闪蒸分离的低温液相甲醇合成的研究
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摘要: 为了强化传质和反应操作,同时实现反应产物与浆液的分离,使用CuCr/CH3ONa催化体系,在鼓泡浆液反应器(BCSR)、闪蒸塔(FC)和浆液循环泵组成的反应系统(BCSRFC)中考察了低温甲醇合成的反应性能。初始浆液由铜铬催化剂、甲醇钠溶液、乳化剂OP10和液相介质二甲苯组成。在BCSR:4.2MPa~4.6MPa,110℃~120℃(反应段)100℃~110℃(扩大段),入口气速0.35cm/s~0.40cm/s;FC:0.25MPa~0.40MPa,80℃~90℃,浆液循环量50L/h下, 100h实验期间,合成气转化率、CO转化率和H2转化率分别从最高的71.0%、79.1%和67.5%降到17.8%、35.0%和12.1%。催化体系失活的主要原因是CH3ONa 和MeF反应生成甲酸钠。液体产物由DME 1.23%、甲醇79.52%、MeF 19.25%组成。甲醇+MeF的选择性大于98%。以系统中催化剂为基准,液体产物的产率则为0.166g/gcat·h; BCSR中CuCr催化剂的液体产物的产率为0.336g/gcat·h。Abstract: In order to promote mass transfer and realize products separation from slurry, reaction performance of CuCr/CH3ONa catalyst used for the lowtemperature methanol synthesis was firstly examined in the bubble column slurry reactor with a flash column(BCSR/FC). The reaction system includes the reaction section of 39mm id. and 4800mm height and the enlarged section of 147mm id and 1200mm height in BCSR,FC of 147mm id. and 1640mm height and a slurry recirculating pump. The initial slurry was composed of the required amounts of sodium methoxide solution and CuCr catalyst and emulsifier OP10 as well as the balanced liquid xylene medium. The results showed that the BCSR/FC can be operated at 4.2MPa~4.6MPa,110℃~120℃ (reaction section)and 100℃~110℃(enlarged section),inlet gas velocity 0.35cm/s~0.40cm/s for BCSR, 0.25MPa~0.4MPa, 80℃~90℃ for FC and slurry recirculation rate of 50L/h. The results showed that the conversions of CO+H2, CO and H2 were decreased from their highest of 71.0%,79.1% and 67.5% to 17.8%, 35% and 12.1% during operation test over 100h respectively. The stability of the catalyst system is poor although its initial activity is quite high.This is probably due to the consumption of CH3ONa caused by the side reaction CH3ONa + HCOOCH3→CH3OCH3 + HCOONa. Liquid products were composed of DME of 1.23%, methanol of 79.52% and MeF of 19.25%. Selectivity of Methanol + MeF is more than 98%.Its yields were 0.168g/g cat·h based on all CuCr catalyst in the system and 0.336 g/gcat·h only based on the CuCr catalyst in BCSR.
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Key words:
- methanol synthesis /
- bubble column slurry reactor /
- methyl formate /
- flashseparation
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