Process for increasing aromatics production (UOP)

CATEGORY: NAPHTHA
PATENT
Process for increasing aromatics production (UOP)
Publication number US20130225886 A1
Publication type Application
Application number US 13/856,349
Publication date Aug 29, 2013
Inventors
Gregory J. Gajda, Mary J. Wier, Clayton Colin Sadler
Original Assignee
Uop Llc
Abstract
Processes for producing aromatics from a naphtha feedstream are provided. An exemplary process includes passing the feedstream to a fractionation unit, thereby generating a first stream including hydrocarbons having less than 8 carbon atoms and a second stream including hydrocarbons having at least 8 carbon atoms. The first stream is passed to a first reformer operated at a first set of reaction conditions to generate a first product stream. The first set of reaction conditions includes a first temperature and a first pressure. The second stream is passed to a second reformer operated at a second set of reaction conditions to generate a second product stream. The second set of reaction conditions includes a second temperature and a second pressure. The first pressure is lower than the second pressure.
TECHNICAL FIELD
The technical field generally relates to the process of enhancing the production of aromatic compounds. More particularly, the technical field relates to the improvement and enhancement of aromatic compounds such as benzene, toluene and xylenes from a naphtha feedstream.
BACKGROUND
The reforming of petroleum raw materials is an important process for producing useful products. One important process is the separation and upgrading of hydrocarbons for a motor fuel, such as producing a naphtha feedstream and upgrading the octane value of the naphtha in the production of gasoline. However, hydrocarbon feedstreams from a raw petroleum source include the production of useful chemical precursors for use in the production of plastics, detergents and other products.
The upgrading of gasoline is an important process, and improvements for the conversion of naphtha feedstreams to increase the octane number have been presented in U.S. Pat. Nos. 3,729,409, 3,753,891, 3,767,568, 4,839,024, 4,882,040 and 5,242,576. These processes involve a variety of means to enhance octane number, and particularly for enhancing the aromatic content of gasoline.
Processes include splitting feeds and operating several reformers using different catalysts, such as a monometallic catalyst or a non-acidic catalyst for lower boiling point hydrocarbons and bi-metallic catalysts for higher boiling point hydrocarbons. Other improvements include new catalysts, as presented in U.S. Pat. Nos. 4,677,094, 6,809,061 and 7,799,729. However, there are limits to the methods and catalysts presented in these patents, and which can entail significant increases in costs.
BRIEF SUMMARY
Processes for producing aromatics from a naphtha feedstream are provided herein. In an embodiment, a process for producing aromatics from a naphtha feedstream includes passing the feedstream to a fractionation unit, thereby generating a first stream that includes hydrocarbons having less than 8 carbon atoms and a second stream that includes hydrocarbons having at least 8 carbon atoms. The first stream is passed to a first reformer to generate a first product stream. The first reformer is operated at a first set of reaction conditions, and the first set of reaction conditions includes a first temperature and a first pressure. The second stream is passed to a second reformer to generate a second product stream. The second reformer is operated at a second set of reaction conditions, and the second set of reaction conditions includes a second temperature and a second pressure. The first pressure is lower than the second pressure. The first product stream and the second product stream are passed to an aromatics separation unit.
In another embodiment, a process for producing aromatics from a naphtha feedstream includes passing the feedstream to a fractionation unit, thereby generating a first stream that includes hydrocarbons having less than 8 carbon atoms and a second stream that includes hydrocarbons having at least 8 carbon atoms. The first stream is passed to a first reformer to generate a first product stream. The first reformer is operated at a first set of reaction conditions, and the first set of reaction conditions includes a first temperature, a first pressure, a first hydrogen to hydrocarbon feed ratio, and a conversion per pass for hydrocarbons having 6 carbon atoms. The second stream is passed to a second reformer to generate a second product stream. The second reformer is operated at a second set of reaction conditions, and the second set of reaction conditions includes a second temperature, a second pressure, and a second hydrogen to hydrocarbon feed ratio. The first temperature is greater than the second temperature, the first pressure is lower than the second pressure, and the second hydrogen to hydrocarbon feed ratio is greater than the first hydrogen to hydrocarbon feed ratio. The first product stream and the second product stream are passed to an aromatics separation unit.
In another embodiment, a process for producing aromatics from a naphtha feedstream includes passing the feedstream to a fractionation unit, thereby generating a first stream that includes hydrocarbons having less than 8 carbon atoms and a second stream that includes hydrocarbons having at least 8 carbon atoms. The first stream is passed to a first reformer to generate a first product stream. The first reformer is operated at a first set of reaction conditions, and the first set of reaction conditions includes a first temperature and a first pressure. The second stream is passed to a second reformer to generate a second product stream. The second reformer is operated at a second set of reaction conditions, and the second set of reaction conditions includes a second temperature and a second pressure. The first temperature is greater than the second temperature and the first pressure is lower than the second pressure. The first product stream is passed to a compressor. The first product stream and the second product stream are passed to an aromatics separation unit. The first product stream is passed to the aromatics separation unit from the compressor and the second product stream is passed to the aromatics separation unit in the absence of further pressurizing
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