SO2反应器最优化(北化化反大作业)
- 格式:docx
- 大小:320.51 KB
- 文档页数:14
目录摘要 (2)前言 (2)一. 设计任务: (2)二.反应机理 (3)2.本征动力学 (3)3.反应热力学 (4)4.有效因子: (4)5.反应温度和压力的影响 (5)三.反应器计算 (5)1.设计方程 (5)2.算法:以两段绝热固定床为例 (6)四.设计评价 (7)参考文献: (8)二氧化硫转换器设计摘要本文通过二氧化硫转化反应机理的分析,以一设计任务为例,利用《反应工程》所学知识,进行了绝热多段间接换热固定床的设计。
本文所陈述的设计数学模型适用于一般绝热多段间接换热固定床的设计计算。
关键词:二氧化硫转化;绝热固定床;数学模型前言二氧化硫转化为三氧化硫,是工业生产硫酸的重要的一个步骤。
二氧化硫氧化反应:SO2+1/2O2⇌SO3此反应为常压下进行的简单可逆放热反应,副反应可忽略。
为了获得≥95%的转化率,且使得反应过程接近最佳温度曲线,二氧化硫氧化反应器通常采用多段间接换热或者多段直接换热(原料冷激气或空气冷激气)形式,也有采用多段间接换热与多段直接换热的组合形式。
一. 设计任务:一座硫酸厂,以废酸泥浆作为转化器前的焙烧炉原料。
已知条件:1.进入反应器原料气的成分:入口温度为450℃表1 原料气组成组分摩尔%SO27.5O211N281.51002.生产量10000N m2/h(以二氧化硫的进气量计算)出口二氧化硫转化率为97%3.催化剂性质(S101型)V2O5−K2O−Na2O−Fe2O3比表面积: S g=1.2m2/g堆密度:ρb=0.57g/cm3孔容: V g =0.35cm 2/g 颗粒密度: ρp =1.20g/cm 3 床层孔隙率 ε=0.4 曲节因子: τm =4反应器内径:3.85m 形状:ϕ5×15 圆柱形二.反应机理1.总述:反应方程式: SO 2+1/2O 2⇌SO 3+Q反应特点:1)可逆反应,存在反应平衡问题,促使反应向正方向进行;2)放热反应,及时移走热量有利于反应转化率的提高;3)可逆放热反应存在最佳温度曲线,尽量使操作条件接近最佳温度曲线,保证获得较大的反应速率和转化率。
北京化工大学北方学院NORTH COLLEGE OF BEIJING UNIVERSITY OFCHEMICAL TECHNOLOGY(2011)届本科生毕业设计外文文献翻译题目:半干法烟气脱硫—反应器的优化学院:理工学院专业:应用化学学号: 070105131 姓名:谷东亮指导教师:孟献民老师教研室主任(负责人):顾明广老师2011 年 5 月 18 日外文文献原稿和译文原稿ABSTRACTThe TURBOSORP process is a dry flue gas cleaning system to remove pollutants like,,mercury,heavy metals, dioxins and furans, and dust. The main principle of this process is tobring flue gas into an intensive contact with calcium hydroxide, open hearth furnace coke, waterand recirculated material in the Turboreactor, which operates as a circulating fluidized bed in themanner of fast fluidization.In 2000 AE&E started a development and research project with the aim to simulate the fluiddynamics of the Turboreactor with a commercially used CFD code. Starting with the developmentof the one-phase simulation the existing reactor geometry was optimized concerning the pressureloss. After this step research activities on a two-phase simulation (gas and solid flow) based on theconcept of Euler-Lagrange should help to better understand the mechanism of solid distribution inthe reactor and to calculate the part of the pressure drop of the fluidized bed depending on thesolids.Among other things the recent results of the start-up phase of a TURBOSORP FGD-plant withoptimized reactor design are described in this paper. As a highlight the Turboreactor pressure losswas reduced by about 20 percent, compared to a conventional reactor design. INTRODUCTIONToday, the application of dry technologies for the cleaning of flue gases of power stations or wasteincineration plants is considered as the state-of-the-art technology. Due to the use of the fluidizedbed technology and of the recirculation of the partially reacted product it hasbeen possible toeliminate prejudices against this technology which were based upon a bad utilisation of the sorbentand low separation performances.Because of the considerably reduced investment costs there is an important market potential for thedry technology in addition to the wet technology. Especially in the field of retrofitting and/orrehabilitation of existing plants the dry technology plays an important role.Presently, various competitors offer dry processes on the market of which the differences in theprocess concept hardly can be discerned. In certain cases, the differences only exist in the planttechnology and in the design of the reactor. Nevertheless, the potential of optimisation aiming atfurther improved desulphurisation performances and at minimum consumption of consumables is not exhausted yet.As state-of-the-art in the field of flue gas desulphurisation removal efficiencies up to 95 % at Ca/Sratiosup to 1.25 can be achieved with this technology without problems. Even in the field of fluegas cleaning after waste incineration plants the emission limits as prescribed by the 17th Decree ofthe German Federal Immission Act (17. BImSchV) can be achieved (see table1.Table 1: Emission regulations for flue gases from waste incineration - EuropeAustrian Energy and Environment AG (AEE), emerged from the traditional companies WaagnerBiro AG and Simmering Graz Pauker AG, was reestablished in July 2002, after a short intermezzowith the German Babcock Borsig Power Group between 1999 and 2002. By way of theTURBOSORPÒ process AEE offers a dry technology for the flue gas desulphurisation and the fluegas cleaning after waste incineration plants. Because of the use of the most up-to-date design tools like e.g. CFD-modeling of critical plant components, AEE is able to provide an optimum design.Additionally, AEE operates a pilot plant where critical operating cases, as for example extreme fluegas compositions, can be simulated duringexperiment.PROCESS TECHNOLOGYIn the TURBOSORPÒ process the flue gas flows through a cylindrical apparatus (fluidized bedreactor) from the bottom to the top. The bed material is made up of solids, consisting of calciumhydroxide, calcium carbonate, the solid reaction products of the flue gas cleaning process, and ashesfrom the combustion process. Fresh and active material, either Ca(OH)2 or CaO, is injected into thereactor while solids, that have already undergone several cycles are recirculated into the reactor(refer to Fig. 1). The term …cycle“ means a complete circulation of the sorbent particles through thewhole plant (Turboreactor, separator, buffering tanks that may be installe.In order to lower the flue gas temperature for achieving an increased desulphurisation capacitywater is injected horizontally or vertically, usually by means of a water nozzle, which is in thevicinity of the flue gas inlet. 6 In addition to the temperature reduction of the flue gas this also leadsto an increase in the relative humidity. Moreover, the wetting of the recirculated sorbents in thereactor makes new and reactive surfaces accessible at the solids particles as product layers whichwere already formed become detached again by thiswetting (refer to Fig. 2.Apart from this activation by means of the water injection a mechanical activation of therecirculated solids particles is also achieved by means of the turbulent flow in the fluidized bedreactor, as the solids particles collide with each other and with the wall. The operating state of thefluidized bed lies within the range of the so-called ²fast fluidized beds², i.e. within the transitionzone to pneumatic conveying.The flue gas inlet of the Turboreactor is designed as a Venturi nozzle. Due to the high flue gasvelocities in the Venturi nozzle the collapse of the fluidized bed and the falling down of solidparticles through the Venturi nozzle is avoided.After the outlet from the Turboreactor the solid particles are separated from the flue gas inaseparator. When using the TURBOSORPÒ process for flue gas desulphurisation either electrostaticprecipitators or fabric filters, preferably with mechanical pre-separators, can be used. When using itfor the cleaning of flue gases of a waste incineration plant, only a fabric filter may be installed. Therecirculation of the separated material in the reactor can be made either pneumatically (fluidizing conveyor) or mechanically (screw conveyor). Fig. 3 shows the process flow diagram of theTURBOSORP process.For the use of the TURBOSORPÒ process within the framework of the flue gas desulphurisationand/or in the field of gas cleaning after waste incineration plants not only the solids separator isdifferent but mainly the operating range of the process.Fig. 4 shows the different applications for the TURBOSORPÒ process. Depending on the relationbetween SO2 and HCl there are three types of applications, the TURBOSORPÒ-FGD (flue gasdesulphurization), the TURBOSORPÒ-FGCB (flue gas cleaning after biomass boilers) and theTURBOSORPÒ-FGCW (flue gas cleaning after waste incinerators).In the TURBOSORPÒ-FGD process the minimum operating temperature depends on the situationof the water dew point of the gas to be cleaned. It is recommended to maintain a minimum distanceof 20 to 25°C from the dew point, which prevents caking or agglomeration of the solids on the wallsin the Turboreactor. The content of chlorine in the flue gas is to be considered as well as thereaction product, which is strongly hygroscopic, and may lead to caking andagglomeration.For the use of the TURBOSORPO-FGCW process in the field of flue gas cleaning after wasteincineration plants the content of chlorine of the flue gas is higher than the content of SO2.Furthermore, in the TURBOSORPO-FGC process open-hearth oven coke (HOC) is injected inaddition to the sorbent containing calcium, which guarantees the separation of dioxins/furans aswell as the separation of the volatile heavy metals like mercury, cadmium, and thallium. In theTURBOSORPO-FGCB process the relation ofwill be between the FGD and the FGCW.The typical range of the operation temperature can be found in Fig. 5. The exact temperaturedepends also on the relative humidity, the fly ash input into the process and the demandedseparation efficiency for the.The product of the TURBOSORPO-FGD process can be dumped in a landfill for non-hazardouswaste without further treatment. Stabilized product can also be used for special building purposeslike sound insulation or the final covering of landfills.The product from the TURBOSORPO-FGBC or FGCW process can be dumped in a landfill fornon-hazardous waste only after a further stabilization which is required because of the mobilizationof the heavy metals that would occur otherwise.CFD-SIMULATIONThe design and optimization of circulating fluidized beds is still a challenging task. To get a betterunderstanding of the behavior of the multi-phase flow inside the reactor, the application ofComputational Fluid Dynamics (CFD) can be a helpful tool. For the optimization and theinvestigation of the TURBOSORPO process, a research project was started in the year 2000 incooperation of Austrian Energy and Environment and the University ofLeoben to perform CFDsimulationsof this process.The following milestones were fixed for the research project:·Development of a strategy to simulate the two-phase flow of solids and flue gases forengineering purposes.· Consideration of the heat transfer between the solids and the gas.· Extension of the model to describe the three-phase flow of gas, solids, and water.· Modeling the evaporation of the water droplets and the drying of the agglomerates. Currently, the third point in the project schedule has been reached.Theoretical backgroundWe use the commercial CFD-Software FIRE 7.3, of AVL-List GmbH. The program is a generalpurpose CFD-software package and it uses the finite-volume method to simulate fluid systems. Thesolution domain is subdivided into a finite number of volume elements. To each volume element,the conservation equation for mass, momentum, energy andadditional parameters of the flow field(e.g. species concentration) are applied.To take into account the turbulence of the gas flow, the k-e two-equation model is used.The description of the multiphase flow is based on the Euler-Lagrange approach. While the gasphase is treated as a continuous fluid, the solid particles and liquid droplets are represented by anumber of numerical particles. The motion of the numerical particles is calculated by solvingLagrangian equations of motions in accordance with Newton’s Second Law. The interactionbetween the continuous and the dispersed phase is considered by two-way coupling.The application of the Euler-Lagrange approach to simulate multi-phase flow in circulatingfluidized beds is somewhat untypical, because it is valid only for dilute flows. Nevertheless, due tothe flow regime of fast fluidization up to pneumatic conveying and the very low overallconcentration of solids and water in the reactor, the assumption of a dilute flow is valid, except nearthe solids feed.The advantages of this way of multi-phase flow modeling are the capabilities of a more detaileddescription of the properties of the dispersed phase like size distribution or inter-particle forces.For the application of FIRE, it was necessary to extend the code with usersubroutines for thedescription of particle-wall, particle-particle interaction, solids input and recirculation as well aswater injection. A routine for the modeling of the interaction of solids particles with the waterdroplets and the resulting formation of agglomerates is currently in the test phase.译文摘要半干法烟气是一个用干燥的流体清洗系统来去除烟气污染物如二氧化硫、盐酸、氢氟酸、水银、重金属、二恶英和呋喃、尘土的脱硫过程。
反应器大作业反应器是化学工程中的重要设备,它在化学反应过程中起到催化剂的作用,加速反应速度,提高反应产率。
在化学工程领域中,研究和优化反应器是一个重要的课题。
本文将以二氧化硫(SO2)的优化反应器为例,详细讨论反应器的工作原理、常见问题和优化方案。
首先,让我们了解二氧化硫(SO2)的反应器。
二氧化硫是一种常见的化学物质,常用于工业生产和环境保护。
它可以通过硫矿石的燃烧、石油炼制以及工业废气的处理等方式产生。
在化学反应中,二氧化硫可以被氧化为三氧化硫(SO3),这是生产硫酸的重要中间产物。
在SO2的优化反应器中,我们面临一些常见问题。
首先是反应效率低。
SO2的氧化反应是一个比较缓慢的反应,反应速率相对较低。
因此,如何提高反应速率,提高反应效率是值得研究和优化的问题。
其次,是如何控制反应温度。
SO2的氧化反应是一个放热反应,反应温度的升高会导致反应速率的提高,但同时也会增加能量的损失。
因此,如何在保证反应速率的同时,控制反应温度是一个挑战。
最后,如何选择催化剂和反应器的设计也是一个重要的问题。
催化剂的选择直接影响反应速率和产物选择性。
反应器的设计则直接关系到反应的均匀性和热传导效率。
针对以上问题,可以采取以下优化方案。
首先,可以通过改变催化剂的活性和选择性来提高反应效率。
选择具有较高活性和较高选择性的催化剂,能够加速反应速率和提高产物的纯度。
其次,可以通过改变反应器的结构和加热方式来控制反应温度。
例如,可以设计反应器壁的冷却装置,使得反应器内部的温度保持在适宜的范围内。
同时,可以使用间接加热方式,来减少能量的损失。
最后,可以通过改变反应器的结构和增加搅拌装置来改善反应的均匀性。
良好的搅拌可以使得反应物更好地混合,提高反应速率和产物选择性。
综上所述,反应器的优化对于化学工程中的反应过程非常重要。
通过优化催化剂的选择、反应器的设计和操作参数的调整,可以提高反应效率和产物选择性。
在SO2的优化反应器中,通过上述方案的实施,能够有效解决反应效率低、反应温度难控制等问题,从而提高反应的效果。
始驾州参艰市线练学校化学反条件的优化——工业合成氨(建议用时:40分钟)[合格过关练]催化剂1.硫酸是一种重要的化工产品,目前主要采用“接触法”进行生产。
有关接触氧化反2SO2+O2△2SO3的说法中正确的是( )A.只要选择适的条件,SO2和O2就能转化为SO3B.该反达到平衡后,反就完全停止了,即正、逆反速率均为零C.在达到平衡的体系中,充入由18O组成的O2后,SO2中18O含量减少,SO3中18O含量增多D.在工业合成SO3时,要同时考虑反速率和反能达到的限度两方面的问题D[反为可逆反,SO2和O2不能转化为SO3,A错;达到平衡后反不停止,正、逆反速率相,B错;达到平衡后充入由18O组成的O2,平衡向正反方向移动,SO3中18O含量增多,因为反可逆,SO2中18O含量也增多,C错;D正确。
]2.德国哈伯发明以低成本制造大量氨的方法,流程图中为提高原料转化率而采取的措施是( ) A.①②③B.②④⑤C.①③⑤D.②③④B[氮气和氢气在高温、高压和催化剂条件下反生成氨气,正反是气体体积减小的放热反。
净化气体是防止杂质气体对催化剂的影响,不能提高原料的转化率,①不符合;加压,平衡正向移动,可以提高原料的利用率,②符合;使用催化剂,可以加快反速率,但平衡不移动,不能提高原料转化率,③不符合;分离出氨气,平衡正向移动,提高了原料的转化率,④符合;氮气和氢气的再循环,可提高原料的转化率,⑤符合。
]3.合成氨反:N 2(g)+3H2(g)2NH3(g) ΔH=-92.4 kJ·mol-1,在反过程中,正反速率的变化如图所示。
下列说法正确的是( )A.t1时升高了温度B.t2时使用了催化剂C.t3时增大了压强D.t4时降低了温度B[t1时反达到平衡,t1~t2,v正先增大后逐渐减小,说明平衡正向移动,根据ΔH<0可知,该反的正反为放热反,升高温度,平衡逆向移动,故t 1时不是升高温度,可能是增大压强或者增大反物的浓度,故A 项错误;t 2~t 3,正、逆反速率同程度增大,可能是使用了催化剂,故B 项正确;t 3~t 4,v (正)先减小后逐渐增大,而增大压强,正、逆反速率都会增大,故C 项错误;t 4时正反速率逐渐减小,是减小反产物(NH 3)的浓度,若是降低温度,则在t 4时v (正)陡降,曲线不连接,故D 项错误。
二氧化硫反应器最优化题目:SO 2+1/2O 2=SO 3,四段绝热反应器,级间间接换热。
1.基础数据:混合物恒压热容C p =0.2549[kcal/kg ·K] -ΔH =23135[kcal/kmol] 床层空隙率ρb =554[kg/m 3]进口SO 2浓度8.0%,O 2浓度9.0%,其余为氮气。
处理量131[kmolSO 2/hr],要求最终转化率98%。
2.动力学方程:式中:3.基本要求:(1)在T -X 图上,做出平衡线,至少4条等速率线;(2)以一维拟均相平推流模型为基础,在催化剂用量最少的前提下,总的及各段的催化剂装量;进出口温度、转化率;并在T-X 图上标出折线; 4.讨论:(1)要求的最终转化率从98%变化到99%对催化剂用量的影响;(2)如果有关系:YO 2+YSO 2=21%,SO 2进口浓度在7-9%之间变化,对催化剂装量的影响()()()[]sec ./112232323222gcat mol P P K P P B B P P K P k R SO SO SO SO SO SO O eff SO +-+-=ξ-()()987.13.11295exp 1026203.227200exp 103.25.7355exp 4814860047535992exp 105128.147542076062exp 106915.75218718223=⎪⎭⎫⎝⎛⨯=⎪⎭⎫ ⎝⎛=⎪⎭⎫⎝⎛⨯=⎪⎭⎫⎝⎛-=-⎪⎭⎫⎝⎛-⨯=-⎪⎭⎫⎝⎛-⨯=--R T K P P K P RT K T B C RT k C RT k P O SO P SO oeff oeff ξ第(1)问计算思路:通过观察反应动力学方程可以发现:反应速率(-r A)是X A和T的函数。
也就是说,这三个变量知道了两个可以求出第三个。
所以,我的计算方法如下:先确定反应速率(-r A)的值(0-4×10-6),再在某一反应速率下,给定温度T,找到X A的值,使得由X A和T算出的(-r A)等于最开始假定的(-r A)值。
操作硫磺回收装置的理论知识题库职业技能鉴定神华鄂尔多斯煤制油分公司题库硫磺回收装置操作工初级工理论知识一、推断题:1.(√)克劳斯反应器床层的脱氧催化剂是为了防止氧化铝催化剂硫酸盐化。
2.(× )酸性气燃烧炉通过烟气吹硫后可直截了当熄火停炉。
3.(×)进入含硫化氢设备容器作业时,只需设备内气体含氧量和硫化氢含量化验合格即可。
4.(√ )制硫燃烧炉看火孔设有反吹风的目的是防止硫磺冷凝阻塞看火孔。
5.(√)加氢反应器超温时的处理办法是落低克劳斯尾气中的二氧化硫含量。
6.(×)克劳斯反应器超温时处理办法是提高配风比。
7.(√)硫磺回收装置烟道温度高的缘故是烟囱温度非常高,而焚烧炉刚好熄火,大量瓦斯冲到烟囱燃烧。
8.(×)仪表风中断后,风开阀现场改由上下游阀操纵举行操作。
9.(×)急冷尾气中二氧化碳多对胺溶剂没有妨碍。
10.(√)设备维护保养的目的是保证在用设备台完好。
11.(√)酸性气压力升高的缘故也许是因为炉膛压力上升引起。
12.(√)切换风机时应先启动备用风机,后停在用风机。
13.(×)液硫夹套阀的作用是防止硫化氢腐蚀。
14.(√)硫磺回收装置停工钝化清洗的目的是防止打开设备后硫化亚铁自燃。
15.(×)溶剂再生部分停工吹扫的冷凝液能够排至雨水管网。
16.(√)尾气系统停工吹扫时,急冷水管道要增加吹扫时刻,是防止硫化氢管道吹扫时刻别够未能吹扫洁净。
17.(√)克劳斯部分停工吹扫时各低点加强排污。
18.(×)加氢催化剂钝化需要严格操纵床层温度,因为加氢催化剂钝化过程是吸热过程。
19.(√)溶剂再生顶温高的调整办法之一是落低富液进塔温度。
20.(×)装置开车前仪表对联锁必须举行校验,因此操作人员别用对联锁举行校验。
21.(×)急冷塔急冷水PH值偏小,能够将一部分急冷水就地排放,并且加入新的急冷水举行置换达到调节急冷水PH值的目的。
化学反应器理论大作业氧化硫转化器最优化氧化硫转化器的最优化题目背景:SO 2 + 1/2O 2=SO 3,四段绝热反应器,级间间接换热。
1. 基础数据:混合物恒压热容 C p = 0.2549[kcal/kg K] •—A H =23135[kcal/kmol]床层空隙率 p = 554[kg/m 3]进口 SO 2浓度8.0%,O 2浓度9.0%,其余为氮气。
处理量131[kmolSO 2/hr],要求最终转化率98%。
2. 动力学方程:—R S O 2 = k eff P 2________ 2q B + (B -1)P SO 2『P SQ + J K P sO2 / P SO 3)式中:3. 基本要求:⑴在T — X 图上,做出平衡线,至少4条等速率线;(2)以一维拟均相平推流模型为基础,在催化剂用量最少的前提下,总的及各段的催化剂装量;进出口温度、转化率;并在 T-X 图上标出折线;(3)程序用C ,Fortran , BASIC 语言之一编制;KP S O2/P S O3(1-©2 )Imol /gcat.sec 】k eff =7.6915xl018exp(420-475oC ) k eff =1.5128<107expI RT 丿 (475 -600oC )(-7355.5、 .T 丿 K =2.3 咒 10』exp(27200]I RT 丿P P SC2 ^2^ J'11295.3、B = 48148expK p =2.26203X10* exp R = 1.987£ =X 4in T tin第四段图2.1反应流程图由上述反应流程图分析可知:根据已知的入口组成,设定入口温度,根据反应 速率对入口温度所求偏导数在这一段内对组成的积分为零可以求得此段出口转化率 和出口温度,即得到下一段的入口转化率,又根据前一段的出口速率等于后一段的 入口速率,可以求得下一段的入口温度;这样又可以计算下一段的出口情况。
1. 背景醋酸乙烯,即乙酸乙烯酯(vinylacetate,下简称V Ac)。
V Ac是世界上五十种重要的化工原料之一,具有十分广泛的用途,主要用于制造聚醋酸乙烯、聚乙烯醇、聚乙烯醇缩丁醛/乙烯-醋酸乙烯共聚物等。
特别是随着聚乙烯醇非纤维领域应用的拓展,使得醋酸乙烯的需求不断增长。
生产V Ac的工艺方法有羟基化法、乙醛乙酐法、乙炔法和乙烯法。
羟基化法和乙醛乙酐法是最先发展的工艺方法,该工艺的缺点是成本较高,不适于大规模生产,现在已被乙炔法和乙烯法代替。
乙炔气相法,是上世纪60年代以前,代替羟基化法和乙醛乙酐法的一种新工艺,由乙炔和醋酸作用而得。
该工艺的反应器型式有固定床和流化床。
60年代中期以后,又逐步被更加便捷的乙烯法代替。
乙烯法分液相法和气相法。
液相法由乙烯和醋酸,经催化剂PdCl-CuCl2,在反应温度110℃~230℃,压力2.94~3.92 MPa的操作条件下氧化而得。
乙烯气相法是以把醋酸钾为主体,以硅酸为载体的贵金属催化剂,在反应温度170~185℃压力0.59~0.83MPa条件下氧化而得。
在此我们选用的是Bayer-I型催化剂,根据文献,Bayer-I型催化剂的组成为:钯、金(作用是防止活性组分钯产生氧化凝聚,使钯在载体上维持良好的分散状态)、乙酸钾(有助于反应组分乙酸在钯金属上缔合,促进物理吸附的乙酸的离解和释放氢离子,使钯-氧间的键结合力减弱,促使乙酸钯的分解;此外,还可抑制深度氧化反应,从而提高了反应的选择性)和硅胶(载体)。
Bayer-I型催化剂具体的特性参数如下表。
催化剂的关键组分组成:Pd 0.5 wt%(3.2g/L)、Au 0.25 wt%(1.4g/L)、KOAc 2.3 wt%(29.0g/L)。
由于KOAc 在反应过程中会流失,根据经验,除初始加入KOAc,随反应物还得添加KOAc,流量为2. 716 kg/h。
表1 Bayer-I型催化剂特性参数表特性参数数值颗粒密度 =6 mm球形堆积密度 =0.598 g/cm总密度 =0.95 g/cm比表面积 =100 m /g孔体积 =0.62 cm /g孔隙率 =59%主反应:C H CH COOH 0.5O →CH COOCHCH H O 146.7 kJ主要副反应: C H 3O →2CO 2H O 1340 kJ此外尚有少量副产物乙醛、醋酸乙酯、醋酸甲酯、丙稀醛、二醋酸二醇酯和聚合物等生成,反应式如下:CH COOH C H →CH COOC H2CH COOH 2C H 3O →CH COOCH 2CO 2H O2CH COOH 2C H 3O →2CH CHCHO 2CO 4H O4CH COOH 2C H O →CH OCOCH CH OCOCH4CH COOCHCH H O→CH COOH CH CHO但由于这些副产物的量较主要副产物来说很少,因此在此次设计中只考虑了主要副反应。
二氧化硫转化器最优化声明:本人使用Fortran90语言独立完成该作业。
在前几届学生遗留下来的作业模板中,多数使用matlab软件或C语言编译,本人至今未见使用Fortran语言编译的作业。
私以为Fortran语言相比于matlab语言或C语言,有着得天独厚的优势,更具有学习价值。
故本作业的独立性毋庸置疑!题目:SO2+1/2O2=SO3,四段绝热反应器,级间间接换热。
1.基础数据:混合物恒压热容C p=0.2549[kcal/kg·K]-ΔH =23135[kcal/kmol]床层空隙率ρb=554[kg/m3]进口SO2浓度8.0%,O2浓度9.0%,其余为氮气。
处理量131[kmolSO2/hr],要求最终转化率98%。
2.动力学方程:其中:()()()[]sec./112232323222gcatmolPPKPPBBPPKPkRSOSOSOSOSOSOOeffSO+-+-=ξ-()()987.13.11295exp1026203.227200exp103.25.7355exp4814860047535992exp105128.147542076062exp106915.75218718223=⎪⎭⎫⎝⎛⨯=⎪⎭⎫⎝⎛=⎪⎭⎫⎝⎛⨯=⎪⎭⎫⎝⎛-=-⎪⎭⎫⎝⎛-⨯=-⎪⎭⎫⎝⎛-⨯=--RTKPPKPRTKTBCRTkCRTkPOSOPSOoeffoeffξ要求1:在T~X 图上,做出平衡线,至少4条等速率线 (1)平衡线:反应简写为:A + 1/2B = C当反应平衡时,(-r A )=0,得到(1-ξ2)= 0 ,即ξ= 1 整理得:P C =K p P A P B 1/2 其中:00.08A y =00.09B y =0.5A δ=-当X A 从0~1范围内变化时,可确定与X Ae 唯一对应的平衡温度T e ,编写程序使X A 从1.0开始,间隔为-0.1 ,分别算出相应的T e ,即得平衡线:图1 平衡温度—平衡转化率示意图00(1)1A A A A A Ay P X P y X δ-=+0001(1)21B A A B A A Ay P y P X P y X δ--=+001A A C A A Ay PX P y X δ=+(2)等速率线由于在同一反应速率(-r A )下,某一转化率X A 可能对应两个温度T ,而某一温度T 下,则对应唯一转化率X A 。
所以..绘制等速率线时,........我.采用的方法为:.......先.确定反应速率......(.-.r .A .).,再..确定..温度..T .,然后对....X .A .从.0.到.1.进行迭代,.....找到..那个唯一的.....X .A .。
当然,在求解X A 时也可以使用割线法等其他迭代算法,那样精度更高。
但是此处绘制等速率线更多的是为了得到X A ~T 的趋势,而精度的降低并不影响曲线的走势。
图2 420~600℃ 下平衡线与等反应速率线要求2:以一维拟均相平推流模型为基础,在催化剂用量最少的前提下,总的及各段的催化剂用量;进出口温度、转化率;并在T-X 图上标出折线。
分析:要使总得催化剂用量最少,则每一段催化剂用量都要达到最小。
当确定每一段的X in 和X out 之后,根据0(,)outinX catAXA A A W dX F r X T =⎰可确定最佳进口温度T in ,使得W cat最小,即满足:(,)10outinX A A A XA inr X T dX r T ∂=∂⎰(式1)。
但在实际计算中,第一段的X in 是知道的,只需假定一个T in 值,即可根据上式得到X out ,进而由操作线算出T out 。
而段与段之间有,,1out iin i X X +=,为使任意两段之间催化剂之和最小,进一步可以得出段与段之间需满足:,,,1,1(,)(,)out i out i in i in i r X T r X T ++=由上式可确定下一段入口温度T in , i+1,如此循环四次即可得到各段反应器进出口温度、转化率,以及催化剂用量。
需要特别注意的是:.........在.计算积分式时,.......采用..的是数值....微.积分方法....。
.在对..X .A .取微小步....长.Δ.X .时,..T .也会沿着操作线移动,..........得到..新的..T .’.,.下一步...的数值微积分是基于新的...........T .’.而计算的,.....如此..循环往复。
.....在.编程的过程中,.......正.是由于本人忽略了这一点,误.............认为..T .值是不变的,从而导致了严重的计算错误,...................始终..得不到正确的解.......,.浪费了...大量时间查.....找算法上的错误,........而.忽略了对问题本质的研究。
............这也..让我想起了导师王健红的一句话:...............“.建模..的关键不是优化算法,而是准确认识模型的原型!......................”. 以下几点计算过程中的问题,也应该得到重视:①由X in 和T in 计算X out 时,X out 有两个限制条件,一是不能越过平衡线,二是X out 和操作线确定的温度不能越过600℃ ②根据,,,1,1(,)(,)out i out i in i in i r X T r X T ++=求解T i n , i+1时,使用割线法对迭代初值要求很严格,如果初值选择不合适,会导致得不到想要的解,甚至无解。
虽然有其他高阶算法可以避免这类问题,但由于反应速率方程难以求得解析导,故不适用。
此处本人选择的是一个“笨办法”,也可以叫做试探法:T 从420℃开始,取微小增量进行迭代计算,直到满足r i+1 = r i 为止。
此法虽然看起来“笨”,精度略低,但却在一定程度上加快了程序运行速度,巧妙得解决了问题。
解题思路:第一步,在420~600℃大范围内,以ΔT =1逐步计算,输出所有X out >0.98的T in 值。
程序运行结果如下表所示。
表1 最终转化率与入口温度关系T in /℃ X out 441 0.98009 442 0.98024 443 0.98029 4440.98027第二步,在440~445℃小范围内,以ΔT =0.05逐步计算,输出所有X out >0.98的T in 值。
程序运行结果如下图所示。
图3440~445℃范围内最终转化率及催化剂总量与入口温度的关系从上图可以看出,在满足最终转化率达到98%的前提下,入口温度越高,催化剂总用量越少,因此选择最佳入口温度为444.55℃,此时出口转化率为98.01%,催化剂总用量为44541.6Kg 。
各段反应器具体操作指标如下表所示。
T in /℃X AW cat表2最终转化率达标、催化剂总量最少条件下各段反应器指标X in T in /℃ X out T out /℃ W cat / Kg W cat / Kg1 0.00000 444.55 0.66917 600.00 4146.77 44541.622 0.66917 450.36 0.90470 505.08 5767.153 0.90470 442.74 0.96243 456.14 10670.24 40.96243420.380.98007424.4823957.47图4T ~X A 图中操作线X T /℃讨论1:要求的最终转化率从98%变化到99%对催化剂用量的影响从程序运行的角度看,始终没有得到转化率超过99%的解。
而从问题的本质来看,当转化率为99%时,平衡温度T e为400℃。
而催化剂的适用温度为420~600℃,故该题最终转化率无法达到99%。
讨论2:y O2+y SO2=21%,SO2进口浓度在7-9%之间变化,对催化剂装量的影响改变y A0的初值,运行程序,输出所有满足转化率>98%的结果,并比较其催化剂总量,找出催化剂用量最少的结果,并记录对应的入口温度值,得到下表。
表3 入口SO2浓度与催化剂总量的关系y A0T in/℃W cat/Kg0.07 465.40 12224.200.08 443.75 16107.800.09 423.75 23355.99从上表可以看出,在满足y O2+y SO2=21%以及最终转化率达到98%的前提下,随着入口SO2浓度的增加,催化剂总量也增加。
源代码:计算过程中所有子程序Module CR_1Implicit NoneReal (kind=8) :: PA , PB , PC , Kp , T , keff , B , K , ksi , rA_C ,&rA , DT , DX , FT , Xmax , S , Xin , Xout , Tin , Tout ,&XA , W , X , TOL , XAe , N , E , FX , det , X0 , FX0 , & Sum ,W_sum , Tin_1 , lmdReal,parameter:: P=1.01325 , yA0=0.08 , yB0=0.09 , R=1.987Contains子程序:计算各组分分压Subroutine Cal_P ()PA=yA0*P*(1-XA)/(1-0.5*yA0*XA)PB=P*(yB0-0.5*yA0*XA)/(1-0.5*yA0*XA)PC=yA0*P*XA/(1-0.5*yA0*XA)End Subroutine Cal_P子程序:计算反应速率Subroutine Cal_rA ()IF (T<748.15) Thenkeff=7.6915E18*EXP(-76062/R/T)Elsekeff=1.5128E7*EXP(-35992/R/T)End IFB=48148*EXP(-7355.5/T)K=2.3E-8*EXP(27200/R/T)Kp=2.26203E-5*EXP(11295.3/T)ksi=PC/Kp/PA/SQRT(PB)rA_C=keff*PB*K*PA/PC*(1-ksi**2)/(SQRT(B+(B-1)*PA/PC)+SQRT(K*PA/PC))**2 End Subroutine Cal_rA子程序:割线法求根Subroutine Secant()IF (N<=1) Thendet = -0.1Elsedet = -FX*(X-X0)/(FX-FX0)End IFX0=XFX0=FXE=abs(det)/(abs(X)+1.)X=X+detEnd Subroutine Secant子程序:计算操作线与平衡线交点的平衡转化率Subroutine Cal_XAe()X=1N=0130 N=N+1FX=2.26203E-5*exp(11295.3/(lmd*(X-Xin)+Tin))*(1-X)*sqrt(P*(yB0-yA0*X/2)/& (1-yA0*X/2))-XCall Secant ()IF (E>=1.E-6) GOTO 130XAe=XEnd Subroutine Cal_XAe子程序:每一段由T in,X in计算X outSubroutine Cal_Xout()S=0DT=0.000001DX=0.00001T=TinXA=XinCall Cal_XAe()Xmax=(873.15-T)/lmd+XinIF (Xmax>1.0) Xmax=1.0100Call Cal_P()Call Cal_rA()rA=rA_CT=T+DTCall Cal_rA()FT=(rA_C-rA)/DT/rA**2S=S+FT*DXIF (XA>=XAe )ReturnIF (XA>=Xmax) ReturnIF (S>0) ThenXA=XA+DXT=lmd*DX+TGOTO 100End IFEnd Subroutine Cal_Xout子程序:计算每一段催化剂装量Subroutine Cal_W()Sum=0T=TinXA=XinDX=0.00001110Call Cal_P()Call Cal_rA()rA=rA_CFT=1/rASum=Sum+FT*DXIF (XA>=Xout) ReturnXA=XA+DXT=T+lmd*DXGOTO 110End Subroutine Cal_W子程序:由上一段T out,X out计算下一段T in Subroutine Cal_T()XA=XoutT=ToutCall Cal_P()Call Cal_rA()rA=rA_CT=420+273.15120Call Cal_rA()IF (abs(rA-rA_C)<1.E-11) ReturnEnd IFT=T+0.0001GOTO 120End Subroutine Cal_TEnd Module CR_1主调用程序:主程序:计算平衡线Module CR_0Implicit NoneReal (kind=8) :: PA , PB , PC , Kp , TReal :: XAReal ,parameter :: P=1.01325 , yA0=0.08 , yB0=0.09 ContainsSubroutine Cal_1 ()PA=yA0*P*(1-XA)/(1-0.5*yA0*XA)PB=(yB0*P-0.5*yA0*P*XA)/(1-0.5*yA0*XA)PC=yA0*P*XA/(1-0.5*yA0*XA)Kp=PC/PA/SQRT(PB)T=11295.3/LOG(Kp*100000/2.26203)End Subroutine Cal_1End Module CR_1Program Te-XAeuse CR_0Implicit NoneOpen (13 , file='data1.csv')XA=0.05100DoWhile (XA<=1.0)Call Cal_1()IF (T>693.15 .AND. T<873.15) ThenWrite (13,*) XA ,',',T-273.15IF (XA <0.95) ThenXA=XA+0.05ElseXA=XA+0.001End IFGOTO 100End DoEndProgram Te-XAe主程序:等速率曲线Program rA_XA_Tuse CR_1Implicit NoneInteger :: iReal :: rAOpen (12 , file = 'data2.csv')Do i=1,5rA=i*1.e-6Write (12,*) "rA=",rAT=693.15200 XA=0.001100Call Cal_P()Call Cal_rA()IF (ABS(rA_C-rA)<1.E-10) ThenWrite (12,*) "XA",',',XA,',',"T",',',T-273.15 End IFXA=XA+0.00001IF (XA<1.0) GOTO 100T=T+5IF (T<=883.15) GOTO 200End DoEndProgram rA_XA_T主程序:输出所有转化率>98%的结果Program mainuse CR_1Implicit NoneInteger :: iOpen( 15 , file = 'Tin-Xout.csv')lmd = 23135*yA0/0.2549/(64.065*yA0+31.999*yB0+(1-yA0-yB0)*28.013) Tin_1= 420+273.15300Tin = Tin_1Xin=1.E-10W_sum=0i=0200 i=i+1Call Cal_Xout()Xout=XATout=lmd*(Xout-Xin)+TinIF (Tout>873.15) Tout=873.14999Call Cal_W()W=Sum*131/3600W_sum=W_sum+WCall Cal_T()IF(abs(T-Tout)<0.5) ThenIF (i<4) GOTO 400End IFTin = TXin=XoutIF (i<4) GOTO 200IF (Xout>0.98) ThenWrite (15 , *) Tin_1-273.15 ,',', Xout ,',' , W_sumEnd IFIF(Tin_1 <470+273.15) Then400Tin_1 = Tin_1 + 0.1GOTO 300End IFEndProgram main主程序:各段反应器操作数据Program mainuse CR_1Implicit NoneInteger :: ilmd = 23135*yA0/0.2549/(64.065*yA0+31.999*yB0+(1-yA0-yB0)*28.013) Tin_1= 444.55+273.15Tin = Tin_1Xin=1.E-10W_sum=0i=0200i=i+1Call Cal_Xout()Xout=XATout=lmd*(Xout-Xin)+TinIF (Tout>873.15) Tout=873.14999Write (*,*) "第几段反应器" , iWrite (*,*) "Xout,i=", Xout ,"Touti" , Tout-273.15Call Cal_W()W=Sum*131/3600W_sum=W_sum+WWrite (*,*) "Wcat,i" , WCall Cal_T()Tin = TWrite (*,*) "Tin,i+1" , Tin-273.15Xin=XoutIF (i<4) GOTO 200Write (*,*) "催化剂总量" , W_sumEndProgram main。