READING ANTHRACITE Co., Pottsville, Pa., August 16, 1960. RESEARCH-COTTRELL, INC., Finderne Plant, Bound Brook, N.J. GENTLEMEN: Samples of coal submitted to our laboratory on August 8, 1960, designated from Potomac Electric & Power Co., Dickerson, Md., your G.O. 2575A, Purchase Order No. 60-0122-H dated August 10, 1960, have the following composition: REPORT OF PERFORMANCE TESTS ON THE COTTRELL ELECTRICAL PRECIPITATION EQUIPMENT INSTALLED FOR POTOMAC ELECTRIC POWER COMPANY AT CHALK POINT, (BRANDYWINE) MD., G.O. 2763-A. & B. 1. INTRODUCTION This report covers the results of tests made to determine the performance of the Cottrell Elecrical Precipitation Equipment installed by Research-Cottrell, Inc. for Potomac Electric Power Company, Chalk Point, Maryland. The equipment, as furnished and erected is, described in proposal dated March 13, 1962 and purchase order number 810055-1 dated September 5, 1962. 2. PURPOSE OF THE INSTALLATION The purpose of this installation is to remove fly ash from the gases coming from two 2,500,000 lbs/hr double reheat steam generator pressurized furnaces pulverized coal fired types. This is designated by the customer as Nos. 1 and 2 Units. 3. DESCRIPTION OF THE INSTALLATION This installation consists essentially of the following components: 3.1 Two precipitators of four units each. Each unit includes. 3.1.1 High tension framework with coppered Bessemer 0.109" diameter discharge electrodes. 3.1.2 High tension insulators. 3.1.3 Tile inlet bushings. 3.1.4 High tension cables, cable terminals, and cable supports or bus duct. 3.1.5 Three sections, each section as follows: 3.1.5.1 Primary section of 37 ducts, each 0′-9′′ x 24′-0′′ high x 6'-0" long. 3.1.6 ASTM A283 steel shell and 16" hoppers. 3.1.7 16" steel ASTM A-283 or equal top housing. 3.1.8 24" round steel inspection doors in hoppers, insulator compartments, side of shell. 3.1.9 Perforated distribution plates in outlet and inlet. 3.1.10 Flue connections. 3.1.11 Syntron discharge electrode rappers. 3.1.12 Magnetic Impulse Gravity Impact collecting electrode rappers. 3.2 Electrical equipment for energizing the installation, as follows: Twelve Silicon, 70 KVp, 1000 ma rectifier sets arranged in cabinets. Control units are located adjacent to the precipitator roof elevation. 4. RATING The normal rated gas capacity for this installation is 960,000 cfm per precipitator at an inlet gas temperature of 250° F, and an inlet gas pressure not to exceed +5.0'' positive pressure. 5. GUARANTEE Research-Cottrell, Inc. guaranteed that when this installation was adjusted and operating within its rated capacity and under the normal operating conditions specified by Research-Cottrell, the suspended matter present in the exit gases from the installation would not exceed 2.5 percent of the suspended matter present in the gases entering the installation for treatment. Research-Cottrell guarantees, when the equipment covered by this agreement is adjusted and operated at the normal operating conditions specified herein, that 972% of the suspended matter present in the gases at the inlet of the equipment shall be removed, provided the gas does not require cleaning below an outlet concentration of .05 grains per cubic foot at 32° F and 29.92'' Hg. 6. OPERATING DATA This installation was placed in operation on August 27, 1964. Prior to tests, plant personnel were instructed in the operation of the installation. Performance tests were run from August 20 to August 24, 1965. The test procedures followed are in general agreement with the ASME Power Test Code and Research-Cottrell test bulletin entitled "Test Method for the Determination of Gas Velocity, Moisture, Dust, Acid, and Tar Contents." The boilers were operating at steaming rates varying between 2.13 to 2.18 x 10 lbs/hr. Test samples were drawn from the sampling stations located in the downcomer breeching before the precipitator and in the breeching immediately before the stack. Remarks: No. 1 precipitator was tested in an “as found" condition. Two inlet sections were grounded so total rectifier outputs were applied to the remaining two sections. No. 2 precipitator was tested following a second outage in which hoppers were cleaned and new discharged electrodes were installed replacing those which were found broken. 7.1 No. 1 Precipitator 7. DISCUSSION OF TEST RESULTS Three tests were made to prove the performance of the installation. 7.1.1 Test No. 2 was at 132 percent of rated volume, or 1,262,000 cfm. corresponding to a steam flow of 2,180,000 lbs/hr. The inlet concentration was 2.74 gr per cu ft; the outlet, 0.0265 gr per cu ft, giving an efficiency of 98.5 percent. 7.1.2 Test No. 3 was at 130 percent of rated volume, or 1,249,000 cfm, corresponding to a steam flow of 2,150,000 lbs/hr. The inlet concentration was 2.88 gr per cu ft; the outlet, 0.286 gr per cu ft, giving an efficiency of 90.2 percent. The resultant low efficiency of this test was due to sampling technique. 7.1.3 Test No. 4 was at 130 percent of rated volume, or 1,249,000 cfm. corresponding to a steam flow of 2,150,000 lbs/hr. The inlet concentration was 3.01 gr per cu ft; the outlet, 0.642 gr per cu ft, giving an efficiency of 98.0 percent. 7.2 No. 2 Precipitator Three tests were made to prove the performance of the installation. 7.2.1 Test No. 1 was at 138 percent of rated volume, or 1,326,350 cfm. corresponding to a steam flow of 2,400,000 lbs/hr. The inlet concentration was 2.69 gr per cu ft; the outlet, 0.066 gr per cu ft, giving an efficiency of 97.6 percent. 7.2.2 Test No. 2 was at 134 percent of rated volume, or 1,282,000 cfm, corresponding to a steam flow of 2,400,000 lbs/hr. The inlet concentration was 2.14 gr per cu ft; the outlet, 0.0865 gr per cu ft, giving an efficiency of 96.0 percent. 7.2.3 Test No. 3 was at 134 percent of rated volume, or 1,282,000 cfm, corresponding to a steam flow of 2,420,000 lbs/hr. The inlet concentration was 2.325 gr per cut ft; the outlet, 0.0553 gr per cu ft, giving an efficiency of 97.62 percent. All test results and other pertinent operating data are shown on the attached summary sheets. 8. CONCLUSION On the basis of the test results, it is concluded that this installation is meeting its guarantee. 2. Requests for data as to the tons per day of flue gas and fly ash discharged into the atmosphere from the stacks at each of Pepco's five generating stations. In response to these requests there is enclosed a copy of a tabulation entitled "Potomac Electric Power Company, Flue Gas and Ash Discharged in 1965 and 1966 from Pepco's Five Steam-Electric Generating Stations".1 Potomac Electric Power Co. flue gas and ash discharged in 1965 and 1966 from Pepco's 5 steam-electric generating stations1 1 Total plant discharge equals tons flue gas plus tons ash. NOTE.-Tons of flue gas includes products of combustion for coal and oil. 1 As I indicated in my testimony, I do not believe that under average weather conditions either Chalk Point or Dickerson contributes measurably to the air pollution problems of Washington. The daily averages for the year 1966, and for the months of highest and lowest fuel consumption, are as follows: In response to this request these data are furnished as to the average particle size of fly ash leaving the boiler and entering the fly ash collector: 99.4 .58 Percent finer than 297 micron (50 mesh). Percent coarser than 297 micron__. NOTE.-1 micron equals 1 inch divided by 25,400 equals 0.00004 inch. The fly ash leaving the collector equipment and being discharged from the stacks into the atmosphere is much finer than that given above. 4. A question was raised as to Pepco's estimate of its proportionate contribution to air pollution in the District of Columbia area. In response to this question we have made a diligent effort to appraise Pepco's effect and have deevloped the following pertinent information: A. No. 6 fuel oil This is the relatively high sulphur content fuel oil about which there is so much concern. Pepco burns this type of oil only at its Benning Station. This oil is furnished by the Steuart Petroleum Company of Washington, D.C., and has an average 2.75% sulphur content. |