Energy Conservation in Textile and Polymer Processing

286 Pages·1979·4.93 MB·English

by  Tyrone L. Vigo and Louis J. Nowacki (Eds.)

Energy Conservatio
Polymer Processing
In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
Energy Conservation in Textile and
Polymer Processing
Tyrone L. Vigo, EDITOR
U.S. Department of Agriculture
Louis J. Nowacki, EDITOR
Battelle Columbus Laboratories
Based on symposia sponsored
by the Divisions of
Cellulose, Paper, and Textiles and
Organic Coatings and Plastics Chemistry
at the 176th Meeting of the
American Chemical Society,
Miami Beach, Florida,
September 11-15, 1978.
ACS SYMPOSIUM SERIES 107
AMERICAN CHEMICAL SOCIETY
WASHINGTON, D. C. 1979
In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
Library of Congress CIP Data
Energy conservation in textile and polymer processing.
(ACS symposium series; 107 ISSN 0097-6156)
Includes bibliographies and index.
1. Textile factories—Energy conservation—Con
gresses. 2. Plastics plants—Energy conservation—Con
gresses.
I. Vigo, Tyrone L., 1939- . II. Nowacki, Louis
J., 1918- . III. American Chemical Society. Cellu
lose, Paper, and Textile Division. IV. American Chem
ical Society. Division of Organic Coatings and Plastics
Chemistry. V. Series: American Chemical Society. ACS
symposium series; 107.
TJ163.5.T48E53 668.4 79-15523
ISBN 0-8412-0509-4 ASCMC 8 107 1-278 1979
Copyright © 1979
American Chemical Society
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In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
ACS Symposium Series
M. Joa
Advisory Board
Kenneth B. Bischoff James P. Lodge
Donald G. Crosby John L. Margrave
Robert E. Feeney Leon Petrakis
Jeremiah P. Freeman F. Sherwood Rowland
E. Desmond Goddard Alan C. Sartorelli
Jack Halpern Raymond B. Seymour
Robert A. Hofstader Aaron Wold
James D. Idol, Jr. Gunter Zweig
In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
FOREWORD
The ACS SYMPOSIUM SERIES was founded in 1974 to provide
a medium for publishin
format of the Series parallels that of the continuing
ADVANCES
except that in order to save time the
IN CHEMISTRY SERIES
papers are not typeset but are reproduced as they are sub
mitted by the authors in camera-ready form. Papers are re
viewed under the supervision of the Editors with the assistance
of the Series Advisory Board and are selected to maintain the
integrity of the symposia; however, verbatim reproductions of
previously published papers are not accepted. Both reviews
and reports of research are acceptable since symposia may
embrace both types of presentation.
In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
PREFACE
lhe polymer-related industries of the United States have developed
-^-with the stimulus of low-cost, readily available sources of energy
and raw materials from petrochemicals and natural polymers. The em
phasis, until recently, has been on obtaining quality desired in the most
expeditious fashion with little concern for energy consumed. However,
during the past several years energy consumption in preparing and using
synthetic and natural polymers has taken on great importance, from the
standpoint of both cost an
forced to curtail productio
natural gas shortage during the winter of 1976-1977. Consequently, alter
nate sources of energy have become extremely important. For example,
radiation curing might be an attractive alternative to baking in that it
substitutes electricity for natural gas. Moreover, the total BTU require
ment can be decreased in certain instances by such changes.
The chapters assembled in this volume cover several polymer uses—
molded plastics, organic coatings, adhesives, and natural and synthetic
fibers. Approaches discussed for conserving energy include redesign of
products, reuse of energy and processing materials, reduction in proc
essing temperatures, improvement in equipment efficiencies, development
of new polymers, curing, finishing, dyeing techniques, and the most
effective use of textiles in indoor habitats. It is hoped that these results
and recommendations will stimulate additional research for achieving
the nationally important goal of conserving energy and reducing its
consumption.
The editors appreciate the support provided by the Cellulose, Paper,
and Textile and Organic Coatings and Plastics Divisions of ACS in
organizing symposia on this topic and encouraging their publication.
U.S. Department of Agriculture TYRONE L. VIGO
SEA Textiles and Clothing Laboratory
Knoxville, TN 37916
Battelle Columbus Laboratories LOUIS J. NOWACKI
Columbus, OH 43201
April 17, 1979
ix
In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
1
Progress and Prospects for Energy Conservation in
Plastics Processing
RUDOLPH D. DEANIN
University of Lowell, Lowell, MA 01854
The 15-fold growth of the plastics industry in the past
three decades has been
cost petrochemical raw
energy. In the past five years the plastics industry has suddenly
become aware that the dwindling supply of petroleum is producing a
steady increase in both the cost of plastic materials and the cost
of processing them. A recent estimate indicated that process
energy was 6% of total production cost; $1.3 billion for U.S.
plastics processors in 1976 (1). With the cost of this energy
rising rapidly, the urgency of energy conservation is obvious.
More optimistically, it has been estimated that plastics proces
sors could use existing technology to save 20-40% of their current
energy costs, and thus increase profits 10-20% (1) . Long-range
future developments could produce much greater savings. In fact,
recent studies by DuPont, Exxon, Midwest Research, and Springborn
Laboratories all indicate that it takes less petroleum to make and
process plastics into finished products than has been required to
convert conventional structural materials - such as metals, glass,
and paper - into comparable products.
Raw Materials Economics
The prices of petrochemical-based plastic materials must ob
viously increase steadily. To some extent it is possible to re
duce the weight of material needed to make a specific product.
Structural foam generally uses 25-50% less material, and often
produces equivalent performance. Dow Chemical's Scrapless Forming
Process and Shell Chemical's Solid Phase Pressure Forming. Process
produce higher properties, permitting use of 20-50% less material
to form products of equivalent performance (1). Stretch blow
molding of bottles produces thinner walls with equivalent perfor
mance making it a major current interest.
Recycle of scrap during manufacturing is conventional prac
tice in the thermoplastics industries. At best it may be blended
with virgin material and recycled in the same plant, often in the
0-8412-0509-4/79/47-107-003$05.00/0
© 1979 American Chemical Society
In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
4 ENERGY CONSERVATION IN TEXTILE AND POLYMER PROCESSING
same application. At worst it is used at lower value in less de
manding products. Fcr example, Western Electric recovers 7000
metric tons/year of PVC from wire and cable insulation by strip
ping, granulating, recompounding, and converting into cable jac
keting, hose, shoes, and mats. The Bell System also recycles
1500 tons/year of ABS from scrapped telephones, uses reground phe
nolic resin as a filler, and pulverizes DAP scrap for use in vir
gin DAP molding compounds (2). While such recycle of thermoset
scrap poses major problems, current studies indicate that chemical
treatment of ground phenolic scrap can make it much more compati
ble fcr blending into virgin phenolic molding powders (3).
Even where plastic scrap cannot be reused in plastics pro
cessing, it offers high fuel value which can be reclaimed by pro
per incineration. Wheelabrator has installed a refuse-fired
steam-generating plant at Saugus, Massachusetts, which is expected
tc benefit from the growin
solid waste; and 40 mor
in the next 12 years (2). Rohm & Haas has turned increasingly to
burning of combustible solid and liquid wastes for their energy
content instead of spending money to discard them (4^.
Ultimately non-petrochemical sources of raw materials will
become more economical, and synthesis of plastics will turn to
these alternate sources, some to produce our present plastics,
others to produce new types of plastics. Coal, forestry, and ag
riculture offer a great variety of interesting opportunities,
whenever the economics appear appropriate (5).
Process Technology
As already suggested, redesign can reduce the weight of mate
rial needed to make a plastic product. This in turn reduces the
amount of energy needed to process it. Redesign of the process
can often reduce the amount of scrap which must be recycled, and
thus reduce the energy input per pound of finished product. For
example, Dow Chemical's Scrapless Forming Process extrudes sheet,
which is cut into blanks, warmed in an infrared oven, pressed in
to preforms with finished edges, and thermoformed into finished
parts; improved properties permit use of 20-50% thinner parts,
lower temperatures and faster cycles (2-3 seconds) also help, and
overall energy saving is 20-30% compared with conventional thermo-
forming (1). Shell Chemical's Solid Phase Pressure Forming makes
polypropylene tubs and trays by heating extruded sheet just below
the melting point, clamping over the thermoforming mold, pushing
the sheet into the mold with heated plugs, then injecting chilled
air through the plugs tc force the sheet against the cold surface
of the mold; material savings are 40-50%, cycle time is 2.5 se
conds, and process energy savings 20-25% (1).
Heat. Thermal energy has proved to be easiest to conserve in
plastics processing. Conservation has taken many forms: produc-
In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.
1. DEANiN Progress and Prospects for Energy Conservation 5
tion, re-use, and reduction of thermal energy.
Production of heat energy at Rohm & Haas has been improved by
better control of combustion in boilers, cleaning and maintenance
of boilers and process heaters to maintain their efficiency, eli
mination of steam leakages, steam trap maintenance, and improved
condensate recovery (4).
Re-use of heat energy has provided major savings in many
plastics processing plants Q ,4.>6) . Mold chillers and hydraulic
pump coolers remove tremendous amounts of heat from process equip
ment. This can be used to heat the plant buildings in winter,
using radiators, fans, and ducts to carry the heat wherever it is
needed. Applications Engineering Company and Essex International
report that use of process heat in this way can supply 67-90% of
the heat needed to warm the buildings in winter, so that the heat
transfer equipment often pays for itself in the first year of use.
During the summer, the fan
the outdoors, and draw
derable cooling of the buildings, making for greater comfort.
For future plant design, it would be desirable to run exo
thermic and endothermic processes in parallel lines, so that heat
transfer between them would provide optimum economies. In many
exothermic polymerization and cure reactions, the heat evolved
could be fed back to warm the materials initially up to their re
action temperature, thus recycling the heat energy within a single
process. Ultimately, it might even be possible to design exotherm
processes which produced more than 100% of their energy require
ments, leaving the excess available for sale at a profit else
where!
Reduction of processing temperatures would reduce the amount
of heat which must be put into a process, and also the amount of
cooling which is required afterwards. Goodrich Chemical is de
signing plastisols which fuse at lower temperatures by use of co
polymer resins, lower molecular weights, and solvent-type plasti-
cizers (7). Many plastic processes can be operated at low or even
room temperatures, typically the casting of epoxies, polyesters,
and polyurethanes. Saum Systems has developed a Displacement Blow
Molding system on a 2-station machine operating on a shuttle prin
ciple; solid resin is melted and extruded, then a plunger shapes
it into a parison, the mold closes around it, and the bottle is
blown, with an overall saving of 25% or more in process energy as
compared with conventional blow molding (8). MIT surface-chlori
nated polypropylene granules, cold-pressed them, used dielectric
heating to fuse the low-melting amorphous surfaces together, then
allowed the heat to diffuse into the high-melting crystalline in
teriors, thus eliminating the need for transferring heat in to
fuse and then heat out to solidify, and also shortening the mold
ing cycle at the same time (9). On a very mundane level, Rohm &
Haas simply reduced the heating level in plant buildings, saving
energy without reaching the discomfort level (4^.
In Energy Conservation in Textile and Polymer Processing; Vigo, T., et al.;
ACS Symposium Series; American Chemical Society: Washington, DC, 1979.