8
www.andritz.com Fläkt Dryer World leading pulp drying technology We accept the challenge!
ww
w.a
ndrit
z.co
m
Fläkt DryerWorld leading pulp drying technology
We accept the challenge!
2
��������������
�����������������
���������� ���������������������
�������������������
The Fläkt Dryer for High Quality Pulp
The Fläkt Dryer is the result ofexpericence gained from more than500 pulp dryer installations since1928 and a continous research anddevelopment work in the pulp dryingfield. More than two-thirds of theworld’s pulp is dried in Fläkt dryerstoday.
Customers around the world arebenefiting from our uniqueexperience to produce high qualitypulp efficiently and reliably in cost-saving dryer systems.
Many mills choose to replace theirold drying equipment to increasepulp production. Higher pulpbrightness reduced maintenance,labour and energy costs are othermotives. A new Fläkt Dryer cansatisfy all of these requirements.
More capacity in less space....
The Fläkt Dryer requires less space for a specificproduction rate or provides more capacity in a givenmachine room when replacing an old dryer.
...... due to an efficient heat transfer system
The Fläkt Dryer is compact because of it’s high-efficiency air impingement system on both sides of thepulp web. The system provides uniform and high heattransfer to the pulp web.
Due to the close distance between the web and furtherimproved bottom Bernoulli blow boxes, heat is transfer-red efficiently to the bottom surface of the web. The topblow boxes allow the transfer of additional heat toincrease drying efficiency and cut drying time. Theoverall result is a compact dryer design.
Low web tension for high operating reliability
The bottom blow boxes, an exclusive Fläkt designutilizing the Bemoulli principle, lift the web clear of thedrying deck and locate it at a fixed distance above thebottom blow boxes.
With this design, the sheet can be dried with minimalweb tension, without sheet flutter.
Because the Fläkt Dryer operates with web tensionssubstantially below those of other air and cylinderdryers, it can handle pulp sheets of lowest tensilestrength.
........ for CTMP, too
Birch, beech, eucalyptus, mixed tropical hardwood andCTMP are examples of low tensile strength pulps thatare being effectively dried in Fläkt dryers today.
3
�����
�����
�����
����
���
��� �
��� �
��� �
������
���������
�����
���� ���� ���� ���� ���� ���� ������������������������
����������
������
��
�����
����
������
��
���������������
Drying temperaturePsycrometric chartfor humid air
Low pulp web temperature for high quality pulp and brightness
The Fläkt Dryer utilizes heated air to dry and supportthe pulp web. The web is fed into the upper deck of thedryer, where it is supported by air while making several
horizontal passes back and forth along the entire lengthof the dryer. The web never touches any heated steelsurfaces.
Brightness is maintained because of a low pulp-webtemperature during air drying. The evaporative coolingeffect permits evaporation to take place at the low wetbulb temperature of the drying air.
The Fläkt impingement system allows gentle drying atlow temperatures for the production of consistently highquality pulp with uniform dryness across the width ofthe sheet.
Sheet cooler for fully bleached pulp
The Fläkt Dryer can be equipped with a sheet coolerthat cools bleached pulp before it is conveyed to thecutter. There are a number of advantages to installing asheet cooler:
- Mininium brightness reversion during storage
- No condensation during pulp storage and transport
- Longer cutter knife life
- More uniform bales
The Fläkt Sheet Cooler is normally integrated with thedryer but can be supplied as a separate unit. In theintegrated unit, the bottom deck is equipped withcooling air blow boxes and isolated from the dryingdecks by insulated panels and the supply air plenum.This arrangement provides a hot and dry interfacebetween the dryer and cooler to eliminatecondensation.
Internal air circulation system
The dryer is designed with a number of identicalvertical sections with steam coils for heating the dryingair. Axial fans distribute the drying air to the blowboxes. The steam coils and fans are specially designedand manufactured for the Fläkt Dryer.
Air enters the fan through the steam coils. After air isdistributed onto the sheet by the blow boxes, it isreturned between the blow boxes to the steam coilcompartment. The humidity of the air increases as itcirculates upward in the dryer. To optimize heateconomy, only a small percentage of the circulation airis exhausted and replaced with make-up air.
4
Two basic models to meet varying production needs
Fläkt Dryer model FCG
FCG is the fully equipped Fläkt Dryerfor high production rates. It has allthe auxiliary equipment necessaryfor dryers of this size such asmovable platforms, broke removaldevice, Fläkt Tail Cutter and theunique Fläkt folded tape threadingsystem.
The folded tape threading systemmakes it possible to thread the tailat normal machine speed up to 200meters per minute. The tape runs onseparate pulleys and the tapesystem is only engaged during thethreading.
Dryer model FCG equipped with anintegrated cooler is designatedFCGC.
The FCG is the successor to thewell-known FCL model of the FläktDryer.
Feeding of pulp tail into tape
Fläkt Dryer model FCS
FCS is the economy version dryerfor lower production rates up toabout 500 tpd. This dryer hascertain limitations when it comes tomachine height and web width. Ithas the single tape threadingsystem suited for lower threading
speeds. The basic design and theoperating ability of FCS is howeverthe same as for model FCG.
FCS Dryer equipped with anintegrated cooler is designatedFCSC.
Single tape threading system
Easy inspection
The top blow boxes of the FläktDryer can be lifted to allowinspection of the drying decks.
5
���������������������������������������������������
���������������
������������
���������������������������
����������������������������
�����������
�����������
������
Fläkt Dryer with cooler deck andcomplete heat recovery boiler
Web tension control
The pulp web travels over the dryerdecks via turning rolls at the endsections. The turning rolls areequipped with over-runningclutches that are free-runningduring normal operation, with theweb pulled by a nip roll arrange-ment at the outlet end.
The pull roll motor is controlled byweb-tension load cells located atthe inlet end of the dryer. Controlpanels are located at each end of
Cost-saving design with low energy consumption
Drying in a Fläkt Dryer results in lowproduction costs, due to reducedenergy consumption and main-tenance.
Since costs for heat energy fordrying pulp account for a large por-tion of overall operating expensesfor a drying line, the optimumsolution is normally to install thedryer offering the lowest heatconsumption.
With its closed recirculating andreheating system, the Fläkt Dryerconsumes much less energy thancylinder machines. The well-
insulated panels and the compactdesign also minimizes the heatlosses.
Drying air entering the bottom ofthe dryer is continuouslyrecirculated and reheated in theinternal air circuits before it isexhausted into the heat recoverysystem. The heat in the humidexhaust air is utilized primarily toheat the make-up air supplied tothe dryer. It can be further used toheat water and ventilation air for themachine room and other sectionsof the mill.
Approximately two-thirds of all initialheat energy used for drying can berecovered economically to heatprocess water and ventilation air.Steam consumption can be furtherreduced by using blow-throughsteam from the dryer condensatesystem - or the condensate itself -to raise the temperature of theprocess water.
Maintenance costs are low, due tothe robust design of the Fläkt Dryerand its few moving parts (only thefan impellers and rolls move duringoperation). One mill with a 750 tpdFläkt Dryer reports that maintenancecosts, including labour andmaterials, averaged less than USD0.05 per ton of pulp during the firstfive years of operation.
Heat recovery system for Fläkt Dryer
the dryer. The web tension can beset up to the desired value bymeans of the electronic equipmentin the control panel at the inlet end.
6
Examples of Fläkt Dryer installations
Fläkt Dryer FCGC , 2756 admt/d, Aracruz Celulose S.A., Brazil
Fläkt Dryer FCGC, capacity 3230 admt/d,Hainan ChangxiangTrading Co. Ltd., China
Auxiliary equipment Fläkt Web Guide
Low web tension throughout the entire dryer is one ofthe unique features of Fläkt Dryers. When operatingwith low web tension, it is important to guide the webproperly to obtain uniform bales, or to minimizetrimming when using reels.
The Fläkt Web Guide controls the lateral webmovement. The position of the web edge is detectedby an electronic sensor. This ensures a stable web rununder different operating conditions.
The Fläkt Tail Cutter using a water jet knife has provento be a very useful tool to facilitate the feeding of pulpinto the cutter lay-boy.
A high-pressure water nozzle is mounted on a carriagepowered by a frequency-controlled motor. The water jetcuts the tail while the carriage moves across the web ata preset speed. A collector located directly in front ofthe nozzle takes care of the used water and pulp fibers.
For easy operation of the Fläkt Tail Cutter, the entirecutting sequence is controlled by a PLC system andonly one operator is required to thread the cutter lay-boy.
Fläkt Tail Cutter
6
Examples of Fläkt Dryer installations
Fläkt Dryer FCGC , 2756 admt/d, Aracruz Celulose S.A., Brazil
Fläkt Dryer FCGC, capacity 3230 admt/d,Hainan ChangxiangTrading Co. Ltd., China
Auxiliary equipment Fläkt Web Guide
Low web tension throughout the entire dryer is one ofthe unique features of Fläkt Dryers. When operatingwith low web tension, it is important to guide the webproperly to obtain uniform bales, or to minimizetrimming when using reels.
The Fläkt Web Guide controls the lateral webmovement. The position of the web edge is detectedby an electronic sensor. This ensures a stable web rununder different operating conditions.
The Fläkt Tail Cutter using a water jet knife has provento be a very useful tool to facilitate the feeding of pulpinto the cutter lay-boy.
A high-pressure water nozzle is mounted on a carriagepowered by a frequency-controlled motor. The water jetcuts the tail while the carriage moves across the web ata preset speed. A collector located directly in front ofthe nozzle takes care of the used water and pulp fibers.
For easy operation of the Fläkt Tail Cutter, the entirecutting sequence is controlled by a PLC system andonly one operator is required to thread the cutter lay-boy.
Fläkt Tail Cutter
Fläkt Dryer FCGC, Veracel Brazil.
Fläkt Dryer FCGC, Hainan ChangxiangTrading Co. Ltd., China
7
Increase production with minimum downtime
Dryer replacements
Keeping production downtime to a minimum is usuallyessential when an old dryer section is replaced.Several pre-erection methods have therefore beenengineered, in which the dryer is partly, or completely,assembled outside the machine room.
One frequently used method is to build the dryer inmodules and then move each module into place bymeans of a crane, or by sliding the modules on rails.
A new 800 tpd Fläkt Dryer was installed to replace an old FläktDryer at Alicel, France. Production downtime was only three weeksfor the entire installation.
Dryer extensions
All Fläkt Dryers can be extended in height or length byadding drying decks or drying sections. Experience hasbeen gained over the past 30 years from more than 30dryer extensions all over the world. We have developedspecial pre-erection and lifting techniques enabling usto extend a dryer within a normal maintenance shut-down period.
This Fläkt Dryer at Howe Sound P & P, B.C., Canada, wasextended in six days with six additional decks to boost capacityfrom 750 tpd to over 1100 tpd.
Booster dryer
When used as a booster dryer or cooler in an existingdryer line, the flexible Fläkt Dryer design has proven tobe very cost-effective by providing maximum dryingcapacity in the available machine room space. Thebooster dryer can be erected during operation therebyminimizing downtime. The booster can be deliveredwith an integrated cooler. For a separate Fläkt SheetCooler the same layout as for the booster can be used.
All data, information, statements, photographs and graphic illustrations made in this leaflet are without any obligation and raise no liabilities to or form part of any sales contracts of Andritz AG or any affiliates for equipment and/or systems referred to herein. © Andritz AG 2008. All rights reserved. No part of this copyrighted work may be reproduced, modified or distributed in any form or by any means, or stored in any database or retrieval system, without the prior written permission of Andritz AG or its affiliates. Any such unauthorized use for any purpose is a violation of the relevant copyright laws. Andritz AG, Stattegger Strasse 18, A-8045 Graz, Austria
www.andritz.com
Andritz AB, Växjö, Sweden Andritz AG, Graz, Austria Andritz Fiber Drying Ltd, Lachine, Canada Phone: +46 470 70 63 00 Phone: +43 316 6902 0 Phone: +1 514 631 77 00
Fläkt DryerWorld leading pulp drying technology
