n-Paraffin

Commercial Applications

Traditionally, producers of n-paraffins, or normal paraffin, have been constrained to using straight-run kerosene feedstock with the leading extraction process. However for over 40 years, ExxonMobil Chemical Company has used a proprietary adsorbent extraction process to gain a feedstock advantage using lower quality kerosene. This n-paraffins extraction technology is now offered to the industry by exclusive license through KBR.

Offering comprehensive services including technology licensing, basic and detailed engineering, construction and support for plant operation such as operator training and start-up services, KBR brings the right people and technology to every project as a key n-Paraffin licensor.

Values and Benefits

The ExxonMobil Chemical n-paraffins process has been optimized to produce highly selective recoveries at lower manufacturing costs. Key features of this technology are:

Superior Adsorbent System

The high tolerance of kerosene feed impurities translates to the elimination of costly pre-fractionation step. Click to Enlarge

  • High Tolerance of Kerosene Feed Impurities – Significant savings in capital cost are achieved by minimizing the need for feed pretreatment before the kerosene enters the recovery system. The ENSORB™ process exhibits a high tolerance to feed impurities, up to 400 ppmwt Sulfur and 80 ppmwt Nitrogen. Mild hydrotreating is sufficient to reduce the impurity levels in the kerosene feed to an acceptable range.
  • No Costly Pre-Fractionation System – The fractionation system is placed at the back end of the plant, to allow the final product to be fractionated to specifications. A range of products can be produced simultaneously, allowing the producer the flexibility to meet market demands. Energy consumption is minimized by purifying only the extracted n-paraffins and eliminating the need for a sharp cut on the kerosene feedstock.
  • Simple Reactor Design – The adsorption system involves simple operation, without mechanically complex valves or special reactor internals. Sieves are easily removed for regeneration.
  • Superior Adsorbent System – The highly selective proprietary molecular sieves offer recovery of 99 wt% n-paraffin for LAB quality product, and exhibit an exceptionally long service life.

Technology Information

Kerosene from a coker or other source is first hydrotreated at mild conditions. The treated kerosene is sent to the proprietary ENSORB™ recovery process developed by ExxonMobil Chemical, wherein the long-chain aliphatic normal paraffins are selectively removed from the kerosene stream in vapor phase by adsorption onto a molecular sieve. Isoparaffins, cycloparaffins, aromatics, and other components not adsorbed are typically returned to the refinery kerosene pool. The cyclical process uses a low pressure ammonia desorbate to recover the n-paraffins from the sieve for use as LAB-quality product or for further purification.

The ENSORB™ adsorbent offers a high recovery of n-paraffins and a tolerance for sulfur and nitrogen that is unparalleled in the industry. Process conditions can be optimized for a targeted range of molecular weights and an optimized post-recovery fractionation section allows for fine-tuning of product compositions. The need for a sharp cut in a front-end fractionation section is eliminated thereby reducing the energy consumption of the process.

For more information on n-Paraffins, please visit our KBR Petrochemicals publications.