LG-Caltex Oil Corp. has chosen the CrystPX crystallization process for its new 400,000 tonne/year (tpy) paraxylene production unit in Yosu, Korea.
GTC Technology, Houston, licenses the technology in an alliance with Lyondell Chemical Corp.
The new plant is scheduled to start up in January 2003. It will separate paraxylene from the xylenes recovered from a toluene conversion unit. The toluene conversion unit will process toluene extracted from LG-Caltex's aromatics recovery unit, commissioned in July 2000 (OGJ, Sept. 18, 2000, p. 57).
LG-Caltex currently operates a 700,000-tpy paraxylene facility at its Yosu complex. This planned expansion, said the company, will make LG-Caltex the world's largest merchant producer of paraxylene from a single site.
New technology
LG-Caltex's application will be CrystPX's first commercial application.
CrystPX uses suspension crystallization to separate paraxylene crystals from a xylene isomer mixture. Washing the paraxylene crystal with the final product in a high efficiency pusher-centrifuge system produces the paraxylene product.
Fig. 1 shows the general flow scheme of the technology.
The crystallizaton equipment is simple, using only crystallizers and centrifuges in the primary operation. The front section of the process produces paraxylene at warm temperatures.
At the back end of the process, a series of crystallizers, operated successively at colder temperatures, recovers more paraxylene.
GTC says that its process recovers 95% of a paraxylene product with a 99.8+ wt % purity.
