A Review on Fluidized Bed Dryer

Mayur M. More, Nilesh K. Nerkar

Department of Pharmaceutical Chemistry, Ahinsa Institute of Pharmacy Dondaicha, Dist. Dhule Maharashtra, India

*Corresponding Author E-mail: mayurmore16092001@gmail.com

ABSTRACT:

The review paper conducted on the study about a demonstration of fluidized bed dryer particular application and principle and other processing. Fluidized bed dryer (also called fluid bed dryer) is a kind of equipment used extensively in the pharmaceutical industries to reduce the moisture content of pharmaceutical powder and granules. The wet solids are lifted from the bottom and suspend in a stream of air (fluidized state). Fluidized bed dryer are very well known to yield high heat and mass transfer hence adopted to many pharmaceutical industries drying process particularly product. In this review paper we show the construction, working, and applications or several disadvantages of fluidized bed dryer (FBD).

KEYWORDS Fluidized, Illustrated, Pharmaceutical, Dryer.

INTRODUCTION:

Fluidized bed dryer (FBD) is well known and widely used equipment in the pharmaceutical manufacturing. It is used in granulation process for drying the material to get desired moisture content in the granules or powder required for perfect compression of tablet formulation.² Drying method is common in the chemical pharmaceutical industries and food production.³ Fluidized bed techniques employing air as the fluidizing medium, have been successfully applied to drying when solid is of suitable physical form. Fluidized belt have been extensively used in the chemical pharmaceutical and food businesses as batch dryer due to their high heat and mass transfer charges as an outcome of high connection between gas particle in the compartment.^9-10

Types of fluidized bed dryers:

There are various types of fluidized bed dryers

1. Conventional fluidized bed dryers:

*Batch fluidized bed dryers

*Semi-continuous fluidized bed dryers

*Well-mixed, continuous fluidized dryers

*Plug flow fluidized bed dryer

2. Modified fluidized bed dryers:

Various types of modified Fluidized bed dryers applied in many industries process to overcome to some of the problems.

· Hybrid fluidized bed dryers

· Pulsating fluidized bed dryers

· Fluidized bed dryer with immersed heat exchange

· Agitated fluidized bed dryer or swirl fluidizers

It should be noted that not all modified fluidized bed dryers are necessarily better than the conventional dryers in terms of product quality or energy efficiency or drying performance.¹

PRINCIPLE:

In fluidized bed dryer hot air (gas) is passed at high pressure through a perforated bottom of the container granules to be dried. The granules are lifted from the bottom and suspended in the stream of air. This condition is called fluidized state. The hot gas is surrounding every granule to completely dry them thus material or granules are uniformly dried.⁸

CONSTRUCTION:

Two types of bed dryers are available, vertical fluid dryer and horizontal bed dryer. The fluidized bed dryer be made of steel case of tubular or quadrangular cross sector. A typical fluidized bed dryer consist of the air handing unit, exhaust blower, control panel, air distribution plate, spray nozzle and solution deliver. The appropriate choice of distributor used during dying process ensures uniform and stable fluidization. The pressure drops across the distribution must be high enough to ensure fluidization.²

FLUIDIZED BED DRYER:

WORKING:

The dryer illustrated in figure consist of a basket of plastic or stainless steel with a perforated bottom mounted in the body of the dryer and into which the material to be dried is placed.⁴

The wet particles to be dried are placed in a attachable vessel. The container is implanted in the dryer air fresh can pass through a pre-filter which is then heated when passing through a heat exchangers hot air flows through the bottom of the container. At the same time the fan starts to rotate. The air speed increase gradually when the velocity of the air is greater than the sedimentation rate of the particles remain partially suspend in the gas stream.

After a specific period a compression point is touched in which the friction drags on the particle is equivalent to the strength of gravity. The granules increase in the vessel due to the high gas velocity of 1.5 to 7.5m per minute and then fall back this method is said to be fluidized state. The gas surrounds each particle to dry them entirely. The air comes out of the dryer passing through the filters in the bag periodically the bags are shaken to eliminate.

The residence time for drying is around 40 min the material is sometimes left in the dryer to touch room temperature. The container is detached for unpacking. The last product is free flowing^.4-6

APPLICATIONS OF FLUIDIZED BED DRYER:

· Fluidized bed dryers are used in chemical, pharmaceutical, food, dairy, metallurgical, dyes and other process industries for drying of powders, mixing, of powders and agglomeration of various materials such as powders, tablets, granules, coals, fertilizers, plastic material etc.²

· It is used for coating of granules.

· Fluidized beds are often used to cool particulate solids following a reaction.^{4 -6}

· The temperature of the fluidized bed dryer is easily controlled.

· Material is dried from particle to particle.

ADVANTAGES:

· *Fluidized bed dryer requires less time to complete drying 20 to 40 min.

· *It is used either as batch type or continuous type.

· *Reduce contact time for drying.¹

· *Reduce labor space, with extraordinary product.^4-6

· *It is available in different sizes with the different drying capacity.

DISADVANTAGES:

· It has a possibility of product loss.

· Requires increased air handling due to extensive recirculation of exhaust air for high thermal efficiency operation.²

· Chance of attrition of some materials resulting in the production of fines.^4-6

CONCLUSION:

In this paper, a thermodynamic analysis in terms of mass, energy and exergy balance in a batch type fluidized bed dryer column is performed. A new original model is proposed for energetic and exergetic analyses of both drying air stream and particles to be dried separately. The thermodynamic analyses of the drying column proposing two separate systems of a control volume for drying air flow and a control mass for particles to be dried provide a novel contribution to the available literature.⁷

REFERENCES:

1. Arun S. Mujumdar (2015). Handbook of Industrial Drying. CRC Press, Taylor and Francis Group, New York.

2. Pharmaceutica Engineering Text Book Of Nirali Prakashan By Dr. Ashok A. Hajare Page No.  7.21.

3. Soponronnarit, S.; Pongtornkulpanich, A.; Prachayawarakorn, S. Drying characteristics of corn in fluidized bed dryer. Drying Technology 1997, 15(5), 1603–1615.

4. Pharmaceutical process engineering, Anthony j. Hickey, David gander ton, volume 112, page no. 101-102.

5. Sarker, M.S.H.; Ibrahim, M.N.; Abdul Aziz, N.; Punan, M.S. Energy and exergy analysis of industrial fluidized bed drying of paddy. Energy 2015, 84, 131–138.

6. Pharmaceutical process engineering, Anthony J. Hickey, David gander ton, volume 195, second edition page no 79-80.

7. Ozahi, E.; Hacımurat, D. A model for the thermodynamic analysis in a batch type fluidized bed. Energy 2013, 59, 617–624.

8. Pharmaceutial Engineering (principles and practices), C.V.S. Subrahmanyam, J.Thimma Setty, Sarasija Suresh, V. Kusum Devi. 

9. Tatemoto, Y.; Mizukoshi, R.; Ehara, W.; Ishikawa, E. Drying characteristics of food materials injected with organic solvents in a fluidized bed of inert particles under reduced pressure. Journal of Food Engineering 2015, 158, 80–85.

10. Srinivas, G.; Pydi Setty, Y. Drying behavior of uniform and binary mixture of solids in a batch fluidized bed dryer. Powder Technology 2013, 241, 181–187.

Received on 24.10.2022 Modified on 22.11.2022

Accepted on 07.12.2022 ©Asian Pharma Press All Right Reserved

Asian J. Res. Pharm. Sci. 2023; 13(1):67-68.

DOI: 10.52711/2231-5659.2023.00012