United States Industrial Environmental Research EPA-600/7-78-164a Environmental Protection Laboratory August 1978 Agency Research Triangle Park NC 27711 Environmental Assessment of Coal- and Oil-firing in a Controlled Industrial Boiler; Volume I. Executive Summary i f 4 Interagency Energy/Environment R&D Program Report ------- RESEARCH REPORTING SERIES Research reports of the Office of Research and Development, U.S. Environmental Protection Agency, have been grouped into nine series. These nine broad cate- gories were established to facilitate further development and application of en- vironmental technology. Elimination of traditional grouping was consciously planned to foster technology transfer and a maximum interface in related fields. The nine series are: 1. Environmental Health Effects Research 2. Environmental Protection Technology 3. Ecological Research 4. Environmental Monitoring 5. Socioeconomic Environmental Studies 6. Scientific and Technical Assessment Reports (STAR) 7. Interagency Energy-Environment Research and Development 8. "Special" Reports 9. Miscellaneous Reports This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT RESEARCH AND DEVELOPMENT series. Reports in this series result from the effort funded under the 17-agency Federal Energy/Environment Research and Development Program. These studies relate to EPA's mission to protect the public health and welfare from adverse effects of pollutants associated with energy sys- tems. The goal of the Program is to assure the rapid development of domestic energy supplies in an environmentally-compatible manner by providing the nec- essary environmental data and control technology. Investigations include analy- ses of the transport of energy-related pollutants and their health and ecological effects; assessments of, and development of, control technologies for energy systems; and integrated assessments of a wide range of energy-related environ- mental issues. REVIEW NOTICE This report has been reviewed by the participating Federal Agencies, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Government, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. This document is available to the public through the National Technical Informa- tion Service, Springfield, Virginia 22161. ------- EPA-600/7-78-164a August 1978 Environmental Assessment of Coal- and Oil-firing in a Controlled Industrial Boiler; Volume I. Executive Summary by C. Leawitt, K. Arledge, C. Shih, R. Orsini, W. Hamersma, R. Maddalone, R. Beimer, G. Richard, and M. Yamada TRW, Inc. One Space Park Redondo Beach, California 90278 Contract No. 68-02-2613 Task No. 8 Program Element No. EHE624A EPA Project Officer: Wade H. Ponder Industrial Environmental Research Laboratory Office of Energy, Minerals, and Industry Research Triangle Park, NC 27711 Prepared for U.S. ENVIRONMENTAL PROTECTION AGENCY Office of Research and Development Washington, DC 20460 ------- DISCLAIMER This report has been reviewed by the Industrial Environmental Research Laboratory, U. S. Environmental Protection Agency, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the U. S. Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. ii ------- ABSTRACT The report gives results of a comparative multimedia assessment of coal versus oil firing in a controlled industrial boiler. Relative environmental, energy, economic, and societal impacts were identified. Comprehensive sampling and analyses of gaseous, liquid, and solid emis- sions from the boiler and its control equipment were conducted to identify criteria pollutants and other species. Major conclusions include: (1) While the quantity of particulates from oil firing is considerably less than from coal firing, the particles are generally smaller and more difficult to remove, and the concentration of particulates in the treated flue gas from oil firing exceeded that from coal firing. (2) NO and CO A emissions during coal firing were about triple those during oil firing. (3) Sulfate emissions from the boiler during coal firing were about triple those during oil firing; however, at the outlet of the control equipment, sulfate concentrations were essentially identical. (4) Most trace element emissions (except vanadium, cadmium, lead, cobalt, nickel, and copper) were higher during coal firing. (5) Oil firing produces cadmium burdens in vegetation approaching levels which are injurious to man; coal firing may produce molybdenum levels which are injurious to cattle. (6) The assessment generally supports the national energy plan for Increased use of coal by projecting that the environmental insult from controlled coal firing is not significantly different from that from oil firing. This report was submitted in fulfillment of Contract Number 68-02-2613, Task 8 by TRW Environmental Engineering Division under the sponsorship of the U.S. Environmental Protection Agency. This report covers a period from October 24, 1977 to May 5, 1978, and work was completed as of May 5, 1978. iii ------- LIST OF ABBREVIATIONS acm/min - - Actual Cubic Meters Per Minute ACFM - Actual Cubic Feet Per Minute DSCM - Dry Standard Cubic Meters ESCA - Electron Spectroscopy for Chemical Analyses FGD - Flue Gas Desulfurization ICPOES - - Inductively Coupled Plasma Optical Emission Spectroscopy MATE - Minimum Acute Toxicity Effluent NAAQS - National Ambient Air Quality Standards NSPS - New Source Performance Standards SSMS - Spark Source Mass Spectrometry TSP - Total Suspended Particulate iv ------- ACKNOWLEDGMENTS The cooperation of the Firestone Tire and Rubber Company and FMC is gratefully acknowledged. We are particularly indebted to Gary Wamsley of Firestone and Carl Legatski of FMC, without whose cooperation this assessment could not have been completed. v ------- EXECUTIVE SUMMARY The industrial nations of the world are being forced to simul- taneously deal with two very difficult and contradictory problems. The relatively cheap and convenient sources of energy are rapidly being depleted while the need for increasingly stringent control of pollution is making the environmentally acceptable use of the energy sources that are available more difficult. One response to these dual needs has been to use the more abundant high polluting fuels in combustion systems that have sophisticated pollution controls. The technologies that are used to control pollution are new relative to combustion technology. Therefore, the subtle short- and long-term effects of these new technologies are not yet completely known. The objective of this program is to conduct a comparative, multi- media environmental assessment of oil vs. coal firing in controlled industrial and utility boilers and to draw conclusions about the compara- tive environmental, energy, and societal impacts of firing oil versus firing coal. A secondary objective of this program is to recommend the approach to be used for subsequent assessments of a variety of combustion related pollution sources. INTRODUCTION This report presents the comparative assessment of controlled Indus- trial boilers. The major technical input for this assessment was feed stream and emissions characterization data collected as part of the Conventional Combustion Emission Assessment Program. These data were derived from rigorous sampling and analysis and specify the types and quantities of all solid, liquid, and gaseous pollutant species of interest in each of the inlet and outlet streams of a controlled oil- and coal-fired industrial boiler. A comprehensive assessment of each fuel type in the controlled industrial boiler was accomplished to determine: The types and amounts of pollutants that are released during coal and oil combustion 1n an uncontrolled boiler: The types and amounts of pollutants that are released during the combustion of each fuel in a controlled boiler; 1 ------- The effectiveness of the controls with respect to each controlled pollutant; If the control devices modify pollutants that pass through the controls; If the controls themselves create pollutants. The comprehensive assessment results for the oil and coal-fired industrial boiler were then used in a comparative emission assessment to determine the differences in the types and quantities of all pollutant species of interest. The results of the industrial comparative emission assessments were then evaluated to determine what conclusions could be drawn about the oil versus coal firing. The comparative impacts identified were summarized by environmental, energy, economic, and societal cateqories. This report is organized in three volumes. Volume I is the Executive Summary. The comparative assessment of emissions and their impacts is presented in Volume II. Volume III describes the test site, the sampling and analysis activities; presents the comprehensive assessments of coal and oil firing; and provides the appendices which contain detailed test and analysis results. There are a number of significant differences in the quantities, characteristics, and impacts of the emissions resulting from coal and oil firing in a controlled industrial boiler. In the following paragraphs the most important of these differences are summarized. It should be kept in mind, however, that the conclusions are based on tests conducted on only one Industrial boiler, one type of coal, and one type of oil. It should not be assumed that these conclusions apply to all industrial boilers under all circumstances. The results of this program should, perhaps, best be thought of as a good indication of the impact differences between coal and oil firing and as a set of guidelines on which future work can be based. TEST AND ANALYSIS The test unit used for this assessment is a dual fuel industrial pro- cess steam boiler operated by the Firestone Tire and Rubber Company in Pottstown, Pennsylvania. The 10 megawatt equivalent boiler 1s equipped 2 ------- with a pilot FMC, Inc. flue gas desulfurization (FGD) unit that is designed to treat approximately one-third of the flue gas produced by the boiler when it is operating at full load (3 megawatt equivalent). The boiler was originally designed to burn coal but was later modified to burn either high volatile eastern bituminous coal or Number 6 fuel oil. Table 1 presents a list of the major boiler parameters. The boiler has no N0X controls. The boiler produces four liquid waste streams: boiler feed water pretreatment waste, steam drum blowdown, mud drum blowdown and cooling water. All liquid waste streams except the cooling water are mixed with process waste water from elsewhere in the plant. This combined stream is then pumped directly into the municipal sewerage system. The boiler cooling water is pumped directly into the municipal sewerage system without mixing with other plant waste streams. TABLE 1. SUMMARY OF BOILER PARAMETERS Manufacturer: Type of burner: Number of burners: Boiler type: Oil/pulverized coal ; face fired; integral furnace; dry bottom Babcock and Wilcox, Type P-22 EL Circular conical 3 Burner arrangement: Triangular, one face Air preheater: Fuel : Number of 6 fuel oil; High volatile bituminous coal, Class II, Group 2, of ASTM D388 Yes Design steam rate: 45,000 kg/hr 000,000 lb/hr); Use: Process steam 3 ------- The pilot FGD unit 1s a double alkali scrubber that produces only a solid cake as a waste product. The scrubber does not produce a liquid waste stream. It is designed as a sulfur dioxide (SO2) and particulate control device, and will operate on either fuel without modification. Test and Analysis Summary Sampling and analysis of gaseous, liquid, and solid pollutants were conducted according to the EPA Level 1/Level 2 criteria, except that both Level 1 and Level 2 sampling were conducted simultaneously because of pro- gram time constraints. Level 1/Level 2 analysis procedures were followed except Level 2 analysis was conducted prior to receiving the results of Level 1 analysis in those cases where sample degradation was anticipated. Figure 2 shows the sampling locations. Table 2 summarizes the samples taken and analyses conducted. SCRUBBER FEED SOLIDS EXHAUST GAS TO STACK EXHAUST GAS TO STACK EXHAUST GAS SfeL SCRUBBER MAI WATER FGD CAKE LANDFILL KEUP ^ MULTICLONES FE6DWATER FROM PRETREATMENT UNIT ~ TO MUNICIPAL SEWAGE TREATMENT FLY ASH fly ash STORAGE EXHAUST GAS STEAM COAL BOILER tf GFND 1 - FUEL 2 - BLOWDOWN 3 - FLYASl A - EXHAUST GAS FGD INLET EXHAUST GAS FGD OUTLET 6 - SCRUBBER CAKE 7 - MAKE UPWATER 8 - SCRUBBER F6EO SOUGS Figure 2. Diagram of boiler and flue gas desulfurlzatlon system showing sampling locations. 4 ------- TABLE 2. PARAMETERS SAMPLED FOR COAL AND OIL FIRING Location Parameter Sampling Method Analysis 1 FUEL (coal & oil) C, H, N, S, ash, moisture, heating value Inorganics Grab Ultimate (lab) Level II (lab) 48.5 COMBINED BLOWDOWN Alkalinity/acidity pH conductivity hardness TSS nitrate sulfate sul fite phosphate aimionla nitrogen organics FLYASH inorganics organics FLUE GAS (inlet & outl CO XO, N0/N05/N0 Ng.Ojj* X S02 so?/so, h2so.,hci. hf, particulate sulfate, total hydrocarbons (as CH ) Cj - Cg organics particulate & vapor particulate sizing Composite dipper On-site HACH kit SCRUBBER CAKE inorganics organics Composite grab et) Continuous, Beckman Model 865 Grab (bag) Grab (bag) Continuous, TECO Model 10A Grab (bag) Continuous, TECO Model 41 Goksoyr-Ross Continuous, Beckman Model 400 Grab (bag) SASS Method 5 Anderson impactor SASS Composite grab Level 1 & 2 (lab) Level 1 & 2 (lab) Level 1 & 2 (lab) Direct reading GC (TCD) on site GC (TCD) on site Direct reading GC (TCD) on site Direct reading Level 2 (lab) Direct reading GC (FID) on site Level 1 (lab) Level 2 (lab) Level 1 Level 2 Level 1 & 2 (lab) Level 1 & 2 (lab) BOILER & SCRUBBER MAKEUP WATER organics Inorganics SCRUBBER MAKEUP SOLIDS Top grab Grab Level 1 (lab) Not requi red Not requi red 5 ------- EMISSIONS Table 3 summarizes the annual emissions resulting from coal and oil firing. The table presents estimates of air emissions both before (inlet) and after (outlet) the scrubber. Liquid effluent and solid waste rates are presented for both the controlled and uncontrolled cases. Outlet emissions were determined on the basis of 100 percent of the flue gas being treated by the scrubber. It was assumed that additional scrubber modules, identical to the existing one, could be added such that all of the flue gas was processed in exactly the same manner as the fraction that actually passed through the scrubber. In this way, emissions from the pilot scrubber could be scaled up to represent the total flue gas flow. All emissions data and conclusions are based on this assumption. COMPREHENSIVE ASSESSMENT OF COAL FIRING Criteria Pollutants Uncontrolled emissions of criteria pollutants generally corresponded well with values reported in AP-42. Although N0X emissions were slightly higher than the average AP-42 value, they appear to be within the normal range for similar Industrial units. N0X reductions varying from approximately 0 to 24 percent were mea^ sured across the scrubber. However, the magnitude of NO* reductions could not be correlated to changes in variables monitored during the test period (I.e., temperature, gas flow rate, liquid/gas ratio, boiler load, etc.). For this reason, it is considered feasible that observed N0X reductions are a sampling phenomenon, perhaps related to leaks in the sample train. Sulfur dioxide removal data Indicated an average scrubber efficiency of 97 percent. Controlled SOg emissions were 36.3 ng/J (0.08 pounds/MM Btu) which 1s less than either existing or proposed NSPS limitations for utility boilers. 6 ------- TABLE 3. ANNUAL EMISSIONS kg/year Scrubber Inlet Scrubber Outlet Coal Firing Oil Firing Coal/Oil Coal Firing Oil Firing Coal/Oil Gaseous NOx (as NO2) 500,810 164,230 3.05 442,520 157,390 2.81 S02 1 ,127,300 906,202 1.24 36,800 24,453 1.51 S03 6,184 7,249 0.85 4,157 5,183 0.80 S04* 67,214 20,894 3.22 8,110 8,303 0.98 CO 16,119 4,991 3.23 14,497 4,845 2.99 Organics (as CH4) 5,870 2,272 2.58 6,377 2,500 2.55 Cl - c6+ <5,606 <4,164 -- <5,606 <4,164 C7 - Cl 6 345 155 2.22 274 18 15.2 C16+ 2,311 2,381 0.97 335 392 0.85 Total Particulates 2,991 ,700 53,832 55.6 18,856 13,686 1.38 <1 -- 11 ,691 11,359 1.03 1 - 3p 5,657 1,642 3.45 3 - 10 1,320 634 1.93 =>10p 188 0* m3/year Liquid Blowdown/Waste Water ^76,000 -v 76,000 Ĥv 1 v. 76,000 -*.76,000 % 1 Cooling Uater -*-86,000 -V. 86,000 -*. 1 86,000 t86,000 <*, 1 Solid Bottom Ash ^ 778,600 % 7,600 -v. 103 v, 778,600 Ğ>. 7,600 Ĥ*-103 Fly Ash -v-1 ,800,000 15,000 Ĥv 120 vl ,800,000 *15,000 *.120 Scrubber Cake 0 0 8,054,100 3,011,000 2.67 ^Assuming 100% load, 45 weeks per year (7,560 hrs/year). These values represent the detection Unit of the Instrument used. These values represent oil firing particulate with a niniw* of coal ash contanination. ------- Mass balance data indicate that the multiclone unit upstream of the scrubber was removing little or no fly ash during the test period. The scrubber was found to remove 99.4 percent of the inlet particulate. Inorganics Although the removal efficiency for total particulates is high, there appears to be a net increase 1n emission rates across the scrubber for particulates less than 3 nm in size. This net increase can be attributed to the poor removal efficiency of the scrubber for fine particulates, and to the sodium bisulfate (NaHSO/j) and calcium sulfite hemihydrate (CaS03' 1/2^0) particulates generated by the scrubber. Both NaHS04 and CaS03*l/2H20 have been identified at the scrubber outlet but not at the inlet. The relatively poor removal efficiency (approximately 30%) for S03 across the scrubber is an indication that S03 1s either present as very fine aerosols 1n the scrubber Inlet, or 1s converted to very fine aerosols as the flue gas stream is rapidly cooled inside the scrubber. Analysis has shown that while there may be higher surface con- centrations of sulfur-conta1n1ng compounds 1n the particulates emitted from the scrubber, most of the sulfur-containing compounds are probably present as solid sulfates and sulfites. Thus, 1t 1s conceivable that sulfuric acid vapor 1s condensed and deposited on the particulates emitted, whereas sodium bisulfate and calcium sulfite hemihydrate are emitted as fine, solid particulates. The overall sulfur balance Indicates that over 92 percent of the fuel sulfur 1s emitted as SC^, less than 1 percent of the fuel sulfur is emitted as SOg, and approximately 3 percent of the fuel sulfur is emitted as S0^ . The overall removal efficiency for trace elements across the scrubber 1s 99.5 percent. Of the 22 major trace elements, 18 exceed their MATE values at the scrubber inlet and four at the scrubber outlet. The four trace elements 1n the scrubber flue gas that pose a potential hazard are arsenic, chromium, Iron, and nickel. In addition, the emission concen- tration of beryllium at the scrubber outlet 1s equal to Its MATE value. The relative removal efficiency for trace elements across the scrubber can be explained by enrichment theory. In general, trace elements that 8 ------- occur as element vapors or form volatile compounds at furnace temperatures are more concentrated in the smaller particulates, as a result of subse- quent condensation and surface adsorption. These are the same trace elements that are removed less efficiently by the scrubber. Mass balance closure for most of the trace elements have been found to be in the 75 to 107 percent range. This closure instills confidence on the validity of the sampling and analysis data for trace elements. Organics Total organic emissions were generally less than 9 ng/J (0.02 pound/ MM Btu) and these emissions appear to be primarily to Cg hydrocarbons and hydrocarbons heavier than C^g. While uncontrolled emission rates for C-j to C-jg and higher hydrocarbons are low, emissions of these organics were further reduced by 21% to 35% in the scrubber unit. Polycyclic organic material (POM) was not found in the scrubber inlet 3 or outlet at detection limits of 0.3 yg/m . MATE values for most POM's are greater than this detection limit. However, since the MATE values for at least two POM compounds - benzo(a)pyrene and dibenz(a,h)anthracene - are less than 0.3 yg/m , additional GC/MS analyses at higher sensitivity would be required to conclusively preclude the presence of all POM's at MATE levels. Liquid Effluents The combined wastewater stream generated from the boiler operation may not pose an environmental hazard, since the discharge concentrations of most inorganics and organics are all well below their MATE values. However, based on the uncertainty in SSMS analyses, cobalt, cadmium, nickel and copper may exceed their MATE values based on ecological considerations. Solid Waste The scrubber cake produced contains a significant amount of coal fly ash. With the exception of boron, trace element concentrations in the scrubber cake far exceeded their MATE values. Because the trace elements may leach from the disposed scrubber cake, these solid wastes must be disposed of in specially designed landfills. 9 ------- COMPREHENSIVE ASSESSMENT OF OIL FIRING Criteria Pollutants Uncontrolled emissions of criteria pollutants do not generally correspond with emission factors from AP-42. NOx emissions were nearly 23% lower than the AP-42 emission factor, although they appear to be within the normal range for similar industrial units. CO emissions were nearly 63% lower than the AP-42 emission factor. SO^ and total hydro- carbons corresponded well with their respective AP-42 emission factors. Particulate emissions, in the absence of coal ash contamination, are approximately twice the value tabulated in AP-42. Sulfur dioxide removal data indicated an average scrubber efficiency of 97%. Controlled S0£ emissions were 26.8 ng/J (0.06 lb/MM Btu) which is less than either existing or proposed NSPS limitations for utility boilers. Inorganics Particulate removal data indicate that, on the average, scrubber efficiency was 84% during the test period. However, based on particulate catches essentially free of coal ash contamination, the scrubber effi- ciency was approximately 75% for oil firing particulates. When emissions are uncontrolled, over 90% of the sulfur in the fuel feed is emitted as S02> less than 1% as SOg, and 1.5% as S0^~. SO2 is efficiently removed by the scrubber (97 to 98% efficiency). The SOg removal efficiency (28 to 29%) suggests that SO3 is associated with fine particulates or aerosols. S0^~ is about 60% removed by the scrubber, and so 1s probably associated with the larger particulates. Of the 22 major trace elements analyzed in the flue gas stream, 11 exceeded their MATE values at the scrubber inlet while only 5 exceeded MATE values at the scrubber outlet. These 5 elements are arsenic, cadmium, chromium, nickel and vanadium. With the exception of chromium, elements exceeding their MATE values at the scrubber outlet were removed from the flue gas stream with efficiencies lower than the overall average removal efficiency of 87%. 10 ------- 3 Beryllium emissions were 0.001 mg/m after scrubbing; this corresponds to half the MATE value for this element. At this emission concentration, the National Standard for Hazardous Air Pollutants limitation of 10 grams beryl- lium per day would only be exceeded by boilers of 100 MW capacity or greater. Mass balance closure for 10 of the 20 trace elements analyzed is between 50 and 136 percent. Poorer mass balance closure was obtained for the remain- der of the trace elements due to the extremely low concentrations and/or contamination of the scrubber recycle solution by coal firing components. Organics Organic emissions determined by FID analysis were generally less than 5 ng/J (0,01 Ib/MM Btu) and appear to be composed primarily of C] to Cg hydrocarbons and organics heavier than Ci6. However, gas chromatograph and gravimetric data indicate that FID values may be low by a factor of 2 to 3. Approximately 88 and 83% of the C7 to C-jg and higher than C]g organics, respectively, were removed by the scrubber. The organic compounds identified in the gas samples were generally not representative of combustion-generated organic materials, but were compounds associated with materials used in the sampling equipment and in various analy- tical procedures. This again confirms the low level of organic emissions. Polycyclic organic material (POM) was not found in the scrubber inlet or outlet streams at detection limits of 0.3 Mg/m3. MATE values for most POMs are greater than this detection limit. However, since the MATE values for at least two POM compounds - benzo(a)pyrene and dibenz(a,h)anthracene - are less than 0.3 /ag/m , additional GC/MS analysis at higher sensitivity would be required to conclusively preclude the presence of all POMs at MATE levels. Liquid Effluents The combined wastewater stream from the boiler operation may not pose an environmental hazard in terms of organic materials since the discharge concen- trations of organics are all well below their MATE values. A similar conclusion may be drawn with respect to inorganic materials since inorganics, with the exception of nickel and copper, did not exceed their MATE values for liquid streams. Owing to uncertainty associated with SSMS analysis, nickel and copper may exceed their MATE values although this 1s not necessarily the case. 11 ------- Solid Waste With the exceptions of antimony, boron, molybdenum and zinc, trace element concentrations in the scrubber cake exceed their MATE values. Because the trace elements may leach from the disposed scrubber cake, these solid wastes must be disposed of in specially designed landfills. COMPARATIVE EMISSIONS ASSESSMENT Criteria Pollutants Uncontrolled emissions of criteria pollutants produced during coal firing correspond well with emission factors from AP-42. This obser- vation does not generally hold true for oil fired emissions. Full load N0X emissions from oil firing were 19% lower than the AP-42 emission factor, although they appear to be within the normal range for similar industrial units. CO emissions from oil firing were nearly 63% lower than the AP-42 emission factor. 011-fired SOg and total hydrocarbons correspond well with their respective AP-42 emission factors. Particu- late emissions from oil firing, 1n the absence of coal ash contamination, are approximately twice the value tabulated in AP-42. N0X emissions Increased with increasing load for both coal and oil firing, as expected. Available data indicate that for boiler loadings between 90 and 100%, N0X emissions from coal firing are approximately three times greater than from oil firing. Observed reductions of N0X emissions for coal firing and early oil firing tests appear to be due, at least in part, to air leakage into the scrubber outlet sampling line. Data from later oil firing tests, not known to be subject to leakage problems, indicate that N0X removal across the scrubber is on the order of 2%. Uncontrolled CO emissions from coal firing were 15.9 ng/J (0.04 lb/ MM Btu) while those from oil firing were 5.47 ng/J (0.01 lb/MM Btu). This factor of three difference 1s at variance with AP-42 data indicating that CO emissions from oil firing are 23% lower than those from coal firing. Apparent reductions in CO emissions across the scrubber are not considered 12 ------- significant due to air leakage in the sampling train and the low sensitivity of analysis at the measured CO concentrations. Uncontrolled SO^ emission rates during coal and oil firing were 1112 ng/J (2.59 lb/MM Btu) and 993 ng/J (2.31 lb/MM Btu), respectively. Removal data indicate an average scrubber removal efficiency of 97% during both coal and oil firing. Controlled S02 emissions for coal and oil fir- ing were 36.3 ng/J (0.08 lb/MM Btu) and 26.8 ng/J (0.06 lb/MM Btu), respectively, which are lower than either existing or proposed NSPS 1 imitations. Particulate loadings prior to scrubbing were 2951 ng/J (6.86 lb/MM Btu) during coal firing and 59.0 ng/J (0.14 lb/MM Btu) during oil firing, in the absence of coal ash contamination. Scrubbing removed 99% of the coal-fired particulates and 75% of the oil-fired particulates. The lower removal efficiency obtained during oil firing is attributed to the increased fraction of particles smaller than 3ym; at least 21% of the uncontrolled oil-fired particulates are less than 3 ym in diameter while substantially less than 1% of uncontrolled coal-fired particulates are under 3 urn. There appeared to be a net increase in emission rates across the scrubber for coal fired particulates less than 3 ym 1n size. This net Increase can be attributed to the poor removal efficiency of the scrubber for fine particulates, and to the sodium blsulfate (NaHSO^ and calcium sulfite hemihydrate (CaS03 1/2H20) particulates generated by the scrubber. Both NaHSO^ and CaSOg *1/2^0 have been identified at the scrubber outlet but not at the inlet. Although a very slight increase in oil-fired particulates in the 1-3 ym range was observed, a net decrease in particulates less than 3ym was observed during oil firing. Based on the results of coal firing tests, it appears reasonable that scrubber generated particulates were present In the scrubber outlet stream during oil firing but that the high fine particulate loading associated with oil firing masked detection of these materials. 13 ------- Inorganics Of the 23 major trace elements analyzed in the flue gas stream during coal firing, 18 exceed their MATE values at the scrubber inlet and four at the scrubber outlet. Similarly, for oil firing, 11 exceeded their MATE values at the scrubber inlet while five exceeded their MATE values at the scrubber outlet. Elements exceeding their MATE values at the scrubber outlet and which are common to both fuels are arsenic, chro- mium and nickel. Additionally, iron exceeded its MATE value at the scrubber outlet during coal firing as did cadmium and vanadium during oil firing. The overall removal of trace elements across the scrubber is 99% for coal firing and 87% for oil firing. Beryllium emissions after scrubbing were less than or equal to the beryllium MATE value during coal and oil firing. At the measured emis- sion concentrations, the National Standard for Hazardous Air Pollutants limitation of 10 grams beryllium per day would only be exceeded by boilers of 50 MW capacity for coal firing and 100 MW capacity for oil firing. The fraction of fuel sulfur converted to S03 during oil firing was 50 to 75% higher than during coal firing. In contrast, the fraction of fuel sulfur converted to sulfates during coal firing was twice that during oil firing. Sulfates are more efficiently removed than SOj (60% removal for oil firing and 88% for coal firing). This Indicates that S0^~ is probably associated with the larger particulates, which are more efficiently removed than smaller particulates. The higher sulfate removal from the coal flue gases is explained by the higher particulate loading during coal firing. Uncontrolled chloride and fluoride loadings were higher during coal firing (5 and 0.2 ng/J, respectively) than during oil firing (0.2 and 0.02 ng/J, respectively). This was attributed, 1n the case of chlorides, to a higher fuel chlorine content for coal than for oil. Chlorides were removed with better than 99% efficiency from coal flue gases and with about 51% efficiency from oil flue gases. This difference was attributed 14 ------- to the higher particulate removal efficiency for coal particulates. Fluorides were removed with greater than 86% and about 87% efficiency for coal and oil firing, respectively. Uncontrolled nitrate emissions were 0.08 ng/J during oil firing, and nitrates were removed from oil flue gases with 57% efficiency. Orqanics Polycyclic organic material (POM) was not found in the scrubber inlet or outlet at detection limits of 0.3 jjg/m3 for either coal or oil firing. MATE values for most POM's are greater than this detection limit. However, since the MATE values for at least two POM compounds - benzo(a)pyrene and dibenz(a ,h)anthracene - are less than 0.3 pg/m3, additional GC/MS analyses at higher sensitivity would be required to conclusively preclude the presence of all POM's at MATE levels. Organic emissions for coal and oil firing were very similar. Total organic emissions were less than 9 ng/J (0.02 Ib/MM Btu) for both tests, and these emissions appear to be primarily C] to Cg hydrocarbons and organics heavier than C-jg. While uncontrolled emission rates for both coal and oil firing are low, emissions of these organics were further reduced by about 75% to 85% in the scrubber unit. The organic compounds identified in the gas samples from both coal and oil firing were generally not representative of combustion-generated organic materials, but were compounds associated with materials used in the sampling equipment and in various analytical procedures. This again confirms the low level of organic emissions. Liquid Waste The combined waste water stream from the boiler operation may not pose an environmental hazard in terms of organic materials since the discharge concentrations of organics are well below their MATE values for both coal and oil firing. The same conclusion may be drawn for inor- ganic compounds with the exception of cobalt, nickel, copper and cadmium for coal firing and nickel and copper for oil firing since these metals may exceed their MATE values. 15 ------- Solid Waste The scrubber cake produced when either fuel is burned contains concentrations of trace elements high enough to exceed most MATE values. Because of these high concentrations the scrubber cake must be disposed of in specially designed landfills. COMPARATIVE ENVIRONMENTAL ASSESSMENT The difference in environmental insult expected to result between coal and oil combustion emissions from a single controlled 10 MW industrial boiler is insignificant. This is because: 1) there are only slight differen- ces in the emissions levels of the pollutants, or 2) the absolute impact of either fuel use is insignificant. The environmental impacts of emissions from a cluster of controlled 10 MW industrial boilers are potentially significant. The impacts include health effects, material damages, and ecological effects from high levels of SO^, N0X and suspended particulate matter; health effects and ecological damage due to trace metal accumulation in soils and plants; and aesthetic degradation from visibility reduction and waste disposal sites. The risk of environmental damage from emissions of controlled industrial boilers, whether oil or coal-fired, is considerably less than the risk posed by emissions from uncontrolled industrial boilers. It should be noted that this finding is based on an exceptional facility. The reference facility 1s very well run and maintained, and emissions are low. The environmental acceptability of a cluster of controlled industrial boilers is more dependent on site specific factors (e.g., background pollution levels, location and number of other sources) than type of fuel utilized. Careful control of the site specific factors can avert potential environmental damages and generally compensate for any differential effects arising between the use of coal or oil . With the possible exception of ambient levels of N0xğ the risk of violating the National Ambient Air Quality Standards (NAAQS) due to the opera- tion of clusters of controlled Industrial boilers is essentially the same whether the fuel combusted is coal or oil. Based on tests of the reference 10 MW boiler (which was not controlled for N0X emissions), localized N0X concentrations produced by coal firing are estimated to be twice the level of that resulting from oil firing, and greater than the levels permitted by the NAAQS for 24-hour and one year averaging periods. 16 ------- Short term (3 hour and 24 hour averaging times) maximum ambient concentrations present the most significant air pollution problem result- ing from operation of controlled industrial boilers. Restrictions imposed by the NAAQS for short term ambient levels would be most con- straining to boiler operation in areas where air quality is already only marginally acceptable. Expected long term concentrations arising from boiler emissions would not appear to pose a risk for violation of the NAAQS. Coal firing appears to produce a greater enrichment of trace elements in the flue gas desulfurization cake than oil firing produces. However, the scrubber cake resulting from either coal or oil firing contains sufficient amounts of heavy metals and toxic substances to pose difficult waste disposal problems. The impact categories considered include public health, ecology, societal, economic, and energy. The specific findings with respect to the various Impact categories are summarized briefly below. Health Effects Based on the Lundy/Grahn Model for health effects associated with suspended sulfate levels, regional emissions levels from controlled oil or coal-fired industrial boilers would not be expected to cause a signi- ficant impact on regional health. Emissions from uncontrolled boilers would result in substantially greater levels of regional suspended sulfate levels, and the associated health effects would be an order of magnitude greater. Emissions from clusters of controlled industrial boilers are expected to cause significant adverse health effects in a localized area near the plant cluster. Oil firing would be expected to result in localized health effects about one third less severe than those resulting from coal firing. The increase in mortality attributable to either controlled coal or oil firing is appreciable less than that associated with uncontrolled industrial boilers emitting higher levels of particulates and S0X. The impact of solid waste generation on health is essentially the same for controlled coal firing and oil firing, provided suitable land 17 ------- disposal techniques are employed to assure minimal leaching rates and migration of trace elements to groundwater and the terrestrial environment. Addition of cadmium to a localized environment in the quantities produced by clustered controlled industrial boilers may result in cadmium concentrations in living plants approaching levels injurious to man. Because cigarettes contain significant cadmium levels, smokers are more apt to achieve thresholds of observable symptoms for cadmium exposure when consuming additional cadmium via the food chain. The concentration of metals 1n runoff waters due to controlled oil firing is predicted to be slightly less than that occurring from controlled coal firing; in either case, hazard to human health by drinking water is remote. Trace element emissions from clusters of controlled industrial boilers may significantly increase local background levels in drinking water, plant tissue, soil, and the atmosphere; however, the expected Increases in the levels of such elements are generally several orders of magnitude less than allowable exposure levels. Oil firing is estimated to cause cadmium burdens in plants approaching levels injurious to man, and coal firing may produce plant concentrations of molybdenum which are injurious to cattle. Ecology The potential for crop damage from either controlled coal firing or oil firing depends greatly on ambient levels of N0xğ SO2, or trace element soil concentrations. If such levels are presently high, localized plant damage would be expected to occur within a 1 to 2 km range from a control- led boiler cluster. Leaf destruction from SOg exposure would be expected to be slightly more severe 1n the vicinity of a cluster of controlled boilers which are coal fired as opposed to oil fired. For boilers uncon- trolled for N0X emissions, plant damage would be expected to be significantly greater in the vicinity of the coal-fired cluster, owing to higher levels of ambient N0X produced. The likelihood of damage occuring in plants due to emissions of trace elements from either controlled oil or coal firing is remote, with the possible exception of injury due to elevated 18 ------- levels of molybdenum and cadmium 1n plant tissue resulting from coal firing and oil firing, respectively. The effect of emissions from industrial boilers on trace element burdens in plants would be greater via soil uptake than by foliar inter- ception. This is because soil concentrations are the result of accumu- lative long term exposure to boiler emissions whereas foliar exposure is determined by the immediate deposition rate of emissions on the plant surface and the lifetime of the leaf. The impact of fossil fuel combustion in controlled oil or coal- fired boilers on plant damage via acid precipitation would be insignificant. The levels of suspended sulfate (the origin of acid rain) would be essentially the same whether the controlled boilers are coal or oil fired. Measurement and analyses of leaching rates at experimental waste disposal sites indicate that landfills of untreated flue gas desulfuri- zation system scrubber cake can be constructed such that significant adverse impacts will not occur. Societal The impact of boiler emissions on corrosion in the local area near a cluster of controlled industrial boilers would be significant. The corrosion rate would be slightly greater when the boilers are coal-fired. However, the extent of this overall impact (oil or coal) is minor compared to that which occurs when industrial boilers are uncontrolled. The increase in annual TSP and soiling damages in the vicinity of a cluster of controlled industrial boilers would result in additional cleaning and maintenance costs about 10 to 15% greater than that already experienced in a typical urban area. The cleaning costs may be slightly greater when the boilers are coal-fired. Emissions of particulate matter from controlled Industrial boilers would result in visibility reduction. This aesthetic degradation would occur in a localized area near the boiler cluster, and would occur to essentially the same extent whether the boilers are oil or coal fired. 19 ------- Total land disposal requirements for scrubber cake waste generated by controlled coal firing are three times greater than those for controlled oil firing. Waste disposal of the scrubber wastes may result in significant depreciation of property value and aesthetic degredation in the area of the disposal site. These impacts would be more severe if boilers use coal rather than oil. Economic The differential direct economic impact between emissions from coal firing and oil firing is generally insignificant with the possible exception of some differences occurring in a limited localized area near clusters of boilers. The extent of the incremental direct economic impacts is proportional to the extent of the incremental environmental damages. Differential second order economic impacts, such as changes in hospital employment, alteration of taxes, or changes in income, are expected to be insignificant between emissions from controlled oil and coal-fired industrial boilers. Energy At the present time, the comparative assessment of the effects of emissions from controlled oil and coal-fired industrial boilers tends to support the national energy plan for intensified utilization of coal. The fuel choice of oil or coal is a relatively minor issue concerning the environmental acceptability of controlled industrial boilers; other site specific and plant design factors exert a greater effect on environmental damages. While it was shown that fuel choice caused significant dif- ferences in impacts to occur when the boiler is uncontrolled for N0X emissions, these differences may be mitigated by the addition of N0X control technologies with minimal overall cost impact. As concern for environmental protection increases, the issue may not be whether coal or oil use is more environmentally acceptable, but whether the Increasing use of fossil fuels can be continued at the present levels of control technology without potential long term damages. If it is found that long term effects of pollution (e.g., trace metals accumulation, lake acidity from acid rains) from fossil fuel combustion and other sources are 20 ------- environmentally unacceptable, it is clear that energy use may be affected. Energy cost will Increase with increasing control requirements, possibly to the level where other cleaner forms of energy become more competitive. 21 ------- TECHNICAL REPORT DATA (Please read Instructions on the reverse before completing) 1. REPORT NO. 2. EPA-600/7-78-164a 3. RECIPIENT'S ACCESSION NO. 4. title and subtitle Environmental Assessment of Coal- and Oil-firing in a Controlled Industrial Boiler; Volume I. Executive Summary S. REPORT DATE August 1978 6. PERFORMING ORGANIZATION CODE 7.author(s) c. Leavitt, K. Arledge, C. Shih, R. Orsini, W. Hamersma, R. Maddalone, R. Beimer, G. Richard, and M. Yamada 8. PERFORMING ORGANIZATION REPORT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS TRW, Inc. One Space Park Redondo Beach, California 90278 10. PROGRAM ELEMENT NO. EHE624A 11. CONTRACT/GRANT NO. 68-02-2613, Task 8 12. SPONSORING AGENCY NAME AND ADDRESS EPA, Office of Research and Development Industrial Environmental Research Laboratory Research Triangle Park, NC 27711 13. TYPE OF REPORT AND PERIOD COVERED Task Final; 5/77-7/78 14. SPONSORING AGENCY CODE EPA/600/13 15.supplementary NOTES jerl-RTP project officer is Wade H. Ponder, Mail Drop 61, 919/ 541-2915. 16. abstract The rep0rt gives results of a comparative multimedia assessment of coal- versus oil-firing in a controlled industrial boiler, to determine relative environmen- tal, energy, economic, and societal impacts. Comprehensive sampling and analyses of gaseous, liquid, and solid emissions from the boiler and its control equipment were conducted to identify criteria pollutants and other species. Major conclusions include: (1) While the quantity of particulates from oil-firing is considerably less than from coal-firing, the particles are generally smaller and more difficult to remove, and the concentration of particulates in the treated flue gas from oil-firing exceeded that from coal-firing. (2) NOx and CO emissions during coal-firing were about triple those du- ring oil-firing. (3) Sulfate emissions from the boiler during coal-firing were about triple those during oil-firing; however, at the outlet of the control equipment, sulfate concentrations were essentially identical. (4) Most trace element emissions (except vanadium, cadmium, lead, cobalt, nickel, and copper) are higher during coal-firing. (5) Oil-firing produces cadmium burdens in vegetation approaching levels which are injurious to man; coal-firing may produce molybdenum levels which are injurious to cattle. (6) The assessment generally supports the national energy plan for increased use of doal by projecting that the environmental insult from coal-firing is not signif- icantlv different from that from oil-firing. 17. KEY WORDS AND DOCUMENT ANALYSIS a. DESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group Pollution Nitrogen Oxides Assessments Carbon Monoxide Boilers Sulfates Combustion Sulfur Oxides Fuel Oil Trace Elements Coal Chemical Analysis Dust Pollution Control Stationary Sources Environmental Assess- ment Industrial Boilers Particulate 13B 07B 14B 13A 21B 2 ID 06A 07D 11G 18. DISTRIBUTION STATEMENT Unlimited 19. SECURITY CLASS (This Report) Unclassified 21. NO. OF PAGES 26 20. SECURITY CLASS /This page) Unclassified 22. PRICE EPA Form 2220-1 (9-73) 22 ------- |