Maximizing LPG Recovery from Fuel Gas Using a Dividing Wall Column

Refinery off gas is a mixture of hydrogen and hydrocarbons from various units within the refinery, pooled together to be used as a fuel for heating purposes. The fuel gas contains valuable components such as propane, which can provide additional revenue to the refinery. The economics of LPG recovery fluctuates with LPG pricing and energy cost. GT-LPG Max provides a cost-effective solution for recovering LPG product using a novel process concept of absorption plus distillation within the same fractionating vessel. The technology is well suited for low-pressure refinery off gas as well as associated natural gas streams. The process is based on avoiding thermodynamic inefficiencies in conventional absorption and distillation columns by incorporating the unit operations in a single top dividing wall column (DWC). The feed side of the top DWC recovers the C3+ components from the fuel gas through absorption. The other side of the DWC uses distillation to split between C3 and C4 components to produce LPG product.

GT-LPG Max offers the following benefits:

• 99% propane recovery without the use of external refrigeration
• Lower operating pressure (200 – 250 psig)
• Lower CAPEX and OPEX