mechprocess
Mechanical
- Jun 23, 2004
- 39
These questions are related to the minimum process liquid contact temperatures during tank cooling.
I am worried that the low tank wall temperature effected by the external cooling jacket may cause aluminum oxide precipitation from the 5.6 M caustic solution inside the tank.
I am designing a tank with an external half-pipe cooling jacket. (Some of you might be wondering why I’m still working on this). Anyhow, I’m almost done.
Tank is cooled by external half-pipe jackets with 45 degree inlet chill water temperatures. The film coefficients inside the jackets are calculated to be 360 btu/hr-ft2-°F, with chill water flow velocities around 3.3 fps. The tank is agitated and the film coefficient inside the tank at the tank wall is 40 btu/hr-ft2-°F.
Based on my research, the tank wall temperature will favor the chill water temperature since the film coefficient inside the jacket is much higher than the same in the tank.
Q1. Since my half-pipe coils are spaced one diameter apart, will the tank metal in-between the half pipe coils act as an extended surface, thereby increasing the average contact temperature at the tank wall?
Q2. Does anyone have any recommendations for cooling 5.6 M Sodium Hydroxide with dissolved aluminum? Precipitation occurs at 60F. By the way the wall temp for this scenario is 53F give or take.
I am worried that the low tank wall temperature effected by the external cooling jacket may cause aluminum oxide precipitation from the 5.6 M caustic solution inside the tank.
I am designing a tank with an external half-pipe cooling jacket. (Some of you might be wondering why I’m still working on this). Anyhow, I’m almost done.
Tank is cooled by external half-pipe jackets with 45 degree inlet chill water temperatures. The film coefficients inside the jackets are calculated to be 360 btu/hr-ft2-°F, with chill water flow velocities around 3.3 fps. The tank is agitated and the film coefficient inside the tank at the tank wall is 40 btu/hr-ft2-°F.
Based on my research, the tank wall temperature will favor the chill water temperature since the film coefficient inside the jacket is much higher than the same in the tank.
Q1. Since my half-pipe coils are spaced one diameter apart, will the tank metal in-between the half pipe coils act as an extended surface, thereby increasing the average contact temperature at the tank wall?
Q2. Does anyone have any recommendations for cooling 5.6 M Sodium Hydroxide with dissolved aluminum? Precipitation occurs at 60F. By the way the wall temp for this scenario is 53F give or take.
