Process Optimization of RTS Technology for Ultra-Low Sulfur Diesel

The RTS technology can produce ultra-low sulfur diesel at lower costs using available hydrogenation catalyst and device. However, with the increase of the mixing proportion of secondary processed diesel fuel in the feed, the content of nitrogen compounds and polycyclic aromatic hydrocarbons in the feed increased, leading to the acceleration of the deactivation rate of the primary catalyst and the shortening of the service cycle. In order to fully understand the reason of catalyst deactivation, the effect of mixing secondary processed diesel fuel oil on the operating stability of the catalyst in the first reactor was investigated in a medium-sized fixed-bed hydrogenation unit. The results showed that the nitrogen compounds mainly affected the initial activity of the catalyst, but had little effect on the stability of the catalyst. The PAHs had little effect on the initial activity of the catalyst, but could significantly accelerate the deactivation of the catalyst. Combined with the analysis of the reason of catalyst deactivation and the study of RTS technology, the direction of RTS technology process optimization was put forward, and the stability of catalyst was improved obviously after process optimization.