Mathematical model and numerical simulation of pre-sulfurization of hydrogenation catalyst in rotary kilns

Abstract

Pre-sulfurization of hydrogenation catalyst is a crucial step in the process of petroleum refining. However, the traditional rotary kiln has challenges such as large temperature gradient and uneven sulfurization, which will reduce catalyst performance. In this work, a novel structural design of rotary kiln equipped with flights and splitter plates on the wall of a rotatory drum is proposed to enhance the mass and heat transfer. And a comprehensive mathematical model is established to investigate the spatiotemporal evolution mechanisms of the gas-solid flow characteristics, temperature distribution, reaction rate, component concentration distribution and pre-sulfurization process of hydrogenation catalyst in the rotary kiln with and without splitter plates. The results show that the rotary kiln equipped with splitter plates and flights reduces particle velocity and material layer height compared with the rotary kiln without splitter plates, which is beneficial to reducing the catalyst breakage. Moreover, the radial and axial distribution of component concentration distribution in the rotary kiln with splitter plates and flights is more uniform, which is conducive to uniform pre-sulfurization of the catalyst. This research is beneficial to better design of the rotary kiln and the control of pre-sulfurization of hydrogenation catalyst.