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
                                                         11

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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.
                                                                                                        13

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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.
                                                                                                     15

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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.
                                                            21

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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.

                                                               23

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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.
                                                              25

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