Outline of Dryers

This quiz contains multiple-choice problems on overview and properties of dryers, the Kelvin equation, moisture isotherms, temperature profile and drying curves, commonly-used dryers, continuous flow dryers and microwave drying.

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Three principal factors define the nature of a dryer. Which of the following is not one of those factors?

The method of material conveyance through the drying section

The pressure and temperature of operation

The humidity of the atmosphere

The method of heating the material

The method of conveyance of the feed through the dryer is not very important as a particular operation setup can handle all types of feed. True or false?

True

False

Which of the following factors must be considered for handling awkward materials like loose fibres, which can tangle together, and very wet sticky feeds?

The method of material conveyance through the drying section

The pressure and temperature of operation

Humidity of the atmosphere

The method of heating the material

A __ dryer will require less labour, fuel and floor space than a __ dryer of the same capacity.

continuous, batch

batch, continuous

packed, batch

batch, packed

__ drying is chosen whenever there are low production rates (under 200 kg/h).

Rotary dryer

Drum dryer

Continuous

Batch

__ drying is chosen whenever many products are to be handled in the same unit.

Rotary dryer

Drum dryer

Continuous

Batch

Dryers particularly heat the feed by

Direct methods

Indirect methods

Indirectly or directly heated

Direct fire contact

Drying can take place by which of the following processes?

Radiation

Conduction

Convection

By any one or all the means simultaneously

Dryers can generate internal heating in the feed by

Dielectric or inductive heating

Convection

Conduction

Combined three means of heating

Which of the following methods removes water molecules by changing their chemical composition?

Drying

Dehydration

Dewatering

De-moisturising

Which of the following processes removes moisture but retains other volatile components in the feed material and is responsible for retaining important aromatic and flavouring properties of that solution/material?

Desiccation

Dehydration

Drying

Dewatering

Which of the following is used to remove water altogether and help preserve foods?

Desiccation

Dehydration

Drying

Dewatering

Which of the following methods removes the moisture content using pressure drop/lowering of applied pressure?

Desiccation

Dehydration