Walnut Shell oil filter
The effective oil filtration in petrochemicals effluents "AK-NUT"
The “AK-NUT” filtration is a coalescent process effective in removing oil/water, water/oil emulsions, free hydrocarbons and suspended solids from petrochemical water effluent. The medium that is used as coalescence is walnut-shell based and shows an excellent oil coalescing and high retention values, thereby, allowing long running times and reduced volumes of backwash water.
The “AK-NUT” is a highly effective process and can replace conventional sand filtration. The function of “AK-NUT” filtration is similar to sand filtration however; it has several advantages over the latter:
- The backwash is tap water
- Does not require air consumption
- Quicker back-wash cycle (12 min)
- Extended operating life
- Lower maintenance
- More effective medium cleaning
Operation details
Initially a reactor tank is filled with walnut – shells. The tank is equipped with differential pressure switches in the inlet and in the outlet in order to monitor the pressure difference, which is indicative of fouling. When a pressure difference between the inlet and the outlet occurs the backwash cycle is activated, an alarm is automatically set and a valve in the bottom of the tank opens. The content of the reactor tank, namely walnut-shells and oil/water, is transferred into a vat which is equipped with an agitator. Under the action of agitation the attached oil droplets are weaned from the walnut – shells, and then the mixture, with the help of a pump, is transferred to another conical bottom tank located by the reactor tank where the back wash is performed. The mixture is left for an adjusted period of time in calm and under the force of gravity the mixture separates. A pump sucks and transfers the walnut-shells back into the reactor tank while the oil is transferred to another tank for further treatment. To replace the annual walnut – shell consumption, a feeding system is provided which includes, a tank, an agitator, water valves and the feeding pump. The injection of the replacement medium is performed without process stoppage.
Available Walnut Shell medium natural grades
- Coarse Grades: 4/12, 6/10, and 8/12 mainly 100 mesh
- Medium Grades: 10/20, 12/20, and 14/30 (coarse)
- Fine Grades: 20/30, 20/40, 30/60, 35/60, 40/60, 30/100, 40/100, 100/200, -60 mesh, -100 mesh, -200 mesh and -325 mesh