Energy-saving solutions forthe paper machine

Mikko OsaraVice President, Sales

Paper business line, Metso

TAPPSA - 2010

© Metso

Board production costs, by main gradesGlobal average cost, FOB mill site

2 Source: Fisher International, Inc. (2007)

0

100

200

300

400

500

600

Linerboard Corrugating Medium Kraft Board Recycled Board

Euro

per

met

ric to

nne

Fiber

PulpChemicals/minerals

Energy

LaborOther

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Energy consumptionModern newsprint machine

3 Metso data

Shortcirculation

12%

Headbox0%

Forming section19%

Press section31%

Dryer section17%

Calender15%

Reel4%

Winder2%

Shortcirculation

11%

Headbox1%

Presssection

13%

Dryer section69%

Ventilation (hall)6%

ElectricityElectricity SteamSteam

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Electricity usage, forming and press sectionsDrives, vacuum and hydraulics, modern newsprint machine

Metso data4

Sectional drives42%

Vacuum system35%

Shower watersystem 11%

Broke collection 6%

Ventilation 4%Hydraulic system 1%

Pressurizedair system 1%

Sectional drives60%

Vacuum system20%

Hydraulic system15%

Brokecollection 3%

Shower water system 2%Pressurized airsystem

Forming sectionForming section Press sectionPress section

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Modern machines are more efficient

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Efficient drying andheat recovery

Film size press

High dryness afterpress with shoe

pressing

Fast tail threadingand break recovery

High time efficiency

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Run with less energy – Levels of improvement

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1. Parhaat ajotavat nykyisillä laitteilla

2. Nykyisen laitekannan huolto

3. Korjaukset

4. Laiteuusinnat

Exte

nt o

f inv

estm

ent

1. Best operational parameterswith the present equipment

2. Maintenence andpreventive service

3. Repairs

4. Rebuilds

5. New technologies

Stock preparation - refining

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One OptiFiner Pro can replace two traditionalrefinersand even deliver 20% electrical energy savings

Energy efficiency andvacuum system analyses

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Energy efficiency analysisResults example: short-term actions

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Grade: FlutingGrammage: 100-200 g/m2

Reel width: 6,680 mmMachine speed: 700 m/min

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Vacuum system upgradesPress section

• Vacuum system design- Typically all systems are designed at “low cost energy time” and based on very

traditional engineering.-> System efficiency loss is high

• Felt types and operation conditions- Many fast running paper machines are today targeting dewatering at the nip

instead of at the Uhle box .- Vacuum levels of Uhle boxes are often also lower than earlier.

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Vacuum system rebuild - energy saving 770 kWEuropean mill, LWC, project start-up Sept 2010

• Preceded by a vacuum system study- total theoretical electric energy saving

potential over 1 MW- About 70 % of savings with relatively small

investment

• Rebuild results- Rebuild in a two day shut-down

in September- Two vacuum pumps were stopped and total

energy consumption decreased by 770 kW

• Metso scope:- Process engineering, automation field

equipment, DCS system softwaremodifications, pick-up logic update

• Customer scope:- Piping materials and installation

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Forming section

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Optimization of dewatering in the formingsection

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It’s all about maximizingthe dewatering and

minimizing the rewetting !

Friction

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New perforated suction box coverInclined drilling and new cover material for lower flow resistance

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Traditional cover

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New perforated suction box cover gives highconsistency with low vacuum

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Press section

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Solutions to reduce energy usagePress section

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Runnability improvementsand cost savings with shoepressing and belt doctoring

(BeltDoc)

From Uhleboxdewatering tonip dewatering

Perforateduhlebox cover

Nip dewatering

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Energy savings due to shift from Uhle box tonip dewateringEstimated normal running loads (kW)

20 Assuming, that blowers/pumps are selected to operate at optimumconditions (no bleed air, no throttling of valves).

800600

400150

500

400

400

240

0

200

400

600

800

1000

1200

1400

Open felt55 kPa

Uhle vacuum

Press section drive NRL, kW

Blower/Pump NRL, kW

Load(kW)

Open felt45 kPa

Uhle vacuum

Dense felt45 kPa

Uhle vacuum

Dense felt25 kPa

Uhle vacuum

Perforated Uhle box cover,shoe pressing &

BeltDoc doctoring

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Perforated Uhle box coverLonger felt lifetime – lower energy load

• Dewatering capacity is based on a largeopen area of the perforation

- Long dwell time in the suction area

• Increases felt dewatering at a lower energyload and vacuum level than a conventionalslotted cover

• Decreases friction between the cover andthe felt

- No slots for the felt to ”dive” into anymore- Gives a longer felt lifetime

• Felt well supported over the entire suctionarea

• Quick and easy assembly to existing Uhleboxes

22 Pilot machine trial data; comparison to conventional slotted cover

Perforated Uhle boxcover *):• 25 kPa lower

vacuum level• 13 kW lower friction

effect• 65 % lower air flow

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Felt behaviour in the suction area

23 Pilot machine trial data

Liner / fluting productionmachineConventional slotted cover

Pilot PM 2

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SymBelt shoe press rebuild

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Case fine papermachine,Width 5,500mm, 1,100m/min

Rollpress

Mini shoe press– Opt 1

Mini shoe press– Opt 2

Mini shoe press– Opt 3

Std shoe press –Opt 4

Linear load (kN/m) 120-130 200 kN/m 350 kN/m Up to 600 kN/m 600-1500

Dry contentincrease

Ref. Approx. 1 – 1.5%

Approx 2 % Approx. 2 – 3 % Approx. 3 - 6 %

Productionincrease or steamconsumptiondecrease

4 – 6 % 6 – 8 % 8 – 12 % 12 – 24 %

Press / Shoe pressroll diameter

700-900 1095 1095 1095 1250-1595

Counter roll Solid roll Existing (newdrive)

Existing (newbearing housing,

new drive)

New SolidL roll New SymZLC rollpackage

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BeltDoc improves dryness and moisture profile

• Minimizes misting around theshoe press

• Increases dryness andimproves moisture profile afterpress

• Close to 100 references

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Support bar

IntegratedBeltDocdoctor

Saveall

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Higher web dry content and speedBeltDoc doctoring solution – WFU line, 80 gsm copy

• Target- Increase web dry content & improve

runnability after the SymPress B press section

• Actions- Installation of BeltDoc with saveall- Saveall close to felt possible to increase

linear linear load from 700 kN/m to 850kN/m

Action Results

Higher linear load 1.5 % web dry content increase after press

BeltDoc & saveall 0.5 % web dry content increase after press

Machine speed From 1,450 m/min to 1,505 m/min

Dry content From 48.5 ..49.5 to 51 – 52 %

Bulk No difference

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Other energysaving solutions

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Energy savings through optimized doctoringat the dryer section

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Relative power consumption of doctor blade materials

Based on laboratory tests in simulated paper machine environment

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7 m wide paper machine running at 900 m/min, using either glass fiber or carbon doctor bladeon cast iron cylinders (dryer can)

Assumptions ResultsWidth 7 m Power consumption to overcome friction

generated by a single blade on a dryer canMachine speed 900 m/min

Load 300 N/m Glass fiber blade 15,75 kWDryer cylinder radius 0,915 m Carbon blade 6,3 kW

µ Glass fiber 0.5 Difference per blade: 9,45 kWµ Carbon fiber 0.2 x 50 blades 472,5 kW

Number of blades 50 Annual difference inRunning days/year 300 energy consumption 3402 MWh

Energy savings through optimized doctoringat the dryer section

• Results: Energy savings, a cleaner cylinder will improve cylinder drying capacity andrunnability, reduced total doctoring costs.

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Example calculation

Potential annual savings €136,080

€0,04 /kWhEnergy price

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High intensity air dryer to replace IR dryersPowerDry Plus

• High drying rate with effective nozzletechnology

• Significant energy savings (50%)compared with infrared drying

• Environmentally friendly, 50% lessfuel burned and CO2 formed

• Low moisture and heat loads tomachine room

• Low maintenance costs

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Summary

• Energy costs are the secondbiggest cost

• Improving efficiency reducesspecific energy cost

• Metso offers many services, newinnovations and technologies thatdirectly reduce energy andproduction costs

• Most of these small investmentshave short payback times and canbe installed as retrofits

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