艺的影响。结果表明，氨中和过程中杂质离子生成磷酸盐沉淀影响磷收率，且杂质离子之间主要以形成复盐沉淀互相影响。通过对比氨中和后滤液的成分可得出最佳工艺条件：P₂O₅质量分数为15%、反应温度为85℃、搅拌速率为250 r/min、反应时间为40 min、pH为4.3，最后以最佳工艺条件制备的磷酸二氢铵产品达到一级产品标准要求。     

氨氯萘醌的合成研究

以甲醇为溶剂,考察了二氯萘醌与氨气反应制备氨氯萘醌的最佳工艺条件。结果表明,氨与二氯萘醌的摩尔比为6∶1,氨甲醇溶液浓度15%-17%,反应时间4 h,反应温度20-25℃,收率可达到96%。     

含氰化氢的混合气磷铵吸氨的实验研究

在玻璃填料塔中,用磷铵吸氨法回收氰化氢和氨气的混合气中的氨,研究了温度、吸收剂的浓度、液气比、进口浓度等条件对氨回收率的影响。结果表明,较好的工艺条件为:吸收温度45℃,吸收液浓度2.1 mol/L,液气比11 L/m~3。     

三套管连续换热式氨合成塔催化床的二维模型

本文建立了三套管连续换热式氨合成塔催化床的二维数学模型,用逸度表示反应速率,求得了床层内轴向和径向温度及浓度分布的数值解。模拟计算结果表明,由于冷却段催化床内插冷管,冷管内与床层内的温差较大,使床层的径向存在较大的温差。采用一维模型进行计算与实际情况存在一定的偏差,这一点在反应器的设计和催化剂的还原中是不容忽视的。     

氨合成塔的优化设计

通过数学模拟计算,定量地分析和讨论了三套管氨合成塔在一定的设计压力、热点温度和氢氮比条件下,催化床进口氨含量、惰气含量、温度、空速和催化荆活性系数对氨合成反应的影响以及这些因素之间的内在关系,提出了在最优调节参数下实现氨合成塔优化操作和确定较适宜工艺设计参数的理论依据和方法。结果表明,催化床进口温度是实现氨合成塔优化操作的最优调节参数。     

Effects of the pretreatment of Cu-Y zeolite catalysts on the reduction of nitric oxide with ammonia

Experiments were conducted to study the effects of pretreating Cu-Y zeolite catalysts on the reduction of nitric oxide with ammonia. Changing the oxidation state and environment of the copper in Cu-Y changed the optimal reaction temperature of the NO---NH₃ reaction and the activity of this catalyst. At the optimal temperature, the activity of Cu-Y after dehydration was higher than that of hydrated Cu-Y. In addition, at the optimal temperature, the activity of Cu-Y after the NO---NH₃ reaction followed by oxidation or ammonia pretreatment followed by oxidation was higher than that of dehydrated Cu-Y. The activity of Cu-Y at the optimal temperature was decreased by reduction at higher temperature but increased by reduction at lower temperature. Furthermore, the activity of Cu-Y increased as the copper loading was increased. The optimal reaction temperatures of the NO---NH₃ reaction over various pretreated Cu-Y catalysts were 106, 126, 220 and 300°C, respectively.     

Experimental Study of Flow Reversal Ammonia Synthesis

Operation of fixed bed reactors with periodic flow reversal as proposed by Matros and co-workers is an unconventional mode of operation for exothermic, equilibrium limited catalytic reactions. In the present paper, reverse flow ammonia synthesis at 240–300 bar over a promoted iron catalyst is considered. The catalyst had a particle size of 1.0–1.5 mm to neglect the intra- and interparticle transport intrusions. Temperature profiles, which developed and moved back and forth through the laboratory scale reactor, depending upon the direction of the flow, and the exit ammonia concentration were monitored. The time average ammonia concentration observed in the non-steady-state of operation was exceeded by 5–27% the ammonia concentration obtained in similar but under steady-state conditions. The enhancement in the ammonia production was mainly due to the transient state of the catalyst surface and the dynamic behavior of the reactor bed.     

SIMULATED BEHAVIOR OF AN AUTOTHERMAL REACTOR UNDER RELAXED STEADY-STATE OPERATION

This paper examines the theoretical relaxed steady-state limit of an autothermal reactor under forced concentration operation. Simulations of a laboratory-scale autothermal ammonia synthesis reactor with a transient high-pressure ammonia synthesis kinetic model show that time-averaged production rates more than twice the optimal steady-state rate are possible. Moreover, milder temperature profiles generally acompany these higher rates, which in practice should increase catalyst and equipment life.     

如何实现氨合成塔的优化操作

采用数学模拟的方法 ,从理论上分析和讨论了连续换热三套管并流式氨合成塔在其催化剂有效使用期内 ,随着催化剂活性系数的逐渐衰减 ,分别调节催化床进口温度或进口氨含量、惰气含量和空速等四个设计参数 (单参数 ) ,观察其对出口温度和氨产量的影响 ,并与最佳出口温度和氨含量进行了比较。计算结果表明 :当进口氨含量或惰气含量为调节参数时 ,氨产量均不能达到设计的生产能力 ;而调节进口温度或空速时 ,氨产量均可超过设计的生产能力 ,其中 ,前者超过的幅度较大且能耗较小 ,可选择为实现氨合成塔优化操作的最佳调节参数     

A301氨合成催化剂最佳操作条件与催化活性的关系

用高压氨合成催化剂性能评价装置 ,研究了反应温度、压力、空速、惰性气体含量、氢氮比和催化剂粒度对 A30 1催化剂活性的影响。A30 1催化剂在 15 MPa下的最适反应温度在 430～ 480℃ ,在 7MPa下在 376～ 45 0℃ ,比 A110 - 2低 15～ 35℃。A30 1催化剂的最佳 H2 ,N2 摩尔比 nm在 45 0℃时为 2 .5 5～ 3.0 ,在 40 0℃时为 2 .2 3～ 2 .5 5 ,在 35 0℃时为 1.76～ 2 .2 2 ,并可用 nm=1 .5 0 +1 .49( c NH3/ c*NH3)来表示。惰性气体含量会使催化剂活性大幅度降低 ,每当惰性气体含量增加 1 % ,出口氨浓度 (氨净值 )平均降低 0 .2 %～ 0 .3 5 %。颗粒大小对活性或反应速率有严重的影响 ,其内表面利用率受反应温度和催化效率两个因素的影响 ,对于高活性的 A3 0 1催化剂 ,催化效率的因素起主要作用。根据实验结果和合成氨反应的基本理论 ,讨论并提出了A3 0 1催化剂在合成氨生产中的最佳操作工艺条件     

Steady‐State Modeling and Simulation of an Axial‐Radial Ammonia Synthesis Reactor

A two‐dimensional model was developed for an axial‐radial ammonia synthesis reactor of the Shiraz petrochemical plant. In this model, momentum and continuity equations as well as mass and energy balance equations are solved simultaneously by orthogonal collocation on the finite element method to obtain pressure, velocity, concentration and temperature profiles in both axial and radial directions. For the catalyst particle, the effectiveness factor is calculated by solving a two‐point boundary value differential equation. The boundary conditions for the Navier‐Stokes and continuity equations are obtained by using equations representing the phenomena of gases splitting or joining in different streams and going through holes in a thin wall. The results of the mathematical model have been compared with the plant data and a good agreement is obtained.