アルカリ及びアルカリ土類金属化合物を触媒とする炭化水素類及び炭素質物質の接触ガス化に関する研究

制度:新 ; 文部省報告番号:甲781号 ; 学位の種類:工学博士 ; 授与年月日:1989-02-28 ; 早大学位記番号:新1493 ; 理工学図書館請求番号:1273早稲田大

Esterification of Acetic Acid by Flow-Type Membrane Reactor with AEI Zeolite Membrane

AEI-type zeolite membrane for dehydration was prepared, and a flow-type membrane reactor for the esterification of acetic acid and ethanol by AEI membrane was developed. A synthesized AEI membrane had suitable molecular sieving property for gas separation (H2/i-butane and CO2/CH4) and pervaporation (H2O/acetic acid). AEI membrane showed H2O permeance of 6.2 × 10−7 mol m−2 s−1 Pa−1 with a separation factor of 67 at 363 K for the equimolar mixture of H2O/acetic acid. AEI membrane maintained stable performance under acidic conditions. The yield of ethyl acetate at 363 K in a flow-type membrane reactor with AEI membrane successfully exceeded the equilibrium of 69.1%, reaching 89.0%. The flow rate of feed solution strongly affected the conversion of acetic acid and the space–time yield (STY) of ethyl acetate. Due to the more significant proportion of water selectively removed from the reaction system at a lower feed flow rate, the thermodynamic equilibrium shifted significantly, resulting in higher conversions. In contrast, STY increased with increasing feed flow rate. Our flow-type membrane reactor exhibited a relatively large STY of 430 kg m−3 h−1 compared with the batch-type membrane reactor previously reported

An Experimental Study of a Zeolite Membrane Reactor for Reverse Water Gas Shift

Reverse water gas shift (RWGS) is attracting attention as one of the promising technologies for CO2 conversion. Selective removal of H2O from the reaction system can improve the CO2 conversion beyond the equilibrium conversion of RWGS in a conventional reactor. In this study, a conventional plug-flow reactor without membrane, and two types of RWGS membrane reactors using ZSM-5 membranes, were developed. The yield of CO without membrane (Case 1) was almost the same as the equilibrium conversion. A membrane reactor (Case 2) showed a CO yield 2–3% above that of a conventional reactor. From the results, the effectiveness of the dehydration membrane reactor for RWGS was verified. In addition, CO yield was further increased in the reactor made up of the combination of conventional reactor and membrane reactor (Case 3). For example, the CO yields in Cases 1, 2, and 3 at 560 K were 21.8, 24.9, and 29.0%, respectively. Although the CO yield increased in Case 2, a large amount of raw materials penetrated through the membrane to the permeation side, and was lost. In Case 3, H2 and CO2 permeation through the membrane were suppressed because of the existence of H2O, resulting in the prevention of the leakage of raw material, and contributing to the high CO yield

Contribution of Pore-Connectivity to Permeation Performance of Silicalite-1 Membrane; Part II, Diffusivity of C₆ Hydrocarbon in Micropore

This study investigated the permeation behaviors of n-hexane and 2-methylpentane through two-types of silicalite-1 membranes that have different pore-connectivity. The permeation mechanisms of these hydrocarbons were able to be explained by the adsorption–diffusion model. In addition, the fluxes through silicalite-1 membranes could be expressed by the modified Fick’s first law. The hydrocarbon fluxes through S-1S with better pore-connectivity were ca. 3–20 times larger than those through S-1M with poor pore-connectivity. For these membranes with different pore-connectivity, the activation energy of diffusion of n-hexane was 17.5 kJ mol−1 for the membrane with better pore-connectivity and 18.0 kJ mol−1 for the membrane with poorer pore-connectivity, whereas for 2-methylpentane it was 17.9 and 33.0 kJ mol−1, respectively. We concluded that the pore-connectivity in silicalite-1 membrane significantly influences the molecular diffusivities