Application: The Topsøe mild hydrocracking/ VGO hydrotreating process upgrades, and if required, converts a variety of vacuum gasoil feed- stocks including straight run (SR) and cracked components from an FCC, Coker, and visbreaker as well as deasphalting units.
Products: Low-sulfur naphtha, diesel and vacuum gasoil. The vacuum gasoil sulfur is adjusted such that when processed by the FCC, it will pro- duce low-sulfur gasoline that does not require post treatment and can be blended directly in the gasoline pool.
Description: This process uses a combination of process conditions and hydrotreating and hydrocracking catalyst to meet the required con- version as well as required product quality specifications. Topsøe has devel- oped amorphous and zeolitic cracking catalysts specifically designed for mild hydrocracking applications. Topsøe ’s engineers utilize their process design experience to adjust the unit flow configuration to meet product quality requirements and provide a cost-effective design.
The unit design also features an industry leader graded-bed design for reactor pressure-drop control as well as state of the art reactor internals design. For FCC pretreater revamps, Topsøe has further developed the Aroshift process that considerably improves FCC profitabili ty at little
investment.
Operating conditi ons: Typical operating pressures range from 55 to 110 barg (800 to 1,600 psig). Typical operating temperatures range from 340°C to 410°C (644°F to 770°F).
Installation: Four units designed by Topsøe for Mild Hydrocrack- ing/VGO Hydrotreating are in service.
Licensor: Haldor Topsøe A/S.
Hydrogen m akeup Fresh feed Pre- treating reactor Mild hydrocracking reactor H2-rich gas Absorber Lean amine HP separator LP separator FCC feed Product fractionator Process gas Naphtha Middle distillate Rich amine Furnace
Hydrodearomatization
Application: Topsøe’s two-stage hydrodesulfurization hydrodearom- atization (HDS/HDA) process is designed to produce low-aromatics distillate products. This process enables refiners to meet the new, strin- gent standards for environmentally friendly fuels.
Products: Ultra-low sulfur, ultra-low nitrogen, low-aromatics diesel, kerosine and solvents (ultra-low aromatics).
Description: The process consists of four sections: initial hydrotreating, intermediate stripping, final hydrotreating and product stripping. The ini- tial hydrotreating step, or the “first stage” of the two-stage reaction process, is similar to conventional Topsøe hydrotreating, using a Topsøe high-activ- ity base metal catalyst such as TK-573 to perform deep desulfurization and deep denitrification of the distillate feed. Liquid effluent from this first stage is sent to an intermediate stripping section, in which H2S and ammonia are
removed using steam or recycle hydrogen. Stripped distillate is sent to the final hydrotreating reactor, or the “second stage.” In this reactor, distillate feed undergoes saturation of aromatics using a Topsøe noble metal catalyst, either TK-907/TK-908 or TK-915, a high-activity dearomatization cata- lyst. Finally, the desulfurized, dearomatized distillate product is steam stripped in the product stripping column to remove H2S, dissolved gases and
a small amount of naphtha formed.
Like the conventional Topsøe hydrotreating process, the HDS/HDA process uses Topsøe’s graded bed loading and high-efficiency patented reac- tor internals to provide optimum reactor performance and catalyst use lead- ing to the longest possible catalyst cycle lengths. Topsøe’s high efficiency internals have a low sensitivity to unlevelness and are designed to ensure the most effective mixing of liquid and vapor streams and maximum utiliza- tion of catalyst. These internals are effective at high of liquid loadings, thereby enabling high turndown ratios. Topsøe’s graded-bed technology and the use of shape-optimized inert topping and catalysts minimize the build-up of pressure drop, thereby enabling longer catalyst cycle length.
Operati ng conditions: Typical operating pressures range from 20 to 60 barg (300 to 900 psig), and typical operating temperatures range from 320°C to 400°C (600°F to 750°F) in the first stage reactor, and from 260°C to 330°C (500°F to 625°F) in the second stage reactor. The Topsøe HDS/HDA treatment of a heavy straight-run gas oil feed yielded these product specifications:
Feed Product Spe cif ic g ra vit y 0.86 0.83 Sulf ur, ppm w 3,000 1 Nit ro g e n, ppm w 400 <1 To t a l aro m a t ics, w t % 30 <10 Ce t a ne ind e x, D-976 49 57
References: Cooper, Hannerup and Søgaard-Andersen, “Reduction of aromatics in diesel,” Oil and Gas, September 1994
Søgaard-Andersen, Cooper and Hannerup, “Topsøe’s process for improving diesel quality,” NPRA Annual Meeting, 1992.
de la Fuente, E., P. Christensen, and M. Johansen, “Options for meet- ing EU year 2005 fuel specifications.”
Installation: A total of five, two in Europe and three in North America. Licensor: Haldor Topsøe A/S.
Diesel feed Makeup hydrogen First stage HDSreactor HDA reactor Second stage HDS stripper HDA separator Diesel product Wild naphtha Water Overhead vapor Steam Diesel cooler Wash water Amine scrubber Recycle gas compressor HDS stripper Product diesel stripper Sour water H D S s e p a r a t o r
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Hydrodesulfurization
Application: Reduce sulfur in gasoline to less than 10 ppm by hydrodesulfurization followed by cracking and isomerization to recover octane.
Description: The basic flow scheme is similar to that of a conventional naphtha hydrotreater. Feed and recycle hydrogen mix is preheated in feed/effluent exchangers and a fired heater then introduced into a fixed- bed reactor. Over the first catalyst bed, the sulfur in the feed is converted to hydrogen sulfide with near complete olefin saturation. In the second bed, over a different catalyst, octane is recovered by cracking and iso- merization reactions. The reactor effluent is cooled and the liquid prod- uct separated from the recycle gas using high- and-low temperature sep- arators.
The vapor from the separators is combined with makeup gas, com- pressed and recycled. The liquid from the separators is sent to the prod- uct stripper where the light ends are recovered overhead and desulfurized naphtha from the bottoms. The product sulfur level can be as low as 5 ppm. The OCTGAIN process can be retrofitted into existing refinery hydrotreating units. The design and operation permit the desired level of octane recovery and yields.
Yields: Yield depends on feed olefins and desired product octane. Installations: Commercial experience with two operating units. Reference: Halbert, T., et al., “Technology Options For Meeting Low Sulfur Mogas Targets,” NPRA Annual Meeting, March, 2000. Licensor: ExxonMobil Research and Engineering Co.
Quench Purge Makeup gas Light ends Recycle gas compressor Reactor Feed Hydrogen-rich gas High-temperature separator Low- temperature separator Low-sulfur, low-olefins, high-octane gasoline Product stripper
Hydrodesulfurization
Application: Reduce sulfur in FCC gasoline to less than 10 ppm by selective hydrotreating to maximize octane preservation.
Description: The feed is mixed with recycle hydrogen, heated with reactor effluent and passed through the pretreat reactor for diolefin sat- uration. After further heat exchange with reactor effluent and preheat using a utility, the hydrocarbon/hydrogen mixture enters the HDS reactor containing proprietary RT-225 catalyst. In the reactor, the sulfur is con- verted to H2S under conditions which strongly favor hydrodesulfuriza-
tion while minimizing olefin saturation.
The reactor effluent is cooled and the liquid separated from gas that is amine scrubbed and recycled to the reactor along with makeup gas. The liquid product is stabilized in a product stripper before being sent to stor- age/blending.
For high-sulfur feeds and/or very low-sulfur product, variations in the design are available to minimize octane loss and hydrogen consump- tion. The feed may be full range, intermediate or heavy fractions. SCAN- fining can be retrofitted to existing refinery units such as naphtha or diesel hydrotreaters and reformers.
Yields: Yield of C5plus liquid product typically over 100 LV%.
Installations: Twenty-four units under design, construction or oper- ation.
Reference: Sweed, N., et al., “Low sulfur technology,” Hydrocarbon Engineering, July 2002.
Ellis,E., et al., “Meeting the low sulfur mogas challenge,” World Refin- ing Association Third European Fuels Conference, March 2002. Licensor: ExxonMobil Research and Engineering Co.
Makeup gas compressor Feed Pretreat reactor Preheater Cooler Preheater HDS reactor Amine scrubber Light ends Low-sulfur naphtha Product stripper Makeup gas Purge Separator
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Hydrodesulfurization
Application: The ISAL process enables refiners to meet the world’s most stringent specifications for gasoline sulfur while also controlling prod- uct octane.
This moderate-pressure, fixed-bed hydroprocessing technology desul- furizes gasoline-range olefinic feedstocks and selectively reconfigures lower octane components to control product octane. This process can be applied as a standalone unit or as part of an overall integrated flow scheme for gasoline desulfurization.
Description: The flow scheme of the ISAL process is very similar to that of a conventional hydrotreating process. The naphtha feed is mixed with hydrogen-rich recycle gas and processed across fixed catalyst beds at moderate temperatures and pressures. Following heat exchange and sep- aration, the reactor effluent is stabilized. The similarity of an ISAL unit to a conventional naphtha hydrotreating unit makes new unit and revamp implementation both simple and straightforward. The technology can be applied to idle reforming and hydrotreating units.
Product quality: The ISAL unit’s operation can be adjusted to achieve various combinations of desulfurization, product octane and yield. Typical yield/octane relationships for an integrated flow scheme pro- cessing an FBR FCC naphtha containing 400 wppm sulfur and 20 wt% olefins are: %Desulfurization, w t % C5+product 93% 98% Yield, vol% 99.5 97.4 99.5 97.2 Sulfur, w ppm 30 30 10 10 Olef ins, w t% 15.3 15.7 14.9 15.3 (R + M)/2 cha ng e –1.9 0 –2.1 0
Economics: The capital and operating costs of an ISAL unit are slightly higher than those of a typical naphtha hydrotreating unit. With this process, refiners benefit from the ability to produce a higher-octane product at incremental additional operating cost primarily related to additional hydrogen consumption.
Installation: Two ISAL applications have been implemented in the U.S. Engineering work has also been completed on three additional ISAL units, with an additional two ISAL units currently in the process design stage.
Licensor: UOP LLC (in cooperation with PDVSA-INTEVEP).
4 3 Wash water Sour water Hydrogen m akeup Fresh feed Light ends Low-sulfur naphtha 1 2
Hydrodesulfurization,
ultra -low -sulfur diesel
Application: Topsøe ULSD process is designed to produce ultra-low- sulfur diesel (ULSD)—5 wppm S—from cracked and straight-run dis- tillates. By selecting the proper catalyst and operating conditions, the pro- cess can be designed to produce 5 wppm S diesel at low reactor pressures (<500 psig) or at higher reactor pressure when products with improved density, cetane, and polyaromatics are required.
Description:Topsøe ULSD process is a hydrotreating process that com- bines Topsøe’s understanding of deep-desulfurization kinetics, high- activity catalyst, state-of-the-art reactor internal, and engineering exper- tise in the design of new and revamped ULSD units. The ULSD process can be applied over a very wide range of reactor pressures.
Our highest activity CoMo catalyst is specifically formulated with high-desulfurization activity and stability at low reactor pressure (~ 500 psig) to produce 5 wppm diesel. This catalyst is suitable for revamping existing low-pressure hydrotreaters or in new units when minimizing hydrogen consumption.
The highest activity NiMo catalyst is suitable at higher pressure when secondary objectives such as cetane improvement and density reduction are required. Topsøe offers a wide range of engineering deliverables to meet the needs of the refiners. Our offerings include process scoping study, reactor design package, process design package, or engineering design package.
Installation: Topsøe has licensed 21 ULSD hydrotreaters with 11 revamps. Our reactor internals are installed in more than 60 units. References: “Cost-Effectively Improve Hydrotreater Designs,”Hydro- carbon Processing,November 2001 pp. 43–46.
“The importance of good liquid distribution and proper selection of catalyst for ultra deep diesel HDS,” JPI Petroleum Refining Conference, October 2000, Tokyo.
Licensor: Haldor Topsøe A/S.
START Product Rich DEA Lean DEA H2 rich gas Makeup hydrogen Furnace Reactor Absorber High-pressure separator Low-pressure separator Fresh feed
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