IsoTherming™ Hydrotreating Process for Ultra Low Sulfur Diesel Fuel

Published December 2007

The IsoTherming™ Hydroprocessing Technology was developed and commercialized in 2003 by Process Dynamics, Inc. The process was acquired by DuPont in 2007.

The key feature of the process is introducing the hydrogen gas to the reactor dissolved in the feedstock instead of the conventional two-phase gas-liquid flow. Conventional commercial catalyst is used. Recycling a portion of reactor effluent returns unreacted hydrogen to the reactor inlet, allows more fresh hydrogen to be dissolved and removes heat from the reactor that is used to directly heat the fresh feed. This approach allows the replacement of the conventional trickle bed reactor with a smaller liquid full, fixed bed reactor. The recycle hydrogen compressor and associated equipment is eliminated.

The new process offers the refiner the following potential benefits:

• Improved cetane index
• Nearly complete nitrogen removal
• Reduced furnace duty through improved process heat integration
• When installed as a pretreat unit, increased hydrotreating capacity can be obtained without modifying the existing hydrotreater and with minimal operating changes
• Low capital cost.

In this Review, we evaluate the process economics of two 30,000 B/cD (31,579 BPSD) middle distillate hydrotreating units producing ultra low sulfur diesel fuel. The first is our concept of the IsoTherming reactor section combined with conventional separation and product recovery sections. The second unit combines our conceptual IsoTherming reactor section with integrated gas and product recovery sections.