By STEVE COLE

Unique PMC and roll technology have a significant effect on reducing paper machine energy consumption

NEW WAYS TO SAVE ENERGY

The primary uses of energy on a paper machine

are in the water removal processes. In the

forming section, 97% of the water is removed

from the paper slurry through gravity, inertia, and

vacuum. In the press section, another 2% is removed

through a nip of nip rolls, vacuum, and press felts

which impart sheet properties and strength. And

even though the dryer section removes the least

amount of water, it is the highest consumer of energy.

This paper will focus on the key products de-

signed to reduce energy consumption and the actual

case histories demonstrating the results each cus-

tomer experienced using Xerium’s innovative product

portfolio, engineered to create financial value for

customers, both in roll and paper machine clothing

(PMC) products.

FORMING SECTION: PMC TECHNOLOGY

Here, the high energy consumption processes are

vacuum systems and related pumps, and sectional

electric drive systems that rotate the forming fabric

which account for 77% of the total energy used.

Weavexx and Huyck.Wangner have recently devel-

oped and launched two product platforms designed to

address energy consumption in the forming section.

EDC (Engineered Drainage Channel) is an in-

novative warp and weave concept that allows for

more efficient drainage of the paper in the formation

zone. This new structural concept provides enhanced

drainage by providing a more open sheet side surface

thereby enabling reduced drainage velocity. This

controlled drainage velocity improves the efficiency

of sheet formation during initial matt building pro-

cess which leads to improved sheet characteristics

and reduced wet-end vacuum requirements.

In addition to the unique EDC fabric structure, a

new raw material technology, EnerSTAR, that signifi-

cantly reduces friction in forming fabrics, has been

introduced.

FORMING CASE H ISTORY #1

A European customer, producing LWC on a twin-wire

former running 1,700 m/min, was not meeting sheet

Pulp & Paper International (PPI) O c t o b e r 2 0 1 1

Fig. 1 - ENERGY CONSuMPTION ON TYPICAL PAPER MACHINE

Fig. 2 - ENERGY uSEd IN FORMING SECTION

w w w . r i s i . c o m - O c t o b e r 2 0 1 1

quality specifications and asked for Xerium’s assistance

in optimizing its forming section. After careful evalu-

ation of the machine and fabric application, Huyck.

Wangner applications engineers recommended a set of

Finetexx forming fabrics incorporating EDC technol-

ogy to improve sheet porosity on heavy weight grades.

After startup of these new fabrics, not only did the

customer experience a reduction in sheet porosity, but

the combination of reduced refining, increased reten-

tion, and reduced sheet drying energy created $280,000

in annualized savings. Integrating Finetexx fabrics also

allowed for a 2% increase in machine speed.

FORMING CASE H ISTORY #2

A European papermaker, producing SC-A at 1,200 m/

min on a twin wire former, requested assistance with

high drive loads and less-than-optimal fabric life due

to premature wear. Huyck.Wangner application en-

gineers recommended a set of advanced triple layer

fabrics with EnerSTAR yarn technology to address the

issue. As a result of incorporating the new fabric and

yarn technology, the machine’s drive load dropped by

10% and fabric life increased by 20% enabling fewer

fabrics and shutdown cycles per year. With the ben-

efits of EnerSTAR technology, the customer reported

a savings of approximately $100,000.

PRESS SECT ION: PMC TECHNOLOGY

Press clothing technology is a major influencing

factor in the efficiency and energy consumption in

the pressing process. Xerium has developed and

introduced exclusive technology to specifically

improve the effectiveness of dewatering and to

improve sheet quality.

CASE H ISTORY #1

A North American customer was looking for help in re-

ducing energy consumption on a tissue machine mak-

ing 16 to 20 g/m2 sheet at up to 1,900 m/min. Weavexx

Application Engineers recommended the Huyspeed

tissue felt. Huyspeed base fabric and batt technology is

specifically designed to maximize pressure uniformity

and dewatering, leading to improved dryness. Im-

mediately upon startup, the customer reported a post

O c t o b e r 2 0 1 1 Pulp & Paper International (PPI)

paper machine clothing

Fig. 3 - INFLuENCING THE dRIvE LOAd (42%)

Fig. 4 - EdC dRAINAGE PATHS THROuGH FORMING FAbRIC

Fig. 5 - EdC FORMING FAbRIC STRuCTuRE

Pulp & Paper International (PPI) O c t o b e r 2 0 1 1

pressure roll consistency improvement of 1.75%. This

improvement translated to nearly $1 million in energy

savings per year. In addition, since adopting Huyspeed

as the standard technology on its tissue machine, the

customer is setting production records.

CASE H ISTORY #2

A tissue customer in Europe was also evaluating

methods to reduce energy costs on its machine

making toweling grades at over 1,500 m/min. Huyck.

Wangner applications engineers recommended and

applied the new Impact felt technology on the tissue

pickup position. Impact incorporates a unique non-

woven base and specially engineered batt technology

which is ideal for machines requiring advanced dry-

ing performance and reduced energy consumption.

The customer immediately experienced a 5% reduc-

tion in drying energy consumption and reordered

additional Impact felts for the position.

CASE H ISTORY #3

A European customer, producing printing and writing

grades on a tri-nip +4th press at 1,500 m/min wanted

to optimize energy consumption in its press. When

Huyck.Wangner became involved with the project, the

customer was applying conventional laminated press

fabrics and using a total of six uhle boxes across the

various positions to condition and dewater the felts.

Huyck.Wangner applications engineers recommended

the new Exxact press fabric technology for all posi-

tions. Exxact felt technology provides an integrated

triple layer structure with compressible base concept

for maximum dewatering. Based on multi-shaft weav-

ing looms with two different warp systems, Exxact is

the world’s first support shute binder (SSB) press fab-

ric. SSB is the triple layer forming technology patented

by Xerium known as Huytexx and Synergie. Exxact’s

patented concept provides high nip dewatering, fast

start-up, uniform profiles and improved runnability.

Upon startup, the customer was able to reduce the

size and number of vacuum pumps in the press result-

paper machine clothing

Fig. 6 - IMPACT NON-wOvEN TISSuE FELT

Fig. 7 - ExxACT vERSuS STANdARd wOvEN FELT

properly applying cover materials, venting options,

and proper hardness levels for ideal nip intensities,

roll cover strategies can either help or hinder the

papermaker’s efforts to reduce energy costs.

CASE H ISTORY #1

A European customer, producing coated grades from

450-800 m/min wanted to increase dryness and

improve sheet bulk, existing of 23.8%. Both press roll

sections were 7 P&J and only grooved and the suc-

tion press roll was 10 P&J, suction, blind-drilled and

grooved, with an open area of 40%. Stowe Woodward

application engineers recommended that for press

rolls in the 1st and 2nd nips, the mill change to

Stowe Woodward Blue Steel 15 P&J blind-drilled and

grooved at 38% open area. For the suction press roll a

recommendation was applied for Stowe’s Eclipse HP

15 P&J suction holes and blind-drilled and grooved

with an open area of 45%.

At the same time, the customer changed from

laminated press felts to Exxact technology for maxi-

mum dewatering. As a result of the press roll and

felt optimization, the customer reported a dryness

improvement of more than 2%, improved sheet

bulk, and $820,000 in combined annualized energy

savings from reduced steam and vacuum pump

operations.

CASE H ISTORY #2

A customer utilizing two rubber roll covers in the

suction pressure and blind-drilled press roll posi-

tions on a European tissue machine operating at

900 m/min engaged Stowe Woodward to help it dis-

cover ways to reduce energy costs and improve run-

nability. The goals of the project were: 1) improve

nip dewatering at these positions, 2) eliminate the

cover failures on the ends of the rubber covers that

the mill had been experiencing, and, 3) eliminate

the use of water cooling of the rubber cover in the

press position.

Stowe Woodward engineers used Thermogra-

phy and NipProfiler® measurements to evaluate

the nip geometry before the polyurethane suction

pressure roll and blind-drilled roll were installed.

PressManager® studies were also done to evaluate

O c t o b e r 2 0 1 1 Pulp & Paper International (PPI)

paper machine clothing

Fig. 8 - PRESS wITH NEw ROLL ANd FELT TECHNOLOGY

Fig. 9 - TISSuE MACHINE wITH NEw ROLL COvER TECHNOLOGY

ing in over $500,000 in annual savings. The customer

also reported over $350,000 in annualized savings in

press drive load costs after reducing the vacuum, for a

grand total of over $850,000 in savings per year.

PRESS SECT ION: ROLLS TECHNOLOGY

Optimizing roll cover technology and press opera-

tional configuration can have significant impact

on energy consumption on the paper machine. By

Pulp & Paper International (PPI) O c t o b e r 2 0 1 1

theoretical dryness improvement potential. This

program balances water flow in the nip and allows

for the proper venting of the cover. Polyurethane

covers are able to run with very high open area with

additional grooves for better nip dewatering and

higher transverse flow.

The NipProfiler® study performed on the suction

pressure roll showed that the edges of the cover were

overloaded. The edge relief was changed on the 25 P&J

polyurethane cover to alleviate this problem. This Rebel

cover has been running for almost one year with im-

proved dewatering due to the grooving of the cover. As a

result, the steam box has been removed from the roll.

The blind-drilled rubber cover had been water

cooled with 16°C water to help control its tempera-

ture. This was causing bonding failures of the cover

due to water migration. The recommendation was

to use another Rebel 30 P&J polyurethane cover that

was blind-drilled and grooved, without water cooling.

This was possible because of the low hysteresis of

Rebel’s unique polyurethane compound. Thermogra-

phy of this cover showed that it operates with a 50°C

surface temperature, a full 5°C cooler than the rubber

cover that was water cooled.

As a result of implementing Stowe Woodward’s

recommendations, the customer realized a steam re-

duction of one tonne/hr, or 10%, equaling a savings

of $207,000/yr, and the ability to turn off water cool-

ing on the blind-drilled pressure roll saved $55,200/

yr. The mill has also observed less vibration on the

paper machine and a more uniform moisture profile.

CASE H ISTORY #3

A bleached board customer was striving to maintain

a minimum caliper at a designated sheet smoothness

level. Pressing the sheet too hard reduces the caliper

and therefore decreases the smoothness by marking

the sheet with the felt. In order to obtain the required

smoothness, the sheet must be calendered, but

calendering the sheet also creates a denser sheet and

resulting thinner caliper. The second function of the

calender stack is to build a uniform reel, requiring the

cross machine sheet caliper to be uniform. Historical-

ly, to ensure that the minimum caliper was achieved,

the customer was required to add basis weight – so

more fiber was added. The sheet was then heavier

than it needed to be; consequently, more energy was

required to dry the heavier sheet.

After consulting with Stowe Woodward applica-

tion engineers, the customer installed two patented

SMART® Rolls, which measure nip pressures in real-

time, to analyze and optimize the moisture removal

in the press section. After the SMART Rolls were

installed, the customer was able to tune each nip

paper machine clothing

Fig. 11 - SMART® TECHNOLOGY CONCEPT

Fig. 10 - REbEL ROLL COvER TECHNOLOGY

thereby generating a more uniform, less dense, and

higher caliper sheet of paper exiting the press section.

The uniform caliper exiting the press section reduced

the calendering required to build the reel, and

eliminated the need to reduce the sheet caliper. The

greater sheet caliper required less fiber to manufac-

ture the same sheet of paper. Less fiber to manufac-

ture the sheet produced a lighter weight sheet which

required less energy for drying.

Not only was energy reduced by drying a lighter

sheet, there was less energy used to produce the

smaller amount of fiber in the sheet. Combining the

energy and fiber savings, the customer saved over

$700,000/yr.

CONCLuS ION

As customers continually look for more ways to

reduce total costs-per-ton, Xerium research and

development efforts will increasingly focus on unique

products and materials to support these efforts.

Energy savings is only one of the major cost drivers

ValueResults has affected. Customers continue to report

significant savings in fiber and chemical usage while

numerous customers are realizing new levels of speed,

production, and overall productivity and efficiency. The

benefits are greatly enhanced with a combined applica-

tion strategy of both PMC and roll technology. PPI

Steve Cole is Director Global Product Management –

Xerium Technologies, US

paper machine clothing

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AcknowledgementsThe following people contributed to this article.Oliver Baumann - Technical Director - Global Forming Fabrics - Huyck.Wangner - GermanyFranz Danzler - Director Application and Marketing - Stowe Woodward AG - GermanyGlen Harvey - Product Support Specialist - Engineered Products and Services - StoweWeavexx - USChristian Küberl - Marketing Director Press Felts & Dryer Fabrics - Huyck.Wangner - AustriaMike McCloud - Director Value Results - Xerium Technologies, Inc. USKeith Rising - Manager Tissue Applications - Weavexx - US

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