본 연구에서는 국내 상용 순환유동층 보일러에서 아역청탄과 혼소용 연료로 사용예정인 폐플라스틱 고형연료(RPF)의 열분해 반응특성을 규명하기 위해 열천칭 반응기를 이용하여 등온(350, 375, 400, 425, 450, 500, 850 ℃) 열분해 실험을 수행하였다. 등온 열분해 결과, 반응온도 구간 375~450 ℃에서의 반응모델 변화는 관찰되지 않았으며, 12개 반응모델 중 1차 화학반응(F1)이 가장 적합한 반응모델로 판명되었다. 이때 Arrhenius 식을 사용하여 계산한 활성화에너지는 39.44 kcal/mol이었으며, Iso-conversional 방법을 적용할 경우 활성화에너지 평균값(0.5≤X≤0.9 구간)은 36.96 kcal/mol로 반응모델 결정 여부와 관계없이 유사한 값을 보였다. 한편 순환유동층보일러의 운전온도인 850 ℃에서 RPF 입도(d) 변화에 따른 탈휘발 시간은 tdev=10.38d2.88으로 표현할 수 있었으며, 보일러 내부에서 RPF가 균일하게 연소되기 위해서는 연료 입도와 평균 분산 거리(x)가 x≤1.58d1.44의 상관관계를 만족하여야 함을 확인할 수 있었다.

In this study, isothermal (350, 375, 400, 425, 450, 500, 850 ℃) experiments were carried out using a custom-made thermobalance to analyze the thermal decomposition properties of refuse plastic fuel (RPF), which is to be used as a cofiring fuel with a sub-bituminous coal at commercial circulating fluidized bed (CFB) boiler in Korea. In isothermal pyrolysis results, no change in the reaction model was observed in the temperature range of 375~450 ℃ and it was revealed that the first order chemical reaction (F1) is the most suitable among 12 reaction models. The activation_x000D_ energy shows similar results irrespective of application of reaction model in that the activation energy was 39.44 kcal/mol and 36.96 kcal/mol when using Arrhenius equation and iso-conversional method (0.5≤X≤0.9) respectively. Meanwhile, the devolatilization time (tdev) according to particle size (d) of RPF could be expressed as tdev=10.38d2.88 at 850 ℃, operation temperature of CFB and for even distribution and oxidation of RPF in CFB boiler, we found that the_x000D_ relationship of average dispersion distance (x) and particle size was x≤1.58d1.44.

Refuse Plastic Fuel (RPF) Isothermal Pyrolysis Damkohler Number (Da) Thermobalance

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