Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

OP-III-23and parameters of synthesis procedure of carbon nanofibers of desired structure will bereported.The considerable theoretical and experimental experience collected for today permits oneto formulate the basically challenges to be faced while transferring the technology from labscaleto pilot plant level. In any case when searching for the principle design of reactor for thesynthesis of CNFs, the defining peculiarity of this process must by taken into account. Thepoint is that the initial volume of loaded catalyst is supposed to be significantly increasing (inhundreds times fold) during the process of carbon nanofibers deposition which makesimpossible the use of conventional reactors with a fixed bed catalyst layer. The carbonnanofibers growing over the stationary layer of catalyst was found to convert into monolithsoon, which causes the suppression of further process of synthesis. That is why thefundamentally new design solutions are required while creating the reactors for CNFsmanufacturing. It should be also noted that the specificity of this process imposes a limits onrealization of synthesis by uninterrupted technology. As soon as the reactor is filled with theproduct it should be stopped, emptied and then refilled with the next portion of catalyst.We have considered and compared a several different types of reactor design:• With the fluidized catalyst bed;• With the moving catalyst;• With the moving catalyst countercurrent to gas flow.Nevertheless, for a variety of reasons we have chosen the type of fully rotating horizontalbarrel with the cylinder shape. While the reactor is revolving on its axis it makes catalystgranules to be continuously moving and over-pouring inside the barrel with favors shakingand stirring of carbonated catalyst to intensify the mass exchange with gaseous phase. Thenanostructured carbon product depositing on catalyst is to occupy gradually the void volumeof rotor reactor that requires further break and overloading.There are three principle structures of nanoscale carbon fibers that can be distinguished:coaxial-conic, coaxial-cylinder and platelet. The combination of said morphologies allowsone to obtain the huge variety of other structures of CNFs. The synthesis conditions for CNFsin extended scale using the prototype rotor reactor will be discussed in the report. Thefollowing types of CNFs will be considered:• Coaxial-conic fibers (herringbone);• Platelet fibers;• Featherlike (disordered) fibers.The morphology of developed samples of CNFs was analyzed and confirmed by scanning(SEM) and transferring (TEM) high resolution electronic microscopy.136