DAVY180万t/a甲醇合成装置稳定运行分析与研究

本文以Johnson Mattey/Davy公司的180万t/a甲醇合成工艺流程为例,分析得出了此甲醇合成装置要稳定运行,最主要的是要保护好催化剂,提高催化剂活性,同时还要依据催化剂的使用情况,控制好新鲜气硫含量小于20ppb、新鲜气氢碳进料比例在2.05、操作压力7.8MPa、合成塔入口操作温度216~230℃、催化剂床层温度在230~280℃之间等因素的结论。     

煤制甲醇工艺甲醇合成塔的工艺设计探讨

以30万吨/年焦炉气制甲醇项目各工序的压力、温度、介质成分、流量等工艺条件,确定合成塔设备排热量及结构形式。甲醇合成塔又称甲醇合成反应器,是甲醇装置中的核心设备之一,也是合成工段中最关键的设备,合成塔为立式绝热管壳型反应器,管内装有C306型低压合成甲醇催化剂,本设计的目的是按照工艺要求设计甲醇合成工段甲醇合成塔,为压力容器设计提供理论依据。     

MK-121型甲醇合成催化剂的升温还原

介绍了甲醇合成回路流程及MK-121型甲醇合成催化剂的升温还原情况。从出水量、耗氢情况来看,催化剂还原得非常彻底;另外,在催化剂还原过程中,循环量、甲醇合成塔进出口气体温度、顶部绝热层温度、进口H_2含量、系统压力等指标都非常平稳。实际运行情况证明,该催化剂具有较高的转化率、选择性、活性和稳定性。     

RK-05型甲醇合成催化剂的应用情况

简要介绍RK-05型甲醇合成催化剂的物理化学性能、装填、升温还原及生产运行情况,并介绍其与一期甲醇系统运行情况相比,具有系统压力低、新鲜气耗低、反应副产物少等特点。但也存在合成塔压差大的问题。     

GC-R023型氨合成塔技术及应用

设计生产能力1 200 t/d大型合成氨生产装置采用低压合成氨生产工艺,其GC-R023型氨合成塔(Ф2 600 mm)是目前完全采用国内专利技术、自主设计、自主制作的大型设备。氨合成塔内件为三径向结构,装填DNCA(A207型)催化剂,介绍了催化剂的升温还原和生产运行情况。目前,该装置在粉煤流量为42～46 t/h时,合成氨产量32～36 t/h,氨合成系统压力10.8～11.2 MPa,系统压差0.55～0.60 MPa,合成塔压差0.15～0.16 MPa,氨净值14.6%～14.8%(体积分数)。     

200kt/a焦炉气制甲醇装置合成催化剂升温还原过程简介

介绍200kt/a焦炉气制甲醇装置合成塔结构及催化剂装填情况,催化剂升温还原过程,导气及低负荷运行状况。     

C207型甲醇催化剂使用过程中的优化措施

介绍了C207型铜基甲醇催化剂的升温还原过程及生产过程中的一些优化措施。甲醇塔升温还原气采用合成氨驰放气经过中空纤维膜的氢回收装置后的高浓度氢气或醇后气,在还原过程中采用高氢、高空速、低水汽浓度法,尽可能使催化剂在低温多出水。升温还原结束后转入正常生产,催化剂在低温活性范围230℃～260℃尽可能多使用一段时间,不轻易提高热点温度,进甲醇合成塔的总硫体积分数控制在≤0.1×10-6;进醇系统的CO2体积分数控制在0.5%～1.0%,从而达到了延长催化剂使用寿命的目的。     

戴维甲醇合成塔超温原因分析与处理措施

介绍戴维（Davy）甲醇合成工艺及甲醇合成塔（SRC）结构特点，结合甲醇装置从原始开车至今的合成塔运行工况，得出合成塔结构、催化剂装填、空速、新鲜气分配失衡等是导致合成催化剂床层局部超温的主要原因，局部超温将使甲醇副反应增多，影响产量和催化剂活性。在通过对催化剂装填高度、氢碳比、空速、两个合成塔分配气量等调整后，缩小了超温范围，降低了超温点温度，保证了催化剂使用寿命，提高了催化剂整体使用效率。     

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。     

Amomax-10H型催化剂在TopsΦe S-200型氨合成塔中的应用

介绍了TopsΦe S-200型氨合成塔催化剂更换、装填及还原情况,阐述了Amomax-10H型催化剂的特性及其在TopsΦe S-200型氨合成塔中的工艺运行情况。通过2年多的实际运行,Amomax-10H型预还原型催化剂具有较好的低温活性和较强的适应性,机械强度高,还原时间短,催化剂活性较好,合成塔出口氨净值较高。     

焦炉煤气制甲醇工艺中影响甲醇产量的因素探析

分析了焦炉煤气制甲醇工艺中影响甲醇产量的多种因素,如反应原料气量、气体成分、合成系统压力及反应温度等。针对这些因素进行了技术改造,提出了提高煤气量及氧气量,保证气体净化效果防止催化剂中毒、防止煤气中的焦油等杂质带入催化剂槽中增加系统阻力、降低转化系统中CH4含量,以及适当提温,在确保合成催化剂低温活性的前提下提高CO合成率等有效控制措施。     

A two-stage catalyst bed concept for conversion of carbon dioxide into methanol

Conversion of CO₂ into methanol by catalytic hydrogenation has been recognized as one of the most promising processes for stabilizing the atmospheric CO₂ level, and furthermore the methanol produced could be used as fuel or basic chemical for satisfying the large demand world-wide. The present work investigates a two-stage catalyst bed concept for conversion of CO₂ to methanol. A system with two catalyst beds instead of one single catalyst bed is developed for conversion of CO₂ to methanol. In the first catalyst bed, the synthesis gas is partly converted to methanol in a conventional water-cooled reactor. This bed operates at higher than normal operating temperature and at high yield. In the second bed, the reaction heat is used to pre-heat the feed gas to the first bed. The continuously reduced temperature in this bed provides increasing thermodynamic equilibrium potential. In this bed, the reaction rate is much lower and, consequently, so is the amount of the reaction heat. This feature results in milder temperature profiles in the second bed because less heat is liberated compared to the first bed. In this way the catalysts are exposed to less extreme temperatures and, catalyst deactivation via sintering is circumvented. In this work, a one-dimensional dynamic plug flow dynamic is used to analyze and compare the performance of two-stage bed and conventional single bed reactors. The results of this work show that the two-stage catalyst bed system can be operated with higher conversion and longer catalyst life time.     

A DUAL-CATALYST BED CONCEPT FOR INDUSTRIAL METHANOL SYNTHESIS

The present work investigates a dual-catalyst bed concept for industrial methanol synthesis. A system with two catalyst beds instead of a single catalyst bed is developed for methanol synthesis. In the first catalyst bed, the synthesis gas is partly converted to methanol in a conventional water-cooled Lurgi type reactor. This bed functions at a higher than normal operating temperature and at high yield. In the second bed, the reaction heat is used to preheat the feed gas to the first bed. The continuously reduced temperature in this bed provides increasing thermodynamic equilibrium potential. In this bed, the reaction rate is much lower and, consequently, so is the amount of reaction heat. This feature results in milder temperature profiles in the second bed because less heat is liberated than in the first bed. In this way the catalysts are exposed to less extreme temperatures and catalyst deactivation via sintering is circumvented. This system results in outstanding technical features due to the extremely favorable temperature profiles over the catalyst beds. In this work, a one-dimensional quasi-steady plug flow model is used to analyze and compare the performance of dual-bed and conventional single-bed reactors. The results of this work show that the dual-catalyst bed system can be operated with higher conversion and longer catalyst life time.     

A DUAL-CATALYST BED CONCEPT FOR INDUSTRIAL METHANOL SYNTHESIS

The present work investigates a dual-catalyst bed concept for industrial methanol synthesis. A system with two catalyst beds instead of a single catalyst bed is developed for methanol synthesis. In the first catalyst bed, the synthesis gas is partly converted to methanol in a conventional water-cooled Lurgi type reactor. This bed functions at a higher than normal operating temperature and at high yield. In the second bed, the reaction heat is used to preheat the feed gas to the first bed. The continuously reduced temperature in this bed provides increasing thermodynamic equilibrium potential. In this bed, the reaction rate is much lower and, consequently, so is the amount of reaction heat. This feature results in milder temperature profiles in the second bed because less heat is liberated than in the first bed. In this way the catalysts are exposed to less extreme temperatures and catalyst deactivation via sintering is circumvented. This system results in outstanding technical features due to the extremely favorable temperature profiles over the catalyst beds. In this work, a one-dimensional quasi-steady plug flow model is used to analyze and compare the performance of dual-bed and conventional single-bed reactors. The results of this work show that the dual-catalyst bed system can be operated with higher conversion and longer catalyst life time.     

甲醇弛放气掺入量的变化对焦炉加热的影响

结合开滦京唐港煤化工园区生产实际,根据甲醇弛放气波动造成煤气热值变化,来计算所需空气和产生废气量以及炉温的变化。结果表明,弛放气掺入量在0%～40%时,若未调节入炉空气量,弛放气每降低10%,理论燃烧温度会升高85℃左右,并提出弛放气波动情况下的调节意见,为焦炉加热调温提供参考。     

滴流床反应器上α-甲基苯乙烯加氢影响因素分析

以α-甲基苯乙烯、氢气为原料在滴流床反应器中催化加氢合成异丙苯。本文主要考察反应温度、压力、循环量及进料α-MS的浓度、氢油比、催化剂、床层设计等因素对加氢反应的影响。结果表明,反应温度提高只在60～120℃范围内能够加快反应速率;压力在0.7～0.8 MPa时加氢反应速率最快,处理能力最大;氢油比的提高在保证原料与催化剂接触时间的前提下对反应有利;循环量及进料α-MS的浓度可以改变反应速率但是不能改变实际处理能力;催化剂的活性稳定是保证加氢效果的前提;床层设计的处理能力限制是造成目前加氢效果下降生产能力受限的主要原因。     

催化裂化催化剂磨损指数分析方法

对催化裂化催化剂磨损指数测定方法进行研究,通过实验优化测定催化剂磨损指数的预处理条件,考察焙烧温度和焙烧时间、催化剂用量、气体流速、纸筒对磨损指数的影响。结果表明,催化剂焙烧温度650 ℃,焙烧时间1 h,催化剂用量10 g,气体流速21 L·min^-1,选择纸筒时系统压力不超过30 kPa。催化剂磨损指数绝对偏差最大值0.16%,最小值0,准确度较高。催化剂磨损指数相对标准偏差低于5%,重复性较好。     

工艺条件对甲醇脱水制二甲醚反应的影响

以La改性氧化铝为催化剂,在模拟绝热固定床反应器中考察工艺条件对甲醇气相脱水制二甲醚反应的影响。结果表明,甲醇进料温度210℃时,甲醇脱水反应剧烈,绝热温升约130℃。催化剂床层热点温度低于380℃时,二甲醚选择性大于98%,过高温度产生大量副产物甲烷。反应压力对反应影响甚微。在甲醇进料温度240℃(热点温度370℃)、甲醇进料空速1.5 h-1和反应系统压力为50 k Pa条件下,甲醇转化率大于84%,二甲醚选择性大于98.5%,连续运转2 000 h,催化剂无明显失活迹象。     

Factors affecting methanol photocatalytic oxidation and catalyst attrition in a fluidized-bed reactor

A resolution IV fractional factorial experimental design explored the effects of seven factors on both the methanol photocatalytic oxidation (PCO) rate and the catalyst particle size distribution using a fluidized-bed reactor. The seven factors were as follows: calcination temperature, calcination time, grinding order, particle size, vibration amplitude, carrier gas humidity, and fluidization velocity. Decreasing calcination temperature from 726 to 623 K increased the activity of TiO₂/Al₂O₃ catalysts for methanol PCO. Attrition during fluidization liberated small TiO₂ particles from the bulk catalyst and the rate of attrition increased with gas velocity. Attrition was the primary cause of catalyst elutriation and not the presence of fine particles initially present in the bed from catalyst preparation. Increasing humidity caused agglomeration of fine particles, which reduced the amount of catalyst carryover. Removal of fines from the catalyst bed prior to fluidization caused an increase in catalyst attrition until the amount of fines present in the bed was similar to that of a bed in which fines were not removed.     

MULTIPLE CATALYSTS PRODUCE A SYNTHETIC FUEL FROM COAL

A recent government study indicates that oil prices will be substantially higher within the next few years. Thus liquid fuels from coal, will be required. The study concludes, however, that the considerable effort, time and money spent to date in trying to make gasoline from coal will be of no help in reducing in the 1990's our almost entire dependence on foreign oil.

Any grade of coal may be gasified with oxygen. The syngas is separated and adjusted, to give substantially a mixture of hydrogen, carbon monoxide, carbon dioxide after sulfur removal, and adjustment of the carbon to hydrogen ratio for methanol. It is then passed at an elevated temperature and pressure through a catalyst bed. A small percentage is converted to methanol with the evolution of a large amount of heat. This heat is removed to prevent overheating the catalyst and, in the past, has been wasted to a large extent. The gas has been recycled to build up a maximum concentration of 3 to 4% methanol containing on condensation 10 to 20% water, which must be separated.

For the American (Wentworth) process, a second catalyst has been developed whose optimum reaction temperature is above that of the gas stream leaving the first catalyst. The gas stream is passed through this second bed of catalyst without cooling, and on through a third bed of previously developed catalyst, whose optimum reacting temperature is still higher. The accumulated heat of the gas stream leaving this third catalyst bed is at a high enough temperature to allow the recovery, along with waste heat from the gasifier steps of most of the reaction heat in a waste heat boiler together with that from subsequent passage of the gas through additional beds of the first two catalysts. This recovered heat supplies energy for the complete operation of the plant including coal handling and oxygen preparation, as well as, for some electric power for sale outside.

Flow sheets with temperatures and material and heat balances show the reasons of the advantages of the multiple catalyst process, including the considerable saving of energy accomplished in the much lower compression needs for recycle of the much lower amount of gas through the beds of catalysts.