Methods, systems, and apparatuses for low-temperature, fischer-tropsch wax hydrogenation

Abstract

A process for hydrogenating a Fischer-Tropsch (“FT”) wax includes placing hydrogenation catalyst particles within a low-temperature hydrogenation reactor having a mixing sub-system and a vent at the top for excess hydrogen, placing the FT wax at a low temperature up to a predetermined level within the low-temperature, hydrogenation reactor, leaving a vapor space above the predetermined level, adding hydrogen under a desired pressure into the low-temperature hydrogenation reactor, mixing the input FT wax, the hydrogen gas and the hydrogenating catalyst particles together to create a mixture using the mixing subsystem and continuing the mixing until the FT wax has hydrogenated, stopping the mixing to allow the hydrogenation catalyst particles to settle, and removing an hydrogenated FT wax with residual hydrogenating catalyst particles from the low-temperature hydrogenation reactor. The hydrogenated FT wax may be filtered and subjected to vacuum distillation. Other embodiments are also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is the national phase entry of PCT Application No. PCT / US2014 / 052052, filed Aug. 21, 2014, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent App. No. 61 / 868,509, filed Aug. 21, 2013, the disclosure of each of which is hereby incorporated herein by reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not applicable.BACKGROUND[0003]1. Field of the Invention[0004]This invention relates to a system and method for treating hydrocarbon waxes; specifically it relates to a system and method for improving the color of waxes produced by a Fischer-Tropsch process.[0005]2. Background of the Invention[0006]The Fischer-Tropsch (or “Fischer Tropsch,”“F-T” or “FT”) process (or synthesis or conversion) involves a set of chemical reactions that convert a mixture of carbon monoxide and hydrogen (known as reformed gas, synthesis gas, or “syngas”) into liquid hydrocarbons (called “liquid FT ...

AI Technical Summary

Benefits of technology

The present patent describes methods and systems for hydrogenating FT wax using a low-temperature, low-pressure hydrogenation reactor. The methods involve placing the FT wax in the reactor, adding hydrogen gas under pressure, and mixing the FT wax with hydrogenation catalyst particles. The resulting mixture is then removed from the reactor and processed to remove any residual catalyst particles. The methods and systems allow for efficient hydrogenation of FT wax, resulting in improved properties such as reduced viscosity and improved flowability.

Problems solved by technology

However, the mechanistic explanation of catalysis is complex.

Nevertheless, there may be sufficient impurities in FT wax, including olefins and oxygenates, that may cause problems with the FT wax product.

The olefins may react with oxygen via a process that leads to the production of aldehydes and ketones associated with an undesirable odor.

Untreated FT wax tends to be colorless to light yellow (liquid), white to off-white (solid) and the color tends to deteriorate in storage.

Olefins in FT waxes are unstable with respect to oxygen.

If an olefin becomes an oxygenated compound, it may become rancid and may cause problems with color or odor in the FT wax.

The trickle bed reactors operate at high temperatures and high pressures and are, accordingly, expensive.

Furthermore, in edible oil process, it is typically not desirable to hydrogenate the edible oil completely; a certain amount of residual olefin can be desirable in these applications.

Accordingly, given these differences, such low pressure, low temperature reactors and processes have not been previously considered for use with FT wax hydrogenation.

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