To Provide More Support for Fischer-Tropsch (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-C 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 %). © 2011 American Chemical Society.