자원리싸이클링 (Resources Recycling)

  • 제29권5호
  • /
  • Pages.64-72
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  • 2020
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  • 2765-3439(pISSN)
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  • 2765-3447(eISSN)
한국자원리싸이클링학회 (The Korean Institute of Resources Recycling)
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산화/환원 소성분위기에서 석회석 및 시멘트 원료물질의 소성거동 특성

Calcination Properties of Cement Raw Meal and Limestone with Oxidation/Reduction Condition

  • Received : 2020.09.14
  • Accepted : 2020.10.20
  • Published : 2020.10.30
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Abstract

시멘트 산업의 질소산화물 배출량 감축을 위해 소성로에 다단연소공정을 적용할 경우, 질소산화물을 질소로 환원시키고 미연소 물질을 완전히 연소시켜 연소효율을 증대할 수 있는 산화/환원 구간이 필수적이다. 이에 본 연구에서는 시멘트 소성로 calciner에 산화/환원 구간 설정 시 최종 생산품인 시멘트 클링커의 품질안정성을 확보할 수 있는 최적 산화/환원 소성분위기를 거시적으로 관찰하고자 하였으며, 소성조건에 따른 원료물질의 질량변화, 탈탄산률, 소성완료율 등을 조사하였다. 실험결과, 대체로 환원분위기보다 산화분위기에서 원료물질의 열분해가 촉진되는 경향을 나타내며, 원료물질 자체 성분특성에 따라 비교적 CaO 함량이 높은 석회석의 열분해가 시멘트 조합원료보다 늦게 진행되는 것을 알 수 있었는데 이는 소성로 내 CO2 분압에 의한 현상으로 생각된다. 산화/환원 소성분위기에 따른 원료물질의 열분해 특성은 일반적인 석회석 열분해 온도보다 낮은 온도범위에서 비교적 큰 차이를 보였는데, 소성온도 750℃ 구간에 산화분위기 형성에 따라 원료물질의 열효율 향상을 기대할 수 있을 것으로 생각된다. 다만, 본 연구의 경우 실험실 규모의 연구로서 현장공정과는 차이가 있기 때문에, pilot plant 규모의 실검증결과가 필요한 것으로 판단된다.

When the multi-stage combustion process is applied to the cement kiln to reduce nitrogen oxide emissions in the cement industry, oxidation/reduction section that can increase combustion efficiency by reducing NOx to NO and completely burning unburned materials is essential In this study, when applied the oxidation/reduction system of the cement kiln preheater and calciner, the optimal oxidation/reduction calcination crisis that can secure the quality stability of the final product, cement clinker, was to be observed macroscopically, and the mass change of raw materials according to the burning conditions, decarbonation rate, and calcination rate were investigated. The results showed that the thermal decomposition of raw materials tends to be promoted in the oxidation condition rather than in the reduction condition, and that the thermal decomposition of limestone, which has a relatively high CaO content, is carried out later than that of cement raw meal, which is thought to be caused by the CO2 fractionation in the kiln. The thermal decomposition properties of raw materials according to oxidation/reducing burning condition showed a relatively large difference in temperature range lower than normal limestone themal decomposition temperature, which is thought to be expected to improve the thermal efficiency of raw materials according to the formation of oxidation condition in the section 750℃ of burning temperature. However, for this study, lab scale. Because there is a difference from the field process as a scale study, it is deemed necessary to verify the actual test results of the pilot scale.

Keywords

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