Will this be an effective method for measuring blend time

[mechprocess]

I want to measure the blend time of a solution containing 5 wt% total solids. About half of the solids are suspended. I defined the blend time as the time it takes to resuspend and totally blend the suspended solids from an initial sludge level. The solution is opaque and dark and the solids concentration is about 80 g/liter so optical sensors are out. I would like to install an acoustical sensor inside the mix tank and record the Total Suspended Solids concentration at the location of the sensor. The blend time will be the time the reading is consistently reading 5 wt% +/- something. The solution is caustic and the temperature should not change nor will the PH during my test.

I can validate this approach by moving the sensor vertically and horizontally after the reading first indicates a steady 5 wt % reading. I should end up with a chart of wt% vs circulation time. If the readings are showing the same results within a statistical range, I can proceed with my blend time tests and not have to move the sensor around anymore. I think this will work since no solids are leaving the tank during the test and the PH isn’t going to change that I know of. I just need something to back up my plan and I can’t find anything. The main reason I want to do it this way is that I have a lot of tests to run and I don’t want to take samples or install some sort of thieving sampling system.

 

[orenda1168]

Since a significant percentage of the contained solids sediment without mixing, how can you ensure a heterogeneous mix without constant mixing....even this will probably not produce a truly heterogeneous mix.....and without use of some suspension aid.

Orenda

 

[mechprocess]

I will be mixing constantly. I have to make a correction. The total SSC is 5 wt% of the mixture. I should not have mentioned the absorbed solids. They will stay in solution. I am only concerned about the suspended solids concentration (SSC). I want to measure the time it takes to get a heterogeneous mix of the SSC. The start of each test will begin with the same initial SS sludge level. The acoustical sensor will be located about 4 inches beneath the supernate level.

Some facts:

Settling time = 19 hours
Viscosity = 10 cp
Density = 10.75 lb/gal

I am trying to validate an agitation scale-up methodology for a unique agitator technology. My dependent scale-up parameter is proportional to the blend time.

P.S. In case your wondering, there is no Computational Fluid Mixing code for this which is why I am testing.

I'm hoping that the acoustical sensor will do the trick.

 

[m777182]

Once I read a paper describing same problem, but a contactless conductivity cell was employed instead of an acoustic sensor. They were using the same principle as the Coulter counter works on.It was claimed that it worked.
m777182

 

[mechprocess]

I'm going to use a Markland 502 suspended solids meter. I'm done thinking about this.