The Effects of the Operating Conditions of Spray Dryer System on the Removal Efficiency of Incineration Pollutants

• Main Authors: Hsin-Yi Wu, 吳欣益
• Other Authors: Ming-Yen Wey
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/18635902755271378582

碩士 === 國立中興大學 === 環境工程學系 === 87 === Owing to the advantages of stabilization, resource recovery and reduction, incineration technique is more suitable for the congested areas, such as Taiwan. However, trace toxic metals may escape from the incineration process and subsequently be collected in dry ashes, in wet scrubbed ashes, or as airborne aerosols emitted into the atmosphere. Acid gas, such as SOx, NOx, may also escape from the incineration process, and result in the formation of acid rain. Organic compounds also are the pollutant of waste incineration, which could give rise to cancer. Therefore, it is imperative to understand the behavior of acid gas, trace heavy metals and of organic compounds in flue gas and the best method to control them. The removal efficiency of acid compounds with alkaline sorbents in simulated flue gas has been investigated in previous studies. However, the removal efficiency of acid gas in incineration flue gas, which contains dust, heavy metals, and acid gas itself, is seldomly mentioned. Furthermore, if bag house was employed after spray dryer system only less dioxin compounds were formed in the exit flue gas, compared to the electrostatic precipitator (ESP) was employed prior to the scrubber system. Therefore, it is suspected that the spray dryer system has the potential of removing part of organic compounds. Be aimed at the harmful acid gas, Organic compounds and heavy metals, such as Pb, Zn, Cd, Cr, Cu and Ni, the effects of the operating conditions of Spray Dryer on the formed particle’s size and on the removal efficiency of the foregoing three pollutants were studied in present work. The operating parameters of the Spray Dryer System evaluated included (1) different absorbents, (2) different additives, (3) different spray pressure and (4) different Stoichiometric Ratio of absorbent. X-ray diffraction analysis was also carried out to determine the species of the metal species. The results showed that the removal efficiency of SO2 in Spray Dryer System were within the compass of 42.23~88.20%, and the promotion of additives on the removal efficiency of SO2 were beyond 0.24~15.37%. For single additive, NaHCO3 had bestest promotion of the removal efficiency of SO2; for complex additive, the highest enhancement of the removal efficiency of SO2 observed when the absorbent mingle with SiO2, NaHCO3 and KMnO4. SiO2 and NaHCO3 migled in absorbent could enhance the removal efficiency of heavy metals besides Zn. However, the removal efficiency of the heavy metals, with the exception of Cr, decreased due to an affix of KMnO4. The removal efficiency of the everysingle heavy metal were with the purview of: Pb: 1.21~ 78.53%, Cr: 1.87~ 83.33%, Cd: 23.79~ 92.79%, Cu: 14.28~ 95.53%, Zn: 57.78~ 96.56%, Ni: 27.69~ 91.58%. The removal efficiency of organic compounds were within the range of 44.15~86.14% with no additives. When NaHCO3 was present, the removal efficiency was decreased and increased around 9% with the presence of KMnO4, the highest removal efficiency was observed when SiO2 together with KMnO4 were present.