Flexible Liquid Distribution Tray

Notes—1 Flexibility normally limited by liquid distribution system. 2 Most common types of tray. 3 No downcomer. 4 Very fouling services. 5 Vacuum services. 6 Very high liquid rates. 

The improvement in vapor-liquid contact can enhance the performance of distillate hydrotreaters. As an example, in testing of an improved vapor-liquid distributor in commercial use, Haldor-Topsoe and Phillips Petroleum found that the new Topsoe Dense Pattern Flexible Distribution Tray (installed in 1996 to replace a chimney type distributor installed in 1995 in a refiney) allowed a 30% higher sulfur feed to be processed at 25°C lower temperatures, while reducing the sulfur content of the product from 500 to 350 ppmw . Albemarle estimates that an improved vapor-liquid distributor can reduce the temperature necessary to meet a 50 ppmw sulfur level by 10 °C, which in turn would increase catalyst life and allow an increase in cycle length from 10 to 18 months. Based on the above data from Haldor-Topsoe, if temperature were maintained, the final sulfur level could be reduced by 50%. Maintaining temperature should have allowed an additional reduction in sulfur of more than two-thirds. Thus, ensuring adequate vapor-liquid contact can have a major impact on final sulfur levels. 

Tray, and Matey Tray (see Oliver9 p. 310 for description), the liquid flows from one bay to the next one below as free falling drops or si mams distributed across the entire column cross section. These trays have not proved as popular as trays equipped with downcomers. Their main disadvantage is a lack of flexibility. Tray holdup and operating characteristics are strongly dependent on vapor, liquid, and gas flow rales. 

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