OXYGEN-GENERATION SYSTEMS

Substance Molecular formula CAS Registry Number Mp, °C Decomp., °C Oxygen g/gcmpd density g/cm  

Chlorate candles ate quite stable. While normally hermetically sealed, these candles have been stored uncontained for as long as 20 years, and then operated successfully with no loss of oxygen output. Thus, they are well suited as emergency oxygen-generation systems (3). Chlorate candles also produce oxygen under pressure and, therefore, can be stored in or operated from pressurized cylinders. 

Materials and Reactions. Candle systems vary in mechanical design and shape but contain the same genetic components (Fig. 1). The candle mass contains a cone of material high in iron which initiates reaction of the soHd chlorate composite. Reaction of the cone material is started by a flash powder train fired by a spring-actuated hammer against a primer. An electrically heated wire has also been used. The candle is wrapped in insulation and held in an outer housing that is equipped with a gas exit port and rehef valve. Other elements of the assembly include gas-conditioning filters and chemicals and supports for vibration and shock resistance (4). 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Basic oxides of metals such as Co, Mn, Fe, and Cu catalyze the decomposition of chlorate by lowering the decomposition temperature. Consequendy, less fuel is needed and the reaction continues at a lower temperature. Cobalt metal, which forms the basic oxide in situ, lowers the decomposition of pure sodium chlorate from 478 to 280°C while serving as fuel (6,7). Composition of a cobalt-fueled system, compared with an iron-fueled system, is 90 wt % NaClO, 4 wt % Co, and 6 wt % glass fiber vs 86% NaClO, 4% Fe, 6% glass fiber, and 4% BaO. Initiation of the former is at 270°C, compared to 370°C for the iron-fueled candle. Cobalt hydroxide produces a more pronounced lowering of the decomposition temperature than the metal alone, although the water produced by decomposition of the hydroxide to form the oxide is thought to increase chlorine contaminate levels. Alkaline earths and transition-metal ferrates also have catalytic activity and improve chlorine retention (8). 

---

THERMOELECTRICENERGYCONVERSION] (Vol23) -oxygen-generating system for [OXYGEN-GENERATION SYSTEMS] (Vol 17) -vitreous silica windows [SILICA - VITREOUS SILICA] (Vol 21)... 

---