Project KEL

FABRICATION AND DESIGN OF VIBRO-FLUIDISED BED DRYERS

Industrial Project Report

SUBMITTED TO

National Institute Of Food Technology Entrepreneurship And Management

Kundli, Haryana

For The Partial Fulfilment of Requirements of Program

Master of Technology (FPEM)

In The Department of FOOD ENGINEERING

SUBMITTED BY

SAQIB GULZAR (212014)

SUJOSH NANDI (212016)

Under Supervision Of

Faculty Guide

DR. P K NEMA

ER. VINKEL ARORA

Organization Guide

MR P K ARORA

MR TUSHAR CHURY

Introduction

Kilburn Engineering Ltd. is a Williamson Magor Enterprise. Williamson Magor has interested in tea, batteries

and engineering with a turnover of US$ 500 million.

The other companies in the group are:

1. Eveready Industries India Ltd.

2. McNally Bharat Engineering Ltd.

3. Mcleod Russel India Ltd.

Kilburn has over 30 years of successful track record in manufacturing world class critically customized process

equipment and completing projects on schedule. Kilburn customers both international and domestic, include

large companies in several industries namely chemical, petrochemical, oil, gas, refinery, fertilizer, nuclear

power plant and food processing industries covering tea, sugar, paddy and coconut.

Products & Services

Kilburn is an ISO 9001-2008 and ASME ‘U’ stamp certified technology led company, specialized in process

design, engineering, manufacturing, project management and installation of equipment and systems for various

process plants. The company is a leader in solid, liquid, gas drying systems and specially designed skid

mounted packages for offshore platforms. Kilburn has systems engineering capabilities with a multi-

disciplinary approach and has a highly qualified and talented pool of engineers in mechanical, chemical,

metallurgical, aeronautical, electronics/ instrumentation and electrical engineering disciplines. Apart from the

process equipment/ systems, the company also undertakes execution of EPC contracts.

EPC contracts

Kilburn undertakes execution of various systems on turnkey basis for projects in diverse Industries namely

Chemicals, Heavy Chemicals & fertilizers, Petrochemicals & Refineries, Nuclear Power Plants offsite systems,

Onshore oil/gas exploration & Gas based power plant etc.

It has successfully completed several such projects covering Detailed Engineering, Shop/ Site fabrication,

Erection & Commissioning involving Process, Mechanical, Electrical, and Instrumentation & Civil activities.

Few projects completed are Caustic Evaporation, Concentration, Prilling & Flaking Plants (5 Projects), Soda

Ash Calciners (4 projects), E-PVC spray Drying system, Rotary Dryers & Coating/ Granulation System,

Storage/ Mixing Silos or PVC Plant, Various Solid Drying/ Adsorption.

Facility Overview

Area of Plot : Total 30960 sq meters

Covered manufacturing area : 13,450 meters

Office space : 2850 sq meters

Installed Power : 1350 KVA with full back up

Maximum lifting capacity- 100 Tons

Plant and Machinery

A. Metal Cutting & Forming

Presses

CNC Press Brake 250 MT Capacity

Hydraulic press 300 MT capacity x 4 M span

Hydraulic press 150 MT capacity x 4 M span

Shears

Shearing Machine (3 M x 13 mm thick.)

Hydraulic NC Shearing Machine (3 M x 15 mm thick.)

Bending Machines

Plate Bending Machine 25 mm x 2.5 M

Plate Bending Machine 16 mm x 1.5 M

Welding Machines

Submerge Arc Welding machine with column

SMAW & Boom, MIG, TIG

Radiography Enclosure

Cutting Machines

CNC plasma cutting machine

Pug Cutting Machine for different thickness

Portable keyway cutting machine

Portable edge preparation machine

Manual Plasma Cutting Machine 100 thick

Other Metal Forming Machines

Electronic Torque Control Tube Expander

Nibbling Machine

Automatic Bevelling Machine

B. Machining

Drilling Machines

Radial Drilling Machine RM 65 - 3 Nos.

Radial Drilling Machine 1·

Pillar Drilling Machine

Magnetic Portable Drilling Machine

Lathes

CNC Multiple tooling long Lathe HMT make

Heavy Duty Long Lathe 7M long

Kirloskar Lathe 3M long

Medium Size lathe 2M HMT make- 3 Nos.

Shaping Machine

1 M x 0.5 M - 2 Nos.

UNIVERSAL MILLING MACHINE 50 Diameter

Spindle x 1.5 long

BFW make Universal-1 No.

C. Material Handling Equipment

EOT Crane 50 MT - 1 No.

EOT Crane 25 MT - 3 Nos.




Mobile Crane 8 MT-3 Nos.

D. Others

Balancing Equipment

Dynamic Balancing Machine FIE Make

Painting

Compressed Air Gun

Controlled Humidity Chamber

Utilities

Pneumatic Compressor for Pneumatic Grinding & Chipping

Diesel Generator 750 KVA -1 No.

Diesel Generator 125 KVA - 1 No

Inspection & Testing Facilities

Efficient in-house quality control systems and associated with several leading reputed third party inspection

agencies

Major Inspection and Testing Facilities

Non Destructive Testing facility

Destructive Test facility

Test run set up

Dynamic Balancing facility

Hardness Testing facilities

Decibel Level and Vibration Meter

Special Instruments

Electrometer for Paint thickness measurement

Surface Comparator

Manufacturing Facilities

Kilburn’s manufacturing facilities are located near Mumbai, well connected by highways and ports, facilitating

transportation of large sized equipment within India and Overseas.

Kilburn manufactures equipment in materials such as Carbon steel, Stainless Steel, Inconel, Hastelloy, Monel,

Nickel and Duplex Stainless Steel.

Location:

Plot No. 6, MlDC Industrial Area, Kalyan Bhiwandi Road, Saravali, Thane-421311, Maharashtra, India

Machine Shop:

a) 133M long x 23 metres wide

b) 10 T EOT Crane

c) 8M under hook height

Light Bay:

a) 133M long x 23 metres wide

b) 30T EOT Crane


Medium Bay:

a) 133M long x 25 meters wide

b) 50T EOT Crane


Heavy Bay:

a) 133M long x 25 meters wide

b) 100 T EOT Crane


R & D

Kilburn is a government approved R&D house. The company’s strength lies in its successful assimilation of the

world class technologies. The company attaches highest priority to its R&D activities on a counting basis. Its

R&D centre has developed new equipment of international standard for its certain end user industries.

Quality Control and Management Systems

Efficient in house quality control systems and associated with several leading and reputed

third party inspection agencies

Asme 'U' Stamp Authorised Shop

Iso 9001: 2008 Certified Company

Registered With National Board Of Boiler & Pressure Vessel Inspectors

Ce Marking

Ped Certification

Collaborates/ Technical Associates

Kilburn has ongoing technical collaborations and case to case tie ups with

Nara Machinery Co. Ltd., Japan

Carrier Vibrating Equipment, Inc., USA

EmDE Industrie- Technik, Germany

Bertrams Limited, Switzerland

Nova-Synergy Industrial Solutions (NOVARGI), Spain

Technicas Reunidas, Spain

Solid Drying Systems :

Rotary Dryers, Calciners, Kilns & Coolers.

Fluid Bed Dryers & Coolers.

Flash Dryers.

Paddle Dryers & Coolers.

Spray Dryers.

Band Dryers.

Vibratory Fluid Dryers & Coolers.

Adsorption System:

Air/ Gas/ Liquid Drying Systems.

Solvent / Vapour Recovery Systems.

Catalytic Purification Systems.

Oil Field Systems:

Instrument Utility Gas Drying Systems.

Fuel Gas Conditioning Systems.

Customised Skid Mounted Packages.

Gas Sweetening Packages.

Air Handling Systems:

Industrial Centrifugal Fans.

Fabricated Equipment:

Pressure Vessels & columns.

Heat Exchangers.

Special Equipment to Customer design.

Office & Other Buildings:

3500 m2 for Design, Engineering, R & D, Pilot Plant, Manufacturing, Marketing, Commercial & Finance

Departments, HR & IR Dept. Canteen & Power House, etc.

Design & Engineering Facilities

Following design & engineering facilities are available

Latest Autocad Edition 2011

PV Elite Software for mechanical design of vessel

3D Autocad Inventor software for equipment modelling.

MRP System for material tracking.

ERP

Various Types of Materials Processed

Duplex Stainless Steel

Incolony 825

Incolony 800

Hastalloy

Monel

Inconel 600

Aluminium

Nickel

Stainless Steel(All Grades)

Carbon Steel(All Grades)

Inspection & Testing Facilities

Following inspection & Testing Facilities are available at ours Works:

Pressure and Vacuum Test-Pneumatic and Hydraulic

NDT: Radiography, Dye Penetration Testing, Magnetic Particle Examination, Ultrasonic Examination.

Dark Room Facility.

Destructive Test - Physical, Chemical, Corrosion Test, Micro, Macro, etc.

Precision Measuring Instruments such as Verniers, Micrometers, Bore Gauges, Dial Indicators,

Hardness Tester, etc.

Qualified Welding Procedures and welding operators for various Exotic materials.

Measurements of noise, vibrations, flow and temperature.

Mechanical Run-test of Rotary equipments.

Performance testing of Blowers on test bed.

Testing Instruments.

List of Engineering Consultants, Inspection Agencies & EPC / LSTK Contractors

We are on the approved vendor list of following Engineering Consultants 1 Contractors for our entire range

of products:

Engineers lndia Limited

Aker Solutions Ltd.

Jacobs Engineering lndia Pvt. Ltd.

Technimont ICB Pvt. Ltd.

Uhde lndia Ltd.

Lurgi lndia Co. Pvt. Ltd.

John Brown Technologies lndia Pvt. Ltd.

Chemtex Engineering lndia Ltd.

Toyo Engineering Ltd.

Technip KT lndia Ltd.

Mott MacDonald Consultants lndia Pvt. Ltd.

Tata Consulting Engineers Ltd.

Saipem lndia Projects Ltd.

IBI Chematur Engineering Ltd.

Lloyds Registrar of Shipping

Development Consultant Pvt. Ltd.

Projects & Development (India) Ltd.

Larsen & Toubro Ltd.

Hindustan Dorr-Oliver Ltd.

McNally Bharat Engineering Co. Ltd.

Hyundai Heavy lndustries Co. Ltd.

Samsung Engineering lndia Pvt. Ltd.

KBK Chem Engineering Pvt. Ltd.

Tata Projects Ltd.

Essar Constructions lndia Ltd.

Indian Oil Tanking Ltd.

Korea Heavy lndustries Corporation

National Petroleum Construction, Company

Sarku Engineering Services Ltd.

List of some of the Important Customers (Domestic)

Oil & Natural Gas Corporation Ltd.

Gujarat Narmada Valley Fertilizers Co. Ltd.

Gujarat State Fertilizers & Chemicals

Reliance Industries Ltd.

Larson & Turbo Ltd.

Nuclear Power Corpn. of India

Chemplast Sanmar Limited

Brooke Bond Ltd.

Hindustan Unilever Ltd.

Nirma Limited

Cochin Refinery Limited

Hindustan Petroleum Corpn. Ltd.

Jindal Praxair Oxygen Co., Limited

Essar Constructions India Limited

United Phosphorus Limited

Philips Carbon Black Ltd.

Hi-Tech Carbon Black Ltd.

Deepak Fertilizer & Petrochemicals Ltd.

GHCL Ltd.

Tata Chemicals Ltd.

First Carbon Technologies Pvt. Ltd.

Essar Offshore Subsea Ltd.

List of some of the Important Customers (Export)

Samsung Heavy Industries, Korea

Korea Heavy Industries, Korea

Formosa Plastics, Taiwan

Cabot Corporation, France & USA

Thai Carbon Black Co., Thailand

Komline Sanderson, USA

Columbian Chemicals, Brazil, Canada & Germany

Mitsubishi Heavy Inds. Limited

National Petroleum Construction Co., Abu Dhabi

Sarku Engineering Services SDN BHD, Malaysia

Bertrams Chemical Plants Limited, Switzerland

SABIC – Saudi Arabia

Petrofac International Limited, Malaysia

Lamprell Energy Ltd., Abu Dhabi

Swiber Offshore Construction Pte. Ltd., Thailand

paddle Dryer

In the realm of paddle dryer, Kilburn introduces a unique cunieform paddle geometry in collaboration with

Nara Machinery, Japan which leads to substantial reduction in the size of continuous conduction dryer.

Principle of operation

Heat transfer from heating medium to the material is by conduction. Efficient drying of

powdery/crystralline/granular material is achieved by bringing it in direct contact with revolving cunieform

hollow paddles, without using any gas as heating madium.

The trough is uniformly heated by passing heating medium through the jacket. This ensures that the entire

material in the dryer is in full contact with the total heat transfer area during its passage through the dryer.

Compact and Sturdy Design

More than 75% of the heat transfer area is compacted in the paddles, which are closely and alternatively

arranged at fixed distances on each hallow revolving shaft. The heat transfer area per unit volume of the dryer is

very large thus reducing the size of the dryer. The space requirement and the civil costs for erection of the dryer

are considerably reduced. The dryer is constructed from thick plates and heavy shafts giving it an inherent

sturdiness.

High Thermal Efficiency

Te revolving paddles alternately and sectionally compass the material at the slanting surface of the paddles, and

expand the material at the cavities behind the paddles. This keeps the material in a constant state of agitation

resulting in very high heat transfer coefficient with consequent reduction in equipment size.

Self-Cleaning Paddles

The combined movement of the slanting surfaces of the revolving paddles and material generates dispersion

forces which automatically clean layers that are liable to stick to the paddles.

Uniform Drying

The intimate mixing action of paddles results in uniformity of temperature at any cross section. The movement

of the material in the dryer is in plug-flow pattern. This enables uniform drying of the material.

Experiment measurement of residence time by using coloured chips

Thermal Processing

Steam, Hot water or oil can be used as heating medium. Drying, calcining, Roasting, Sterilizing, Cooling,

Crytalizing and Solvent recovery can be carried out by using different heat transfer media. By partitioing the

shaft and jacket, two different heating media can be incorporated in the same equipment. This feature facilitates

two temperature drying, drying-cum-cooling, drying-cum-roasting.

Minimal Dusting

The paddle Dryer is totally enclosed and the entire heat transfer is achieved by conduction. Only a small

quantity of hot air is used to scanvenge evaporated moisture thus preventing condensation. This results in

minimal dusting and reduces or eliminates dust collection equipments. Heat loss through exhaust air is also

substantially reduced.

Suitability For All Types of Powders

The number of thermal shafts, the speed of revolving paddle sets, and the temperature of heating medium can

be selected to suit the individual drying characteristics of the material. Dust free operation enables efficient

drying of dusty powders.

The geometry of the paddles and the casing is such that the material is homogenously mixed with no stagnant

pockets.

Material of Construction

The paddle Dryer can be made of any weldable material of construction. For abrasive materials, the wear parts

can be hard faced or stellited.

W-Type(2 Shafts)

T-Type(4 Shafts)

Component of Paddy Dryer

In the fabrication of paddy dryers, the first step is the understanding of General assembly drawing also called as

GA drawing. In GA drawing all the components of the drying system are shown as per the process flow. There

are separate drawings for all the components.

1. Control Gear for F D Fan

2. F D Fan (Along with duct)

3. Feed Hopper for FBD

4. Fluidised Bed Dryer

5. Exhaust hood for FBD

6. Air heating system for FBD

7. Discharge system for FBD

8. Air Heating System for VFBD

9. Control Gear for Hot Air Blower

10. ISO piping for Steam Heater for FBD

11. Feed Hopper for VFBD

12. Hot Air Blower (Along with duct)

13. Flexible Bellow Assembly

14. Flexible bellow Assembly between Feed Hopper and Discharge of FBD

15. Vibro Fluid Bed Dryer (VFBD)

16. Exhaust System for VFBD

17. Discharge system (Chute)

Paddy is dried in 2 phases, first in Fluid Bed Dryer where the moisture content of the parboiled paddy drops

from 37% to 24% and in the second phase in Vibro Fluid Dryer the paddy achieves its final Moisture content

of 13 to 14% as per the storage requirement.

FBD is installed to reduce the moisture load on the VFBD and to increase the capacity of the dryer.

The fabrication of the paddy dryer starts with the fabrication of individual components. First the critical

components are fabricated, followed by the fabrication of non-critical components to have maximum time for

any rectification in the critical component.

Usually the fabrication starts with the main frame on which the Plenum Chamber and Drying Chamber rests.

The Main frame is a framework of channels and Angles made of MS. Followed by the Main frame the

fabrication of Plenum chamber takes place. Plenum Chamber is the component used for supplying air inside the

drying chamber. It is made in 2 parts which are joined by nut bolts by providing flanges, reason being the large

size of plenum chamber which hampers in its transportation. There are 2 Plenum Chambers in Paddy dryer; first

one for the FBD and other is for VFBD.

Upon the plenum chamber rests the Perforated Stainless Steel sheets on which the material is dried. These

sheets come in the length of 2.5m x 1.2m.

Drying Chamber for FBD is different than that of VFBD. FBD drying chamber is made of MS and has a

trapezoid shape. It is also supplied with side window for inspection.

For FBD the hot air is supplied by using a FD fan which has a motor of capacity 40 HP

Plenum Chamber of VFBD is similar in function as that of FBD but is structurally different in size and shape.

Above the Plenum Chamber is placed Drying chamber which is nothing but the SS sheets formed into a

chamber like structure. In VFBD four Perforated Sheets are used. These Sheets have circular openings of dia.

2mm.

Plenum Chambers are made by MS sheets. For Strength and providing insulation, it is made in double layers of

inner and outer sheet with channels welded and insulation placed in between.

Hot air is blown into feed side of VFBD by a Hot Air Blower (HAB). It has a 100 HP motor which receives the

hot air from the Heater and blows it into the Plenum Chamber. Plenum chamber has 3 divisions to blow air in

different zones of the Drying Chamber. Air Flow rate through the Plenum chamber is controlled by providing

Dampers at its inlet.

Plenum chamber for FBD has 6 dampers while as there is a single damper for VFBD. Besides the dampers,

there are control gears installed between Heater and HAB to regulate the amount of air into HAB. Insulation of

Glass Wool is provided to decrease heat losses in Plenum Chamber, HAB and also in FD Fan.

The Feed hopper of the VFBD and discharge duct of FBD has Flexible Bellow in between them. This Bellow is

made up of Teflon sandwiched in a rectangular frame. This bellow is provided to avoid the transmittance of the

vibrations from VFBD to static feed hopper.

Above the drying chamber is placed the Exhaust hood which has an Axial fan to remove off the moisture and

hot air from the Dryer. Axial fan has a motor of 7.5 HP capacities.

VFBD has an excitation system which provides vibratory motion to the dryer. The excitation system is placed

at the base of the dryer attached with the Plenum chamber. It is motor driven with a 10 HP motor and an

eccentric shaft connected to the link and Shaft of motor to give vibratory action.

Springs are provided on the sides of plenum chamber connected to the main frame to provide shock resistance

caused by vibrational motion.

Paddy is removed off by a discharge chute made of SS which is of the shape of a traditional winnower.

Specification of Paddy Dryer

Perforated Sheet

Triangular Pitch(P): 5 mm

Circular hole (φ) :2mm

Material :SS430

Size :14g (2mm) x1.25m x2.5m

Number of Sheet : 9

Opening :15%

Motor

For FD Fan

Material of Construction: TEFC squirrel cage induction type

Ampeire 415 ± 5% 50 Hz 3Phase AC Supply with IP55 Protection,

Insulation : Class F 40OC amb temp, Standard Shaft length

Operating Temperature: 300 c

Shaft Power : 40 hp

Motor Speed 1465 rpm

Blower Speed : 35000 m3/hr

Operating Pressure : 150 mm of WC

For HAB


415 ± 5% 50 Hz 3Phase AC Supply with IP55 Protection,



Shaft Power : 100 HP

Motor Speed : 1480 rpm

Operating Speed : 1237 rpm



Exhaust Fan


415 ± 5% 50 Hz 3Phase AC Supply with IP55 Protection



Shaft Power : 7.5 HP


Operating Speed : 1237 rpm



Excitation System

Exhaust Fan (1 No.) 7.5 HP x1000rpm Imax amp Direct Drive: Motor to be mounted on seperarate

Support

MOC: Shell CS 19g min thk

Impeller: Aluminium Cast

Pulley

HABPulley(M) : 280 PCD x4CX ø75 Bore

Iddler Pulley : 335PCD x4CX ø75 Bore

Spare Pulley : 200PCD x 4C x ø70 Bore

Steam Air Heater

Mass flow :93000Kg/hr

Operating Temperature : (30-120)OC

Heat Load: 2500000 Kcal/hr

Steam Flow Rate : 4840 Kg/hr @ 3 bag(g)

Tube: CS(A106 Gr B- Seamless) 20 NB Sch 10 pipe with extruded type Al fins, Fin OD 57± 1 mm 9-10

fins/inch

No. of Modules: 2;

No. of rows per module: 4 Nos;

Total No of tubes: 4 x47+ 4X 48 = 380

Surface Area =1620 m2

Face Area: 2880 mm(L) x2880 mm(W)

Overall Dimension: 3030 mm(L) x3030mm(H) x1225mm(W)

Inlet Outlet Connections: 100 NB / 50 NB x150# SORF Flange

Design Basis: 15 TPH feed EL 3 TPH 8OC/90%RH to 120OC Heat Load 25 LKcal/hr

Steam Fitting

40 NB CI Ball Float Trap Model-FT14-10, BSPT(F) 2 Nos.

40 NB Y Strainer BSPT(F) 2 Nos.

40 NB CI Disc Check Valve DCV3 ASA150# Flange 2 Nos.

Gate Valves -A216 GR. WCB, PTFE, ASA150# Flange

100 NB - 2 Nos. 40 NB - 4 Nos.

Tea Dryer

Kilburn Engineering Ltd. plays significant role in Tea sector in India their world class Vibro-fluid bed dryer

since 1979. By using Government of India approved research and development centre, pilot plant has been

established in tea garden which facilitates drying and testing procedure at the tea gardens only to ensure quality

in terms of flavour, taste and aroma properties, under different drying temperature, humidity and residence

time. Fluidisation and drying characteristics of CTC and orthodox teas were studied under various sets of

parameters. After their continue research, they draw conclusions that 1) Wet tea is difficult to fluidise only with

air. 2) Wet tea can be fluidized with combination of vibration and air velocity. 3) Uniform fluidisation is must

for better heat and mass transfer to improve quality of made tea. 4) Tea must be dried at controlled rate.

Fabrication of Tea Dryer

There are four models in Tea dryer based on the capacity viz. MM, DD, EE, FF, GG; with GG being the largest

in size and MM the smallest.

The fabrication process is similar to that of KPD with a few changes. There is no FBD in tea dryer for initial

moisture removal as the total moisture content to be removed is less than that of KPD.

In the Tea Dryer, plenum chamber is almost same as Paddy Dryer in shape with a perforated sheet and drying

chamber but difference lies in the opening of the perforated sheet. Here the perforations are oblong shaped.

There are three zones in the drying chamber to which the air is supplied from three different section of the

plenum chamber. In addition, a cold air blower is used in tea dryers to control the temperature. This cold air is

supplied along with the hot air which mixes in the mixing chamber installed at the mouth of the plenum

chamber.

For EE model, hot air blower with the motor capacities of 20 to 25 HP and for CAB 3 HP motor is used.

Also to provide uniform loading of feed into the drying chamber, feeding system with the motor capacity of 1

HP is installed.

The exhaust system of KTD is entirely different to that of KPD. The exhaust assembly comprises of two

DUSTRACTORS. A dustractor has a cuboidal shape with 6-8 cone shaped chimneys which are placed above

the drying chamber to remove off the moisture and the exhaust gases from the dryer. The dustractor has an axial

fan with a 5 HP motor.

At the discharge end of the Dryer there is a twin cyclone separator to retain some of the tea particulates which

are removed in the exhaust system.

Description of Main Components

Hot Air Blower

Hot air blower which is used to deliver hot air into plenum chamber is placed followed by heating assembly

with a 100 HP capacity motor. HAB, consists of centrifugal fan, has two inlet ports which sucks air at

80000m3/hr.

Plenum Chamber

Plenum Chamber, made of Mild Steel, is used for supplying air inside the drying chamber. It is made in 2 parts

which are joined by nut bolts by providing flanges, reason being the large size of plenum chamber which

hampers in its transportation. Excitation system is attached below the plenum chamber facilitates vibration. A

motor of 5 HP is attached with excitation system by an eccentric shaft.

Plenum chamber has 3 divisions to blow air in different zones of the Drying Chamber. Air Flow rate through

the Plenum chamber is controlled by providing Dampers at its inlet.

Plenum chamber is made of two sheets, inner sheet and outer sheet. Inner sheet is 2mm thick while depending

on the capacity and length of dryers, outer sheet thickness varies from 3-5 mm. Flanges, which are used to

attach two part of chamber; thickness varies from 6-8 mm.

Drying Chamber

Upon the plenum chamber rests the Perforated Stainless Steel sheets on which the material is dried is known as

Drying Chamber. In drying chamber, tea is dried in contact with hot air. Drying chamber is made of 3mm

thickness of 8 SS sheets.

Perforated Sheet

It is placed between plenum chamber and drying chamber to control the air flow rate into drying chamber. SS-

304 with 2mm thickness is used to make perforated sheet. By attaching 3 sheets of 2 meters length using

tungsten welding perforated sheet is made. The opening varies 2.5-4% according to capacity of dryers.

Dustractor

Exhaust system of tea dryer is consisted of two dustractors which help to depart hot air from drying chamber by

separating tea from hot air. A dustractor has a cuboidal shape with 6-8 cone shaped chimneys. The bottom

portion of chimneys which are placed inside drying chamber, have lot of wings help to create swirl motion of

air. It has axial fan attached with 5 HP motor.

Mixing Chamber

Mixing chamber is installed at the mouth of plenum chamber to mix hot air along with cold air coming through

cold air blower. It is divided into two portions by a square perforated section with triangular projection.

Heating Assembly

Heating assembly comprises of two things. First one is Heat Exchanger and another one is control gear which

controls the air flow rate.

Cyclone Assembly

At end of drying chamber cyclone blower is installed to remove the air from drying chamber which is

connected with cyclones. From the cyclone, after separation of tea air goes to air heater through Hot Air

Regeneration Duct and tea is collected. Specification of Cyclone

Air Flow Rate : 12000m3/hr


Operating Pressure : 80mm WC

Operating Temperature : 800C

Feed Hopper

A rotating rod comprises with impellers is attached with feed hopper to control feed rate. Rotating rod is

controlled by a 1HP motor.

Bellow

Bellow is placed between mixing chamber and inlet port of plenum chamber which deter vibration to transmit

into heating system. Below is made of two square connected with a Teflon cloth.

Excitation System

Excitation is installed at the bottom of the plenum chamber. Eccentric shaft which produces vibration has ------

eccentricity. Eccentric shaft is mounted with 3 HP motor.

Design and Development of Commercial Model

First they came in the commercial market with Phase -1 (Model A1) Vibro-fluid bed dryer which was very

simple in construction and operation. It consisted of two separate large cyclone connected with one last

discharge chute. However rest of the two chutes were open which enhanced the losses. After that Phase-I

(Model-A2) were launched which equipped with one cyclone connected with all three discharge chutes.

VFBD Phase II Dryer was compact than Phase-I. Dustractors were introduced in this phase.

In Phase-III, the refiring system was introduced with each discharge chute minimizing losses and placed the

cyclone blower at top of the end of drying chamber.

In phase-IV Dryer, centrifugal fan with axial dust extractor and removable impeller were introduced.

Multilouver damper in mixing chamber which was another modification in Phase-IV dryer, improved the

mixing of hot and cold air and also controlled the rate of air flow into plenum chamber.

In Phase-V dryer, again construction of dustractors were changed and axial flow fan with centrifugal dust

extractor were used instead of centrifugal fan with axial dust extractor.

With continues R & D works on energy consumption, operational convenience and tea quality, Field data

analysation and based on customer’s review, Phase-VI dryer has been launched in market.

Major changes in VFBD Phase – VI Model

1) Modification in mixing chamber for better mixing of hot and cold air (with lower resistance).

2) Increase in drying chamber height to avoid any side fly off.

3) Change in the design of deflector plates.

4) Increase in dryer area by modifying the design of distribution plate.

5) Dust extractor system now use axial flow fans with axial flow dust extraction for handling larger

capacity of exhaust air.

6) Modification in plenum chamber design to reduce air flow resistance.

7) Modification in exhaust system for lower resistance. Relocation of motor to vertical on dust extractors

with aerodynamic design to handle flow.

ADVANTAGES OF KILBURN VFBD PHASE VI

1) Dust Extractor changed for ease of maintenance & for more uniform air flow. Increase in output by 8%

- 10% thereby reducing the fuel consumption.

2) Cold air blower connected to the stationary section for uniform mixing of hot and cold air in Mixing

Chamber.

3) Newly designed Cold Air Mixing Chamber to ensure better mixing of hot & cold air, resulting in

improved quality of made tea.

4) Better Quality of Teas because of More uniform & better mixing of hot & cold air in mixing chamber.

5) More efficient axial type Dust Extractor System resulting in practically eliminating the carry over of

fines.

6) Motor mounting position of Dust Extractor changed for ease of maintenance & for more uniform air

flow.

7) Stainless construction of parts prone to corrosion in contact with tea.

8) Double inlet – double width Hot Air Fan for more uniform flow ( resulting into further improvement in

Quality of Teas)

9) Reduced maintenance.

10) Flexibility of use for CTC and / or Orthodox teas.

Reduction in Power

Upgradation of Various Model

Drying of CTC Tea

TECHNICAL SPECIFICATION FOR CTC TEA DRYER

Capacity Chart for CTC Tea Dryer

Drying of Orthodox Tea

To handle Orthodox Grade (Leafy), unique system was developed using vibration, mechanical mixers and air

velocity to ensure suspended bed with fluidisation which helps in uniform drying of tea resulting in improved

quality of tea produced.

Technical Specifications for Orthodox Tea Dryer

Capacity Chart for Orthodox Tea Dryer

Withering of Green Tea Leaf

Introduction

Withering influences to a great extent in the process of black tea production. It is necessary to regulate this

process to get consistent desired quality of final made black tea.

In the process of withering there are chemical as well as physical changes in green tea leaf. Total process of

wither is dependent on atmospheric condition and therefore can not be controlled which lead to affect the final

quality of made tea.

To ensure uniform quality with consistent parameters during holding of green leaf without any loss of moisture

for chemical wither and later with reduction in moisture during physical withering will improve the quality.

There is considerable saving in labour cost as well as reduction in space requirement.

System Description

After plucking and transportation of green leaf to factory, fresh leaf is fed into double deck vibratory

feeder / screen for removal of any foreign material from green leaf.

Green leaf is conveyed through belt conveyors to holding bins for chemical withering process.

Holding bins have reversible belt conveyor and distributor drum for uniform spreading of green leaf

over the entire length of holding bins.

Fine mist of water spray is also added to ensure relative humidity in the bin will be in the range of 98 –

100%. Leaf should not release any moisture during holding time. System will have provision to purge

saturated air to take away heat generated due to friction between green tea leaf layers.

Green leaf is removed by the movement of mesh type conveyor holding / supporting green leaf and

special vertical discharge feeder using circular pipe to lift green leaf and taken out the incline guides

between pipes.

Holding time during chemical wither will be approx. 4 hours.

Green leaf is conveyed through belt conveyor into physical withering 3 – tier mesh type conveyor.

For physical withering, system used axial flow fan to push hot air over the conveyor for removal of

moisture.

System include steam heater for heating of atmospheric air to required level Temperature of hot air will

be controlled using control valve in steam line.

For uniform distribution of air, distribution plate will be provided for the entire length of conveyorised

system.

As the system has three tier conveyorised system to carry leaf, sealing is incorporated to avoid short

circuiting of air between conveyors.

Residence time during physical wither will be approx. two hours with 150 – 180 mm bed height of tea

leaf over the conveyor.

Process Flow Sheet for Continuous Withering System

Technical Parameters & Equipment Sizing

Design of the FBD used for Radiator design based on the following parameter:

1. Production rate of the Plant (C)

2. Feed rate of the Plant (F)

3. Inlet moisture content (wb)

4. Product moisture content (wb)

5. Inlet temperature of the Material (TM1)

6. Material to be heated upto for drying (TM2)

7. Outlet temperature of the material (TM3)

8. Ambient Air Temperature (TAM)

9. Bulk density of the Material (BKD)

10. Specific Heat of the Material (CPS)

11. Hot air inlet temperature (Tg1)

12. Ambient air humidity (H1)

13. Wet bulb temperature of hot air inlet temperature (Tw)

14. Latent heat of evaporation at Tw (λ)

15. Average Particle Size

Design Calculation

In calculation part following parameters is taken into consideration and calculated accordingly:

1. Moisture Load

Here we calculate the amount of moisture removed from Moisture content in the feed and moisture

content from the outlet product and also we are able to know the feed rate of the material.

2. Drying Air Outlet Temperature

Here we first calculated LMTD .

Temp. Difference in the cold side T1d = Tg1- TW

Temperature Difference in the Hot side T2d = Tg1 - TM2

As the temperature of the steam is constant throughout the dryer and the temperature of outlet

material is near about the wet bulb temperature of hot inlet air, so for calculate the temperature

difference of cold side we use Tg1 and Tw.

LMTD=(T 1 d−T2 d)

[ log(T1 d

T 2 d)]

Exhaust Drying Air outlet Temperature (Tgd) = Tg1 – LMTD

3. Energy Balance- Drying

Energy required to heat dry solid (Q1) = DS × CPS × (TM2- TM1)

Energy required to heat water from TM1 to TW (Q2) = W1 × 1 × (TW – TM1)

Energy required to vapourise water (Q3) = W × λ

Energy required to heat remaining water from TW to TM2 (Q4)= W2×1×(TM2-TW)

Energy required to heat water vapour from Tw to Tgd (Q5) = W ×0.45× (Tgd – TW)

Heat Required= Q1+ Q2 +Q3+ Q4+ Q5= Qd

Assuming Heat loss 10% , Heat Required (QTd) = Q × 1.1

4. Drying Air flow rate

Mass flow rate of drying air = QTd / [0.24 × ( T g 1−T gd ) ]

5. Air Heater

Energy required to heat drying air= Mgd× 0.24×(Tg1 - TAM)

6. Dryer surface area(Vd) =

22.4 ×[(1/29)+(H1/18)]× [(273+15.5)/273]

Volume of drying air at exhaust temp (Vd) = Mgd x vd

Then we assume Fluidisation velocity as 1.65m/s

Dryer area required Ad = Vd/(vd x 3600)

7. Drying Air Fan Capacity

Mass flow rate of drying air (Mgd)

Inlet temp of drying air to the fan (Tgl)

Sp. volume of drying air (Vad)

Air flow rate (Mgd x Vad)

Static Pressure across drying fan (ΔP)

Power required to drive the fan = 2.72x10-5 x Vad x ΔP/10

Motor Rating (Assuming 75% efficiency)

8. Cooling air outlet Temp

Temp difference of hot side T3c

Temp difference of cold side T4c

LMTD (T3c-T4c)/[ln (T3c/T4c)]

Exhaust cooling air outlet temp Tgc

9. Energy Balance- Cooling

Energy to be removed to cool dry air Q6 = Ds x Cps x (TM2-TM3)

Energy to be removed to cool moisture Q7 = W2 x 1 x (TM2-TM3)

Heat to be removed (Assuming 10% extra) QTc = (Q6 + Q7)x 1.1

10. Cooling air flow rate

Total energy to be removed QTc

Mass flow rate of cooling air = QTc/[0.24 x (Tgc-TAM)]

Flow rate of cooling air (Assuming 10% extra) Mgc = 1.1 x QTc

11. Cooling surface area

Sp. volume of cooling air at exhaust temp.(vc)

Volume of cooling air at exhaust temp (Vc) = Mgc x vc

Assume velocity v1c = 1.5 m/s

Cooling Area required Ac = Vc/(v1c x 3600)

12. Cooling air fan capacity

Mass flow rate of cooling air Mgc

Sp. Volume of cooling air vac = 22.4 ×[(1/29)+(H1/18)]× [(273+TAM)/273]

Cooling air flow rate Mgc x vac

Assuming 10% extra Vac

Static Pressure across drying fan (ΔP)

Power required to drive the fan = 2.72x10-5 x Vac x ΔP/10

Motor Rating (Assuming efficiency of fan at 75%)

Paddy Dryer for Rice Mill

(Patent applied for)

Kilburn Continuous Paddy Drying System:

What is Parboiling?

Drying Principle Parboiling is “par”-tially “boiling”. It is a Hydrothermal process involving water and heat

(steam) resulting in the gelatinization of the starchy kernel without disturbing the shape and form of the paddy.

Parboiling conventionally is “Presteam-Soak-Drain-Cook-Dry” process. Cleaned and conditioned paddy is

subjected to dry saturated steam followed by soaking for a desired time-temperature. The water is then drained

and the paddy is steamed to gelatinize the starch.

Paddy after parboiling contains around 35-40% wb moisture. For safe storage it has to be reduced to around 12-

13% wb. Properly dried parboiled paddy would give minimum breakage.

There are three drying periods which will occur consecutively in time:

Preheating period: When wet grain is exposed to hot air, all the heat provided in the drying air is used to heat up the grain

to the drying temperature.

Constant-rate period: Once the grain is at the drying temperature, water starts evaporating from the surface of the grain

and the drying rate is constant with time. All the heat from the drying air is used to evaporate the surface moisture.

Falling-rate period: As the time passes, the surface remains no wet. It takes more time for internal moisture to appear at

the surface, drying rate declines and some of the heat from the drying air heats up the grain. The transition from constant

to falling rate occurs at around 18% wb moisture and is called the critical moisture content (Ms)

Kilburn Drying Concept

The rice grain is susceptible to cracking only below critical moisture where if the drying rate is too fast it becomes a

serious source of grain damage and cracking. Moisture evaporates only from the surface; so the moisture from the inner

layer first diffuses to the surface and only then it evaporates. This process therefore sets up a steep moisture gradient in

the grain, as the surface being excessively dry and the core still wet, results in moisture stress and the grain releases the

stress by cracking. Kilburn has devised a system to properly dry the grain to the desired moisture by way of gentle

handling.

The recommended combination for Drying Parboiled Paddy is : Kilburn VFBD + Column Dryer

Advantages:

Reduction in drying cycle time of the combination system compared to conventional Column Dryers thereby

increasing the production.

VFBD when used as a pre-dryer increases the production per column dryer.

VFBD conveys by means of mechanical vibration and the air which ensures “gentle handling” of the paddy.

VFBD dries paddy partially resulting in increased flow-ability. Thus paddy handling becomes easier.

VFBD though a continuous dryer can be used as a pre-dryer to column dryer(s). The latter can operate either in

batch or in continuous mode.

VFBD + Column Dryer combination drying process can be mapped to optimise number of parboiling tanks.

VFBD comes with a robust modular steam air-heater with optional flash recovery system for efficient utilization

of steam.

VFBD Paddy contact surface is made of stainless steel to ensure longevity of the dryer.

Longevity of Column Dryer increases as it handles low moisture paddy.

Capacity

Kilburn offers capacities from 5 to 15 Tons/hr @ 36-38% wb feed to VFBD (Corresponding weight of the dry paddy

would be 3.5 Ton/hr and 11Ton/hr respectively @ 13% wb, but exact capacity would depend on the Moisture content,

Inlet hot air temperature and crop type)

Higher capacities can be obtained by installing parallel units.

Overall plant capacity would depend upon size, drying cooling and unloading time of Column Dryer.

Fluidisation Techniques are gaining increasing importance for unit operations involving drying, cooling,

calcinations and reaction engineering in Chemical, Petrochemical, Fertiliser, Pharmaceutical, Foods and other

industries.

KILBURN ENGINEERING LTD. has acquired in-depth technology, expertise and experience in this by

technical collaboration with M/s NARA MACHINERY CO. LTD., Japan

Kilburn Engg. is in position to offer advanced and sophisticated designs for thermally efficient operations

ADVANTAGES

Fluidised Bed Techniques offer following advantages

Intimate contact of hot air and solids result in high heat transfer co-efficient. This makes the drying

system compact.

Higher operating temperatures possible because of rapid heat and mass transfer rates.

No overheating of heat sensitive products because of special constructional features.

Lower capital costs.

Easy handling of feed and product.

No moving parts, stabilised operation and negligible maintenance.

FLUIDISATION

Fluid means a liquid. A substance is said to be fluidised when it starts behaving like a liquid. When a

determined quantity of air is passed below a perforated bed, carrying the substance to be dried, say PVC, the

material starts bubbling and it behaves like a fluid. Much depends upon the substance, its moisture content, size

of perforations, and air flow. When the air velocity is low, the bed of solids remains still. As the air velocity

increases, the particles on the upper part of the static bed begin to move and separate from each other.

When the air velocity is further increased, the particles begin to float. The particulate bed is expanded and the

movement of particles become an active formation of a mixture of air and particles. This gas-solid mixture is

called ‘Fluidised Bed’.

When the air velocity through the fluidised bed is increased further, the particles bubble more and more

vigorously, and some of the particles begin to gradually fly-off. When the air velocity exceeds the terminal

velocity of the particles, all of the particles may be blown-off resulting in ‘Carry Over’.

FLUIDISATION VELOCITY

The onset of fluidisation occurs when the drag force of the upward moving gas equals or is more than the

weight of the particles. Voids, particle geometry and particle size distribution play an important role in pressure

drop and fluidisation velocity. As seen from Pressure Drop (P) vs Air Velocity (V) graph, the fluidisation

velocity increases without any appreciable change in pressure drop.

Fluidisation velocity is best determined by pilot plant experiments on representative sample of product. This

data can be cross examined with empirical and other computerised data. Practical experience can determine the

values for commercial size plants. Improperly fluidised beds not only adversely affect the heat and mass

transfer rates but may also affect the product quality. Figures show as to how slugging and channelling affect

the pressure drop-velocity relationship.

The flow rate of heat transfer media varies from minimum fluidisation velocity (Vmf) to the terminal velocity

(Vt), which causes pneumatic transport of solids because of entrainment. For this reason, fluidisation velocity

(Vf) is kept between Vmf and Vt. The ratio of terminal velocity to minimum fluidisation (Vt/Vo) varies from

10 to 90. Smaller the particle size, lower is the ratio. Thus the practical value of fluidisation velocity is

determined by particle size distribution, shape, density and similar other considerations.

DRYING CHARACTERISTICS OF PARTICLES ON A FLUIDISED BED

The Drying characteristic of a product is displayed by plotting moisture and temperature over time. The Drying

characteristics of a product depends on its physical properties. These are identified by conducting drying tests at

the Test Centre in a small sized fluid bed dryer.

As free or surface moisture is evaporated, the drying rate remains constant. A transition or critical point is

reached when the drying rate starts falling, till equilibrium moisture is reached. The drying time is determined

by constant-rate drying, moisture content at the critical point and the falling-rate drying.

FLUID BED SYSTEM

Fluidised Bed Technique is most effectively utilised in a number of heat and mass transfer applications like:

DRYING

COOLING

CALCINATION/ ROASTING

CARBONISATION

REACTION

STERLISATION

BASIC COMPONENTS

Following are the basic components of a Fluid Bed System.

1. Distributor Plate.

2. Plenum Chamber.

3. Drying Chamber.

4. Hot Air System.

5. Feed System.

6. Dust Collection System.

7. Product Discharge System.

A typical Fluid Bed Dryer is schematically shown here……….\\\\\\\\

FOUR VITAL ELEMENTS OF A FLUID BED SYSTEM

REGULATED FEED SYSTEM:

A fluid Bed System requires an inbuilt feeding mechanism which will ensure a regulated feed, and also alter the

feed rate as and when desired. There may be a number of occasions when product moisture variation needs to

be controlled by regulating the feed rate.

MECAHINCAL SCATTERER:

While handling wet feed having higher moisture content, it is desirable to spread the wet feed over as large area

as possible. The wet feed which is not initially fluidised, starts fluidising after losing its moisture partially by

coming in contact with material already in the fluid bed. The mechanical scatterer acts as a de-lumper and

distributes the material uniformly across the bed.

DISTRIBUTOR PLATES:

Quality of fluidisation is very sensitive to the design of Air Distributor. A properly designed Distributor ensures

requisite size of bubble formation and gas solid contact. This ensures uniformity of heat and mass transfer.

Configuration of Distributor Plate is selected based upon particle size, fall through, other material

characteristics, and operational requirements, such as change of grades, cleanability etc.

PRODUCT DISCHARGE SYSTEM:

An overflow and underflow product discharge system is found extremely useful. This controls the height of the

fluid bed and handles agglomerates effectively.

BATCH TYPE CONTINUOUS FLUID BED DRYER

It comprises of a cylindrical or square vessel fitted with a distributor plate. The fluid bed plate can be rotated

90°. Hot air is supplied from below through a conical vessel. Wet material is fed from the top and dried product

is discharged downward by rotating the plate.

Such a system allows continuous feed and discharge.

SALIENT FEATURES:

1. Accurate control of retention time and uniform drying.

2. High co-efficient of heat transfer.

3. Simple operation.

4. No damage to particle by attrition.

APPLICATIONS:

Drying, heating, cooling, sterilization or ripening process for Polymers, Chemicals and Fertilizers.

CONTINUOUS FLUID BED DRYER

The distributor plate is fixed at the bottom of a rectangular vessel. Hot air is passed through the Distributor

Plate and wet material is led continuously by a screw feeder at constant rate. The air velocity can be varied as

desired. After lapse of designed residence time, the dried product is continuously discharged at the overflow

and underflow outlets. The exhaust air is vented out after processing through a dust separation system.

SALIENT FEATURES:

1. Operation can be easily controlled by adjusting feed and temperature of hot air based on the temperature

at the outlet.

2. Over and under flow features provide uniform drying of small and large size particles.

3. Wet feed is mixed with semi-dried product in the chamber, hence products with higher moisture content

can also be fluidised and dried

4. The drying chamber can be partitioned by baffle plates resulting in more uniform drying.

VIBRATORY FLUID BED DRYER

Vibratory fluidised bed dryer (Patent No. 155757) is an extension of fluidised bed techniques, by using

vibrations as an external aid to fluidisation. All materials cannot be fluidised because of one or more of the

following reasons:

1. Excessive moisture

2. Strong surface forces

3. Wide particle size distribution

4. Fine Powder

5. Other product characteristics

Some of the materials having such properties can also be fluidised well with the aid of mechanical vibrations.

Vibrations breakup the inter particle forces of attraction and improve quality of fluidisation. Bubbling of hot air

in a stationary fluid bed may cause violent agitation. When vibrations are used as an aid, gas velocities are

reduced and the fluidisation is gentle. Particle attrition is reduced. Thus substances having low mechanical

strength can be dried without damage.

There are two methods of imparting vibrations:

a) Constant Force System

b) Constant Displacement System

Choice is exercised based on application.

ADVANTAGES

1. Suitable for materials having wide particle size distribution.

2. Effective fluidisation of difficult materials

3. Low air and energy consumption.

4. Low dust emission because of low air flow rates.

5. Self discharging.

6. Easy control of residence time, product moisture and overall operation.

TYPICAL APPLICATIONS:

Potassium Chloride

Common Salt

Citric Acid

Urea Pesticides

Milk Powders

Instant Coffee

Tea

Sugar

Paddy

Soya

Maize

PILOT PLANT TESTS

Design of a commercial size Fluid Bed System is not just heat and mass transfer calculations or sizing. It is an

art! Pilot plant tests, experience and field data are important for designing an optimised Fluid Bed System for

continuous application. Consideration of fluidisation velocity, operating temperature, particle size distribution

of material, distributor plate, bed height and dedusting system require pilot plant tests.

Kilburn Engineering Limited has a fully fledged Test Centre, where exhaustive facilities are available for Pilot

Plant Tests. All variable parameters can be adjusted to study the drying characteristics of a substance and

thereby determine values of important parameters. This data is further supplemented with the empirical and

actual field data.

Project KEL

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