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The IsoTherming® process uses a novel approach to introduce hydrogen into the reactor that allows much higher space velocities than conventional hydrotreating reactors. Reaction rates in typical hydrotreaters are limited by mass transfer of the hydrogen from the vapor phase into the liquid phase. The IsoTherming® process has removed the mass transfer limitation and operates in a kinetically limiting mode since hydrogen is delivered to the reactor in the liquid phase as soluble hydrogen.
Most of the reactions that take place in hydroprocessing are highly exothermic and as a result, a great deal of heat is generated in the reactor. In the IsoTherming® process, treated diesel is recycled back to the inlet of the IsoTherming® reactor. This recycle stream is used to deliver more hydrogen to the reactor but also acts as a heat sink and results in a more isothermal reactor operation, resulting in fewer light ends being made.
One of the biggest problems in hydroprocessing is catalyst coking. Cracking often takes place on the surface of the catalyst. If the amount of hydrogen available is not sufficient, cracking can lead to coke formation and can deactivate the catalyst. In the IsoTherming® process, coking can be greatly reduced because there is always enough hydrogen available in solution to avoid coking when cracking reactions take place. This should lead to much longer catalyst life. The process is designed to use conventional, off-the-shelf catalysts.
Benefits of using IsoTherming® technology include:
| Lower total investments. |
| Reduced operational severity on existing hydrotreater operations when installed in the pre-treat configuration. |
| Higher reaction rates which result in smaller reactors and less catalyst volume--less cost to the refiner. |
| More isothermal reactor operation which results in better yields,less light ends made, and greater catalyst life. |
| Improved diesel cetane. |
Improved aromatic saturation. |
| Operating cost advantage. |
| High pressure unit performance out of existing low pressure units. |
| Increased nitrogen removal. |
| Longer catalyst life in existing reactor. |
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