Solvent Removal
Indirectly heated rotary kilns are used to continuously remove and recover liquids/solvents from solids. They are especially applicable in cases like yours where the fine particle size makes it more difficult to use direct content due to particle entrainment. In addition the liquid volatilized is undiluted by the heating gas and therefore easier to recover.
Steam can be used as a sweep gas through the kiln and lifting flights are used to shower the material through the gas stream to enhance steam stripping.
The furnace surrounding the indirect kiln can be heated with natural gas, light oil or electricity. In your case electrical heating may be the energy of choice since it allows for more precise control of the temperature particularly at the lower temperature that you require. ■
Desolventising Wet Cake
Hi,
We have an application wherein we have to desolventise and recover n-hexane from de-oiled spent bleaching earth.
The cake is discharged from a Rotary Vacc Drum filter and there is approximately 20% hexane in the cake.
The flow rate is 2 Tons/hour and the process needs to be continuous.
We have an existing desolventiser which is vertical schumacher type which desolventises at 110 degC but have trouble in maintaining levels in the chambers since the indicator float sinks into the powder. We also give open steam to assist the hexane stripping process. A condensor above the desolventiser maintains a slight vacc of -15 mm water col inside.
The wet cake rapidly crumbles into fine powder when hexane is removed.
The particle size in the cake is 5-30 microns
Please suggest the best method of desolventising and the equipment required.
Thanks in advance. ■