Drying is an important unit operation in many industries.Hence the drying units are often implanted in various layouts .This presentation covers the layout of drying plants in various industries with requisites & general considerations. If you like it ,Please press the thumb up button & donot forget to give your feedback in comments section it extremely valuable to me . Any query ? Feel free to post in comments section. All the best ! Enjoy !

1. Drying plant layout
,blender ,mixer,
emulsification mills,
homogenizers
By – ANSHIKA SAXENA
INDIAN INSTITUTE OF FOOD PROCESSING TECHNOLOGY

2. CONCLUSIONS
FROM
PREVIOUS
CLASSES
Rational distributions of functions of food
processing plant

3. II. GENERAL
CONSIDERATIONS
– Designs are based mainly on practical experience,as mathematical models &
computer simulations cannot be describe handling & processing solid & semi-
solid food materials
– Drying is a heat & mass transfer process.
– Cost-effective
– Effective Area
– Preserve or improve the quality of the product.
– Particular attention must be given to the safety, nutritional quality & consumer
acceptance (convenience) of the dehydrated food products.

4. DRYING PLANT LAYOUT
Layout depends on -
– Type of produce to be handled
– Operating conditions
– Cost effectiveness
– Flexibility in working /operation
– Easy Facilitation of alternatives
– I/O factors , Process & production technology
– Auxillary requirements
– Material handlers , CIP Systems

5. Documentation & prerequisites
– Drying units & plant are not commonly used as separate plant but often
commercialized integrated .
– Budget documentation (wref .std. des .)
– Technical specifications & constraints (std/des.a.pr. Req)
– Drawings & possible plans (floor plans, ceilings , chambers, cabinets,
orientation,area archs etc )
– Flowcharts
– Overall layout & detailed drawing.

6. Technical Consideration for a
drying plant
– Type of dryer
– Capacity /area / material
– Dimensions defining floor area required (incl. int. equipment)
– Hopper type /form
– Air/ steam requirements
– Building /construction material required.
– Energy /fuel consumption
– Wall / floor / ceiling
– Outlet
– In line / Connectives requirement.
– Feasibilty to other equipments attached

7. Selection of drying plant
– Selection of the optimal dryer type & size is crucial as it should satisfy all process & product requirements at
minimum cost. Includes strict requirements for food quality , hygiene & safety.
– Depends on
the equipment
the material
the overall process flowsheet.
– The algorithm steps:
1. Define the problem & supply the needed material & flowsheet data.
2. Make basic choices of feed/product form, operation/heating, single- or multi-stage.
3. Evaluate merit factors for individual dryers & perform approximate size estimation.
4. Study subtypes & refinements of the selected dryers.
5. Assess all remaining possible dryers & make final decision.

8. DESIGN OF A CONVEYOR BELT
DRYER
– The air conditions for design can be considered constant due to the high air recirculation,
which is shown in the dryer cross-sectional diagram .

9. – Heat & Mass Transfer controls the drying rate of most food.
– Internal transport properties strongly affect the drying rate, & they
should be known or determined experimentally for each food material.
– surface heat transfer coefficient h (W/m2K)
– surface mass transfer coefficient HM (kg/m2s)
– The drying rate of a product depends on the
material characteristics & the drying
– air conditions
– Capacity of plant.
– Operating characteristics.

10. Operating characteristics.
– operating conditions,
– residence time
– drying temperature.
– Drying rates
– Evaporation capacity
– Air vel.

12. Infra…..
– The Room Or The Building Enclosure Are Usually Made Of Concrete Masonry /Rcc .
– Processing Rooms Are Lined With Ceramic Tiles External Enclosure With Prefabricated Panels Of
Rcc.
– Floor Drain Channels Are Covered With SS Grids
– Floor In Processing Are Should Have Slope Of 0.5-1%
– Channels Carry Waste Water & Sludge.
– The Drain Channels Made With Bricks Are Lined
With Cement & Epoxy Resins .
– For waterproofing , tile is bonded to asphalt bed .
– Some times they also dilatation joints

13. SS Drain channels
Pipes & joints
Src : blucher.com

14. Requisites for some drying plants
Steam generators
Heat exchangers
Pipes & fittings
Triple tube H.Ex.

15. CONTROL PARAMETERS
– Air velocity between 0.2- 3 m/s
– Air temperature between 50 & 100ºC .
– Load Density Of Drying Bed Between 40 & 50 kg/m2 .
– Air RH between 20 & 100%
– Hot air recycling between 0 & 100% (if economiser available).
These deduce form & size of pilot plant.

17. Drying pilot plant
Src : Lopez et al., 1997

18. Src: fao.org
Fruit & vegetables dry
processing plant
layout

19. Src : fao.org
FRUITS &
VEGETABLE
PROCESS LINE

20. Dry salted meat production layout

21. Apple &
Pear
Processing
Industry
Layout

25. Alfalfa Drying Plant

26. Peach processing plant

27. Apple processing plant
Src : Barbosa - canovas , lopez – Gomez , Food Plant Design

28. Milk powder – spray dryer

30. Powdering plant layout

31. TUNA PROCESSING
FLOWCHART & DESIGN

32. PROCESS LINE OF
MILK
PRODUCTION
UNIT
Src : Barbosa -canovas , Lopez - gomez ,
Food Plant Design

33. Lay8out Drying plant @ Syshka ,
Slovakia

35. Schematics of
Soap drying
plant

39. Wood pellet production
Similar to
biomass
pelletization

40. Schematics of
fish processing
plant

41. Processing of extended
shelflife Of milk-
Flowchart.

43. Src : Super Critical CO2 pasteurized whole milk Gabriele Di Giacomo et al.,2009

44. Schematics of milk reception-pasteurization &
standardization line

45. Blenders & mixers
– For low viscosity liquids, turbine & propeller mixers may be used to premix the
phases.
– For viscous liquids & pastes, pan mixers, kneaders & some types of continuous
mixers used to disperse one phase throughout another.
– Various types of blenders are available.
 Ribbon blender
 Tumbling mixers (for mixing powders )
 Paddle mixer
 Turbine mixer
 Propeller mixer etc.

46. V-Y BlenderBin Blender Conical Blender

47. Conta Blender
Octagonal Blender
Powder
Blender
U- Blender V- Blender

48. High shear mixer
– For viscous materials
– Robust
– But smaller working capacity
– High power consumption
– The speed of rotation is relatively low .

49. Paddle Mixer
– Consists of a flat blade attached to a rotating shaft located centrally
in the mixing vessel .
– Low speed of rotation ~ 20–150 rpm.
– Promotes rotational and radial flow but very little vertical flow.
– 2 or 4 blades may be fitted to the shaft.
– Forms :
 Gate agitator (for more viscous liquids)
 Anchor agitator (rotates close to the wall of the vessel to promote
heat transfer and prevent fouling in jacketed vessels )
 Counter-rotating agitators (develop relatively high shear rates near
the impeller).
 Simple paddle agitators (to mix miscible liquids & dissolve soluble
solids )

50. Pan Mixers
– In pan mixer the bowl rests on a rotating turntable .One or more mixing
elements are held in a rotating head located near the bowl wall.
– Another type of pan mixer, the bowl is stationary. The mixing elements rotate
and move in a planetary pattern, thus repeatedly visiting all parts of the bowl.
– The mixing elements are shaped to pass with a small clearance between the
wall and bottom of the mixing vessel .
– Various designs of mixing elements :
– gates, forks, hooks and whisks.

51. Kneaders (Dispersers, Masticators)
∆ consists of a horizontal trough with a saddle shaped bottom.
∆ 2 heavy blades mounted on parallel & horizontal shafts rotate towards each
other.
∆ Tangential movement of blades possible .
∆ Different speeds - ratio of 1.5 : 1.0.
∆ Mixing times ~ range 2–20 min.
∆ Some of them features Z- or Σ- blade elements.

53. Continuous Mixers for Pastelike
Materials
– For mixing viscous materials on a continuous basis.
– Screw conveyors rotating inside barrels, may force such materials through perforated plates or wire
meshes.
Static Inline Mixers
– Less energy required .
– When viscous liquids are pumped over specially shaped stationary mixing elements located in pipes, mixing
may occur.
– The liquids are split and made to flow in different directions (depends on design).

54. Turbine mixer
– 4 or more blades attached to same shaft , usually located centrally.
– Have Smaller blades.
– High rotation speed ~ range 30–500 rpm.
– Simple vertical blades promote rotational & radial flow.
– Liquid circulation is more vigorous than produced by paddles.
– Use of baffles minimises Swirling & vortexing .

55. Tumbling Mixers
– Consist of partly filled hollow vessels, which rotate about
horizontal axes.
– Main mechanism of mixing is diffusion, segregation can
be a problem if the particles vary in size.
– May contain baffles or stays to enhance the mixing
effect and break up agglomerates of particles.

56. Fluidized Bed Mixers
 for mixing particulate solids with similar sizes, shapes and densities.
 The inclusion of spouting jets of air plus main supply of fluidizing air, can enhance
the mixing.
Vertical Screw Mixers
 Consist of tall, cylindrical or cone-shaped vessels containing a single rotating screw
for elevation and circulation of particles.
 The screw may be located vertically or set at an angle to the vertical and made to
rotate passing close to the wall of the vessel
 Convective mechanism of mixing.

57. Homogenizers
– Principle : premixed phases are pumped through a narrow opening at high
velocity.
– An Opening between a valve & its seat.
– A pressure homogenizer consists of 1 or 2 valves & a high pressure pump.
– As the liquids pass through the gap, 15–300 m wide, between the valve & seat
they are accelerated to speeds of 50–300 m/s.
– Droplets Ø 0.1–0.2 micrometer are attainable in pressure homogenizers

58. HOMOGENISER FOR DAIRY
INDUSTRY
( TETRA PAK ALEX 7741)

60. Different Valve designs

61. Hydro shear
Homogenizers
– In this , premixed liquids are pumped into a cylindrical chamber at relatively low pressure, up to 2000
kPa.
– Enter via tangential port at its centre.
– Exit via two cone-shaped discharge nozzles at the Chamber ends.
– At the entrance liquids are accelerated to very high velocity & spread out to cover the full width of the
chamber wall & flow towards the centre, rotating in ever decreasing circles.
– High shear develops between the adjacent layers of liquid.
– Droplets sizes in the range 2–8 microns are produced by this equipment.

62. Microfluidisers
– Homogeniser capable of producing emulsions with very small droplet
sizes directly from individual aqueous & oil phases.
– Separate streams (aqueous & oil phases) are pumped under high
pressure, up to 110 MPa.
– Liquids are accelerated to high velocity
– Intense shear & turbulence develop which lead to a break up of the
droplets of the internal phase & the formation of an emulsion.

64. Membrane Homogenisers
– If the internal phase liquid is forced to flow through pores in a glass
membrane into the external phase liquid an emulsion can be formed.
– Glass membranes can be manufactured with pores of different diameters to produce emulsions with
different droplet sizes, in the range 0.5–10 m. Such membranes can produce o/w or w/o
emulsions with very narrow droplet size distributions.
– 2 versions :
– Batch (the internal phase liquid is forced through a cylindrical membrane partly immersed in a vessel containing
the external phase. )
– Continuous (, a cylindrical membrane through which the external phase flows is located within a tube, through
which the internal phase flows.

65. Ultrasonic Homogenisers
– Liquid subjected to ultrasonic irradiation : alternate cycles of compression and
tension develop. This can cause cavitation in any gas bubbles present in the
liquid, resulting in the release of energy.
– An ultrasonic transducer consists of a piezoelectric crystal encased in a metal
tube.
– When a high intensity electrical wave is applied to such a transducer, the crystal
oscillates and generates ultrasonic waves & it is partly immersed in a vessel
containing two liquid phases, together with an appropriate emulsifying
agent(s), one phase may be dispersed in the other to produce an emulsion.
– Ultrasonic generators are used on industrial-scale .
– #Wedge resonator-blade- jet of liquid –low pressure-1-2micron droplets

66. COFFEE CRÈME

67. AUTOMATIC FEEDER

69. Emulsification : a brief intro…
– A mixing operation
– Food emulsions consist of 2 phases:
– an aqueous phase consisting of water with hydrophilic materials like
salts & sugars in solution &/or other organic & colloidal substances
– an oil phase which may consist of oils,fats, hydrocarbons, waxes &
resins, so called hydrophobic materials.
– Emulsification : achieved by dispersing one of the phases in the form of droplets or
globules throughout the second phase.
– The material which broken up in this way is known as the dispersed, discontinuous
or internal phase, while the other is referred to as the dispersing, continuous or
external phase.
– Achieved by emulsification mills or by adding other substances, known as
emulsifying agents, included in small quantities, to produce stable emulsions

70. EMULSIFICATION MILLS
∆ General Principle : based on introducing energy into the system by
subjecting the phases to vigorous agitation
∆ The most effective type of agitation subjects the large droplets of
the internal phase to shear so that the droplets are deformed from
their stable spherical shapes & break up into smaller units
PARAMETERS
 Temperature (sensitivity)
 Speed of agitation

71. Colloid Mills (paste mill)
– Premixed emulsion ingredients pass through a narrow gap between a stationary surface (stator)
and a rotating surface (rotor).
– Shear & turbulence –disrupts [phases.
– The gap between the stator and rotor is adjustable ~ range 50–150 m.
– Rotor speed (ranges: 3000 rpm for a rotor 25 cm Ø - 10 000 rpm for a smaller rotor 5 cm Ø)
– For emulsifying viscous materials.
– For lower viscosity materials the rotor is mounted on a horizontal axis and turns at higher
speeds, up to 15 000 rpm.
– CONSTRUCTION
– The rotor turns on a vertical axis in close proximity to the stator. Rotors and stators usually have
smooth stainless steel surfaces.
– Carborundum surfaces are used when milling fibrous materials.
– Jacketed for temperature control.
– Mills fitted with rotors and stators with matching corrugated surfaces are also available.

73. Src : techgen.com

74. Milk Pasteurisation plant layout

76. References
– Book chapter[15] - Mixing, Emulsification and Size Reduction by James G. Brennan
– Fao.org
– Pasteurization and Sterilization of Milk by Supercritical Carbon Dioxide Treatment Gabriele Di
Giacomo et al.,2009
– Food plant design by Lopez –Gomez ,Barbosa- Canovas .
– Techgen.com
– Blucher.com
– Food Process Design - Zacharias B. Maroulis
– http://dairyprocessinghandbook.com/chapter/pasteurized-milk-products

77. GRACIAS !!

78. Additional slides

79. TUNA
CANNERY

81. SKIPJACK
CANNERY

82. WHIPPED CREAM

84. Significance
• Multiple emulsions e.g. oil in water in oil (o/w/o) or water in oil in
water (w/o/w) structures.
• The latter structure having the most applications.
• w/o/w emulsions may be produced in two stages.
• First a w/o emulsion is produced by homogenization using a
hydrophobic agent.
This is then incorporated into an aqueous phase using a hydrophilic
agent.

85. SARDINES IN
OIL CANNERY

86. SARDINES IN
OIL
CANNERY

89. Interesting stuff !! Do check that
out !
– @ www.fao.org
– Sardines cannery layout
– Shrimp cannery layout
– & many more