Finding the Freeze Point of Limestone Slurry 1

[mechtimeng]

I have recently created a excel spreadsheet that models
how long it takes bare carbon steel pipes to freeze under
constant environmental and stagnant flow conditions. I chose water as my analysis fluid, and then created the calculations. The calculations will be used to determine
which plant lines will be electrically heat traced, and
insulated.

Now my superiors, would like to see what the freeze times
will be if the working fluid was changed from water to a limestone slurry. The limestone slurry will be 30% by volume. The second part of my analysis will deal with an effluent slurry made of gypsum.

My Question to the forum, is there a method or perhaps a reference, to find the freeze point of a limestone slurry and of a gypsum slurry.

Any help would greatly be appreciated.

Thanks,

Tim

 

[hacksaw]

The freezing point will depend on the solubility of your limestone(low), but how long it takes for a mass of fluid to freeze will depend on the the heat capacity of the mixture. The heat capacity of the mixture.

 

[pardal]

Freezing point is for a given fluid a fixed point .
That is because the heat is used only to change the fluid state, so no temp is increased or decreased , depending if frezing or melting.

When I need to check the frezing -melting point I do it as follow:

In a Freezer I freez a sample far below the frezz point
If possible in small dice , if not, on a plastic bottle and I broke it in small parts when freezed.
Then I make fluid sample on the "ROCKS" with the sample dice.The least liquid to contain the dices
Guess the dice are at -15°Centigrade , a easy temp to reach on a house freezer.
The liquid sample at a few degree above the 0°centigrade , so sure it is liquid.

In a deep can I mix both the fluid and the dice and stir it.

With a thermometer you will notice a low temp that will increase to a point where it will be constant up all the dice are melt.

I use a datalogeer inside a hermetic vessel or just wraped with film streech enouhg to make it water proof

The temperature tha is keep constant is teh freez point of such fuid.

Other consideration is the SLUDGE temp point , it shall be take by experience.










Pardal

 

[cawse001]

Hacksaw is spot on in that the only thing that changes the freeze point is the molality of dissolved solids/salts. Assume that you wouldn't slurry limestone with high quality water and hence you will have a difference from pure water.

You could look up the heat capacity for CaCO3 from Perry 6th Ed Table 3-181 or use a value of 1 kJ/kg.K, which approximates most solids.

Cheers

 

[25362]

Slurries may sometimes agglomerate and gel irreversibly when exposed to freezing temperatures for a short time.
It seems that a lab-bench checking of the behaviour of the slurries under consideration would be a logical option.