No abstract

in Wiley InterScience (www.interscience.wiley.com).The application of four-point optical probe has been for the first time extended to a slurry system in a 10.2-cm ID column. Bubble dynamics (local gas holdup, bubble chord length, bubble velocity, bubble frequency, and specific interfacial area) were investigated using an air-water-catalyst system under atmospheric pressure. With an increase in solids loading, the local gas holdup, specific interfacial area, and bubble frequency decreased, while the bubble velocity changed slightly. Bubble chord length increased noticeably, and the bubble chord length distribution spread more widely at high solids loading. It has also been found that the probe orientation is important for an investigation using probes, especially in the wall region of the column.

No abstract

To provide more support for FischerÀTropsch (FT) slurry bubble column reactor design, scale-up, and performance, the effects of operating conditions on the heat transfer coefficients were investigated in a mimicked FT cold flow system (compressed air:C 9 ÀC 11 :FT catalyst carrier). The studied operating conditions varied in superficial gas velocity (up to 0.3 m/s), pressure (up to 10 bar), and solids concentration (up to 25 vol %). The effects of these variables on heat transfer coefficients are discussed and analyzed. The increase in pressure tended to reduce the heat transfer coefficient, while the increase in solids loading enhanced the heat transfer coefficient, especially at high solids loading (25 vol %).