AGITATED NUTSCHE FILTER

Manju R, Mukesh B, Naveen Sinoy, Vignesh E and Yahya K MIII Semester, Department of Chemical Engineering, BMS College of Engineering

Bengaluru-560019, India

INTRODUCTION

Agitated Nutsche filter (ANF) is a filtration technique used in applications such as dye, paint and pharmaceutical production and wastewater treatment.

An agitated nutsche filter dryer (ANFD) is one class of such filter dryers that has been specifically designed so all these operations can take place within one vessel.

Safety requirements and environmental concerns due to solvent evaporation led to the development of this type of filter wherein filtration under vacuum or pressure can be carried out in closed vessels and solids can be discharged straightaway into a drier.

Agitated Nutsche filters are used widely in the production processes of pharmaceutical, chemical and laboratory industries, among others.

They are manufactured as agitated Nutsche filter dryers (ANFD'S) for the filtration and drying in the same unit of active pharmaceutical ingredients (API) and chemical compounds.

CONSTRUCTION

Different manufacturers use different heating technology, ANFDs should have a

heating jacket on the walls as standard, on the top dome if necessary and heated

agitator shaft and blade options for direct contact with the cake if required. One

method of drying is through direct under-plate heating systems that are located in

the filter plate at the bottom of the vessel.

AGITATOR

A multipurpose agitator is the unique feature of this system. The agitator performs a number of operations through movement in axes both parallel and perpendicular to the shaft.

Important points

•Slurry contents can be kept fluidized until most of the mother liquor is filtered through.

•When filtration is complete, the cake develops cracks causing upsets in the vacuum operation. This hinders removal of mother liquor. The agitator can be used to maintain a uniform cake.

•The cake can be washed after filtration by reslurrying the cake.

•After washing, the mother liquor can be refiltered. The cake can then be discharged by lowering the agitator and rotating it in such a manner that it brings all the cake towards the discharge port.

• The basic principle of operation is Vacuum or pressure filtration• In modern designs, in addition

to just vacuum or pressure filtration, cake drying is also introduced within the nutsche in modern equipments.

• A typical unit consists of a dished vessel with a perforated plate. The entire vessel can be kept at the desired temperature by using a limpet jacket, jacketed bottom dish and stirrer (blade and shaft) through which heat transfer media can flow. The vessel can be made

ADVANTAGES

•Vacuum or pressure filtration possible.

•Inert gas atmosphere can be maintained.

•Minimal contamination of the cake.

•Very high solvent recovery.

•Considerable saving in manpower.

•Solvents are in closed systems, so no toxic vapors are let off in the atmosphere.

Figure: Representing modern nutsche filter completely leak-proof for vacuum or pressure service. •Closed environment can be maintained.

MATERIALS OF CONSTRUCTION• Agitated Nutsche filters can be fabricated in materials like Hastelloy C-276,

C-22, stainless steel, mild steel, and mild steel with rubber lining as per service requirements. Recently, agitated Nutsche filters have been fabricated out of polypropylene fibre-reinforced plastic (PPFRP).

•Personal safety is maintained and heat transfer surfaces can be provided to maintain filtration temperature.

•Uniform bed can be maintained throughout the filtration.

COMMERCIAL USES

• Agitated Nutsche filters are used widely in the production processes of pharmaceutical, chemical and laboratory industries, among others.

• They are manufactured as agitated Nutsche filter dryers (ANFD'S) for thefiltration and drying in the same unit of active pharmaceutical ingredients (API) and chemical compounds.

Figure: Representing Nutsche filter (MOC-PPFRP)

Figure: Representing nutsche filter(MOC- Hastelloy C-276)

REFERENCES1) Bennett, Bill; Cole, Graham (2002). Pha r maceu t ical P r odu c ti o n: An

Engin e e r ing Guide . Institution of Chemical Engineers (IChemE). p. 89. ISBN 0 - 85295 - 440 - 9 . Retrieved 2008-06-24.

2) Cheremisinoff, Nicholas P. (2001). Handbook of W a ter and W a s te w a t er

T r eatme n t T echn o lo g ie s . Butterworth-Heinemann. p. 199. I S B N 0 - 750 6 - 749 8 - 9. Retrieved 2008-06-24.

3) Sparkler Filters, Inc.,ht t p : // w w w .googl e .co m /pa t e n t s/US5139667 2012.4) Michelle Frisch, Powder Systems Ltd, h t t p: //ww w .p o w d e rsys t e m s .co m /pi l o t -

and - plan t - prod u ct i on.ht m l , 2012.