Synthetic Phenolic Antioxidants in Middle Distillate Fuels Analyzed by Gas Chromatography with Triple Quadrupole and Quadrupole Time-of-Flight Mass Spectrometry

CATEGORY: MIDDLE DISTILLATES 
Synthetic Phenolic Antioxidants in Middle Distillate Fuels Analyzed by Gas Chromatography with Triple Quadrupole and Quadrupole Time-of-Flight Mass Spectrometry

Type	Journal Article
Author	Renée L. Webster
Author	Paul M. Rawson
URL	http://dx.doi.org/10.1021/ef402144v
Volume	28
Issue	2
Pages	1097-1102
Publication	Energy & Fuels
Date	February 20, 2014
Abstract	Describes methods for the selective determination and quantification of 10 synthetic phenolic antioxidants (SPA) in jet and diesel fuels. The analytical procedure involves no sample preparation and uses direct injection of the diluted parent fuel into the GC column. Researchers showed the method to be rugged and robust. Because no extraction is required, it does not require estimation of extraction efficiencies. It is suited to volatile SPA compounds included in jet and diesel fuel specifications. The method is appropriate for the estimation of SPA in fresh and in-service middle distillate fuels stored on military bases and tankers or in use on aviation or naval platforms.

Downstream Refining Challenges and Future Configuration

CATEGORY: MIDDLE DISTILLATES
2013 SPE Kuwait Oil and Gas Show and Conference, 7-10 October 2013, Kuwait International Fair, Kuwait City, Kuwait
Downstream Refining Challenges and Future Configuration
Shailendra Mohite, Kuwait Petroleum International, Kuwait
Abstract
Precise predictions and solutions for tomorrow’s needs are the key elements to build a growing, sustainable refining business. This requires a mixture of vision, strategic risk taking business model and investment in new technology.
Refining trends forecast for the next 15 years are useful for predicting its possible landscape by 2030, where in a larger context the main challenge for the industry would be to meet twice the energy levels from today with half the CO2 emissions.
Well-to-wheels GHG emissions would drive unconventional fuels programs; and countries with insufficient oil resources would attempt to secure supply and reduce dependence by including Gas-derived fuels, besides supplementing with CTL, GTL and BTL into supply chain.  In several cases, effect of above three key factors would be multiple and cross-linked.
During the next 15 years in the field of clean fuels, tremendous improvements in technologies will include hydrotreating and dearomatization, hydrocracking, fluid catalytic and resid cracking, reforming, and alkylation.
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Process For The Production Of Middle Distillate From A Conventional Heavy Feedstock Including A Step For Selective Hydrogenation Of The Ex Fcc Hco Cut (IFP Energies Nouvelles)

PATENT
Process For The Production Of Middle Distillate From A Conventional Heavy Feedstock Including A Step For Selective Hydrogenation Of The Ex Fcc Hco Cut (IFP Energies Nouvelles)
United States Patent Application 20130137907
Inventors:
Feugnet, Frederic (Lyon, FR)
Hudebine, Damien (Lyon, FR)
Roux, Romain (Rueil Malmaison, FR)
Application Number:
13/683134
Publication Date:
05/30/2013
Assignee:
IFP Energies Nouvelles (Rueil-Malmaison Cedex, FR)
Abstract:
The present invention describes a process for the conversion of a heavy feedstock for improving the production and selectivity for middle distillate, said process using a catalytic cracking unit followed by a unit for selective hydrogenation of the heavy distillate cut (HCO) or any other cut rich in triaromatic compounds before recycling it to the FCC reaction zone in order to maximize the middle distillate cut.
FIELD OF THE INVENTION
The present invention relates to a process for the conversion of a heavy hydrocarbon feedstock with improved selectivity for middle distillate. More precisely, the process of the present invention can be used to co-produce gasoline in a reduced yield, and to improve the production of middle distillate by at least 2% by weight with respect to the feedstock, which is highly significant having regard to the tonnages involved in the process.
Historically, catalytic cracking units, known by the abbreviation FCC (fluid catalytic cracking), are optimized for the production of light products—liquefied gas (or LPG), light olefins and gasoline—in order to satisfy the polymer market or the requirements of gasoline consumption in the automobile market.
In that type of function, the production of gas oil bases remains limited.
Currently, because of huge increases in the use of diesel on the automobile market, the demand for gas oil type products has increased greatly. As a consequence, it is becoming ever more necessary to orientate refinery production towards the production of gas oil bases and to limit the production of gasoline. Since FCC units, which are present in almost half of refineries, are on the one hand the principal source of gasoline and on the other hand a major source of light olefins, it is imperative to be able to convert them into units favouring the production of gas oils. The skilled person encapsulates this trend by using the term “maxi LCO mode FCC”, where LCO in this case designates the middle distillate cut, i.e. a cut with a distillation range in the range 220° C. to 360° C.
The process of the present invention can be used 1) to improve the production of gas oil bases in fluidized bed catalytic cracking units, 2) limit the production of heavy cuts that are difficult to upcycle, and also 3) limit the production of gasoline, since this cut is not wanted for maxi LCO mode running.
The present invention essentially consists of a concatenation of a FCC unit with one or more units for the selective hydrogenation of the heavy distillate cut (HCO) produced in the FCC, or any other cut which is rich in triaromatic compounds obtained, for example, from visbreaking, coking, “H-oil” units or the Pygas cut from a steam cracking unit.
This heavy distillate cut is selectively hydrotreated in order to minimize the proportion of triaromatics, while maximizing the ratio of diaromatics to monoaromatics. It is then recycled to the reaction zone of the FCC in order to significantly increase the yield of middle distillate (LCO) and also the selectivity of that cut with respect to gasoline while limiting the production of additional coke.
In the context of the present invention, the “middle distillate” cut (LCO) has a distillation range in the range 220° C. to 360° C.
The FCC process can be used to convert heavy hydrocarbon feedstocks with an initial boiling point which is generally more than 340° C. into lighter hydrocarbon fractions, in particular a gasoline cut, by cracking molecules of the heavy feedstock in the presence of an acid catalyst. FCC also produces liquefied petroleum gas (LPG) in large quantities with high olefins contents.
The process of the present invention may also generally be presented as a process for the production of middle distillate with an improvement of the selectivity for middle distillate over gasoline.
The present invention employs a catalytic cracking unit followed by one or more units for selective hydrogenation of the heavy distillate cut with a distillation range in the range 320° C. to 490° C. and primarily composed of triaromatics. This cut is usually denoted (HCO), an abbreviation which we shall retain in the text below.
The selective hydrogenation unit may also treat any other cut which is rich in triaromatic compounds obtained, for example, from visbreaking, coking, an H-oil unit or the Pygas cut from a steam cracking unit.
The process of the invention essentially consists of a concatenation of a catalytic cracking unit and one or more hydrotreatment units which selectively treat the HCO cut, with a recycle of the hydrotreated HCO cut to the catalytic cracking unit, as well as fine-tuning the hydrotreatment operating conditions in order to selectively transform the triaromatics of the feedstock for the unit into diaromatics, while maximizing the diaromatics to monoaromatics ratio. When recycled to the FCC reaction zone, the selectively hydrotreated HCO cut can be used to very significantly improve the selectivity for middle distillate of the process as well as limit the additional production of gasoline and coke.
The present invention is compatible with all catalytic cracking reactor technologies, whether it is gas-solid upflow technology or downflow technology.
The catalytic cracking unit employed in the present process may be classified into a number of modes, with a single reactor or a plurality of reactors, each reactor being able to operate in upflow or in downflow mode.
In the case of a plurality of selective hydrogenation units associated with the catalytic cracking unit, they can be arranged in series or in parallel.
EXAMINATION OF THE PRIOR ART
The prior art teaches recycling the cut known as the heavy distillate (HCO) to the reaction zone of the FCC, but not recycling said selectively hydrotreated cut with a view to maximizing middle distillate formation. One essential difference of the present invention over the prior art process cited above pertains precisely to the selective nature of the hydrogenation and to fine-tuning its operating conditions.
Patent FR 10/04 585 describes a process for the conversion of a heavy feedstock that can be used to improve the selectivity for middle distillate by using a catalytic cracking unit followed by one or more olefin oligomerization units in order to preferentially produce an additional middle distillate cut.
The present invention consists of a concatenation of a catalytic cracking unit (FCC) and one or more units for the selective hydrogenation of heavy distillate in order to significantly improve the production of middle distillate and at the same time to improve the selectivity for middle distillate over gasoline while at the same time limiting the formation of additional coke.
BRIEF DESCRIPTION OF THE INVENTION
The invention concerns a process for the conversion of a “heavy” hydrocarbon feedstock, i.e. constituted by hydrocarbons with a boiling point of more than approximately 340° C., with a view to improving the production of middle distillate and of reducing the production of gasoline.
The term “middle distillate”, denoted LCO, means a cut with a distillation range in the range 220° C. to 360° C.
The term “gasoline” means the cut with a distillation range of 70° C. to 150° C.
The process of the invention comprises at least two reaction steps, a first catalytic cracking step to process a heavy hydrocarbon feedstock such as a vacuum distillate or an atmospheric residue, or even in some cases a vacuum residue, and a second step for selective hydrogenation of the heavy distillate cut resulting from FCC, denoted HCO, alone or as a mixture with any other cut which is rich in triaromatic compounds obtained, for example, from visbreaking, coking, “H-oil” type units or the Pygas cut from a steam cracking unit.
The selective nature of the hydrogenation of the heavy distillate cut (HCO) can be used to limit the formation of monoaromatics which increase production of the gasoline cut after cracking in the FCC riser, the gasoline cut not being wanted in the maxi LCO operational mode, which is precisely the mode employed in the present invention.
The transformation of triaromatics can be employed to produce diaromatics which are vital to the production of LCO, but also to limit the formation of coke, a major product of these compounds after passing through the FCC. In the end, selective hydrogenation of the heavy distillate cut (HCO) can be used to substantially improve the middle distillate (LCO) to gasoline selectivity compared with a recycle of that cut to the FCC without hydrotreatment or with conventional hydrotreatment.
In the remainder of the text, the terms “hydrotreatment” and “selective hydrogenation” should be considered to be synonymous. Thus, both “hydrotreated HCO cut” and “selectively hydrogenated HCO cut” will be employed interchangeably.
The process of the invention can be used to satisfy two objectives:
• ◦upcycle the heavy distillate cut (HCO) or any cut which is rich in triaromatics, limiting the production of additional coke thereby;
◦increase the production of middle distillate (LCO) at the same time as the middle distillate to gasoline selectivity.
The middle distillate cut (LCO) corresponds to a hydrocarbon cut with a distillation range in the range 220° C. to 360° C.
The primary aim of upgrading the heavy distillate cut (HCO) produced in the FCC or any cut which is rich in triaromatics is achieved by sending that cut to one or more hydrogenation units in order to reduce its triaromatics content, coke precursors, and heavy compounds that cannot be upgraded after recycling to the FCC reaction zone.
The second aim in improving the production of middle distillate (LCO) and the middle distillate to gasoline selectivity is obtained by fine-tuning the operating conditions for the selective hydrogenation of the ex FCC HCO cut in order to selectively transform the triaromatic compounds into diaromatics, middle distillate precursors, while minimizing the production of monoaromatics, which are gasoline precursors.
The heavy hydrocarbon feedstock is cracked in a fluidized bed catalytic cracking reactor in the presence of a cracking catalyst.
The heavy distillate cut (HCO) or any other cut which is rich in triaromatic compounds is selectively hydrotreated in the presence of a hydrotreatment catalyst composed of one or more metals from group VIB, preferably molybdenum or tungsten, usually associated with one or more metals from group VIII, preferably nickel or cobalt, deposited on an amorphous mineral support, preferably alumina, silica, silica-alumina, magnesia, clays and mixtures of at least two of these elements.
The support may also comprise other compounds, for example, such as oxides selected from the group formed by boron oxide, zirconia, titanium oxide and phosphoric anhydride. The catalyst may be fresh, partially coked or regenerated.
It is possible, for example, to use a catalyst comprising 1% to 10% by weight of nickel, preferably 1% to 5% by weight of nickel (expressed as nickel oxide, NiO) associated with 1% to 30% by weight of molybdenum, preferably 5% to 20% by weight of molybdenum (expressed as molybdenum oxide, MoO3) on an alumina support.
The hydrotreated heavy distillate fraction from selective hydrogenation is cracked with the same cracking catalyst, separately or as a mixture with the heavy hydrocarbon feedstock.
The effluents from catalytically cracking the two feedstocks are sent to a common fractionation zone and the catalyst used for cracking the two feedstocks is regenerated in a common regeneration zone.
As will be disclosed in the next paragraph, the catalytic cracking unit may be classified into a number of modes, with a single reactor processing the heavy hydrocarbon feedstock and the selectively hydrotreated heavy distillate (hydrotreated HCO), or two reactors, one processing the heavy hydrocarbon feedstock, and the other the selectively hydrotreated heavy distillate (hydrotreated HCO).
In addition, each reactor may operate in upflow or downflow mode.
In the case of a plurality of selective hydrotreatment units associated with the catalytic cracking unit, they may be arranged in series or in parallel.
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