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1 ppm of sulfur dioxide for either plant. It was agreed that concentrations slightly above that level may occur infrequently on the plateau north of Clifty Creek Plant, with an occasional peak value just reaching the odor threshold. In general it was found that the original calculation of concentrations at both plants had given somewhat higher values than were actually experienced.

The most gratifying finding was that the meteorological condition which was expected to give rise to a severe problem, namely the breakup of nighttime inversions, with calculated concentrations of 5 to 10 ppm, failed completely to follow the mathematical model. This model, which did not involve the Sutton equation, was based on the idea that the gas would all be confined to a narrow wedge of quite limited height below the inversion. Although there was a tendency for the recorded ground level concentrations of sulfur dioxide to occur during the mid-morning hours, there was not a single case of the very high concentrations typical of fumigations. The results seem to indicate that the more restrictive ideas concerning the maximum size of thermal plants based on purely theoretical fumigation calculations (5) should be reviewed and considerably modified toward permitting larger aggregation of power generation equipment at a given site.

It was found that recording of any sulfur dioxide was an unusual event, averaging only 1.8% of the daylight hours, with a maximum at the valley station of 3.0%. Night hours showed So, present only an average of 0.3% of the time. When sulfur dioxide was present it averaged only 0.10 ppm with short-term peaks at some stations reaching 0.40 ppm. The records clearly establish the fact that these tall stacks eliminate ground level concentrations during inversions. Only a small proportion of the observed concentrations occurred at night when the inversions were normally present. When concentrations did occur at night, it was generally apparent from the winds, temperatures, or observations by the plant personnel that no inversion was present. Thus, the inversion which is so often described as a “lid” holding down noxious gases, actually becomes a shield preventing the return of stack gases if they are first emitted at a height, velocity and a temperature which are reasonable and appropriate.


The design of the stacks for Cardinal Plant which will have a total generation on one site of approximately 2100-2300 mw represents, in many ways, the culmination of all of the information, design and operating experience obtained since the building of Clifty and Kyger Plants. The similarity of this terrain to that at Clifty is shown on Figure 3. Here again, the plant is upwind of a substantial plateau but this plateau is broken by major and minor streams in a highly irregular fashion.

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After considering all factors, a stack height of 825 feet above grade was selected. This was based on many considerations, among which were the following:

(a) It was decided that this height represented the maximum reasonable limit to which the existing technology of stack construction could be reliably extrapolated.

(6) The combining of the flue gases from two or more units into a single stack would be beneficial from an air pollution viewpoint and was contemplated However, the experience with stack repairs at Clifty Creek argued agains such a choice. As it is, a single unit per stack represents approximately a 50 per cent extrapolation in capacity beyond the Clifty Creek stacks.

Also since regulations covering so, emissions may be instituted under the Clean Air Act of 1963, it is possible that the third unit might have to have a higher stack than was selected at this time.

(c) Since only two units of the total plant development were to be built at this time, it seemed certain that there would be a period of not less than fire years operation of these units before decisions were required concerning the third stack. This period of operation and observation would permit an exact evaluation of the plant's effect upon the SO, concentrations in the surrounding countryside.

7. SUMMARY-HIGH STACKS It has become apparent that high stacks offer the only presently available pragmatic solution to the problem of disposing of SO2. Efforts to remove sulfur from the fuel before burning it have, so far, come to naught. Numerous studies seeking to remove SO, from the flue gas have arrived at estimated costs which make the process completely unacceptable even before the operating problems have been evaluated by actual construction and operation.

It is possible that high stacks can be accepted only as an interim solution to this problem. There is need for careful studies before and after the installation of every major power plant having high stacks in order to obtain a more extensive evaluation of the diffusion equations. This might be done along the lines that have been started by the Tennessee Valley Authority (6). Such studies might provide the designer with a degree of confidence in evaluating the disposal of SO, that he does not possess at the present time.

8. THE COMING ERA OF 2500-4000 MW PLANTS AND SO, PROBLEMS 8.1. The general solution

The era of 2500 mw-4000 mw steam electric plant is not a fact that needs to be anticipated—it is here. Mention has been made of Cardinal. Recently, announcement was made of a new generating station to be located on the American Electric Power System in West Virginia with an initial installation of two 800 mw units and with a third unit to be installed sometime after 1971. The most likely size of this third unit will be 1050 mw. Thus, for coal burning plants, we are confronted with the need to critically examine the problem that a plant designer will be called upon to solve to harmlessly dispose of 1250 tons of sulfur per day or 100 tons per hour when converted into oxides of sulfur, mainly SO.

The authors believe that this offers no occasion for fear or dismay. The high stack properly designed can, without question, take care of every require ment- ecological, economic, and esthetic. A number of special areas in connet tion with the adoption of this solution warrant further, if only brief, discussion. These follow : 8.2. The multi-compartmented, integrated stack

Such stacks have many advantages from the standpoint of obtaining the maximum rise of the hot gas, the increase in the plume's ability to pierce inversions and the maintenance of reasonable exit velocity when one or more units is shut down. Offsetting these advantages, are the costs associated with the poor utilization of the stack's cross section, the cost of horizontal duet work required to reach a stack of this type and finally, the question of ability to work on and around an idle liner while the other two or three are in use. It appears likely that several years may elapse before stacks of this general type are built in the United States.

8.3. The problem of height, material construction and maintenance

In applying very high stacks, a considerable problem with the aeronautical authorities must be faced. This is somewhat mitigated by the fact that it is already recognized that perhaps in level terrain, heights beyond 800 or 900 feet do not significantly improve the ground level concentrations. However, in hilly country such as the terrain in which the plants described are located, it is conceivable that stacks as much as 1200 or 1500 feet in height may ultimately be required.

Stack design has undergone more rapid change in the past ten or twelve years than at any time since the power industry's beginning. New materials have been tried, different construction techniques utilized, and new problems have been faced.

Currently, the stack design consisting of a reinforced concrete shell with a low-alloy, corrosion resistant steel (such as Corten) liner, appears to be adequate after approximately six years' service. Obviously, it would be desirable to have double or triple this amount of experience before concluding that it has completely solved the problem. 84. The monitoring and building up of technological history

The fortunate development of the high stack as a solution to the sulfur-, dioxide problem presented by large coal burning plants was carried out on the basis of very meager experience. But for the future it is most important that this deficiency be remedied. The authors most earnestly recommend, therefore, as new high stacks are designed and constructed, that an effort be made to obtain data on the ground level concentrations of So, for extensive periods before and after operation. Needless to say, adequate meteorological information for the evaluation of these results should be obtained either from other sources or by special instrumentation at the site.

Every generation's engineers have been the heirs to the ingenious work, records and experience compiled by and transmitted to them by their professional forebears. Air pollution represents an area in which today's engineers must in turn develop such necessary data and make it available to the generations that will follow.

REFERENCES 1. P. Sporn and V. M. Marquis “The OVEC Project: Economic, Engineering and Finance Problems of the 2,200,000 KW, 18,000,000,000 Kilowatt-Hour Power Project of the Ohio Valley Electric Corporation” AIEE Annual Meeting N.Y.C.1954, Paper No. 54–57. Also presented at CEGRE Meeting, 1954.

2. Bosanquet, Carey and Halton "Dust Deposition From Chimney Stacks" Institution of Mechanical Engineers pp 355–367, 1950.

3. Sutton, 0. G. "The Theoretical Distribution of Airborne Pollution from Factory Chimneys” Royal Meteorological Society, Quarterly Journal, 73: 426 435, 1947.

4. Smith, M. E. "The Variation of Effluent Concentrations From an Elevated Point Source” Archives of Industrial Health, Vol. 14. pp 56-68, July 1956.

5. Pooler, F. “Potential Dispersion of Plumes From Large Power Plants" Environmental Health Series. U.S. Public Health Service--Publication No. 999 AP-16, 1965.

6. Gartrell, F. E. "Monitoring of so, in the vicinity of Coal-Fired Power Plants—TVA Experience” Proceedings American Power Conference XXVII, 1965.

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As president of the Industrial Gas Cleaning Institute, I attended your committee hearing on Thursday, July 21, and again with members of our IGCI Government Relations Committee on Tuesday, August 9, 1966. We want you to know that we are very favorably impressed with the work your subcommittee is doing and the knowledge and understanding of the committee members. We are confident that better and more practical approaches to research on pollution control will result from your efforts.

Let us first acquaint you with the Industrial Gas Cleaning Institute. The IGCI is a national association of manufacturers of gas cleaning equipment. We are concerned with the collection of particulate matter and as an institute are not presently involved with the control of gaseous emission. The IGCI encompasses all four types of air pollution control devices (particulate collectors) : Electrostatic precipitators, mechanical collectors, bag filters, wet scrubbers. We represent most of the major manufacturers and an estimated 80 to 85 percent of the dollar volume of industrial dust collecting equipment sold in the United States.

We are in complete agreement with many of the statements made by the witnesses appearing before your committee and in the report of the Research Management Advisory Panel, and would like to comment briefly on what we feel are some of the more pertinent statements.

Page 3 of your report states: "Policies which aid the efficient and timely deployment of private sector scientists and engineers are desirable." We wholeheartedly endorse this statement and that of Dr. Bueche when he says, “Industry has the needed skills and facilities." We believe that such skills and knowledge are available within the gas cleaning equipment industry. Many of these concerns have been working in this area for 30 or 40 years.

We agree with the statement on page 11 of the report that "What the Nation needs is not the revenue from penalty fines imposed on polluters; rather, the need is for reduction in the volume of pollutants discharged to the environment.” Industry needs help and incentive, not penalties. This is particularly true of the marginal operators who could be forced out of business by the cost of control equipment. This may sound contradictory coming from people whose business it is to sell control equipment, but it is extremely important and should be carefully considered.

Dr. Beuche said, in his most commendable statement, that the “job * * * will be completed most rapidly if attacked on a competitive basis." We firmly believe in this philosophy and were extremely gratified to note the committee's awareness of, and attitude toward, the value of profit as an incentive. The outstanding example of the value of the profit motive is the problem of SO, which was mentioned

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so often throughout the hearings. As you know, there is no economical means of removing SO, from effluent gases. Why? Because until the past year or so there were no controls covering the emission of SOz. As a result, there was no market. People in business do not spend any significant amount of money on research of nonmarketable products. Even today, there are controls in only three or four small areas of the country and these regulations are met by burning lower sulphur and higher cost fuels. The controls must come first, but there must also be time to permit industry to develop an economically feasible solution.

On the question of who is to do what research, the answer was clearly and succinctly stated by Dr. Bueche when he divided research into two categories:

1. Research that will produce information useful for establishing standards, determining necessary regulations, enacting appropriate laws and suggesting methods; and

2. Research that will produce information useful in developing hardware and systems that can be manufactured and sold. No. 1 is strictly within the realm of the Government and No. 2 that of industry. Also, due to the urgency of the problem, there should be some governmental support of private research.

During Dr. Bishop's testimony, Mr. Daddario, you raised the question of how the steel industry selects a collector to do a certain job and why there isn't an industry standard for a given application. It is regretable that there wasn't ample time for Dr. Bishop to give a more complete and definitive answer because, at this point, we felt that there was a lack of rapport between the witness and the members of the committee. In areas such as this, we feel that our institute could lend the committee valuable assistance. In this letter, we cannot go into all of the details involved relative to your steel industry question; but, because two or three types of equipment will do the job required, many things must be considered in selecting the equipment to be used, such as

1. First cost versus operating and maintenance costs.
2. Available space.
3. Availability of water.
4. Power consumption.

5. Disposal of waste product, wet or dry. In Mr. Arthur C. Stern's testimony on July 21, there is, perhaps, an implication that industry, and in particular the air pollution control industry, is not making an adequate effort in research. We would like to clarify this situation in regard to the gas cleaning industry. Because there is little or no control of gaseous emissions to date, and our members account for 80–85 percent of the particulate collectors sold, we essentially are the air pollution control industry as it is presently constituted.

Contrary to popular belief, ours is not a large industry. The total annual domestic sales of the members of the IGCI (no auxiliary equipment or installation costs included) for the past 5 years are:

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