Power consumption and pumping characteristics in a loop reactor

Abstract

Measurements of power consumption in a loop reactor of 10 cm i.d. with pitched paddle impellers were carried out in the range of mixing Reynolds number Re,,, = lo2 to 2 X io5 using water and corn syrup solution (p = 1-60 mPa*s) as working fluid. The effect of pitched angle of the impeller blade, I #J , upon power consumption is expressed by the equation N P a (sin $)2 at Re,,, > 200 where flow is turbulent. There exists no influence of baffle condition and no difference between batch and continuous operations. The circulation velocity was controlled by changing the opening size of throttle rings and length of tubing loop as well as changing the impeller speed. The results were rearranged into the pumping characteristic curves based on the idea that the impeller region and the tubing loop behave independently. The characteristics of the impellers tested are similar to that of the axial-flow pump. By use of the resultant characteristic curves, an approach to estimated power consumption is proposed.

Numerical Investigation of Mixing Time in a Torus Reactor

“…These results show that, the power consumption increases with the increase of the impeller speed and the impeller diameter to reactor diameter ratio, and is proportional to N 3 (d/D) 4.5 . As reported before, Murakami et al [9] have found that the dependence of the power number on the mixing Reynolds number was similar to that obtained in the conventional stirred tank reactor [26], and the power number was proportional to (sin φ) 2 . Similar observations were achieved by Tanaka et al [10], while the exponent of (sin φ) was 1.5.…”

“…This model indicates that the resulting flow is mainly a function of the impeller speed and the sine of the impeller blade angle. Murakami et al [9] predicted the effect of the reactor geometry, baffles, impeller type, blade angle, impeller diameter, impeller speed and operating mode on the power consumption. They found that the power number is proportional to (sin φ) 2 in the region of high mixing Reynolds number (Re > 10 4 ); where φ is the impeller blade angle and almost independent of the baffles and operation mode.…”

Étude expérimentale du mélange réactif au sein d'un réacteur torique ondulé (RTO)

“…Ils induisent de faibles taux de cisaillement ainsi que de faibles pertes de charge (Khalid, 1992). De plus, leur puissance consommée est relativement faible (Murakami et al, 1982). Des travaux récents ont montré l'intérêt des réacteurs toriques pour des transformations biochimiques ainsi que dans le cas de réactions mettant en jeu des fluides visqueux telles que la polymérisation en suspension (Tanaka et O'Shima, 1988et Tanaka et al, 1989.…”

Casein hydrolysis by immobilized enzymes in a torus reactor

“…A torus reactor, which can be considered as a loop reactor, presents some advantages over other stirred tank reactors including efficient mixing of reactants [1,2], easy scale-up and design ensured by the absence of dead volume, low power consumption [3], high heat transfer capacity [4], prevention of deposition of polymer or biomaterial on the reactor wall [4,5] and efficiency [3,6,7].…”