Continuous synthesis of zeolite NaA in a microchannel reactor

We demonstrate the application of a stainless steel microchannel reactor for the continuous synthesis of zeolite NaA. Some influence parameters such as the aging time of the synthesis solution, the residence time and the crystallization temperature had been studied. It was found that aging of the synthesis solution was a key procedure to avoid the blockage of the microchannel. By using the aged synthesis solution, it took 1/10 of the crystallization time needed in the batch system to synthesize zeolite NaA in the microchannel reactor. On the other hand, the mean particle size and the particle size distribution of zeolite NaA synthesized in the microchannel reactor were, respectively, smaller and narrower than in the batch system. In the microchannel reactor, long aging time of the synthesis solution led to small mean particle size and narrow particle size distribution of the products. When synthesized at high temperature, zeolite NaA with big mean particle size but narrow particle size distribution could be produced even within short residence time, which would result from the fast heat transfer and auto-creation segmented flow of the synthesis solution in the microchannel.