Carbon Monoxide Combustion Promoter

Early attempts by Mobil to minimize after-burning in TCC imits led to the addition of chromium oxide to their Durabead catalyst to oxidize carbon monoxide, but this uirfortunately also decreased cracking selectivity. Mobil then introduced a platinum/alumina additive in 1976 to control carbon monoxide combustion in the regenerator. Platinum was added either as a component of the cracking catalyst or in separate particles. Complete combustion of carbon monoxide was achieved by adding the equivalent of 0.5 ppm of platinum to the catalyst inventory. 

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PGM catalyst technology can also be appHed to the control of emissions from stationary internal combustion engines and gas turbines. Catalysts have been designed to treat carbon monoxide, unbumed hydrocarbons, and nitrogen oxides in the exhaust, which arise as a result of incomplete combustion. To reduce or prevent the formation of NO in the first place, catalytic combustion technology based on platinum or palladium has been developed, which is particularly suitable for appHcation in gas turbines. Environmental legislation enacted in many parts of the world has promoted, and is expected to continue to promote, the use of PGMs in these appHcations. 

Utilize combustion promoter to catalyze oxidation of carbon monoxide in the dense bed if already in nse, increase addition rate [7]... 

The CBC technology operates at relatively low temperatures [approximately 1600°F (870°C)], thus reducing operation costs. The high turbulence produces a uniform temperature and promotes the complete mixing of the waste material during combustion. The effective mixing and relatively low temperature also reduce emissions of carbon monoxide and nitrogen oxides. 

The emphasis on environmental protection in the last three decades, as industrial and economic growth gave birth to many forms of pollution threatening human health and Earth ecosystems, resulted in the growth of environmental catalysis. So, catalysts ate not only used to promote processes in the production field, but also to reduce the emissions of undesirable or hazardous compounds to the environment. For example, catalytic combustion has been proposed and developed as an effective method for controlling the emissions of hydrocarbons and carbon monoxide. 

There has been a great recent market demand for halogen-free fire-retardant polymers. Zinc borates are also multifunctional fire retardants in halogen-free polymers. They can promote char formation, reduce the Rate of Heat Release, smoke evolution, carbon monoxide generation, and afterglow combustion. When used in conjunction with metal hydroxides, they can also display synergy in fire test performance. 

For metals promoting other metals, an interesting case was studied by Hurst and Rideal.2 In the combustion of mixtures of hydrogen and carbon monoxide, using copper as the basic catalyst the ratio of the gases burnt depends on the temperature, and also on the amount of small additions of palladium made to the copper. The proportion of carbon monoxide burnt is increased by addition of palladium, a maximum proportion of carbon monoxide being burnt when 0-2 per cent, of palladium is. present. With further amounts of palladium, the ratio CO H2 burnt falls off slowly until, with 5 per cent, palladium, it is nearly the same as with pure copper. This effect of palladium is ascribed to the introduction of a new type of surface, the line of contact between palladium and copper, though the proof that this is the cause of promotion is perhaps not complete. Mit-tasch and others,3 in elaborate studies of the promotion of various metal catalysts, particularly molybdenum, for the synthesis or decomposition of ammonia, concluded that the formation of intermetallic compounds... 

With the catalytic ozone analyzer described, ozone concentration can be measured by the temperature differential between two thermistors placed in the gas stream. One of the thermistors is coated with a catalyst promoting the decomposition of ozone the other is uncoated and is used as reference to the temperature of the gas. The two thermistors are part of a bridge circuit, the output of which is fed directly to a recorder. The instrument is not affected by the presence of water vapor, carbon monoxide, chlorine, nitrogen dioxide, sulfur dioxide, organic peroxides, hydrocarbon vapors, and combustion smokes at their usual concentrations in polluted atmospheres. 

A minimum content of 2%i oxygen, by weight, to promote cleaner combustion, especially to reduce carbon monoxide emission. 

The three-way exhaust catalytic converter is used to complete the combustion of carbon monoxide and unburned fuel elements and to remove the NO and N02 produced during combustion. The primary components of the catalytic converter are the catalyst and its physical support. The catalyst is composed of a high-surface-area support that incorporates the primary catalytically active materials, typically mixtures of one or more of platinum, palladium, or rhodium (precious group metals, PGMs). The catalyst also contains promoters that improve the efficiency and stability of the PGM. Of these, the most important is cerium oxide, a... 

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