environmental considerations of energy-conserving industrio process chonges ------- 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 ------- 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. ------- Figure 1 TOTAL U.S. ENERGY USE 1OO Household I and Commercial Transportation Industry ------- 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). ------- 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. ------- 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. ------- 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 ------- 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 ------- 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 ------- 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 ------- . O CO >Q o i Q_ ^ O CO / |\ LU (J; 0) Q LI- CO LU CO o > oo £V J. - o CO __J LU O C C ODD to to to 0 CD 0 (/) CO CO to to to 19 ------- 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 ------- 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 ------- 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 ------- ------- |