Post on 17-Apr-2020
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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