Clean Technology (청정기술)

The Korean Society of Clean Technology (한국청정기술학회)
권호 표지
DOI QR코드

DOI QR Code

Reaction Characteristics of Kaolinite-based Additives and Alkali Salts

Kaolinite 계열의 첨가제와 알칼리염의 반응 특성

  • Jun, HyunJi (Department of Chemical Engineering and Applied Chemistry, Chungnam National University) ;
  • Choi, Yujin (Korea institute of energy research) ;
  • Shun, Dowon (Korea institute of energy research) ;
  • Han, Keun-Hee (Korea institute of energy research) ;
  • Bae, Dal-Hee (Korea institute of energy research) ;
  • Rhee, Young-Woo (Department of Chemical Engineering and Applied Chemistry, Chungnam National University)
  • Received : 2020.09.03
  • Accepted : 2020.09.18
  • Published : 2020.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

When the waste solid fuel (SRF, Bio-SRF) is burnt in a boiler, a problem occurs in the combustion process involving the alkali components (Na, K) contained in large amounts in the fuel. The alkaline component has a low melting point, which usually forms low melting point salt in the temperature of the furnace, with the resulting low melting point salts attaching to the heat pipe to form a clinker. Various additives are used to suppress clinker generation, and the additive based on the kaolinite has alkali-aluminum-silica to inhibit the clinker. In this study, the reactivity of the additives based on the kaolinite was compared. The additives utilized were R-kaolinite, B-kaolinite, and A-kaolinite. Also silica and MgO were sourced as the comparison group. The experimental group was employed as a laboratory-scale batch horizontal reactor. The additive and alkaline salts were reacted at a weight ratio of 1 : 1, and the reaction temperature was performed at 900 ℃ for 10 hours. The first measurement of HCl occurring during the experiment was performed 30 minutes after the detection tube was used, and the process was repeated every hour after the experiment. After the reaction, solid residues were photographed for characterization analysis by means of an optical microscope. The reaction characteristics of the kaolinite were confirmed based on the analysis results.

폐기물고형연료(SRF, Bio-SRF)가 보일러에서 연소 될 때, 연료에 다량 함유되어있는 알칼리 성분(Na, K) 들이 연소과정에서 문제를 발생시킨다. 알칼리 성분은 낮은 melting point를 가지고 있어 통상 연소로 온도 내에서 저융점 염을 형성하고, 생성된 저융점 염들은 전열관에 달라붙어 클링커를 형성한다. 클링커생성을 억제하기 위해 다양한 첨가제가 사용되고 있으며, 고령석 기반의 첨가제는 알칼리-알루미늄-실리카가 형성되어 클링커를 억제한다. 본 연구에서는 고령석을 기반으로 하는 첨가제의 반응성을 비교 하였다. 사용된 첨가제는 R-kaolinite, B-kaolinite, A-kaolinite를 사용하였고 비교군 으로 silica와 MgO를 사용하였다. 실험은 실험실 규모의 회분식 수평형 반응기를 사용하였다. 첨가제와 알칼리염은 중량비 1:1로 반응토록 하였으며 반응 온도는 900 ℃에서 10시간 수행하였다. 실험 중 발생한 HCl은 검지관을 사용하여 30분 후 첫 측정을 하고 이후 1시간마다 반복하여 측정하였다. 반응 후 고체 잔여물은 특성 분석을 위하여 광학현미경으로 촬영하였다. 분석결과를 토대로 고령석의 반응특성을 확인하였다.

Keywords

References

  1. Rhu, J. K., "Facilitation Techniques for Development, Use, Supply of Advanced and Renewable Energy," Korea Legislative Studies Institute, 16(1), pp. 153-164 (2010).
  2. "World Energy Outlook 2018," IEA, p. 38 (2018).
  3. Lee, C. Y., Jeong, B.-H., and Chung, J.-D., "A Study on the Characteristics of Pollutants in CFBC Boiler with Ammonium Sulfate Injection," J. Korea Soc., Waste Manag., 35(8), pp. 754-761 (2018). https://doi.org/10.9786/kswm.2018.35.8.754
  4. Khan, A. A., de Jong, W., Jansens, P. J., and Spliethoff, H., "Biomass Combustion in Fluidized Bed Boilers: Potential Problems and Remedies," Fuel Process. Technol., 90(1), 21-50 (2009). https://doi.org/10.1016/j.fuproc.2008.07.012
  5. Park, J. H., Lee, D.-H., Han, K.-H., Shin, J.-S., Bae, D.-H., Shim, T.-E., Lee, H. J., and Shun, D. W., "Effect of Chemical Additives on Hard Deposit Formation and Ash Composition in a Commercial Circulating Fluidized Bed Boiler Firing Korean Solid Recycled Fuel," Fuel, 236, 792-802 (2019). https://doi.org/10.1016/j.fuel.2018.09.020
  6. Michelsen, H. P., Frandsen, F., Dam-Johansen, k., and Larsen, O. H., "Deposition and High Temperature Corrosion in a 10 MW Straw Fired Boiler," Fuel Process. Technol., 54(1-3), 95-108 (1998). https://doi.org/10.1016/S0378-3820(97)00062-3
  7. Kim, B. J., Ryu, C. K., Lee, U. D., Kim, Y. D., Lee, J. W., and Song, J. H., "A Technical Review on the Protective Measures of High Temperature Corrosion of Boiler Heat Exchangers with Additives," Clean Technol., 23(3), 223-236 (2017). https://doi.org/10.7464/ksct.2017.23.3.223
  8. Qinyan, Y., Ying, S., and Baoyu, G., "Impact Factors and Thermodynamic Characteristics of Aquatic Humic Acid Loaded onto Kaolin," Colloids Surf. B: Biointerfaces, 72(2), 241-247 (2009). https://doi.org/10.1016/j.colsurfb.2009.04.010
  9. Kim, S. G., and Song, T. W., "Effect of the Heating Temperature on the Alkali-activation Reaction of Calcined Kaolin Powder," J. Korean Ceram. Soc., 49(6), 601-607 (2012). https://doi.org/10.4191/kcers.2012.49.6.601
  10. Xu, L., Liu, J., Kang, Y., Miao, Y., Ren, W., and Wang, T., "Safely Burning High Alkali Coal with Kaolin Additive in a Pulverized Fuel Boiler," Energy Fuels, 28(9), 5640-5648 (2014). https://doi.org/10.1021/ef501160f
  11. Boman, C., Bostrom, D., and Ohman, M., "Effect of Fuel Additives Sorbents(kaolin and calcite) on Aerosol Particle Emission and Characteristics During Combustion of Pelletized Woody Biomass," 16th European Biomass Conference & Exhibition, 2-6, Valencia, Spain, (2008).
  12. Bostrom, D., Grimm, A., Lindstrom, E., Boman, C., Bjombom, E., and Ohman, M., "Abatement of corrosion and deposits formation in combustion of oat," 16th European Biomass Conference & Exhibition, 2-6, Valencia, Spain, (2008).
  13. Tran, K.-Q., Iisa, K., Hagstrom, M., Steenari, B.-M., Lindqvist, O., and Pettersson, J. B. C., "On the Application of Surface Ionization Detector for the Study of Alkali Capture by Kaolin in a Fixed Bed Reactor," Fuel, 83(7-8), 807-812 (2004). https://doi.org/10.1016/j.fuel.2003.10.014
  14. Steenari, B. M., Lundberg, A., Pettersson, H., Wilewska-Bien, M., and Andersson, D., "Investigation of Ash Sintering During Combustion of Agricultural Residues and the Effect of Additives," Energy Fuels, 23(11), 5655-5662 (2009). https://doi.org/10.1021/ef900471u
  15. Kyi, S., and Chadwick, B. L., "Screening of Potential Mineral Additives for Use as Fouling Preventatives in Victorian Brown Coal Combustion," Fuel, 78(7), 845-855 (1999). https://doi.org/10.1016/S0016-2361(98)00205-1
  16. Purbasari, A., Samadhi, T. W., and Bindar, Y., "Thermal and Ash Characterization of Indonesian Bamboo and Its Potential for Solid Fuel and Waste Valorization," Int. J. Renew. Energy Dev., 5(2), 95-100 (2016). https://doi.org/10.14710/ijred.5.2.95-100