Paraxylene

Chevron Phillips Chemical is one of the largest marketers of paraxylene in the world. We produce paraxylene at our Pascagoula, Mississippi and Guayama, Puerto Rico plants. One of our affiliates sells paraxylene from Pertamina’s Cilicap Indonesia refinery.

Paraxylene is currently manufactured by crystallization and adsorption processes. The  Pascagoula plant uses Chevron Phillips Chemical's patented hybrid crystallization/adsorption technology to produce paraxylene. This process is characterized by the use of adsorption technology to produce a medium-purity paraxylene feedstock stream that goes into a low-temperature crystallization plant to produce crystals. These crystals are centrifuged and washed to produce high-purity (99.9%) paraxylene.

The Puerto Rico plant uses Parex^™ adsorption technology licensed from UOP LLC to produce paraxylene. This process is based on the principle of the continuous selective adsorption in the liquid phase using a fixed bed solid zeolite adsorbent. The zeolite is manufactured so that it selectively retains paraxylene in preference to the other xylene isomers. A special desorbent material (toluene or p-diethyl-benzene) is used to flush paraxylene from the adsorbent. The desorbent can be easily separated from paraxylene by distillation. The separation is affected by small differences in affinity of the different feed components and is not totally dependent on shape-size selectivity.

Paraxylene is transported by vessel or tank car from our Pascagoula plant and only by vessel from Puerto Rico.

What It's Used For

Paraxylene is primarily used as a basic raw material in the manufacture of terephthalic acid (TPA), purified terephthalic acid (PTA) and dimethyl-terephthalate (DMT). TPA, PTA and DMT are used to manufacture polyethylene terephthalate (PET) saturated polyester polymers. Polyesters are used to produce fibers and films. PET bottles are widely used for carbonated beverages because of good carbon dioxide barrier properties. In addition, they are light-weight, shatter-resistant and possess high tensile strength. Polyester uses include:

• Carbonated and non-carbonated beverage containers
• Containers for household chemicals, toiletries, cosmetics, etc.
• Fabrics for curtains, upholstery, clothing, etc.
• Microwave oven packaging material
• Films for x-rays, magnetic tapes, photographic film and electrical insulation
• Packaging for boil-in bags, processed meats, shrink films and blister packs