Application: The IsoTherming process provides refiners an economical means to produce ultra-low-sulfur diesel (ULSD), low-sulfur and lownitrogen feedstocks and other very low-sulfur hydrocarbon products. In addition, IsoTherming can also be used for feed upgrading in a mild-to partial-conversion hydrocracking mode in conjunction with or in lieu of conventional hydrotreating.
Products: ULSD, low-sulfur FCC feed, low-sulfur gasoline-kerosine type products.
Description: This process uses a novel approach to introduce dissolved hydrogen in excess of reaction requirements into the reactor. This approach allows operation at higher space velocities than conventional trickle-bed reactors. The IsoTherming process eliminates problems associated with flow mal-distribution, gas-liquid mass transfer and catalyst wetting. The process obviates the need for some equipment in conventional hydrotreating thereby lowering cost.
The technology can be installed as a pre-treat unit ahead of an existing hydrotreater reactor or a new stand-alone process unit. Fresh feed, after heat exchange, is combined with recycled product and hydrogen in a mixer internal to the reactor. The liquid feed with soluble hydrogen is fed to IsoTherming reactor/bed one where partial desulfurization occurs. The stream is combined with additional hydrogen in a second mixer and fed to the second IsoTherming reactor/bed where further desulfurization takes place.
Treated oil is recycled back to the inlet of reactor one. This recycle stream delivers more hydrogen to the reactors and also acts as a heat sink; thus, a nearly isothermal reactor operation is achieved.
The treated oil from the second IsoTherming reactor/bed may then be fed to additional IsoTherming reactors/beds and/or a trickle-bed hydrotreating reactor (revamp case only) acting in the polishing mode to produce an ultra-low-sulfur product.