Vacuum Tower Design Techniques for Optimum Performance and Reliability

Description:

In today’s refineries, operators are pushing units harder to maximize yields. In crude vacuum towers this corresponds to higher severity and deeper cutpoints. These conditions can compromise product quality and unit reliability if appropriate design and operation procedures are not followed. Higher severity conditions coupled with longer run lengths demand vacuum tower designs that focus on reliability as well as performance. The key to achieving crude vacuum tower performance often becomes the wash bed design. The wash bed often has the most direct effect on the gas oil product quality. At the same time, the wash bed is most prone to coking. The focus then on vacuum tower performance and reliability must be the wash bed. However, the wash bed performance and reliability are determined by many factors. Feed characterization, simulation, vapor and liquid distribution, and wash bed design all play a major role in determining vacuum tower performance and reliability. Errors in any of these areas translate to a project that does not meet yield, quality, or reliability targets. With tight crude margins such errors can have a significant impact on refinery profitability.