Stacking of low activity or regenerated catalyst above higher activity catalyst

摘要

Processes are provided for using employing lower activity hydrodesulfurization catalysts while achieving a desired product sulfur content. After determining effective reaction conditions for hydrodesulfurization using a reference catalyst system, an upstream portion of the catalyst system can be replaced with a lower activity upstream portion. The process allows tailored product sulfur levels to be achieved using reaction conditions similar to those for the reference catalyst system.

主权项

1. A method for treating a distillate feed with a plurality of hydrodesulfurization catalysts, comprising:
determining effective reaction conditions for processing a distillate feed with a first catalyst, including an effective volume of the first catalyst, a temperature, a pressure, a ratio of hydrogen treat gas volume to feed volume, and a liquid hourly space velocity, the effective reaction conditions being suitable to form a distillate product having a target sulfur content of about 100 wppm of sulfur or less; providing a first volume of the first catalyst; providing a second volume of a second catalyst in place of a portion of the effective volume of the first catalyst, the second catalyst having a hydrodesulfurization activity from about 75% to about 90% of a hydrodesulfurization activity of the first catalyst, the first volume being from about 50% to about 90% of the effective volume; and processing the distillate feed under second reaction conditions that are substantially similar to at least the temperature, the pressure, the ratio of treat gas rate volume to feed volume, and the liquid hourly space velocity of the effective reaction conditions, the distillate feed contacting the second volume of catalyst prior to the first volume of catalyst, to produce a distillate product having a sulfur content within about 10 wppm of the target sulfur content.