Tougher economic conditions challenge refiners to be profitable under severe situations. In refineries, vacuum units greatly impact profitability. For the vacuum unit, profitability largely depends on product yields and unit run length. Many published articles provide valuable guidelines on how to operate to obtain higher yields and longer run lengths. These articles mostly discussed the vacuum tower critical sections.¹ However, there are economic opportunities in debottlenecking the vacuum transfer line. The transfer line is one of the important critical sections on a vacuum unit. We will discuss the effects of the transfer line on the vacuum tower operating conditions and products yields and specifications, as well as modifications to achieve more yields.