Carbon canister applications

The use of activated carbon canisters in the control of running loss evaporative emissions will be presented through the use of an example vehicle application. In this example, the vehicle to be studied is a representative standard size sedan equipped with a 3.0 liter, V6 engine and a 72 liter (18 gallon) fuel tank. The vehicle is assumed to have an evaporative emission control system similar to the one presented in Section 3. 

Fire extinguishers. Because carbon dioxide does not support combustion, this gas finds extensive application in the manufacture of several different kinds of fire extinguishers. In one type, a small, stoppered canister of sulfuric acid is mounted inside a much larger cylinder. Inversion of the appratus permits the stopper to fall off of the acid canister. This permits the acid to mix with the sodium carbonate (or sodium hydrogen carbonate) solution contained in the main vessel and to generate carbon dioxide gas ... 

Pulsating flow through a bed and breakthrough times. An important application for activated carbons is their use in canisters for life-supporting gas masks. In use, the airflow is not constant but pulsates with respiration. Nir et al. (2002), in their review, state that previous studies had reported that the breakthrough time (Tg) was independent of flow pattern for butyl alcohol, methyl chloroform, cyclohexane and ethyl acetate. On the contrary, evidence is presented that (Tg) could be reduced by 5-30% under conditions of sinusoidal, rectangular and square profiles. 

The USA demand for activated carbon will very probably reach 200,000 tonnes per year by 2005, and the market will very probably be negatively affected by imports from the Asia-Pacific region. The trend is for more rapid growth in gas-phase applications, mainly air purification, solvent recovery and motor vehicle emission canisters. This means that granular activated carbon will have a better growth potential than powdered activated carbon. 

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