mesh in the reaction process nitrogen passes continuously into the pellets and carbon monoxide is released the pellets must therefore be porous and their porosity controls the rate of the conversion reaction since the rate of the chemical conversion is in part dictated by pore size and density it is desirable that the pore size and the distribution of pores within each agglomerate be uniform a well controlled size distribution is desirable to the efficient operation of the continuous fluid bed reactor because the residence time of an agglomerate in the bed is a function of the size of the pellets with a faster conversion reaction occurring with smaller pellets also segregation of the agglomerates by size within the bed can occur so size uniformity is desirable additionally if big pellets and small pellets are put into the reactor together and the pellets are left in until even the big pellets have reacted grain growth can occur in the smaller pellets consideration of the above factors indicate that if the pellet size is not adequately controlled the products will be non uniform and of low purity the gas velocity for fluidization is chosen based on the mean particle size for the case of this illustration a gas flow rate of 2 standard cubic feed per minute scfm was chosen.