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

提出了一种利用热等离子体流化床反应器分解回收和销毁包括CFC’s在内的卤代有机物的新方法。该技术是在Ar热等离子体中分离卤代有机物，在流化床中回收卤素组分，以氯甲烷（CH_3Cl）作为卤代有机物的最简单模型。通过热力学计算建议用氧气进行分解。流化介质采用直流电弧放电产生的Ar热等离子体，流化床采用CaO颗粒和CaCO_3颗粒。氯化氢气体作为分解产物之一与CaO和CaCO_3在流化床反应器中反应并固定为CaCl_2。用离子计测定了颗粒中的氯元素。实验结果表明，CaO颗粒能有效地分解氯甲烷，并能高效地回收其中的氯成分。但是，如果Ca ...更多信息 CO_3粒子，由于反应速率和粒子形态的差异，回收率不高。经电子显微镜分析，这些颗粒是由小颗粒组成的。CaO在颗粒表面反应迅速，而CaCO_3在颗粒内部反应缓慢，CCl_2F_2在颗粒内部发生分解。在流化床中，以CaO颗粒为催化剂，以氧气和氢气为催化剂进行分解.分解生成的氯化氢气体和氟化氢气体在流化床反应器中与CaO颗粒反应并固定为CaCl_2和CaF_2。用离子色谱法测定了颗粒物中的氯、氟元素。在反应初期，氯元素主要以CaCl_2形式固定。随着时间的延长，氯元素的回收率迅速下降。另一方面，以CaF_2形式固定的氟元素的回收率从反应开始时一直保持在0.4%左右。根据实验结果，提出了提高流化床温度和连续操作的方法，以改善颗粒转化率低的问题。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