Technology

GT-BTX^® is an aromatics recovery technology that uses Extractive Distillation (ED) to remove Benzene, Toluene and Xylene (BTX) from refinery, petrochemical or coke oven aromatics streams such as catalytic reformate, pyrolysis gasoline or coke oven light oil (COLO).

The flow scheme of the GT-BTX process consists of two columns: an Extractive Distillation Column (EDC) and a Solvent Recovery Column (SRC).

Hydrocarbon feed is preheated with hot circulating solvent and fed at a mid-point into the EDC. Lean solvent is fed at an upper point and selectively extracts the aromatics into the tower bottoms in a vapor/liquid distillation operation. The non-aromatics hydrocarbons exit from the top of the column. A portion of the overhead stream is returned to the top of the column as reflux, which washes back any entrained solvent.

Rich solvent from the bottom of the EDC is routed to the SRC, where the aromatics are stripped overhead. The SRC is operated under a vacuum to reduce the boiling point at the bottom of the column.

Lean solvent from the bottom of the SRC is passed through a heat exchanger before returning to the EDC. A small portion of the lean circulating solvent is processed in a solvent regeneration step to remove heavy decomposition products.

The SRC overhead mixed aromatics product is routed to the purification section, where it is fractionated to produce chemical-grade benzene, toluene and xylenes.

Source: SULZER, GT-BTX^®: Aromatics Recovery.