PDF Selected Reading Material - University of Michigan
Industrial Engineering and
Operations Research
Nlr'OfJA. PCUUTION PPEVENTlON CENTER FOR HlGhER ECUCAllON
Selected Reading Material
Robert A. Frosch and Nicholas E. Gallopoulos:
"Strategiesfor Manufacturing." ScientificAmerican 261 (September 1989): 144-152.
H. C. Haynsworth and R. Tim Lyons: "Remanufacturing By Design, the Missing Link." Production
and Inventory Management (2nd Quarter 1987): 24-29.
Robert 1.Kraft:
"Incorporate Environmental Reviews into Facility Design." Chemical Engineering Progress 88 (August 1992):46-52.
National Pollution Prevention Center for Higher Education = University of Michigan Dana Building, 430 Easl Unlverslry, Ann Arbor MI 48104-1 115
Phone: 31 3.764.1412 Fax: 313.647.5841 E-mail: nppc@umich.edu
May be reproduced freely lor non-commercial educational pufposes.
Pollulion Prevention Syllabi ApriT 1995
Strategies for Manufacturing
Wastes from one industrial process can serve
~eprintedwith as the raw materials for another, thereby reducinp
permission. Copyright @ 1989
V
the impact o f industry on the enviro.'nment
by Scientific
American, Inc.
All rights
by Robert A. Frosch and Nicholas E. Gallopoulos
reserved.
People create new technologies and industries to meet human needs more effectively and at lower cost. Innovation is a major agent of progress, and yet inno\.ators' incomplete knowledge sometimes leads to undesirable side effects. Such unforeseen consequences of new inventions are not unique to the feverish industrialization of the 19th and 20th centuries. The ancient Greek myths tell of Pandora and the box full of plagues, of Prometheus punished for stealing fire from the gods and of Icarus. who plummeted from the sky when the sun's heat melted the wax of his ~ i n g sI.n historical times the shift from rawhide to tanned leather, although it made for garments and tools that lasted much longer and were more comfortable to wear and use, brought stenches and disease, so that tanneries had to be segregated from the communities they served.
Today such inadvertent effects can have a global impact. Consider, for example, the invention of chlorinat-
ed fluorocarbons. Before crc's were
developed in the 19301s,refrigerator compressors contained ammonia or
ROBERT A. FROSCH and NICHOLAS E. C,UIOPOULOS work at the General Motors Research Laboratories in Warren. Mich. Frosch, who has a Ph.D. in theoretical physics from Columbia Universily. has been \-ice-presidentin charge of the research laboratones at GM since 1982. Before that he was head of the National Aeronautics and Space Administration. associate director of the Woods Hole Oceanographic Institution and assistant executive director of the United Nations fnnronment Program. Gallopoulos has -ecently been appointed head of GM's englne research department; he was previously head of the enb-ironmental sclence department and assistant head of the fuels and lubricants department. Gallopoulos received his MS. In chemical enginwring from Pennsylvania State Unnersity and his B.S. from Texas A&M I 'nwersit).
sulfur diodde; either chemical was toxic, and leaks killed or injured many people. c r c ' s saved lives, saved money and provided such elements of mode m life as air-conditioned buildings and untainted food. Only later did atmospheric scientists determine that crc's contribute to global warming and affect the chemistry of the upper atmosphere,where they destroyozone.
Such failures should not diminish the fact that technology has improved the lot of people everywhere. Standards of living in many parts of the world are better today than they were 20 or 30 years ago. Many of the adverse effects of industrialization have been brought under control by further applications of technology. Yet as the world's population and standard of living increase, some of the old solutions to industrial pollution and everyday wastes no longer work. There is often no "other side of town" where the modern equivalents of tanneries can be put, no open space beyond the village gates where garbage can be dumped and d o no harm.
By the year 2030, 10 billion people are Bkely 0live on this planet; Ideally, all would enjoy stan-
dards of living-equivalent to those of
industrial democracies such as the U.S. or Japan. If they consume critical natural resources such as copper, cobalt, molybdenum, nickel and petroleum at current U.S. rates, and i f new resources are not dkco\.ered or substitutes developed, such an ideal
would last a decade o r less. On the
waste side of the ledger. at current U.S. rates 10billion people would generate 400 billion tons of solid waste every year-enough to bury greater Los Angeles 100 meters deep.
These calculations are not meant to be forecasts of a grim future. Instead they emphasize the incentives for recycling. conservation and a s ~ i t c hto altemative materials. Thcy lead to the recognition that the traditional model
of industrial activity-in which individual manufacturing proccsses take in raw materials and generate products to be sold plus waste to be disposed of-should be transformed into a more integrated model: an industrial ecosystem. In such a system the consumption of energy and materials is optimized, waste generation is mmimized and the effluents of one process-whether they are spent catalysts from petroleum refining, fly and bottom ash from electric-power generation or discarded plastic containers from consumer products-serve as the raw material for another process.
The industrial ecosystem would function as an analogue of biological ecosystems. (Plants synthesize nutrients that feed herbivores, which in turn feed a chain of carnivores whose wastes and bodies eventually feed further generations of plants.) An ideal industrial ecosystem may never be attained in practice. but both manufacturers and consumers must change their habits to approach it more closely if the industrialized world is to maintain its standard of living-and the developing nations are to raise thein to a similar level-without adversely affecting the environment.
If both industrialized and developing nations embrace changes. it will be possible to develop a more closed industrial ecosystem, one that is more sustainable in the face of decreasing supplies of raw materials and increas-
INDUSTRIAL PLANTS such a s this oil refinery In New Jersey make the products and materials that sustain mode m life. They also emit pollutants that are difficult to dispose of and that may have long-lasting adverse effects on the environment. Meeting environrnental needs calls for manufacturing plants that not only produce goods more efficiently but also fit together into a more harmonious industrial ecosystem At the same time. consumers must learn to use those products less wastefully.
144 S c l r : ~nnc AWRICANSeptember 1989
ing problems of waste and pollution waste can be fed direcrly back into
Industr!alized nations hill have to that process or into a related one.
make major and mlnor changes in Other manufacturers are designing
their current practices. Developing na- packaging to incorporate recycled ma-
tions hill have to leapfrog older. less tenals wherever possible or are find-
ecologically sound technologies and ing ~movativeuses for materials that
adopt new methods more compatible were formerly considered wastes.
with the ecosystem approach.
T $laterials In a n deal industrial eco-
system are not depleted any more than those in a biological one are; a
hree examples delineate some of the issues involved in developing self-sustaining industri-
chunk of sreel could porentially show al process systems, the conversion of
u p one year In a tin can, the next tear petroleum denvatikes to plastics, the
in an automobile and 10 years later In conversion of iron ore to steel, and the
the skeleton of a building. Manufac- refining and use of platinurn-group
rurlng processes in an mdustrial eco- metals as catalysts. We have picked
system simpl) transform circulating these examples because each repre-
stocks of materials from one shape to sents a different stage in the evolu-
a-other; the circulating stock dccreas- tion of a closed cycle. Examining their
c ,..hen some material is unavoidably workings and shortcomings should
lost. and it increases t o meet the needs pro\ide insight into how subsystems
of a growing population Such r e v can be improved so as to develop an
MINING AND REFINING
cling still requires the expenditure of industrial ecosystem.
energy and the unavoidable genera- The iron cycle. in which recycling
tion of wastes and harmful by-prod- is well established, is a very mature
ucts, but at much lower levels thanare process with a h~storydating back
typical roday.
thousands of years, even though ex-
Todafs industrial operations do not tensive production of steel did not ~
~
-
E C Y CCE stanOs ~
form an ideal industrial ecosystem, begin until the 19th century. The plas- with resources and progresses to a h-
and many subsystems and processes tics cycle, in which reuse is just be- lshed product that can be recycled (blue)
are less than perfect Yet there are ginning to make its mark. is less than
developments that could be cause for 100yearsold; the first completely syn-
optimism. Some manufacturers are al- thetic plastic, Bakelite, was introduced catatysts became widely used only in
ready making use of "designed offai." shortly after the turn of the century. the early 1950's, and the widespread
or "engineered scrap," in the manufac- The platinum-group-metals cycle-in use of noble metals to reduce pollu-
ture of metals and some plastics: tai- which reuse is common because of the tion from automotive exhaust dates
loring the production of waste from a high cost of the materials involved-is back less than 15 years.
manufacturing process so that the even younger: industrial noble-metal The plasrics system is potentialIy
highly efficient, bur realizing that po-
tential poses challenges that have yet
EST'[MATEDLIFETIMES OF SOME GLOBAL RESOURCES
to be met. Plastics are a diverse group
of chemically complex compounds
whose use has grown explosively, s o
that they now present a growing dis-
posal problem. Plastics are formed
ALLlMlNUM
into any number of products. and different plastic resins are difficult to
COPPER
distinguish This difficulty leads to problems in collection, separation and
COBALT
recycling. Moreover, breaking plastics down to their original chemical con-
stituents is often technologically in-
feasible or econormcally unattractive.
The drawbacks of plastics must
nonetheless be weighed against their
benefits. Plasttc containers, for exam-
ple, are safer than the glass containers
they replace. Countless injuries. from
minor cuts to severe lacerations, have
been prevented by the substitut~on
of plastic for glass in milk bottles
and containers for bathroom products
W O W STOCKS of some essential taw materials wfll drop perilousty low if less deveIoped countties increase their consumption to match that of the industrialized
world. Figures show reserves (quantities that can be profirably exrracted with current technology)and resources (total quantities thought toexist). Estimates of yearr left until depletion are based on current global consumption (/en)or on the assump tion that in 2030 a population of 10 billion w i l l consume at current U.S. rates (righr).
such a s shampoo. Plastic containers
are generally lighter than glass or metal ones, s o that less energy is required to transport them; they also require less energy to make than glass o r metal containers. especially if they are
after use to enter a e cycle again as a raw material (Tbe h n (green)are added. and waste heat and by-products are gencr-
and steel ~ c l ies shown herel At each stage in tbe manu- a t e d in an op- c y d c wastes u p caprnred and reused ei. facturhg process, energy (red)and additional raw mareriah ther in the same manulacruring process or In a merent o n e
recyded The Midwest Research Insti- The efficiency of the production de almost all of their in-house scrap.
tute in Kansas City, Mo., determined process has already been improved At General Motors, for example, scrap
that compared with glass containers. For example. manulacrurers have generated in the manufacture of PVC
half-gallon poiyvmyl chloride (WC) dweloped more eiRcient membrane parts such as decorative trim. seat
containers require less than half the cells for the eiectrolysis of sodium covers and d a s b d s is segregated
energy to produce and transport and chloride to produce the required do- by color, reground, melted and used
consume one twendetb the mass of rine (The sodium chloride. common along with virm WC
raw materials and less than one third table salt, is dissolved in cells rhrough Once plastic enters the consumer
as much water in their manufactwe. which a current flows; sodium ions market. however, recycling becomes
They also generate less than half of migrate to one electrode. and chlonne considerably more complicated. Only
the waste of glass manufacturing.
ions migrate to the 0ther.A membrane about 1 percent of the PVC dscarded
Each land of plastic poses different separates the two electrodes.) The by consumers is recycled The wide
problems depending on i t s pamcular membrane cells also elirmnate the as- range of products in which WC is
composition and use. W C of whch bestos and m e w requred in older found makes coUeetfon and recovery
almost four rmllion tons are produced elecwlysis cells, thus reducing haz- more diacult, but it also creates in-
every year in the US., is a partjcdar- ardous wastes.
teresting opportunities. For example,
lv dramatic example of the complex Even so. the WC production process potential health hazards and Liabdi-
threats plastics pose to the environ- exemplifies classic "end of pipe" con- ty concerns prevent recycled plastics
ment PVC,whch accounts for about trol measures for reducing poIlutants. from being incorporated into contain-
one sixth of total plastic production. Emissions of vinyl chloride monomer ers where the plastic touches food:
is made into products ranging from during manufacturing are tightly con- recyded bottles may find their way
plpes to automobile parts to shampoo trolled. a practice instituted when it into drainage pipes instead
bottles. Its production requires both became known that the monomer is Other vinyl products that cannot
hydrocarbons and chlorine. (The chlo- both toac and carcinogenic. Unreacr- eas~lybe recycled can be burned to
nne makes the plastic's impact on the ed vinyl chloride is generally snipped produce heat or dectriciw. PVC con-
emironment greater than it would be from the finished WC by low-pressure tains roughly as much energy as wood
if only hydrocarbons were required- steam Most of the monomer is recov- or paper, but its chlorine content pos-
a s is the case for polyethylene, for ered and recycled, but some of it is es problems: incinerators that burn
e.uarnpleJ N a n d gas is the mosr com- present at concentrations too low for WC must have saubbers to prevent
monly used feedstock for WC in the easy recovery and recycling; instead it emissions of hydrochloric acid. which
U.S.; elsewhere it is naphtha, a petro- is sent to an incinerator to be broken contribute to add rain. Dunng com-
leum fraction In either case the feed- dawn. Srrubbers remove hydrochloric bustion the chlorine can also form
stock is converted to ethylene. which acid from the exhaust.
small amounts of dioxins. whkh are
is. chlorinated to form vinyl chloride Recycliug of W C during rnanufac- believed to Ix potent carcinogens. .4s monomer; the monomer moieculesare m g is fairly straightforward. Plants a result, the incineration of djscarded
then M e d to fonn WC.
that make WC products typically recy- WC is discouraged Although recent
S c m c AMER~C~WSeptember 1989 14i
tests by the New York State Energ) spun into polyester fibers that go into 610 million tons: at the end of 1987
Research and Development Authority pillows, stuffed furniture, insulated the figure had risen to more than 750
have shown that properly designed clothng and carpeting.
million A major reason for the in-
and operated incinerators do not emit As the infrastructure for collect- crease is that U.S. production of iron
significant quantities of hydrochloric ing and somng PET and other con- and steel during this period was the
acid or dioxins, environmentalists and sumer plastics grows, recycling rates lowest it had been since the end of
regulators are not convinced that in- should increase significantly. Accord- World War n. The demand for scrap
cmerators would achleve such low ing to recyclers such as Wellman Inc., to make steel decreased while iron
emission levels in practice.
of Shrewsbury, N.J., whlch currently and steel products continued to be
Because of its chlorine content. WC processes about 100 million pounds scrapped at the previous rate.
is a worst-case example of the prob- of PIX a year, the market for recycled Shifting patterns of steel manufac-
lems plastics pose. Other polymers plastics is limited by collection el%- turing, both in the U.S. and around the
such as polypropylene and polyethyl- ciency rather than by demand.
globe, are responsible for the increase
ene present fewer en~lronmentahl azards. They have physical properties similar to those of WC, but they contain no chlorine. Polyeth\,lene tere-
The indusmal system for iron presents a different picture. Techmques for recycling are
in scrap. One subtle culprit is a technology shift from open-hearth furnaces to basic owgen furnaces for producing steel. Basic oxygen furnaces
phthalate (PET),the matenal used in well established, and there is a strong (SO called because they make steel in a
carbonated beverage bottles, is r e v - infrastructure for collecting scrap. Yet large closed vessel supplied with pres-
cled in nine states that have mandato- discarded metal continues to pile up surized oxygen) require only 23 tons
ry deposit laws: California. Connecti- in scrapyards and across the US. be- of scrap steel to be mixed with every
cut, Delaware, Maine, Massachusetts, cause there is not enough demand for 100 tons of pig iron from the blast
mchgan, New York, Oregon and Ver- it. Elemental iron, the predominant furnace, as opposed to a nearly equal
mont. Bottles collected in these states component of both steel and cast iron, mix for the open hearth.
account for 150 million of the 750 is the backbone of modem life: it is The s h f t to basic oxygen furnaces
million pounds of PET resin produced used in roads, in the automobiles that began in the U.S. about 1958. and to-
every year. Recyclers pay from SlOO pass over the roads and in buildings. day open-hearth furnaces account for
to %I40 per ton of PET, making it In the U.S. iron production begins less than 3 percent of total produc-
the second most valuable component when ore is mined in huge open pits tion. Open-hearth fumaces were re-
of municipal solid waste after alumi- a s deep as 100 meters or more. The placed to improve manufacturing effi-
num. The PIX is reconstituted into ore is concentrated and formed into ciency and reduce air pollut~on,but
resins for injection molding to pro- pellets at the mine and then converted their disappearance led to a d e c h e
duce products ranging from automo- into pig iron in a blast furnace, where in iron recycling. In making these
bile parts to electronic devices or is it is heated with coke, lunestone and changes, steelmakers had no econom-
air. The coke adds carbon to the mix, ic mechanism for talang account of
and the Limestone and the oxygen in the adverse environmental impacts of
the air react with impurities in the ore scrap accumulation or the possible
to form slag, which is then removed. long-term effects of consuming more
Small admumrres of other elements iron ore for each unit of steel
yield steel to be cast, rolled or forged More recently minunills have been
into billets, slabs, beams or sheets. built that rely on electric-arc furnac-
Once iron has been formed into es and consume scrap steel almost
products, which are eventually dis- exclusively. These low-volume mills
carded, its properties (especially its have increased their share of U.S. steel
ferromagnetism) facilitate identifica- production, but not enough to com-
tion and separation The enormous pensate for the lost demand for scrap
amount of iron in circulation makes to feed open-hearth furnaces. Further-
recycling relatively easy and economi- more, minimills produce only a limit-
cally attractive. It is not surprising, ed range of steel products, and many
therefore, that every year millions of of those products must be made from
tons of scrap join iron ore to produce scrap containing very low levels of
steel products. The scrap generated by impurities. Scrap that contains excess
stamping steel parts for automobiles. copper, for example. i s not suitable for
for example, is recycled into engine makmg sheet steel, because the result-
blocks and other castings. All four ing sheet is too brittle to form into
foundries that GM operates rely en- products. ff electric-arc fumaces are
tirely on scrap steel obtained from to make significant inroads into the
other GM operations and on scrap iron U.S. stock of scrap iron, they must be
BEVERAGE CONTAINERS, seen here bound into bales at a major recycling center in New Jersey.can be reprocessed into plastic products such as polyester fiber and molded parts. Some 150 million pounds of bottles made from polyethylene terephthalate (PIT)were collected last year from the nine U.S. states that have mandatory deposit laws; 750 million pounds are produced nationwide.
generated during the casting process. Although iron recycling is a relative-
ly simple process, the system is not a closed loop. Much of the scrap from discarded consumer products is not recovered but is scattered around the countryside. where it corrodes away a little every year and is considered a
blight rather than an asse't. In 1982 recoverable iron scrap amounted to
coupled to production facilities that produce a wider range of products, and better techniques must be developed for dealing with impure scrap.
Platinum-group metals (platinum. palladium, rhodium, ruthenium, iridium and osmium) were, untll the mid. 19701s,part of a ver) efficient industrial system. These metals were
1 4 3 S C I E N ~ F I.CWERIGW September 1989
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