environmental considerations of energy-conserving industrio process chonges
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environmental considerations of energy-conserving
industrial process changes
executive briefing
technology transfer
U.S. ENVIRONMENTAL PROTECTION AGENCY
Environmental Research Information Center
Cincinnati, Ohio
May 1977
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HIGHLIGHTS
THE
STUDY
The environmental considerations of industrial energy-con-
serving process changes in 13 industries.
ITS
PURPOSE
To determine whether new industrial processes likely to be
adopted will have adverse environmental effects.
THE
CONCLUSION
New processes will not have severe adverse environmental
effects, and, in some cases, the net effects will be beneficial.
The major environmental problem concerns substituting
coal for oil and gas.
POLICY
IMPLICATIONS
Most industrial process changes for energy conservation
can be encouraged and are environmentally acceptable.
Research and development programs are identified for
those areas in which additional technology is needed.
Continuing assessment by EPA is necessary to keep abreast
of the environmental impact of energy-conserving changes.
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Figure 1
TOTAL U.S. ENERGY USE
1OO
Household I
and
Commercial
Transportation
Industry
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Table 1
1971 ENERGY CONSUMPTION OF THE
13 MAJOR INDUSTRIES CHOSEN FOR THE STUDY
Industry
1971
Energy Consumption
(quads)3
PRIMARY METALS INDUSTRY
Blast furnaces and steel mills
Alumina and primary aluminum
Primary copper
PETROLEUM AND COAL PRODUCTS • Petroleum
refining
CHEMICAL AND ALLIED PRODUCTS
Olefinsb
Ammoniab
Fertilizers
Alkalies and chlorine
Phosphorus and phosphoric acid
PAPER AND ALLIED PRODUCTS
STONE, CLAY, AND GLASS PRODUCTS
Cement
Glass
3.49
0.59
0.08
2.J
0.98
0.63
0.08
0.24
0.12
1.59
0.52
0.31
TEXTILE MILL PRODUCTS
Total
0.54
12.13
aA quad is 1 quadrillion (1015) Btu.
b Includes the fuel value of the raw materials (feedstock energy).
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Table 2
ENVIRONMENTAL IMPACT SUMMARY
Product
Manufacturing
Process
Considered
Probable Environmental
Impacts and Control
Requirements
ALUMINA AND
ALUMINUM
Produce alumina from clay
instead of bauxite.
AMMONIA
CEMENT
CHLORINE AND
CAUSTIC
Use Alcoa chlorination proc-
ess using titanium diboride
cathodes in the existing Hall
electrolysis process.
Replace natural gas with
coal as the basic raw
material.
Replace natural gas with
heavy oil as the basic raw
material.
Convert to suspension pre-
h eaters.
Use flash calciners.
Use fluidized-bed cement re-
actors to replace dry rotary
kilns.
Convert to coal from natural
gas and oil.
lie anodes -and p&pjaee;
!^bes;te)s*i|/ithi *poli/mep
membranes in *riew
% -^
plants. ..; ^ •••*?;"
More solid waste is produced in the form of clay
slimes, but mined clay areas are available for disposal.
Because bauxite is imported, no disposal site for
muds is created under the existing technology. Some
additional water soluble nitrates may be produced,
and new air emissions and wastewater streams may be
generated.
Costs for air pollution control are reduced, but sulfur
from coking and hydrogen chloride from the chlori-
nation step are new pollutants that require control.
Less carbon monoxide is produced, but more sludge
and sodium chloride purge must be handled.
Gaseous sulfur compounds, nonmethane hydro-
carbons, increased wastewater, slag, and ash are
produced, requiring significant additional pollu-
tion control processes.
More wastewater is produced that requires biological
treatment for control. Sulfur in the fuel also requires
recovery.
No environmental effect is expected.
Lower nitrogen oxide emissions result.
Lower nitrogen oxide emissions result and fewer
particulates are produced, but the collected particu-
lates have a high percentage of soluble salts.
Runoff from coal storage and additional solid wastes
are produced, but the control technology is well
proven. No other significant environmental effects are
expected.
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Table 2-Con.
ENVIRONMENTAL IMPACT SUMMARY
Product
Manufacturing
Process
Considered
Probable Environmental
Impacts and Control
Requirements
GLASS-CON.
Use an electric melting fur-
nace instead of a gas-fired
furnace.
Modify the melting furnace
to better use heat.
Reduced environment impact at the glass plant site
increases the use of energy at the electric power
station, where control technology is available.
Positive environmental effects result from reduced
fuel use.
IRON AND STEEL
Recover carbon monox-
ide from basic oxygen
furnaces.
Desulfurize the hot metal ex-
ternally.
Reduce iron ore directly.
The environment improves because of better
dust recovery and because fewer very small
particulates are produced.
High-sulfur coal can be used for coke manufacturing.
Pollution control costs are reduced because of the
elimination of fluorides.
OLEFINS
Use heavier feedstocks
instead of ethane or pro-
pane.
Heavier feedstocks cause increased production
of byproducts and wastes, and pollution con-
trol costs increase.
PETROLEUM Burn asphalt in heaters/
boilers.
Convert asphalt by hydro-
cracking.
Convert asphalt by flexicok-
ing.
Generate power internally.
Generate hydrogen by partial
oxidation of asphalt.
PHOSPHORUS
AND PHOSPHORIC
ACID
Use byproduct sulfuric acid.
SO? emissions control expenses increase.
S02 emissions control expenses increase.
Waste treatment costs increase, as do S02 emissions.
S02 emissions increase, unless controlled.
S02 emissions increase. This effect is controllable by
modifications to existing sulfur recovery systems.
No change occurs at the phosphoric acid plant, and
the environment benefits from the increased use of
sulfur wastes. There is an additional environmental
impact from raising process steam now obtained from
the sulfuric acid plant.
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RESEARCH AND
DEVELOPMENENT NEEDS
Several general conclusions, as well as recommendations for specific proj-
ects, are included in the 13-industry study. Many of the R&D needs related
to the new processes are not significantly different from those for existing
processes.
• There is an overriding need for increased quantitative evaluation of the
total impact of changes, including
—studying secondary effects on other supporting industries
—tracking the final disposition of pollutants
• Improved instrumentation for rapidly monitoring pollutants would enhance
the quality of data needed for evaluating the environmental effects of
new processes.
The general conclusions related to air pollution control are as follows:
• Improved technology is needed for removing fine particulates.
• Collection of fugitive emissions from process equipment continues to be
a problem.
• A better definition of the environmental, medical, and biological effects
of gas, smoke, and smog-causing emissions is required.
Water pollution control R&D needs include the following:
• A better definition of the effects of substances that cannot be controlled
by the best available technology economically achievable (BATEA) under
the current law {Public Law 92-500).
• Improvements in energy-conserving technologies for the removal of spe-
cific compounds not now being removed by BATEA, especially organic
compounds and dissolved solids
Solid waste disposal problems will continue. The following two major needs
remain:
• Demonstration of adequate landfill techniques for industrial wastes
• Improved destruction techniques for hazardous residues
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Table 3
IDENTIFIED RESEARCH AND DEVELOPMENT NEEDS SUMMARY
Industry
Research and Development Needs
Comment
ALUMINUM
AMMONIA
Conduct material research to produce improved
titanium diboride cathodes, which would allow in-
creased operating life.
Thoroughly assess the pollution potential of
using coal as a basic feedstock.
Determine the most environmentally sound
alternative to natural gas for feedstock.
Energy will be saved and car-
bon monoxide emissions will
be reduced.
The path of the metals in the
coal should be determined.
Many technologies applied in
other areas require evaluation
for specific use in ammonia
plants.
CEMENT
Characterize the effect of high-sulfur coal on emis-
sions from cement plants and on cement properties.
Possibly cement plants can
use high-sulfur coal with little
or no environmental effect
because the sulfur reacts with
the product, freeing low-sul-
fur coal for other uses.
CHLORINE AND
CAUSTIC
Characterize the emissions from a flash calciner-
equipped rotary kiln.
Characterize the trace elements in dust from various
kiln systems and assess their ecological and medical
impact.
Analyze and study methods of using waste kiln dust.
Provide support in critical areas to accelerate
existing trends toward improved technology.
Current trends are favorable
for both energy conservation
and environmental protec-
tion.
COPPER
Study the changes in distribution and the ultimate
fate of impurities in copper ore for new technologies.
Develop techniques for impurity removal.
If impurities can be removed,
one-step smelting can be
used, which would decrease
SOo emissions.
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Table 3-Con.
IDENTIFIED RESEARCH AND DEVELOPMENT NEEDS SUMMARY
Industry
Research and Development Needs
Comment
PETROLEUM RE-
FINING
PHOSPHORIC
ACID
PULP AND PAPER
TEXTILES
Improve the reliability and economics of small
flue gas desulfurization units.
Encourage the development of technology that
could increase the yield of;clean fuels, such as
more rugged hydrqcracking catalysts.
Develop environmentally acceptable means of dispos-
ing of CaCI2/H20.
Support the development of improved Kraft
pulping processes.
Encourage commercialization of the alkaline-
oxygen process.
Support improved technology for,'de-inking
operations.
Quantify improvements in energy and pollution
control through improved drying and wasting
techniques.
Extend demonstrations of polyvinyl alcohol
recovery.
Demonstrate the energy conservation and pollu-
tion control benefits of improved washing and
drying, additional recovery of chernieals, and
reuse of heated wastewater.
Determine the effects of solvent losses in
solvent processing and develop improved con-
trol technology.
This improvement is a major
need in many industrial areas.
This development is needed
in many other scrap and
waste use processes.
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Table 4
COMPARISON OF ENERGY EFFICIENCY OF MERCURY CELLS AND
DIAPHRAGM CELLS IN MANUFACTURING CHLORINE AND CAUSTIC
Energy Source
Mercury Cells
With Dimensionally
Stable Anodes
Standard Diaphragm
Cells With
Dimensionally
Stable Anodes
Diaphragm Cells With
Expandable3 Dimensionally
Stable Anodes or
Stabilized Diaphragms
ELECTRICAL
d.c. power to cells
Electrical losses
Total d.c. Power
a.c. power required to provide necessary
d.c, power at 97 percent conversion
efficiency
Process a.c. power
Auxiliary a.c. power
Total a.c. Power
3,221
65
3,286
3,716
per ton of chlorine
2,774
30
2,804
3,151
2,459
30
2,489
3,387
315
14
2,891
250
10
2,566
250
10
2,826
•million Btu per ton of chlorine-
THERMAL
Evaporator steam ~
Miscellaneous plant steam 1.13
Credit for byproduct hydrogen (assuming all
hydrogen is usable as fuel) -2.94
Thermal equivalent of electrical energy 39.02
Total Energy Consumption 37.21
7.05
0.90
-2.94
33.09
38.10
7.05
0.90
-2.94
29.67
34.68
9An expandable anode allows adjustment of the final gap between electrodes after the cell is assembled, giving greater
electrical efficiency.
17
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GENERIC TECHNOLOGY
When energy-conserving technology being developed by different industries
is investigated, it becomes apparent that there are several generic approaches
to reducing industrial energy consumption.
These approaches are in various stages of development. The primary stimulus
for their use in a particular industry has not always been energy conservation.
The concept for each generic approach may be the same, but it is obvious that
the format for use will vary with the design patterns (configuration, temperature,
etc.) for individual industries. Furthermore, because of the general nature of
these concepts and their applicability to a variety of industries, it is not
possible to quantify either their energy savings potential or their environmental
consequences. It can only be said that, in sample instances where they have
beenorare being applied, such techniques have demonstrated specific levels
of energy conservation, have exhibited certain environmental impacts {some
of which can be generalized), and have presented certain environmental
problems as worthy of further study. The sections that follow describe some
examples of generic technology pertinent to this project.
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PREHEATING
Preheat raw materials such as the feed to a glass furnace, a coking oven, or
a cement kiln, particularly with waste off-gases. Fuel use and, consequently,
SOX, NOX, particulate, and organic emissions should be reduced. The result-
ing staged heating of materials and, in some cases, controlled water loss
could affect the entire pollutant profile. Scrubbing effects might also be ob-
served, depending on system design for a particular industry.
Research needs include identifying specific processes where the technique
would reduce energy use and quantifying environmental benefits, including
reductions in thermal pollution.
SULFUR REMOVAL FROM HOT GASES
Conversion from one fuel or feedstock to heavier petroleum stocks or coal
(including by gasification) in many instances offers potential for conserving
natural gas and assuring continuity of supply (e.g., in glassmaking, ammonia
manufacture, and petrochemical syntheses). However, the need to remove
sulfur body impurities continues to be a major stumbling block. Conventional
technology, where available, requires cooling the manufactured gaseous fuel
or feedstock to remove sulfur bodies or other pollutants. Subsequent reheat-
ing to combustion temperatures is a source of serious energy loss and a de-
terrent to more widespread use of such alternative fuels or feedstocks. The
same problem exists in the current technology for removing particulates and
other pollutants from off-gases, and in treating wastewaters that contain other-
wise reusable thermal energy.
Research is needed to develop techniques for removing sulfur, particulates,
and other pollutants from hot waste streams, both air and water. Such tech-
niques could reduce pollution control costs and would permit other areas or
industries to recover thermal energy, fuel, or feedstock values from these
streams.
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SOLVENT PROCESSING
Several industries—particularly textiles, pulp and paper, and to a lesser de-
gree the food industry—are exploring techniques that use volatile solvents
rather than water tor their processes. Significant savings in energy can be
achieved where solvent removal is a necessary stage in the sequence.
Research is needed to improve solvent recovery and purification in all these
systems to minimize economic losses and environmental contamination. It
may be necessary also to investigate long-term health risks inherent in the
use of products contaminated with low concentrations of solvents.
SUMMARY
Development of generic technology and improvements in conventional en-
gineering unit operations offer a broad-based means of conserving energy.
As always, however, such changes have both immediate and long-range con-
sequences, including their environmental impacts, which must be identified
and then evaluated to assure that other, serious problems are not generated
while energy problems are solved.
Tap from electric-arc furnace, Middletown, Ohio.
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