AIR POLLUTION ENGINEERING MANUAL - epa.gov

1 AIR POLLUTION ENGINEERING MANUAL SECOND EDITION Compiled and Edited bY John A. Donielron AIR POLLUTION CONTROL DISTRICT COUNTY OF LOS ANGELES ENVIRONMENTAL PROTECTION AGENCY Office of Air and Water Programs Office of Air Quality Planning and Standards Research Triangle Park 27711 May 1973 The AP series of reports is published by the Technical Publications Branch of the Information Services Division of the Office of Administration for the Office of Air and Water Programs, Environmental Protection Agency, to report the results of scientific and ENGINEERING studies, and information of general interest in the field of air POLLUTION .

2 Information reported in this series includes coverage of intramural activities and of cooperative studies conducted in conjunction with state and local agencies, research institutes, and industrial organizations. Copies of AP reports are available free of charge to Federal employees, current contractors and grantees, andnonprofit organizations - as supplies permit - from the Air POLLUTION Technical Information Center, Environmental Protection Agency, Research Triangle Park, North Carolina 27711 or from the Superintendent of Documents. Publication No. AP-40 xvii . Variables Affecting Scrubber Emissions .. Collection Efficiencies Attained.

3 Future Trends in Air POLLUTION Control Equipment .. CONCRETE-BATCHING PLANTS .. The Air POLLUTION Problem .. Wet- Concrete . Batching Plants .. Air POLLUTION Control Equipment .. Dry-Concrete-Batching Plants .. Air POLLUTION Control Equipment .. Central Mix Plants .. The Air POLLUTION Problem .. Hooding and Ventilation Requirements .. Air POLLUTION Control Equipment .. CEMENT-HANDLING EQUIPMENT .. The Air POLLUTION Problem .. Hooding and Ventilation Requirements .. Receiving Hoppers .. Storage and Receiving Bins .. Elevators and Screw Conveyors .. Hopper Truck and Car Loading Air POLLUTION Control Equipment .. ROCK AND GRAVEL AGGREGATE PLANTS.

4 The Air POLLUTION Problem .. Hooding and Ventilation Requirements .. Air POLLUTION Control Equipment .. MINERAL WOOL FURNACES .. Introduction .. Types and Uses of Mineral Wool Products .. Mineral Wool Production .. The Air POLLUTION Problem .. Hooding and Ventilation Requirements .. Air POLLUTION Control Equipment .. Baghouse Collection and Cupola Air Contaminants Afterburner Control of Curing Oven Air Contaminants .. Reducing Blowchamber Emissions .. Controlling Asphalt Fumes .. Cement-receiving and storage system . 335 .. Cement weigh hopper . 336 .. Gathering hoppers . 336 The Air POLLUTION Probiem .. Hooding and Ventilation Requirements.

5 Dust created by truck movement . 337 .. PERLITE-EXPANDING FURNACES .. Introduction .. uses .. Mining Sites .. Perlite Expansion Plants .. Expansion Furnaces .. Gas and Product Cooling .. Product Collectors and Classifiers .. The Air POLLUTION Problem .. Hooding and Ventilation Requirements .. Air POLLUTION Control Equipment .. FEED AND GRAIN MILLS .. Introduction .. Receiving. Handling . and Storing Operations .. Feed-Manufacturing Processes .. Receiving. Handling. and Storing Operations .. Feed-Manufacturing Processes .. Hooding and Ventilation Requirements .. Receiving. Handling. and Storing Operations .. Feed-Manufacturing Processes.

6 The Air POLLUTION Problem .. 330 332 . 334 334 334 335 333 . 336 337 337 337 337 338 339 339 339 339' 339 339 339 340 340 340 340 341 341 341 342 342 342 342 343 344 347 347 347 349 349 350 350 350 350 350 350 350 350 351 351 351 352 352 353 354 355 356 357 357 357 358 334 MECHANICAL EQUIPMENT PERCENT LESS THAN GIVEN PARTICLE SIZE, microns Figure 229. Plot of particle size of dust at the inlet and outlet of a cyclone and multiple cyclone from test C-537. CONCRETE-BATCHING PLANTS Concrete-hatching plants store, convey, measure, and discharge the ingredients for making concrete to mixing or transportation equipment. One type is used to charge sand, aggregate, cement, and water to transit-mix trucks, which mix the hatch en route to the site where the concrete is to he poured; this operation is known as "wet batching.

7 I' Another type is used to charge the sand, aggre- gate, and cement to flat bed trucks, which trans- port the batch to paving machines where water is added and mixing takes place; this operation is known as "dry hatching. I' A third type employs the use ofacentralmixdant. from whichwet con- shell crane, or bucket elevator to overhead storage bins. Cemcntfrom bottom-discharge hopper trucks is conveyed to an elevated storage silo. Sand and aggregatcs lor a hatch are weighed by successive additions fromthe overhead bins to a weigh hopper. Cementis deliveredby a screw conveyor irom the silotoa separate weigh hopper. The weighed ag- gregates and cement are dropped into a gathering hopper and flow into the receiving hopper to the transit-mixtruck.

8 Atthe same time, the required amount of water is injected into the flowyng stream of solids. Details and variations of this general rxocedure will be discussed later. crete is delivered tothe pouring site in open dump trucks. The Air POLLUTION Problem Dust, the air contaminant fromwet-concrete-hatch- WET-CONCRETE-BATCHING PLANTS ing, results fromthematerial used. Sbnd and ag- gregates for concrete production come directly In a typicalwet-concrete-batching plant, sand and froma rockandgravelplantwherethey are washed aggregates are elevated by belt conveyor or clam toremove silt and clay-like minerals. They thus Concrete-Batching Plants 335 I 0 to S 5 to 10 10 to 20 20 to 40 40 to SO 50 to 66 66 to 99 99 to 250 250 (60 mesh) Bulk density, lblft3 arrive aL the batch plant in a moisr condition and hcncc do not usuallypresent a dust problcm.

9 Whcn, however, lightweight aggregates are used, they do pose a problem. These materials are formed by thcrinal expansion of certainminerals. Theyleavc the aggregate plant vcry dry and create consider- ablcdustwhen handled. The simplcst way to deal withthis problem is to wct each load of aggregate thoroughly bclorc it is dumped from the delivery truck. Attempts to spray the aggrcgatc as it is heins dumped have had vcry limited effectiveness. 13. 2 9. 6 15. 1 25. 7 36. 6 6. 0 0 4. 0 0 0 0 0 0 0 1 If, thcrcfore, wet or damp aggregate is uscd, practically all the dust generated from concrete- batching operations originates from the cement.

10 Particlc size distribution and other characteristics of the dust vary according to thc grade of cement. A rangc ol 10 to 20 percent by weight of particles of 5-micron size or less is typical for the various grades OI cement. Bulk density ranges Irom 50 to 65 pounds per cubic foot of cement. Table 97 shows additional characteristics of three common grades ol cement. Specific gravity, g/cm3 at 82 F 1 j Table 97. CHARACTERISTICS OF THREE GRADES OF CEMENT Cement, wt 0: Grade 11 Grade I1 I Grade 111 Distribution, il Cement dust can be emitted from several points. The receiving hopper, the elevator, and the silo- are the'points of possible emission from the ce- ment-receiving station.