HYDROGEN SULFIDE POISONING OF METHANOL SYNTHESIS Cu-BASED CATALYST (II') POISONING OF COMMERCIAL CATALYST

In the absence of H₂S and with the addition of inlet H₂S content 719 ppm for 4 hours, 8 hours and 12 hours respectively, the global reaction rates of methanol decomposition were determined over φ 5×5 mm cylindrical pellet of C207 Cu -based catalyst at atmospheric pressure in an internal recycle gradientless reactor. The pore size distribution, the profile of sulfur in pellet, and the tortuosity factor of the poisoned catalyst were also measured. The hydrogen sulfide poisoning of commercial catalyst was considered as the shell-progressive poisoning. The experimental values of the non-poisoned dimensionless radius x_c by Auger Electron Spectroscopy were 0·938, 0·916 and 0·896 respectively with the addition of H₂S for 4 hours, 8 hours and 12 hours, which were in agreement with the values calculated by the intrinsic deactivation kinetics.     

HYDROGEN SULFIDE POISONING OF METHANOL SYNTHESIS Cu-BASED CATALYST (III) EFFECTIVENESS FACTOR OF POISONED CATALYST

The single component model and the multicomponent model of the effectiveness factor ζ_d, of the poisoned catalyst have been proposed and solved by the orthogonal collocation method. The center equilibrium dead zone was founded in catalyst pellets. The calculated values ζ_d, were respectively 0·1229-0·2907,0·1298-0·2445 and 0·0690-0·2155 for No. 1, No. 2 and No. 3 catalyst. The average of the absolute values of the relative deviations between the experimental values and the calculated values by model for ζ_d was less than 11 per cent. The models can be used to calculate the effectiveness factor of the poisoned catalyst.     

ROLE OF IN-SITU PRODUCED METHANOL ON THE CATALYST DEACTIVATION IN THE LIQUID PHASE METHANOL SYNTHESIS PROCESS

The role of methanol produced in-situ in the liquid phase methanol synthesis process has been experimentally examined. The catalyst crystallite size is found to be more stable when the produced water and methanol are consistently removed from the catalyst active sites. The experimental evidence shows that in-situ produced water is not the only culprit for the catalyst crystallite size growth, rather, methanol is also responsible for contributing to crystallite growth and therefore catalyst deactivation

Hydrothermal leaching of the catalyst was also determined to be an active participant in catalyst deactivation. Two experimental designs were run to assess the influence of temperature, leaching solution concentration and pretreatment conditions on the extent of leaching of the methanol synthesis catalyst. Water and methanol were found to be active participants in the reduction of catalyst activity. Hence, the methanol/water solutions serve as potentially harmful agents in the leaching of aluminum and copper from the synthesis catalyst     

ROLE OF IN-SITU PRODUCED METHANOL ON THE CATALYST DEACTIVATION IN THE LIQUID PHASE METHANOL SYNTHESIS PROCESS

ABSTRACT

The role of methanol produced in-situ in the liquid phase methanol synthesis process has been experimentally examined. The catalyst crystallite size is found to be more stable when the produced water and methanol are consistently removed from the catalyst active sites. The experimental evidence shows that in-situ produced water is not the only culprit for the catalyst crystallite size growth, rather, methanol is also responsible for contributing to crystallite growth and therefore catalyst deactivation

Hydrothermal leaching of the catalyst was also determined to be an active participant in catalyst deactivation. Two experimental designs were run to assess the influence of temperature, leaching solution concentration and pretreatment conditions on the extent of leaching of the methanol synthesis catalyst. Water and methanol were found to be active participants in the reduction of catalyst activity. Hence, the methanol/water solutions serve as potentially harmful agents in the leaching of aluminum and copper from the synthesis catalyst     

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.     

KINETICS OF METHANOL SYNTHESIS IN THE SLURRY PHASE

The kinetics of methanol synthesis, from synthesis gas, over a commercial Cu-Zn-Al catalyst, in a three phase slurry reactor was studied in a 1 liter, top agitated, baffled autoclave. From the rate data on methanol formation, a Langmuir-Hinshelwood type rate expression has been developed which is sufficient for desing calculations,process improvement, and optimization of operating conditions. The kinetic model developed is free from pore diffusional resistances and is not masked by any mass transfer effects. The results of this kinetic model are in good agreement with the experimental results.     

KINETICS OF METHANOL SYNTHESIS IN THE SLURRY PHASE

ABSTRACT

The kinetics of methanol synthesis, from synthesis gas, over a commercial Cu-Zn-Al catalyst, in a three phase slurry reactor was studied in a 1 liter, top agitated, baffled autoclave. From the rate data on methanol formation, a Langmuir-Hinshelwood type rate expression has been developed which is sufficient for desing calculations,process improvement, and optimization of operating conditions. The kinetic model developed is free from pore diffusional resistances and is not masked by any mass transfer effects. The results of this kinetic model are in good agreement with the experimental results.     

硫化氢对FX—02催化剂烷基化性能的影响

研究了H2S对FX－02催化剂上苯与稀乙稀烷基化反应的影响。认为是H2S占据了催化剂的活性位,妨碍了反应物的吸物和反应。结果表明,在FX－02催化剂上利用干气制乙苯时,应对干气进行脱硫预处理。     

Pt/MOR催化异丙苯临氢脱烷基的失活动力学研究

在固定床积分反应器中实验研究了Pt/MOR催化剂催化重芳烃临氢脱烷基的失活动力学。实验以异丙苯为反应原料,在反应压力0.8 MPa、温度范围673.15~733.15K、体积空速1~2h-1的条件下,得到了失活动力学数据。基于实验现象建立了Pt/MOR催化剂幂函数表观失活动力学模型,即由反应产物引起的连串失活。通过拟合实验数据估计了失活动力学模型的参数。结果表明:外扩散对脱烷基反应的影响可以忽略不计,内扩散对脱烷基反应的影响较小;异丙苯临氢脱烷基的反应活化能和催化剂失活的活化能分别为44.15kJ/mol和79.00kJ/mol。Pt/MOR催化剂失活动力学模型的秩和与残差分布检验结果表明,该失活动力学模型在显著性水平α=0.05下是显著的,即所得失活动力学模型有较高的拟合精确度和可信度。     

甲醇制二甲醚用工业催化剂的失活原因

采用低温氮吸附、热重-差示扫描量热、X射线衍射、红外、扫描电子显微镜等手段,研究了工业上使用的氧化铝系二甲醚催化剂的失活原因。结果表明:在工业使用条件下,二甲醚催化剂床层积炭2.43%~4.46%;部分γ-氧化铝发生再水合反应,生成薄水铝石,晶粒度变大,表面积下降,这些原因共同导致了催化剂活性下降。     

新型耐热联醇催化剂的研制

从改善催化剂结构入手 ,采用快速高温共沉淀工艺 ,添加适量第四组分 Ba,制得 JC 1型联醇催化剂 ,其催化活性、热稳定性、使用寿命等性能超过国内现普遍采用的联醇催化剂 C2 0 7型同类样品的水平     

LS-941硫化氢选择性氧化超级克劳斯催化剂的研究

介绍了用于超级克劳斯工艺的LS-941 H2S选择性氧化催化剂的实验室研制及活性评价结果。该催化剂以惰性氧化铝为载体，以Fe／Cr为活性组分并添加专有助剂制备而成。在反应温度270℃、常压、空速为2500h^-1，φ(H2s)=1．0％，φ(O2)-0．6％及φ(H2O)-20％的反应条件下，连续反应1000h后，LS-941催化剂脱除H2S的平均转化率和选择性一直保持在90％以上，表明具有较高的活性和稳定性，已达到设计要求，可替代同类进口催化剂使用。     

低压合成甲醇催化剂还原的研究

对低压合成甲醇催化剂进行了低、高浓度氢还原的研究。对影响催化剂的还原温度、压力、空间速度也进行了探索。为工厂的实际还原操作,提供了参考。     

POST-REDUCTION TREATMENT OF LIQUID PHASE METHANOL SYNTHESIS CATALYST USING CARBON DIOXIDE

ABSTRACT

This work focuses on the investigation of the catalyst post-treatment in the liquid phase methanol synthesis process. The novel post-treatment process, using carbon dioxide, has been developed and experimentally proven to be effective not only in maintaining the initial catalytic activity over a long period of usage but also in improving the mechanical and chemical strength of the catalyst. It was also found that the role of ZnO in the catalytic reaction, if any, can be nicely replaced by ZnCO₃.     

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

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.     

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.     

THE COMPARISON OF NUMERICAL SOLUTION OF THREE KINDS OF MODELS OF THE INTRAPARTICLE EFFECTIVENESS FACTORS FOR MULTIPLE REACTIONS SYSTEM OF METHANOL SYNTHESIS IN THE PRECSENCE OF Cu-BASED CATALYST

Abstract

In this paper for methanol synthesis from the hydro-genation of CO and CO2 over surface poisoned or unpoi-soned Cu-based catalyst, three kinds of diffusion models for calculating the intraparticle effectiveness factors of the multiple reactions have been presented. They are one dimensional multi-components diffusion model, one demensional simplified multi-components diffusion model and one dimensional key-components diffusion model. Numerical solution of the intraparticle effectiveness factors solved by orthogonal collocation method have been obtained. Key-components diffusion model was available for calculating effectiveness factors only for the reactions over slightly poisoned catalyst. As poisoned fraction increases the deviation of effectiveness factors calculated from key-components diffusion model and multi-     

氟化氢/USY分子筛催化合成对叔丁基苯酚

以USY负载HF为催化剂,以甲基叔丁基醚(MTBE)、苯酚为原料,在微型反应器上催化合成了对叔丁基苯酚。考察了HF负载量、反应温度、空速及原料配比对烷基化反应的影响及催化剂的稳定性。结果表明,HF改性后USY的L酸中心增加,B酸中心减少,苯酚转化率增大。L酸中心是烷基化反应的主要活性中心。在反应温度160℃、HF负载量1%、反应空速1.7h~(-1)、n(MTBE):n(苯酚)=1.5:1条件下,苯酚的转化率为91%,对叔丁基苯酚的选择性为79.05%。催化剂使用120h后,仍保持较好的催化活性。     

POST-REDUCTION TREATMENT OF LIQUID PHASE METHANOL SYNTHESIS CATALYST USING CARBON DIOXIDE

This work focuses on the investigation of the catalyst post-treatment in the liquid phase methanol synthesis process. The novel post-treatment process, using carbon dioxide, has been developed and experimentally proven to be effective not only in maintaining the initial catalytic activity over a long period of usage but also in improving the mechanical and chemical strength of the catalyst. It was also found that the role of ZnO in the catalytic reaction, if any, can be nicely replaced by ZnCO₃.