Kolmetz.com CMAI 2000 Joe Page 2
GT-STDP
SM
- Selective Toluene Disproportionation
In the GT-STDP process, toluene is converted to paraxylene-rich (typically >80 wt%)
mixed xylenes and benzene at toluene conversion rates of around 30%. The process is
based on a proprietary high-silica zeolite catalyst. The process flow scheme is typical of a
toluene-conversion process and consists of a vapor-phase reactor, associated heat-
exchange, and product stabilization equipment.
Product
Distillation
Reactor
Heater
H2 Makeup
Toluene
Toluene Recycle
Offgas
Stripper
P-Xylene Concentrate
C9+Aromatics
Light
Hydrocarbons
Benzene
Product
Separator
Hydrogen Recycle
Figure 1. Typical STDP Process
Typical operating conditions for the GT-STDP are shown below.
Temperature (°C)
=
390 - 400
Pressure (kg/cm
2
)
=
30
WHSV (hr
-1
)
=
4.0 - 4.5
Toluene conversion
=
28-30% (typ.)
Paraxylene selectivity, wt%
=
80-90
A comparison with other commercially available processes for selective toluene
disproportionation is shown below.
