Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower
Tóm tắt
The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2–3 and further to 80.2% at L/G of >3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream.
Tài liệu tham khảo
Bratveit M, Haaland IM, Moen B, Malsnes A: Exposure to sulfuric acid in zinc production. Ann Occup Hyg. 2004, 48: 159-170. 10.1093/annhyg/meh011.
Shangina O, Brennan P, Szeszenia-dabrowska N, Mates D, Fabia’Nova E, Fletcher T, Mannetje AT, Boffetta P, Zaridze D: Occupational exposure and laryngeal and hypo-pharyngeal cancer risk in central and eastern Europe. Am J epidemiology. 2006, 164: 367-375. 10.1093/aje/kwj208.
Hsu Y-M, Wu C-Y, Lundgren D, Birky BK: Size-resolved sulfuric acid mist concentrations at phosphate fertilizer manufacturing facilities in Florida. Ann Occup Hyg. 2007, 51: 81-89.
USDHHS: Report on carcinogens. Department of Health and Human Services, public health service. 2005, Research Triangle Park, N.C, USA: National toxicology program
CAS: Sulfuric acid chronic toxicity summery. CAS registry no: 7664-93-9. 2001, Columbus, Oh, USA: American Chemical Society, a100-a108.
Brown CA, Hohne PA: Eliminating a sulfuric acid mist plume from a wet caustic scrubber on a petroleum coke calciner . Environ Prog. 2001, 20: 182-186. 10.1002/ep.670200314.
ACGIH: Industrial ventilation a manual of practice Cincinnati, Ohio. 2010, USA: American conference of governmental industrial hygienists
Jiuan YL: Evaluation of wet scrubber systems. Mechanical Engineering: Thesis Report. 2005, Queensland, Australia: University of southern Queensland
Manyele S: Toxic acid gas absorber design considerations for air pollution control in process industries. Educational Research and Review. 2008, 3: 137-147.
Gumnitsky Y, Dereyk K: Theoretical analysis of chemisorption of gases in a three-phase system. Theor Found Chem Eng. 2007, 41: 343-348. 10.1134/S0040579507040021.
Mussatti D: The epa air pollution control cost manual. 2002, Research Triangle Park, NC, USA: EPA
Thomas D, Colle S, Vanderschuren J: Designing wet scrubbers for so2 absorption into fairly concentrated sulfuric acid solutions containing hydrogen peroxide. Chemical Eng Technol. 2003, 26: 497-501. 10.1002/ceat.200390074.
Perry R, Green DW: Perry's chemical engineer's handbook. 1999, Totowa, New Jersey, USA: Mcgraw-hill companies Inc
Wang LK, Pereira NC, Hung YT: Air pollution control engineering. 2004, Totowa, New Jersey, USA: Humana press
Theodore L: Air pollution control equipment calculations. 2008, Hoboken, NJ, USA: John Wiley & Sons, Inc
Lin C, Chang D: Formation and emission of chlorinated by-products from a bench-scale packed bed odor scrubber. Water Air Soil Pollut. 2005, 162: 19-35. 10.1007/s11270-005-5990-z.
Usepa: Method 8, determination of sulfuric acid mists and sulfur dioxide emissions from stationary sources: EPA. 1979, Research Triangle Park, N.C. USA: Air Pollution Control Office
Martin RM: Construction of iso-kinetic source sampling equipment, document pb-203-060 available from NTIS; EPA. 1971, Research Triangle Park, N.C, USA: Air Pollution Control Office