GT-STDP
SM
and GT-TolAlk
SM
world class technologies from Indian Petrochemical Corporation Limited (IPCL)
and GTC Technology Corporation.
Toluene to Paraxylene Selective Conversion Processes
Lead the Way to Quick, Low Cost PX Production
Summary
Toluene-based routes to paraxylene production are attractive due to feedstock and by-
product flexibility. As a single component or along with other co-feedstocks, toluene can
be converted into mixed xylenes and benzene in varying ratios. The selectivity of toluene
conversion processes into paraxylene-concentrates has steadily improved over the years,
leading to processes capable of producing 80-90+ wt% paraxylene streams. Such
development results in an increasing use of these technologies for paraxylene production.
They also point towards the need for making selective toluene conversion processes an
integral part of traditional aromatic complexes that produce paraxylene and other
aromatic products.
Often, the paraxylene recovery section and associated feed preparation operations of the
popular adsorption-based aromatics complex are the most capital intensive. The
inclusion of selective toluene conversion processes in the aromatics complex utilizes
lower-cost paraxylene recovery technologies, such as crystallization, and reduces the
capital investment of the complex.
This presentation will identify new toluene conversion technologies that will provide
paraxylene producers a quick and low-cost way to produce paraxylene. We will review
selective disproportionation of toluene into benzene plus xylenes, selective alkylation of
toluene with methanol, and some ways these processes can be integrated into a
traditional xylenes-based complex.
Selective Toluene Conversion Processes
Catalytic processes for toluene conversion have been commercially practiced for several
decades. However, the application of selective toluene conversion processes has been
less widespread. A key factor is the difficulty in finding catalysts that can display high
selectivity towards paraxylene, while maintaining reasonable toluene conversion rates.
Although such catalysts have been developed in the past, their use has been restricted by
performance, market conditions, and technology supplier constraints.
Highly selective paraxylene technologies that are now available and offer competitive and
innovative routes to paraxylene are:
·
GT-STDP
SM
- Selective Toluene Disproportionation
·
GT-TolAlk
SM
- Toluene Alkylation
