Decomposition of Spent CFC's with Thermal Plasma Fluidized Bed Reactor

提出了一种利用热等离子体流态化反应器对包括氯氟烃在内的卤代有机物进行回收和破坏的新方法，该技术是为了分散Ar热等离子体中的卤代有机物，并回收床中的卤素组分。根据热力学计算，分解是在氧气中进行的。采用直流弧光放电获得的Ar热等离子体作为流态化介质，CaO颗粒和CaCO3颗粒作为流态化床层。分解产物之一的氯化氢气体与CaO、CaCO3反应，在床内以CaCl2的形式固定。用离子计法测定颗粒物中的氯元素。实验结果表明，使用CaO颗粒可以很好地分解氯甲烷，并能高效回收氯组分。然而，在Ca…的情况下CO_3颗粒较多，由于反应速度和颗粒形态不同，回收不够充分。根据电子显微镜分析，这些颗粒是由细小的颗粒组成的。CaO在表层反应迅速，而CaCO3在颗粒中反应缓慢，作为制冷剂的氟利昂12(CCl_2F_2)分解。以氧气、氢气和CaO颗粒为床层进行分解。分解产物生成的氯化氢气体和氟化氢气体与CaO颗粒反应，在沸腾床中固定为CaCl2和CaF2。用离子色谱法测定颗粒物中的氯和氟元素。在反应初期，氯元素主要以CaCl2形式被固定，随着时间的推移，氯元素的回收率迅速下降。反应开始后，以CaF_2形式固定的氟元素的回收率保持在0.4左右。根据这些结果，提出了采用连续颗粒操作和提高床层温度的方法来改善颗粒的低转化率。较少

We proposed a new decomposition method using thermal plasma fluidized bed reactor for recovery and destruction for halogenated organic compounds including CFC's. This technique was to distract halogenated organic compounds in the Ar thermal plasma and recover halogen component in the fluidized bed.Chloromethane (CH_3Cl) was used as the simplest model of halogenated organic compounds. The decomposition was carried out with oxygen suggested by thermodynamic calculations. The Ar thermal plasma obtained by DC arc discharge was used for fluidized medium, CaO particle and CaCO_3particle for the fluidized bed. Hydrogen chloride gas formed as one of the decomposed products was reacted with CaO and CaCO_3 and fixed as CaCl_2 in the fluidized bed reactor. Chlorine element in the particle was measured with ion-meter. The experimental results showed that chloromethane was perfectly decomposed and the chlorine component was recovered in high efficiency when using CaO particle. However in case of Ca … More CO_3 particle, the recovery was not sufficient owing to deference of reaction rate and particle form. According to analysis using electron microscope, these particles were composed small grains. CaO reacted rapidly at surface layr, however CaCO_3 reacted slowly in particle uniformly.Freon12 (CCl_2F_2) used as refrigerant was decomposed. The decomposition was carried out with oxygen and hydrogen, and CaO particle for the fluidized bed. Hydrogen chloride gas and hydrogen fluoride gas formed as the decomposed products were reacted with CaO particle and fixed as CaCl_2 and CaF_2 in the fluidized bed reactor. Chlorine and fluorine element in particle were measured with ion-chromatography. In the beginning of the reaction, chlorine element was fixed as mainly CaCl_2. Rapidly as the time proceeds, the recover of chlorine element was decrease. The other side, recovery of fluorine element fixed as CaF_2 was maintained about 0.4from the commencement of the reaction. From these results, in order to improve the low conversion of particle, continuous particle operation and increasing temperature of fluidized bed were proposed. Less