Application of methanol synthesis reactor to large-scale plants Application of methanol synthesis reactor to large-scale plants

Application of methanol synthesis reactor to large-scale plants

  • 期刊名字:应用化工
  • 文件大小:769kb
  • 论文作者:LOU Ren,XU Rong-liang,LOU Shou
  • 作者单位:Hangzhou Linda Chemical Technology Engineering Ltd
  • 更新时间:2020-07-08
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论文简介

第35卷增刊应用化工VoL. 352006年10月.Applied Chemical IndustryOet. 2006Application of methanol synthesisreactor to large-scale plantsLOU Ren ,XU Rong liang , LOU Shou-lin( Hanghou Linda Chemical Technology Engineering Ltd, Hangzhou 310013 ,China)Abstract: The developing status of world large. -scale methanol production technology is ana-lyzed and Linda' s JW low-pressure methanol synthesis reactor with uniform temperature isdescribed. JW serial reactors have been scessfully introduced in and applied in Harbin Gas-ification Plant and the productivity has been increased by 50% and now nine sets of equip-ments are successfully running in Harbin Gasification Plant , Jiangsu Xinya, Shandong Kenli ,Henan Zhongyuan , Handan Xinyangguang, 'Shanxi W eihua and Inner Mongolia Tianye. Now ithas manufacturing the reactors of 300 , 000 Va for Liaoning Dahua. Some solutions for thestructure problems of 1000 ~ 5000 Vd methanol synthesis rectors are put forward.Key words :methanol ; synthesis ; reactor; large -scaleChina Book Code:TQ 223Literature Mark:AWhether being the raw chemical material ( for producing formaldehyde , propeneor ethene) or being the energy source (methanol gasoline fuel) , the application andsize of the latter-day methanol are increasing consistently. The size of the foreign e-quipments has reached million-ton grade , and China has listed the methanol synthetictechnology as it essential project in its “9h 5-year Plan and 10 5-year Plan”. The .leaders of the State Council gave many important instructions on the production ofmethanol. In April 2004 , the State Development and Reform Council held a session a-bout“On the Development of Methanol Fuel” , and now the Methanol & Aether andMethanol & Aether Clean Automobile Association of Sinopetrol have been estab-lished. The methanol gasoline is promoted in four trial provinces such as Shanxi. Un-der the situation that the size of the methanol production is increasing consistently andtoward the large-scale development, it is possible for China to develop its own modernmethanol production technology. For decades , China has imported over 20 large am-monia synthesizing reactors during constructing large fertilizer plants. But now, wecan build large methanol production facilities with our own intellectual property.1 The status quo of the large methanol中国煤化工gy in foreigncountriesYHCNMHGThe low pressure approach is the major one in the modern methanol synthesizingproduction technology due to the energy-saving. It is said that the technologies of增刊LOU Ren et al:Application of methanol synthesis reactor to large- scale plants261British ICI Company and the German Lurgi Company occupies 70% min of the foreignproduction facilities , and which represents the technology level of the foreign methanolsynthesizing production. Now the single reactor that has the largest productivity is theunited one-Lurgi united reactor which is composed by 3 reactors and with productivityof 5000 t/d , and started production in Atlas , Trinidad in June ,2004. The structure ofthe ICI methanol reactor is simple , has a large coefficient for flling the catalyzer andeasy to be enlarged. .At present , it has the facilities that can product 3000 V/d with single set , but thetemperature difference at the layer of the catalyzer bed is huge , the retur and mixingof the air are heavy and the efficiency of synthesizing is poor.For the Lurgi Tube and Shell methanol reactor , the temperature difference at thelayer of the catalyzer bed is small. It is easy to be operated and the efficiency of syn-thesizing is good. But the catalyzer bed of the reactor has strong wall effect , whichwill impact the increasing of the time and space productivity. It has a small coffcientfor flling the catalyzer , its structure is complicated , and the single reactor is not pro-ductive and hard to be enlarged.There are also TOPSOE radial flow reactors , where the heat is exchanged be-tween the towers , the global KBR reactors , the horizontal CASALE multiple bed reac-tor , where the heat is exchange between the sections. This kind of reactor is composedor stringed by multiple units or multiple beds and the exterior heat exchanger con-figured between the towers or sections can remove heat from reaction. The pressureon the bed layer of this kind of reactor is lowered and it is easy to be enlarged , but the .cost on the equipments is huge , the process for manufacturing the reactor is complicat-ed and the distribution of the catalyzer bed is not good enough.In the above three kinds of methanol reactors , the production strength of the suc-cessive heat exchanging and constant temperature catalyzer are the best:0.9~1.0 kg(L. h) ;while the cold treating type is the worst: 0. 35 ~0. 40 kg (L. h) ;the indirectheat exchanging and heat insulation type is between them:0. 55~0.6 kg (L. h).2 The methanol synthesizing technology with China own intellectual propertyIn recent years, the technology of low pressure methanol synthesizing has beendeveloped greatly and the Productivity Promotion中国煤化工ssociation andothers have done a great deal of works. HangzhoMYHCNMH Gst China Uni-versity of Science and Technology and some Design Institutes have undertaken a se-ries of methanol project jointly. Hangzhou Linda Company has a series of successful262应用化工2006年第35卷增刊innovated technologies about the methanol and ammonia synthesizing reactors,and ithas applied for the international patents , European patents,Russian patents, the USApatents and domestic patents including PTC.Till now, it has gotten 16 domestic or international patents. It has developedsuccessfully the large-scale , low pressure and even temperature type methanol synthe-sizing technology after having developed successfully intermediate pressure integratedmethanol reactor applying for the integrated methanol production in the synthesizedammonia plant , and the reactor has become the most applicable one in the integratedmethanol production units in China. The effect of this technology has been provenwhen it was used in multiple plants and was honored the National Innovation Award2004.The methanol synthesizing is a strong heat reaction. The synthesized raw materialgas that should go into the catalyzer layer should not react before being heated to thereaction temperature( > 210C) , while the low pressure methanol synthesized cata-lyzer( copper base accelerant ) is easy to be overheated and lost activity( > 2809C )and the reaction heat from the methanol synthesizing should be removed timely. Asthis synthesizing reactor has combined the heating of the raw material gas and the heatremoving during the reaction, the reactor and the heat exchanger are combined andremove heat successfully, and it can also reduce the size of the equipments and thetemperature difference at the catalyzer layer so as to reach the goal of“even tempera-ture, high efciency and easy to be enlarged" .This low pressure and even temperature type methanol reactor is a completelynew reactor structure which is different from the existing foreign methanol reactor andis the first one internationally and domestically. After the initial inspection and tes-ting by PCT, as well as the real reviewing by the state , it was honored a patent and hasmany unique creative technologies. Its key part is that the double U shape pipe cool-ing pipe pot structure with 2 innovative and unique elbows , big and small , as the heatexchanging component. The U-shape pipe with small elbow is in the U-shape pipe .with big elbow to form a pair of U-shape pipe. The U-shape pipe with the big andsmall elbows in the double U-shape pipes is jointed in a counter-direction array, andthe air flows up and down in each 2 cooling pip中国煤化工each other andthe directions are refluence, so as to achieve thYHC N M H Gal temperaturereaction at the accelerant layer and the temperature difference can be as low as 109C.As the completely free extensive and compound seal structure has been developed,增刊LOU Ren et al :Application of methanol syntheais reactor to large- scale plants263the ring pipe is in the free space above the catalyzer and the double U-shape pipe isin the catalyzer layer. As there is no welding point on the cooling pipe, the structureis reliable. Another one is the low temperature and even temperature type methanolreactor with double ring pipes at the upper and lower parts. The cooling pipe pot hasan upper ring pipe and lower ring pipe. The upper ring pipe connects the air inletpipe and the downward cooling pipe,while the lower ring pipe connects the downwardcooling pipe and the upward cooling pipe.The creative development has been applied successfully in the Reactor Designer-reactor analog computing software of methanol synthesizing. After corrected by quanti-ty of real production data , the math model is more near to the real effect. The integrat-ed reactor that applies in the even temperature single ( integrated ) methanol reactor ,the Tube and Shell type reactor , ICI Quench type reactor and the large methanol e-quipments includes various of dynamics data of the methanol catalyzer , so the designof the reactor can be easily optimized and which can provide a powerful backing todeveloping and optimizing the high-performance methanol synthesizing reactor.2.1 The operation effect and main technical parameters of the Linda metha-nol synthesizing reactorNine sets of new synthesizing reactor have been operated. Comparing with the a-bove said foreign equipments ,they present the features of small reactor , low tempera-ture difference at the accelerant layer, high CO conversion rate , high output and lessgas consumption.After Harbin Gasification Plant has change its 中2000 Quench reactor into theJW even temperature type methanol tower , the temperature difference at the acceleranthas lowered from the former 30 ~T0C to the <59C at the same level and <10C ra-dially. Under the condition that there is no increasing in raw gas, the inlet gas or theaccelerant for methanol synthesizing, the output of the methanol has been increasedby 50% . The raw material consumption for each ton of methanol has decreased by 129Nm' and the power consumption has decreased by 120 kW●h. Under the effective syn-thesizing pressure of 5 MPa, the production strength of the methanol catalyzer canreachO. 69 V(m' .h) ,comparing with the 0. 382 V( m3●h) from the Quench tower,it has been increased by over 50% , and also highar than th i-mI and foreign Lu-中国煤化工igi Tube and Shell type(0. 58 /( m'●h) )anddYHCNMHGthe comparisonof the main technical indexes between the JW Tower, the Quench Reactor and thetube and shell Type Methanol Tower, see table 1.264应用化工2006年第35卷增刊Table 1 Comparison of Jw reactor ,quench type reactor and tube shell type reactorTypes of the reactorQuenchTube- ShellJW even Temp. Innercooling in whole bedTemperature difference at the catalyzer layer/C30~7010 ~305~15Reference time and space productivity/[V(m3●h)-"] 0.3~0.4 .0.5~0.650.6 ~0.73The flling cofficient of the reactor accelerant> 703>7Power consumption/%130100The catalyzer consumption for the same output/%150 ~ 200< 100The size of the equipment with the same productivity/%50The investment /%7(<50The result of real use shows that the JW low pressure and even temperature typereactor has combined the advantages of the quench methanol reactor-simple structure,large catalyzer flling coefficient; and the advantages of the Tube Shell type methanolreactor-lower temperature difference at the methanol reactor bed layer and effectivesynthesizing. With the same productivity , its size is smaller than the 2 types of reactorabove said ( see table 2).Table 2 Size comparison of Jw reactor and tube -shell reactorProductivity 1000 Vd100 .200300Lurgi Tube -Shell Reactor/m3.24.0Hard to produceJW even temperature reactor/m23.03.82.2 The information about the application and promotion of the Linda metha-nol synthesizing reactorNine sets of equipments with this technology have been operated successfully andthe total productivity has been over 700 ,000t/a. The enterprise has gotten good eco-nomical and social benefits. Before 2000 , the output of the Harbin Gasification Plantwas only 40 ,000 Va. But since it enlarged its productivity with the JW low pressuremethanol reactor , its productivity has reached 150 ,000t/a. Till now , total 20 contractsfor tranferring this technology have been signed中国煤化ircing integrated .methanol with gas and with the materials convefYHC N M H Gcoal or variousother materials. For details, see table 3.增刊LOU Ren et al:Application of methanol synthesis reactor to large-scale plants265Table 3 Projects with the Jw reactorsNo.ClientsDiameter ProductivityDelivery and running starting timeHarbin Gasification Plant2000508020013 Henan Zhongyuan Gasifcation Plant702003Shandong Kenli Fertilizer Plant160030Jiangsu Wujin Chemical Plant1400202004Hebei Hendan XinyangguangYunnan Qujing Jiaohua2008 Inner Mongolia Tianye Group30002005Shanxi Weihua Group200610Henan Junma Group1Liaoning Benxi Group190012Fujian Zhangzhou Changtai200713Dalian Dahua Group320030014Shanxi Yulin Group210010015Yunnan Yunwei Group16Shanxi Tianhao GroupShanxi Lanhua GroupThe successful development and application have stopped the long. term impor-ting of the modernized reactor technology. In three large plants _W eihua , Tianye andDahua-which ammonia reactor has adopted foreign technologies, our technology haswon over the foreign ones and saved plenty of foreign exchanges that should be costfor importing them. After the completion and starting operation of the equipments withthis technology , the total productivity will be over 1 million Va. In adition , severalcoal-gases made and cookery made methanol projects plan using this technology, suchas that the 600 ,000 Va methanol project in Jiaocheng Shan-xi has adopted this tech-nology and has passed the appraisal by the experts. Except for the above JW low pres-sure methanol reactor , Linda Company has also water cooling type methanol synthesi-zing reactor with the by-product intermediate pressure steam( water goes in pipes) ,aswell as the water-cooling & air cooling combine中国煤化工g process andthe PCT international patent has been applied:TYHCN MH Gd ICI QuenchReactor with 4 m-up diameter in Inner Mongolia and Sichuan asked for technical ren-ovation with this technology so as to improve their productivity. This technology is ver-266应用化工2006年第35卷增刊y competitive internationally and many foreign companies have discussed it with us.3 How to solve the structural problems of the large methanol synthesizing re-actorAs the single series enlarged methanol production equipments can decrease theinvestment and the production cost , it has become the essential development directionfor the methanol production technology. About this issue, as the Tube-shell reactor isactually an undividable large pipe array heat exchanger that integrates pipe plate andshell body , it is hard to be enlarged. For example, under the 5MPa pressure, the di-ameter of the single 200, 000t/a Tube-Shell reactor has reached 4m, and this hasbeen the width limitation of the highway transportation in China. If it is over 4m, itwould be hard to be transported. Therefore , the equipments over 200 ,000 t/a shouldbe paralleled with multiple Tube Shell reactor , while this would bring some problemssuch as more investment to the equipments. One way for decreasing the diameter is in-creasing the ratio between the height and the diameter. Some ratio between the heightand the diameter for the quench reactor in China has reached 10. Such a large ratiobetween the height and diameter not only adopts the axes reactor but also has large re-sistance. Even though the radial reactor is adopted, it is not sure if the methanol cata-lyzer that is shaped by pressing and with low strength will be grinded or powdered if asuccessive catalyzer bed is used. Although increasing the synthesizing pressure canimprove some productivity on the reactors with certain diameter , it may increase thepressure difference between the inside and outside of the reacting pipe , as well as be-tween the reaction gas at upper and lower part of the pipe plate and the vapor of theshell distance. It also increases the investment in equipments and makes it more diffi-cult for the manufacturing technology. JW even temperature reactor has many advan-tages for enlarging it.(1) First, the JW reactor has a large coefficient for the accelerant flling. Withthe same productivity and the filled catalyzer,the size of the reactor is minimized ( seetable 2) , therefore the productivity of the single 5 MPa synthesizing reactor with4 mdiameter can reach 300 ,000 t/a.(2) When the JW reactor increases its synthesizing pressure, the pressuredifference between the inside and outside of the中国煤化主Therefore onlythe designed pressure of the shell is increasedTYHCN MH Ges are added onthe technologies for manufacturing the inner parts , and the productivity under certaindiameter can be improved easily by improving the synthesizing pressure. The produc-增刊LOU Ren et al:Application of methanol synthesis reactor to large-scale plants267tivity of the single reactor with about 9 MPa synthesizing pressure can reach600 ,000 t/a.(3) The separated cooling pot and the multiple coaxial packages are adopted asthe inner parts of the JW reactor. Therefore ,even if the diameter is over 4 m, the innerparts can be separated and transported to the assembly site. The shell can be weldedheat treated on site. Linda Company has bought several synthesizing reactor which di-ameter is over4 m,4.3 m,4.5 m and 4.8 m, and has rebuilt them. The productivityof such single reactor can reach 1 million t/a.(4) With combination of multiple reactors. In the foreign plans on enlarging re-actor of the methanol synthesizing equipment,ICI is the single reactor with the en-larged reactor diameter; Tope strings three radial heat insulation reactors; in thepast, Lurgi advised two paralleled Tube -Shell type reactor co-using one bubble , butnowadays ,it advocates using the reactor combining the water cooling -air cooling-thatis,they are combined with a cooling pipe synthesizing reactor by air cooling and thewater cooling reactor by the outside cooling by-product vapor. The raw material gasgoes in the air coling reactor first. This combination needs one air cooling reactorwith over 4 m diameter and a water cooling reactor with over 6 m diameter. If the di-ameter of the water cooling reactor is same as the one of the air cooling reactor andthe air goes through the reaction pipe , the section for air flowing is half of the air cool-ing reactor ,its resistance is huge. As it is difficult to manufacture the Tube-Shell typereactor with 6 m diameter , Lurgi parallels two water cooling reactors and combines oneair cooling reactor. While for the reactor combining the water cooling and the aircooling developed by Linda Company , the vapor produced by the water goes throughthe pipe and the catalyzer is flled outside the pipe. As the air flow section is the samesize as the air cooling reactor ,only one watercoling reactor and one air cooling reac-tor is required. Comparing with Lurgi' s method, one water-cooling reactor is less-ened;therefore its configuration is more reasonable and more cost effective. For thesuper-large reactors with over 5000t/ d productivity, this type can be adopted. An in-ternational PCT patent has been applied for it.Except for applying for synthesizing methanol , Linda' s JW low pressure synthe-sizing reactor is very applicable for the reactiol中国煤化工yl ether by de-hydrating methanol. Caleulated as the design, t:MYHCNMHG00t/adimeth-yl ether reactor is 3.6 m,much smaller than the 4. 6 m of the Tube-shell type reactorand the 4.4 m of the heat insulation reactor.应用化工2006年第35卷增刊4 ConclusionChina is rich in the coal and natural gas resource and that are the very profitableconditions for producing methanol ( dimethyl ether). At the same time , methanol has agreat future in the market , either as the chemical material or as the clean fuel. Enlar-ging methanol production and decreasing the cost have been the inevitable require-ment for being the fuel replacer and replacing the oil pipe to producing the mainchemical products such as ethene and propene.Multiple foreign companies have made great progress in enlarging the productionof methanol. Represented by Linda Company , some domestic enterprises have also de-veloped some new technologies with our own intellectual property in enlarging the pro-duction of methanol. It is a must that the breakthrough on the domestic technology ofenlarging the production of methanol promotes the quick development of the methanolproduction in China.中国煤化工MYHCNMHG

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