Yu Yunliang

Hydrodynamic Behavior in a Rotating Zigzag Bed

Abstract As a high gravity (HIGEE) unit, the rotating packed bed (RPB) uses centrifugal force to intensify mass transfer. Zigzag rotating bed (RZB) is a new type of HIGEE unit. The rotor of RZB consists of stationary discs and rotating discs, forming zigzag channels for liquid-gas flow and mass transfer. As in RPBs, some hydrodynamic behavior in RZB is interesting but no satisfactory explanation. In this study, the experiments were carried on in a RZB unit with a rotor of 600 mm in diameter using air-water system. The gas pressure drop and power consumption were measured with two types of rotating baffle for RZB rotors, one with perforations and another with shutter openings. The circumferential velocities of gas were measured with a five-hole Pitot probe. The pressure drop decreased rapidly when the liquid was introduced to the rotor, because the circumferential velocity of the liquid droplets was lower than that of the gas, reducing the circumferential velocity of gas and the centrifugal pressure drop. The power consumption decreased first when the gas entered the RZB rotor, because the gas with higher circumferential velocity facilitates the rotation of baffles.

A preliminary study on hydrogen-rich gas production by pyrolysis of glycerol in molten alkali

Experiment study on the pyrolysis of glycerol for hydrogen-rich gas production in molten alkali has been carried out in a self-designed reactor. The impact of molten alkali on the distribution of gas production was discussed. Operation parameters like pyrolysis temperature, carrier gas flow rate and feed rate, as well as catalyst types, were investigated for their influences on the hydrogen production yield. The results show that components like CO and CO2 in pyrolysis gas were absorbed by molten alkali, so there are only H2 and a small amount of CH4 in product gas. Higher carrier gas flow rate and lower feed rate are favorable to improve the hydrogen production yield, and the hydrogen production yield could reach 0.966 Nm3 H2/kg of glycerol when pyrolysis temperature was 400_, carrier gas flow rate was 200 L/h, feed rate was 3.38 g/min. The catalysts of MCM-41 zeolite and NiCl2 are helpful for improving the hydrogen production yield.