STATISTICAL ANALYSIS OF REACTION RATE DATA OF LIQUID PHASE SYNTHESIS OF DIMETHYL ETHER FROM METHANOL

The liquid phase catalytic dehydration of methanol to dimethyl ether (DME) is a key reaction step in the single-step synthesis of DME from CO-rich syngas in a slurry reactor. The effect of process variables including temperature, pressure, impeller speed, and feed methanol flow rate on DME synthesis rate has been studied by a systematic 24 full factorial experimental design with single replicate. The significant effects and interactions have been quantified by F-tests. The estimates of significant effects have been obtained by Yates' algorithm. Residual probability and normal probability dots have been obtained to test model adequacy. Finally, a computational model has been developed to predict the DME synthesis rate alt various values of process variables. The model has excellent interpolational predictive capability as evidenced by parity plots.     

STUDY OF KINETICS OF LIQUID PHASE DIMETHYL ETHER SYNTHESIS FROM SYNTHESIS GAS

The kinetics of liquid phase dimethyl ether synthesis from synthesis gas had been studied when catalyst concentration varied in the range from 10 to 30 grams of dual catalyst in 300 mL of liquid paraffin. DHE productivity and methanol equivalent productivity decreased with increasing catalyst concentration, and as reaction temperature was increased, the two productivities reached their peaks at 280 °C. Unlike above productivities, methanol productivity decreased with both catalyst concentration and reaction temperature. A lump reaction rate expression was developed for the methanol equivalent productivity in terms of CO partial pressure. Both the prequency factors and activation energies are functions of catalyst concentration, increasing with catalyst concentration increasing.     

KINETICS OF LIQUID PHASE CATALYTIC DEHYDRATION OF METHANOL TO DIMETHYL ETHER

The kinetics of the liquid phase catalytic dehydration of methanol to dimethyl ether were investigated. The experiments were carried out under low concentrations of feed in a 1-L stirred autoclave, according to a statistical experimental design. The inert liquid phase used for this investigation was a 78:22 blend of paraffinic and naphthenic mineral oils. A complete thermodynamic analysis was carried out in order to determine the liquid phase concentrations of the dissolved species. A global kinetic model was developed for the rate of dimethyl ether synthesis in terms of the liquid phase concentration of methanol. The activation energy of the reaction was found to be 18,830 cal/gmol. Based on a step-wise linear regression analysis of the kinetic data, the order of the reaction which gave the best fit was 0.28 with respect to methanol. Effects of the solid to liquid and the gas to liquid mass transfer resistances on the kinetic rate have also been investigated.     

THERMAL STABILITY ANALYSIS OF THE LIQUID PHASE METHANOL SYNTHESIS REACTOR

The effect of addition of an inert liquid phase on the rate of heat generation in the catalytic synthesis of methanol from syngas has been studied. Gas compositions typical of product gases from Lurgi and Koppers-Totzek gasifiers, represented by H₂-rich and CO-rich syngas respectively, were used to experimentally verify the “slope” and “dynamic” critria in a three-phase fixed bed recycle reactor. The liquid medium, witco-40 oil, has been effective in controlling the rate of heat generation and in preventing catalyst overheating, signifying that the liquid phase synthesis is thermally far more stable than the vapor phase synthesis. The experimental thermal stability study provides crucial and valuable information in commercializing the liquid phase methanol synthesis process. The current approach of thermal stability analysis does not require any a priori assumption or predetermined reaction kinetics.     

THERMAL STABILITY ANALYSIS OF THE LIQUID PHASE METHANOL SYNTHESIS REACTOR

ABSTRACT

The effect of addition of an inert liquid phase on the rate of heat generation in the catalytic synthesis of methanol from syngas has been studied. Gas compositions typical of product gases from Lurgi and Koppers-Totzek gasifiers, represented by H₂-rich and CO-rich syngas respectively, were used to experimentally verify the “slope” and “dynamic” critria in a three-phase fixed bed recycle reactor. The liquid medium, witco-40 oil, has been effective in controlling the rate of heat generation and in preventing catalyst overheating, signifying that the liquid phase synthesis is thermally far more stable than the vapor phase synthesis. The experimental thermal stability study provides crucial and valuable information in commercializing the liquid phase methanol synthesis process. The current approach of thermal stability analysis does not require any a priori assumption or predetermined reaction kinetics.     

REGENERATION OF LIQUID PHASE METHANOL SYNTHESIS CATALYST

ABSTRACT

This work focuses on the influence of changes in catalyst structure on the catalytic activity in liquid phase methanol synthesis process. Long-term methanol production experiments were performed under various reaction environments in order to investigate the relationship between the catalytic activity and the crystallite size in the methanol synthesis catalyst. The regeneration experiments were also conducted in order to reduce the crystallite size of aged catalysts by inducing metallic phase redispersion. The experimental results showed that the drop in the catalytic activity was closely linked to the growth in the crystallite size in the catalyst. The crystallite size was reduced successfully by cyclic oxidation-reduction treatments and as a result the lost activity in aged catalysts was recovered.     

REGENERATION OF LIQUID PHASE METHANOL SYNTHESIS CATALYST

This work focuses on the influence of changes in catalyst structure on the catalytic activity in liquid phase methanol synthesis process. Long-term methanol production experiments were performed under various reaction environments in order to investigate the relationship between the catalytic activity and the crystallite size in the methanol synthesis catalyst. The regeneration experiments were also conducted in order to reduce the crystallite size of aged catalysts by inducing metallic phase redispersion. The experimental results showed that the drop in the catalytic activity was closely linked to the growth in the crystallite size in the catalyst. The crystallite size was reduced successfully by cyclic oxidation-reduction treatments and as a result the lost activity in aged catalysts was recovered.     

甲醇气相脱水合成二甲醚用固体酸催化剂的研究

研究了耐温阳离子交换树脂、γ-氧化铝、分子筛等固体酸催化剂对甲醇气相脱水制二甲醚反应的催化性能,酸碱滴定、氨程序升温脱附、X射线衍射、热重-差热分析对催化剂样进行了表征。结果表明,达到相同的甲醇转化率,催化反应温度顺序为:t(γ-氧化铝)t(树脂)t(分子筛)。以耐温阳离子交换树脂为催化剂,甲醇转化率低于70%,当反应温度高于190℃时树脂很快失活;以γ-氧化铝为催化剂,在280～380℃之间,甲醇转化率高于80%,当温度为365℃时寿命大于500 h;以分子筛为催化剂,在200～280℃之间,甲醇转化率高于85%,分子筛易积碳失活。     

甲醇脱水制二甲醚的催化剂研究

在甲醇气相脱水合成二甲醚反应中,考察了催化剂酸性及反应工艺条件对反应的影响。分子筛的Bronsted酸中心和Lewis酸中心都是甲醇脱水反应的活性中心,而强酸中心是烯烃产生的主要场所。研究表明,采用硅铝比为60的HZSM-23分子筛作为催化剂,适宜的工艺条件为:反应质量空速5 h-1,温度300℃,压力0.1MPa,甲醇转化率为97.6%,二甲醚选择性为95%。     

甲醇氧化羰基化合成碳酸二甲酯的研究进展

综述了碳酸二甲酯的物化性质及甲醇氧化羰基化法合成碳酸二甲酯的研究进展。详细阐述了近年来甲醇氧化羰基化法的合成工艺及所用催化剂的开发现状,分析了各种合成工艺的优缺点,并指出甲醇氧化羰基化法合成碳酸二甲酯的发展趋势。     

MODELING OF A LIQUID ENTRAINED REACTOR FOR LIQUID PHASE METHANOL SYNTHESIS PROCESS

The liquid phase methanol (LPMeOH^TM) synthesis process is to be commercially carried out in a liquid entrained reactor (LER), where the catalyst-inert oil slurry is pumped through the reaction zone along with the syngas fed separately. A computer model was developed based on the experimental results, for the LPMeOH^TM process in a liquid entrained reactor. This computer program accurately predicts the multicomponent phase equilibria, ultimate chemical equilibria and the compositions of each reactant and product species exiting in the entrained reactor. The prediction of the results of this modeling agrees well with the experimental data from the LaPorte pilot plant entrained reactor.     

MODELING OF A LIQUID ENTRAINED REACTOR FOR LIQUID PHASE METHANOL SYNTHESIS PROCESS

ABSTRACT

The liquid phase methanol (LPMeOH^TM) synthesis process is to be commercially carried out in a liquid entrained reactor (LER), where the catalyst-inert oil slurry is pumped through the reaction zone along with the syngas fed separately. A computer model was developed based on the experimental results, for the LPMeOH^TM process in a liquid entrained reactor. This computer program accurately predicts the multicomponent phase equilibria, ultimate chemical equilibria and the compositions of each reactant and product species exiting in the entrained reactor. The prediction of the results of this modeling agrees well with the experimental data from the LaPorte pilot plant entrained reactor.     

甲醇气固相催化制甲酸甲酯

甲酸甲酯的传统制备路线是将甲醇与甲酸酯化。为了降低生产成本,作者研究了甲醇气固相催化直接脱氢制甲酸甲酯的方法,考察了催化体系组成和最佳反应条件。     

STATISTICAL ANALYSIS OF OLEFINS YIELD IN FIXED BED CONVERSION OF DIMETHYL ETHER

ABSTRACT

Selective conversion of dimethyl ether to lower olefins is a process of commercial significance. Lower olefins are intermediates in the conversion of dimethyl ether to higher hydrocarbons. Conversion of dimethyl ether to hydrocarbons has significant advantages over its counterpart methanol conversion process in the areas of heat duties, hydrocarbon selectivities, product yield, and reactor size

The present work examines the effect of key process variables on the dimethyl ether conversion to lower olefins in a fixed bed reactor system. The effect of process variables, namely reactor temperature, reactor pressure, feed dilution with nitrogen, and the weight hourly space velocity of dimethyl ether has been investigated using a 24 full factorial experimental design, with three replicates of the center point of the design. The estimates of significant main and interactive effects have been quantified using the Yates algorithm and conducting F-tests. A computational model has been formulated to predict the olefin yield at different values of process variables. Normal probability plots have been obtained to test model adequacy. The predictive capability of the developed model has been proved as illustrated by parity plots     

STATISTICAL ANALYSIS OF OLEFINS YIELD IN FIXED BED CONVERSION OF DIMETHYL ETHER

Selective conversion of dimethyl ether to lower olefins is a process of commercial significance. Lower olefins are intermediates in the conversion of dimethyl ether to higher hydrocarbons. Conversion of dimethyl ether to hydrocarbons has significant advantages over its counterpart methanol conversion process in the areas of heat duties, hydrocarbon selectivities, product yield, and reactor size

The present work examines the effect of key process variables on the dimethyl ether conversion to lower olefins in a fixed bed reactor system. The effect of process variables, namely reactor temperature, reactor pressure, feed dilution with nitrogen, and the weight hourly space velocity of dimethyl ether has been investigated using a 24 full factorial experimental design, with three replicates of the center point of the design. The estimates of significant main and interactive effects have been quantified using the Yates algorithm and conducting F-tests. A computational model has been formulated to predict the olefin yield at different values of process variables. Normal probability plots have been obtained to test model adequacy. The predictive capability of the developed model has been proved as illustrated by parity plots     

二氧化碳加氢合成二甲醚的热力学分析

对二氧化碳加氢合成甲醇、二氧化碳加氢合成二甲醚过程进行了热力学计算。计算结果表明：在相同反应条件下,二氧化碳加氢合成二甲醚反应较二氧化碳加氢合成甲醇反应具有更高的ＣＯ２平衡转化率;对二氧化碳加氢合成二甲醚反应而言,ＣＯ２平衡转化率随温度的增加呈单调下降,增加反应体系的压力有利于二氧化碳加氢合成二甲醚反应的进行,Ｈ２／ＣＯ２比值越大,越有利于二氧化碳加氢合成二甲醚反应的进行。     

SYNTHESIS OF HYDROCARBONS FROM DIMETHYL ETHER: SELECTIVTTIES TOWARDS LIGHT HYDROCARBONS

ABSTRACT

The depleting supplies of non-renewable petroleum reserves, as well as their escalating costs, have directed a great deal of research toward the synthesis of hydrocarbons from coal. Synthesis of methanol from coal-derived synthesis gas is a well established technology, and methanol has been used as a feedstock for the synthesis of gasoline range hydrocarbons and olefins commercially. However, an efficient hydrocarbon synthesis process has been developed at the University of Akron using dimethyl ether as the starting feedstock. This UA/ EPRI' s DTH ( Dimethyl Ether to Hydrocarbons) process has significant advantages over its counterpart methanol conversion process in the areas of heat duties, hydrocarbon selectivities, product yield, and reactor size

Lower olefins are the intermediate products in the conversion of dimethyl ether to aromatic hydrocarbons. C2-C4 olefins and paraffins can be selectively produced by varying the operating parameters of the process, viz., temperature, pressure, DME concentration in the feed, space time, catalyst-to-inert packing ratio, etc. The present work focuses on the effect of key process variables on the dimethyl ether conversion to low molecular weight hydrocarbons in a fixed bed microreactor system over ZSM-5 type zeolite catalyst. Experimental results with respect to gaseous hydrocarbon product yields and selectivities have been examined in this study     

二氧化碳和甲醇直接合成碳酸二甲酯的研究进展

从催化体系和反应体系方面,综述了近年来 CO_2和甲醇直接合成碳酸二甲酯的研究进展。评价了不同催化体系包括烷氧基金属有机化合物、负载型金属有机化合物、碱金属催化剂、乙酸盐催化剂、氧化物催化剂、杂多酸催化剂和表面复合物光催化剂,介绍了对超临界体系、离子液体体系、电化学合成体系、以及脱水剂、膜反应器、微波技术的应用,并指出了 CO_2和甲醇直接合成碳酸二甲酯的发展趋势。     

SYNTHESIS OF HYDROCARBONS FROM DIMETHYL ETHER: SELECTIVTTIES TOWARDS LIGHT HYDROCARBONS

The depleting supplies of non-renewable petroleum reserves, as well as their escalating costs, have directed a great deal of research toward the synthesis of hydrocarbons from coal. Synthesis of methanol from coal-derived synthesis gas is a well established technology, and methanol has been used as a feedstock for the synthesis of gasoline range hydrocarbons and olefins commercially. However, an efficient hydrocarbon synthesis process has been developed at the University of Akron using dimethyl ether as the starting feedstock. This UA/ EPRI' s DTH ( Dimethyl Ether to Hydrocarbons) process has significant advantages over its counterpart methanol conversion process in the areas of heat duties, hydrocarbon selectivities, product yield, and reactor size

Lower olefins are the intermediate products in the conversion of dimethyl ether to aromatic hydrocarbons. C2-C4 olefins and paraffins can be selectively produced by varying the operating parameters of the process, viz., temperature, pressure, DME concentration in the feed, space time, catalyst-to-inert packing ratio, etc. The present work focuses on the effect of key process variables on the dimethyl ether conversion to low molecular weight hydrocarbons in a fixed bed microreactor system over ZSM-5 type zeolite catalyst. Experimental results with respect to gaseous hydrocarbon product yields and selectivities have been examined in this study