Читать книгу Agitator Design for Gas-Liquid Fermenters and Bioreactors - Gregory T. Benz - Страница 16

All conditions impacting the agitator design, the mass transfer rate, and ancillary functions such as heat transfer must be delineated. A partial list follows:

 Fluid density (e.g. specific gravity or density such as kg/m3)

 Fluid viscosity (e.g. cP or Pa‐s). If the fluid is non‐Newtonian, the model and parameters describing it must be included

 Operating temperature

 Mean barometric pressure

 Back pressure in vapor space

 Heat capacity of the process fluid at constant pressure, CP. Sample units J/g‐C or BTU/lb‐F

 Thermal conductivity of the process fluid, k. Sample units J/h‐m‐C or BTU/h‐ft‐F.

 For the ancillary heat transfer calculations, need the above thermal properties for the heat transfer medium as well

 For the heat transfer calculations, need the available flow and temperature of the heat transfer medium

 Concentration of oxygen (or other species to be transferred) in the feed gas (usually, we will assume air at 21% oxygen)

 Henry’s law constant, or alternatively, saturation concentration at feed gas concentration at process temperature at a reference pressure (typically 1 atm)

 Minimum required dissolved oxygen concentration for organisms to thrive

 Maximum allowable CO2 concentration in the exit gas, either as mole fraction or as actual partial pressure

 Any other process constraints affecting design