Drying and filtration are widely regarded as crucial operations in a number of industrial processes that require separating liquid from solid matter. It should be noted that solids can easily be discharged directly into a dryer. However, in the case of an agitated nutsche filter/dryer, the function of drying is carried out by the same equipment.
Nutsche filtration can be termed as a batch filtration technique that makes use of vacuum or pressure in a closed vessel. What are some of the benefits associated with using this technology? They include product isolation, reduced product handling, minimal operator exposure, in addition to environmental protection against solvent vaporization. This apart, the containment level supplied may even comply with GMP as well as other safety and health requirements that companies face the heat for. It is for these reasons that the nutsche filter/dryers are more popularly used in pharmaceutical, dye and paint production, waste water treatment and fine chemical applications.
The basic steps that constitute the drying and filtration process in nutsche dryers/filters include:
Filling or Charging is the first step. It involves transferring the product to be filtered from the primary location to the filter/dryer.
 |
| Nutsche filtration | nutsche dryers/filters |
The filtering step involves using pressure and/or vacuum to force liquid through the filter media and solid bed.
The displacement washing process involves the spraying of fresh wash liquid on top of the solid cake. One should take care not to disturb the surface. The liquid is usually pushed through with pressure or vacuum.
Reslurry washing is usually performed if dissolving of impurities or additional extraction is necessary.
The smoothing process usually follows the filtration or wash process, most notably after the final wash. The agitator comes in handy to close cracks and compress the cake to ensure minimal residual moisture.
The drying or cooling process is done to ensure the solid is evacuated into a second dryer in order to complete the drying, as well as the cooling process. In agitated nutsche filter/dryers, both functions are combined. In fact, drying may even take place in the same vessel. In order to make this a success, the vessel surfaces are heated. The types of drying that can be conducted include vacuum drying and convection drying.
The discharging process is the final process. This is carried out through the valve/port which is placed on the vessel sidewall.
No comments:
Post a Comment