Sorption Capacity Surface Area and Pore Volume

13 Sorption Capacity Surface Area and Pore Volume 

Adsorption measurements allow the determination of coke location. When the volume occupied by coke is much smaller than the volume inaccessible to adsorbates, it means that there is a pore blockage. However, in many cases the adsorption study is carried out at a different temperature than the reaction, and therefore diffusivity could be quite different. Another aspect that should be taken into account is that if the pretreatment for adsorption measurement requires temperatures higher than the reaction temperature, an important fraction of carbonaceous deposits could be stripped off the catalyst and, therefore, the pore volume measured in this way will be higher than the actual volume under reaction conditions. A modification in the coke structure might also occur under these circumstances  

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