Paper Machine Rebuilding – Time worthy decision
Paper Machine Rebuilding – Time worthy decision
Delowar Hossain, CEO @ PAPTECH | B.Sc. Hon’s + M.Sc. (Chemistry) + MBA – DU | +880 1730 430 800, delowar@paptechbd.com
Now a day’s paper industry in Bangladesh is passing a very harsh time, Electricity and fuel cost become double during last 1 /2 years. Raw material crisis. Machineries and raw material import difficulties due to dollar crisis, more over Giant Group of Industries are trying to dominate this market. So especially small & old paper mills are passing difficult time for balancing cost and profit. Several paper mills are now shout down.
Mainly small and old paper mills (Machine is older than 40 – 50 years) production capacity decreased by 50%. Same time big projects are coming of which can produce up to 500 TPD where else small paper mills production is around 900 – 1400 TPM only. Some paper mills have single layer fourdrinier machine. They can produce only medium paper grade.
To survive in this industry and do compete with big players, It is very important to take decision of existing paper mill rebuilding and modification with latest technology.
Single layer fourdrinier paper machine usually produce medium paper and Kraft paper, but the finish paper quality is not satisfactory due to very old equipment and process. That’s why some paper makes are suggesting rebuild the PM with cylinder mould machine.
Advantage of Cylinder Mould Machine:
- It can produce 45 GSM to 500 GSM
- Can produce Kraft, Medium, Liner, Simplex, Duplex Paper
- 150 GSM Medium / liner paper can produce in 3 /4 layers. So the tensile strength will be good of the finish paper.
- Paper makers can change the grade of paper any time.
- Easy Operation and low maintenance cost compare to Fourdrinier wire Machine.
Paper mills can install from 3 to 6-cylinder mould based on market demand and space allocation. The top and bottom layer can be pressurized former and mid layers can be done with VAT or Box type Cylinder Mould. Each cylinder mould can produce from 30 GSM to up to 130 GSM with maximum 150 mpm running speed if the diameter of the mould is 1500mm. Customer can adjust the cost per ton of paper by adjusting raw materials of each layer.
The drawback of cylinder mould paper is the formation. Finish paper quality will not be good as compare to fourdrinier wire machine and control GSM is an expert thing.
To do rebuilding of the forming section, paper mills also need to consider stock preparation process upgradation as well as vacuum system, press section with bigger diameter press roll and adequate dryer cylinder to increase drying capacity. It is better to do sectional drive instead of line shaft machine to run at good operation speed.
Suction box should be chosen carefully. Ceramic suction box is well recommended due to its long service life, low maintenance as well as it supports better paper web formation.
The Cylinder Mould cover top net mesh can be 30 – 50 mesh and bottom net can be 8 – 14 mesh based on target finish paper GSM and quality.
The pulp stock should pass with fan pump separately to each Pressurized former mould to ensure the pulp consistency and finish paper GSM.
In the Press section a jumbo press with Top Granite Roll and bottom Rubber roll is a good selection to optimize paper moisture in the press section. To enhance the dewatering efficiency
paper mills can add a Vacuum couch roll although it is very expensive.
A baby press with top granite (Ø 400 mm) and bottom rubber roll (Ø 350mm) is good for high GSM board paper.
Keeping same sole plate design, the production per day can increase 10 – 50% based on each paper machine situation.
We PAPTECH team has done several rebuilding projects successfully in Bangladesh. We have our own team We can design, supply and do complete turnkey project-based work with full confidence and warranty.
