인도네시아산 발전용 수입 석탄 2종의 연소특성 비교 평가

Combustion characteristics of two imported Indonesia coals as a pulverized fuel of thermal power plants

  • 이현동 (한국전력공사 전력연구원) ;
  • 김재관 (한국전력공사 전력연구원)
  • 투고 : 2010.04.20
  • 심사 : 2010.06.20
  • 발행 : 2010.06.30

초록

국내에 수입되어 사용되고 있는 발전용 석탄 2종에 대하여 기초적인 열중량분석기를 이용한 열특성 분석실험과 대용량 시험연소로를 이용한 연소시험을 수행하였다. 실험결과 고수분탄이 비록 착화 온도가 낮고 및 연소 구간이 짧아 초기 연소특성은 좋지만 비교탄에 비해 연소완료가 빨리 종결되지 못해 결과적으로는 연소 효율이 좋지 않았으며, 고수분탄의 활성화에너지는 고수분탄이 79 kJ/mol로서 비교탄의 53 kJ/mol에 비해 높은 특성을 보였다. 또한 시험연소로 시험과정에서 고수분탄의 화염 내 검은 색의 석탄분사체(Coal Jet) 형태가 비교탄에 비해 비교적 뚜렷이 관찰되어 연소속도가 다소 떨어지는 상호 연관성이 잘 설명되었고 연소후 미연분 발생량에서도 고수분탄이 다소 높게 나타났다. 그러나 고수분탄의 경우 낮은 유황분 함량으로 인해 연소 시 황산화물 배출량이 적어 고유황 함량의 석탄과의 혼합연소 시 유용하게 활용 될 수 있을 것으로 예상되었으며, 또한 회성분 분석결과 $Na_2O$$K_2O$ 등의 알카리비금속화합물 함량이 기존의 역청탄에 비해 매우 적고 회분자체의 함량도 매우 낮아 회분의 융착 정도가 높지 않게 나타났다.

Combustion reactivity and thermal behavior of two imported coals used as a pulverized fuel of commercially thermal power plant were investigated by thermogravimetric analysis (TGA) and large scale test furnace of 200 kg/hr. TGA results showed that combustion efficiency of high moisture coal has lower than reference coal due to the slow combustion completion rate although it has the low ignition temperature, and activation energies of high moisture coal with 79 kJ/mol for overall combustion was higher than reference coal of 53 kJ/mol. Test furnace results ascertained that flame of black band of high moisture coal during the combustion in boiler broke out compared to reference coal and then it becomes to unburned carbon due to the less reactivity and combustion rate. But, Blending combustion of high moisture coal with design coal of high sulfur are available because sulfur content of high moisture coal was too low to generate the low SOx content in flue gas from boiler during the combustion. The ash analysis results show that it was not expected to be associated with slagging and fouling in pulverized coal fired systems due to the low alkali metal content of $Na_2O$ and $K_2O$ compared to bituminous coal.

키워드

참고문헌

  1. Raask E. Mineral impurities in coal combustionbehaviour problems and remedial measures, New York: Hemisphere Publishing, 1985.
  2. Couch GR. Understanding slagging and fouling during the combustion. IEACR/72, IEA Coal Research, London, UK, 1994.
  3. Benson SA, Jones ML, Harb JN. Ash formation and deposition. Smoot D, editor. Fundamentals of coal combustion for clean and efficient use, Amsterdam: Elsevier, 1993. pp. 293-373, Chapter 4.
  4. Wall TF. Mineral matter transformations and ash deposition in pulverised coal combustion. Proceedings of 24th Symposium (International) on Combustion. The Combustion Institute, Pittsburgh, PA, 1992. pp. 111-26.
  5. Durie RA. The science of Victorian brown coals, London: Butterworth Heinemann, 1991.
  6. Reid WT. External corrosion and deposits-boilers and gas turbines, New York: Elsevier, 1971.
  7. Lindner ER, Kosminski A, Taylor C, Williams RG. Effects of additives on fouling behaviour characteristics of south Australian brown coals. Proceedings of Australian Coal Science Conference, The University of Adelaide, 16-18 May, 1988. p.B2:11.1-B2:11.14.
  8. Domazetis G, Buckman S. Fly ash formation and sulphation during the combustion of brown coal, vol. 3C. Effects of aluminium based additives on ash formation, NERDDC project 933, End of Grant Report, State Electricity Commission of Victoria, Research and Development Department, Report No. ND/87/043, 1987.
  9. Ledger RC. Short term combustion tests using additives. State Electricity Commission of Victoria, Research and Development Department, Report No. SO/89/158, 1989.
  10. Ledger RC. Pilot plant testing of the effects of additives on fouling by Latrobe valley coals. State Electricity Commission of Victoria, Research and Development Department, Report No. SO/87/134, 1987.
  11. Lowe AJ, McCaffrey DJA, Richards DG. Fuel Process Technol 1993;36:47-53. https://doi.org/10.1016/0378-3820(93)90009-S
  12. Bobcock & Wilcox, Steam: its generation and use, 39th edition, Bobcock & Wilcox company 1978; 15.1-15.9
  13. 한국전력공사, 연소실무, 한국전력공사 1989;4.21-4.22.