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The effects of modes of hydrogen input and reactor configuration on reaction rate and H 2 efficiency in the catalytic hydrogenation of alkynol to alkenol
Author(s) -
NavarroFuentes Francisca,
Keane Mark,
Ni XiongWei
Publication year - 2020
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23615
Subject(s) - hydrogen , residence time (fluid dynamics) , catalysis , work (physics) , reaction rate , materials science , plug flow reactor model , volumetric flow rate , continuous stirred tank reactor , chemistry , nuclear engineering , continuous flow , chemical engineering , thermodynamics , mechanics , physics , engineering , organic chemistry , geotechnical engineering
Hydrogenation often involves three phases where hydrogen‐on‐demand is the typical mode of operation in industrial scale reactors. In research labs and publications, however, continuous hydrogen flow has been used. This paper investigates the effect of such modes of operation on reaction rate using a selective hydrogenation of 3‐butyn‐2‐ol over Pd/Al 2 O 3 to obtain 3‐buten‐2‐ol as the model reaction. The two modes of operation were first tested in a commercial PARR stirred tank reactor and then repeated in an oscillatory baffled reactor (OBR) in order to validate the experimental results. Our investigation demonstrates that an enhanced reaction performance and 10 times better H 2 efficiency were obtained when the pressure was maintained constant during the reaction by feeding gas as required, ie hydrogen‐on‐demand mode. The method of a continuous flow of hydrogen in hydrogenation means that excess hydrogen is vented out when operating at ambient pressures or builds up at elevated pressures. Our work also enables a comparison of reactor designs on reactor performance, and three times higher H 2 efficiency and 2.3 times shorter residence time were achieved when using the OBR instead of the PARR due to its enhanced and uniform mixing, regardless of the mode of operation.