IN-SITU ACTIVATION OF METHANOL SYNTHESIS CATALYST IN A THREE-PHASE SLURRY REACTOR

ABSTRACT

In the liquid phase methanol synthesis process, syngas reacts in the presence.of fine catalyst particles slurried in the oil phase, in a three phase slurry reactor system. A method for activating high concentration ( ?25 wt. %) of the CuO-ZnO-Al₂O₃ catalyst in the catalyst-oil slurry has been successfully developed. This catalyst activation process can be of crucial significance in the research and development of the methanol synthesis process in a liquid entrained reactor.

The reducing gas contains 2% hydrogen in nitrogen mixture and this activation procedure is carried out at a pressure of 125 psi. The catalyst-oil slurry is subjected to a controlled temperature ramping from 110° to 250° C. The catalyst has beemshown to be effectively reduced after following this activation procedure, that is valid especially for high catalyst loadings in slurry. Since the reduction is carried out in the process liquid medium and inside the reactor system, the catalyst-oil slurry after the treatment is ready for the synthesis of methanol.     

MODELING OF A MECHANICALLY AGITATED SLURRY REACTOR FOR LIQUID PHASE METHANOL SYNTHESIS PROCESS

In the liquid phase methanol synthesis process in a mechanically agitated slurry reactor (MASR), catalyst particles in powder form are slurried in the oil phase, and this catalyst-oil slurry is continuously agitated by the impeller in the reactor. Syngas, which is fed to the reactor, reacts in the presence of the activated catalyst-oil slurry, to form the product, methanol.

A computer model was developed based on the experimental results, for the liquid phase methanol synthesis process, in a mechanically agitated slurry 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 agitated slurry reactor The results of the modeling predictions, agree well with the experimental data collected from the agitated slurry reactor.     

MODELING OF A MECHANICALLY AGITATED SLURRY REACTOR FOR LIQUID PHASE METHANOL SYNTHESIS PROCESS

ABSTRACT

In the liquid phase methanol synthesis process in a mechanically agitated slurry reactor (MASR), catalyst particles in powder form are slurried in the oil phase, and this catalyst-oil slurry is continuously agitated by the impeller in the reactor. Syngas, which is fed to the reactor, reacts in the presence of the activated catalyst-oil slurry, to form the product, methanol.

A computer model was developed based on the experimental results, for the liquid phase methanol synthesis process, in a mechanically agitated slurry 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 agitated slurry reactor The results of the modeling predictions, agree well with the experimental data collected from the agitated slurry reactor.     

STATISTICAL MODEL FOR SLURRY PHASE METHANOL SYNTHESIS PROCESS IN AN ENTRAINED REACTOR

The process feasibility analysis on the liquid phase methanol synthesis (LPMeOH) process was performed in an entrained slurry reactor system. In this three phase mini-pilot plant system, finely powdered catalyst is slurried in the inert oil phase and this catalyst-oil slurry is continuously recirculated through the entrained reactor, where it is contacted with the cocurrent flow of syngas to form the product methanol

The effect of various operating conditions which included the reactor temperature, the reactor pressure, the flow rate of catalyst-oil slurry, the flow rate of syngas, the slurry holdup tank pressure, the syngas composition, and the catalyst loadings in slurry, on the productivity of methanol in the reactor was studied. Using the operating conditions, a statistical reaction rate model not based on the kinetic mechanism, was developed to predict the productivity of methanol in an entrained reactor. The rate of production of methanol predicted by this model agreed well with the experimental results. This statistical model assists in the development, scale-up, and commercialization of the methanol synthesis process in an entrained slurry reactor.     

STATISTICAL MODEL FOR SLURRY PHASE METHANOL SYNTHESIS PROCESS IN AN ENTRAINED REACTOR

ABSTRACT

The process feasibility analysis on the liquid phase methanol synthesis (LPMeOH) process was performed in an entrained slurry reactor system. In this three phase mini-pilot plant system, finely powdered catalyst is slurried in the inert oil phase and this catalyst-oil slurry is continuously recirculated through the entrained reactor, where it is contacted with the cocurrent flow of syngas to form the product methanol

The effect of various operating conditions which included the reactor temperature, the reactor pressure, the flow rate of catalyst-oil slurry, the flow rate of syngas, the slurry holdup tank pressure, the syngas composition, and the catalyst loadings in slurry, on the productivity of methanol in the reactor was studied. Using the operating conditions, a statistical reaction rate model not based on the kinetic mechanism, was developed to predict the productivity of methanol in an entrained reactor. The rate of production of methanol predicted by this model agreed well with the experimental results. This statistical model assists in the development, scale-up, and commercialization of the methanol synthesis process in an entrained slurry reactor.     

LIQUID PHASE METHANOL SYNTHESIS IN AN ENTRAINED REACTOR—DEVELOPMENT OF A GAS-LIQUID MASS TRANSFER CORRELATION

Abstract

Research on various aspects of the methanol synthesis was performed in a liquid entrained reactor. The catalyst-oil slurry is pumped through the tubular entrained reactor and syngas is fed cocurrently with the upward flow of slurry. The effect of different operating conditions, syngas composition and catalyst loadings on the productivity of methanol, was studied.

The data obtained from the experiments at high catalyst loadings in slurry, was used to develop a gas-liquid mass transfer correlation for the liquid phase methanol synthesis in an entrained reactor. The productivity of methanol in an entrained reactor was then predicted using the developed mass transfer correlation. This predictive model also helps in the design, development, scale-up and commercialization of the liquid phase methanol synthesis process in an entrained reactor.     

CATALYST EFFECTIVENESS FACTORS UNDER GAS-TO-LIQUID MASS TRANSFER LIMITING REGIME IN LIQUID PHASE METHANOL SYNTHESIS PROCESS

The effectiveness factors of methanol synthesis catalyst were experimentally measured under condition of gas-to-liquid mass transfer limiting regime in the liquid phase methanol synthesis process, where the synthesis catalyst is slurried in an inert liquid phase. The experimental measurements of effectiveness factors were based on an intrinsic methanol synthesis rate per unit mass of catalyst (gmol/kg cat.h) which is not limited by external mass transfer. The experiments were carried out under well-defined conditions of temperature, pressure, syngas feed flow rate, and impeller speed. The experiments were carried out in a 1-L stirred autoclave. The catalyst slurry ratios were varied from 10 g in 550 mL of Witco-40 oil (corresponding to a slurry ratio of 2.2%) to 150 g in 550 mLof Witco-40 oil (corresponding to a slurry ratio of 25.1%). The experimental measurements have been summarized in one single plot as generalized catalyst effectiveness factor as a function of catalyst slurry ratio. The results of this study are extremely significant and practical in their applicability because the data were obtained using commercial methanol catalysts under actual commercial operating conditions of liquid phase methanol synthesis process.     

KINETIC RATE EXPRESSION FOR METHANOL SYNTHESIS IN A LIQUID ENTRAINED REACTOR

In the three phase entrained reactor for the liquid phase synthesis of methanol, the catalyst-inert oil slurry is pumped through the tubular reactor and syngas is fed to the reactor cocurrently with the upward flow of slurry.

According to an elaborate experimental design plan, the effect of different operating conditions on the liquid phase synthesis of methanol in an entrained reactor, was studied. The parameters of this experimental study included reactor temperature, reactor pressure, slurry flow rate, syngas flow rate, slurry holdup tank pressure, and syngas composition.

The data obtained from the experiments at low catalyst loading in slurry, were used to develop a kinetic rate expression for the liquid phase methanol synthesis process in an entrained reactor. This in turn helps the scale-up and commercialization of the methanol synthesis process in an entrained reactor.     

KINETIC RATE EXPRESSION FOR METHANOL SYNTHESIS IN A LIQUID ENTRAINED REACTOR

Abstract

In the three phase entrained reactor for the liquid phase synthesis of methanol, the catalyst-inert oil slurry is pumped through the tubular reactor and syngas is fed to the reactor cocurrently with the upward flow of slurry.

According to an elaborate experimental design plan, the effect of different operating conditions on the liquid phase synthesis of methanol in an entrained reactor, was studied. The parameters of this experimental study included reactor temperature, reactor pressure, slurry flow rate, syngas flow rate, slurry holdup tank pressure, and syngas composition.

The data obtained from the experiments at low catalyst loading in slurry, were used to develop a kinetic rate expression for the liquid phase methanol synthesis process in an entrained reactor. This in turn helps the scale-up and commercialization of the methanol synthesis process in an entrained reactor.     

METHANOL PRODUCTIVITY COMPARISON BETWEEN AN AGITATED SLURRY REACTOR AND AN ENTRAINED REACTOR

The effect of various operating conditions including the catalyst loading in slurry, on the productivity of methanol in an agitated slurry reactor were studied. The modeling of the mechanically agitated slurry reactor was performed with the aid of the reaction rate expression and the gas-liquid mass transfer correlation that were developed, to predict the rate of methanol production for any inlet condition

The equilibrium limitation encountered in the liquid phase methanol synthesis process in an agitated slurry reactor can be alleviated by conducting this process in an entrained reactor, where the product methanol formed is continuously flashed out of the system. After developing a kinetic rate expression and a gas-liquid mass transfer correlation, the modeling of the entrained reactor was performed to predict the reactor productivity for any process condition. The rate of methanol production predicted for nominally identical operating conditions in an entrained reactor and in a mechanically agitated slurry reactor are compared with the aid of the computer models developed     

METHANOL PRODUCTIVITY COMPARISON BETWEEN AN AGITATED SLURRY REACTOR AND AN ENTRAINED REACTOR

ABSTRACT

The effect of various operating conditions including the catalyst loading in slurry, on the productivity of methanol in an agitated slurry reactor were studied. The modeling of the mechanically agitated slurry reactor was performed with the aid of the reaction rate expression and the gas-liquid mass transfer correlation that were developed, to predict the rate of methanol production for any inlet condition

The equilibrium limitation encountered in the liquid phase methanol synthesis process in an agitated slurry reactor can be alleviated by conducting this process in an entrained reactor, where the product methanol formed is continuously flashed out of the system. After developing a kinetic rate expression and a gas-liquid mass transfer correlation, the modeling of the entrained reactor was performed to predict the reactor productivity for any process condition. The rate of methanol production predicted for nominally identical operating conditions in an entrained reactor and in a mechanically agitated slurry reactor are compared with the aid of the computer models developed     

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.     

羰化-氢解法低温合成甲醇 Ⅴ.催化反应宏观动力学研究

采用磁传动搅拌反应器 ,对使用自制的铜铬氧化物甲醇合成催化剂的低压宏观反应动力学特性进行了实验研究。采用幂律法对实验数据进行处理 ,建立了催化剂的宏观反应动力学方程。在 35 3～ 393K温度范围内 ,催化反应的活化能为 6 7 0kJ/mol,这一数值与甲醇羰化制甲酸甲酯的活化能相近     

DIRECT CATALYTIC CONVERSION OF METHANE TO HIGHER HYDROCARBONS

Using a plug-flow reactor we have been able to demonstrate the conversion of pure methane gas to liquid hydrocarbons via the intermediate formation of methanol. The reaction Was carried out at an intermediate pressure (about 20 atm) and moderate temperature (about 400°C). In the first stage of the reactor methane and oxygen react to produce methanol. In the second stage the methanol was converted by HZSM-5 catalyst to a mixture of hydrocarbons. Analysis of the reaction products showed that all of the oxygen Was used in the reaction. Apart from the unconverted methane the product was composed of oxides of carboy water and C₃+ hydrocarbons. Interestingly, among the liquid hydrocarbons, aromatics were found to be the major constituents.     

IN-SITU REDUCTION OF A METHANOL SYNTHESIS CATALYST IN A THREE-PHASE SLURRY REACTOR

ABSTRACT

A new method for the reduction of metal oxide catalysts has been developed, for the reduction of the CuO - ZnO - A1203 catalyst for liquid phase methanol synthesis. The reducing agent is a 5% hydrogen in nitrogen mixture and the operation is carried out at 446.09 KPa. This method makes it possible to reduce finely crushed catalyst (-100 + 120 mesh) in a three phase slurry reactor. This method offers several advantages over methods in which the catalyst is reduced in a gas-solid contact mode and then slurried for use. The catalyst has been shown to be very effectively reduced and reaches its full production capacity after reduction.     

THE ROLE OF WATER IN METHANOL SYNTHESIS

This work focuses on the influence of water in determining the rate of methanol synthesis over CuO/ZnO/Al₂O₃ catalysts. The experimental investigations were conducted in a 1-L slurry reactor based on the novel liquid phase methanol synthesis process. The liquid medium used was a blend of paraffinic and naphthenic mineral oils with a mean molecular mass of 250. It was found that the methanol rates attained a maximum at an optimal water content which was dependent on the reaction temperature. The catalytic activity was found to decline with time at lower temperatures in the presence of a relatively large excess of water. The influence of water was also found to be firmly linked to the corresponding carbon dioxide content in the reactor feed. The experimental data bear additional significance because this was the first such study to be performed on the liquid phase process. Emphasis was therefore placed on the use of a CO-rich syngas in order to simulate anticipated process conditions.     

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.     

IN-SITU REDUCTION OF A METHANOL SYNTHESIS CATALYST IN A THREE-PHASE SLURRY REACTOR

A new method for the reduction of metal oxide catalysts has been developed, for the reduction of the CuO - ZnO - A1203 catalyst for liquid phase methanol synthesis. The reducing agent is a 5% hydrogen in nitrogen mixture and the operation is carried out at 446.09 KPa. This method makes it possible to reduce finely crushed catalyst (-100 + 120 mesh) in a three phase slurry reactor. This method offers several advantages over methods in which the catalyst is reduced in a gas-solid contact mode and then slurried for use. The catalyst has been shown to be very effectively reduced and reaches its full production capacity after reduction.     

MASS TRANSFER CCMPARISON BEIWEEN MECHANICALLY AGITATED SLURRY REACTCR AND LIQUID ENTRAINED REACTOR IN THE METHANOL SYNTHESIS PROCESS

ABSTRACT

The commercial reactor proposed for the liquid phase methanol synthesis process (LPMeCHTM) is a liquid entrained reactor (LER), since it possesses several operational advantages over a mechanically agitated slurry reactor (MASR). This paper discusses in detail the develocment of a correlation for the prediction of the overall gas-liquid mass transfer coefficient (KLiaB) in a LER. The overall mass transfer coefficient experimentally determined for the LER, is compared with the corresponding value obtained for the MASR under nominally identical operating conditions. It was observed that the overall gas-liquid mass transfer coefficient and hence the overall rate of methanol production per unit mass of catalyst, is significantly higher in the LER compared to the MASR at identical operating conditions. In the LER mode, the limitation posed on the system by chemical equilibrium, is alleviated by selective renewal of products thus making the process ideal for the once-through methanol (CIM) This justifies the proposed commercial mode of synthesis of methanol in the liquid entrained reactor.     

A SINGLE-STAGE,LIQUID-PHASE DIMETHYL ETHER SYNTHESIS PROCESS FROM SYNGAS I. DUAL CATALYTIC ACTIVITY AND PROCESS FEASIBILITY

ABSTRACT

A novel process for manufacturing dimethyl ether (DME) from CO-rich syngas in a single stage has been developed. This novel approach was based on the application of dual catalysis in the liquid phase process, in which two functionally different catalysts are slurried in the inert mineral oil. The experimental reaction rate studies for methanol and dimethyl ether synthesis were conducted in a three-phase, mechanically agitated slurry reactor. The effects of catalyst ratio, temperature, and pressure on the dual catalytic activity were studied. The experimental data bear additional significance because this is the first study of such kind to be conducted on the liquid phase methanol synthesis process.