COMPONENTES Y ESTRUCTURAS

Application: Lube raffinates from extraction are dewaxed to provide basestocks having low pour points (as low as –35°C). Basestocks range from light stocks (60N) to higher viscosity grades (600N and bright stock). Byproduct waxes can also be upgraded for use in food applications. Feeds: DILCHILL dewaxing can be used for a wide range of stocks that boil above 550°F, from 60N up through bright stock. In addition to raf- finates from extraction, DILCHILL dewaxing can be applied to hydro- cracked stocks and to other stocks from raffinate hydroconversion pro- cesses.

Processes: Lube basestocks having low pour points. Although slack   waxes containing 2–10 wt.% residual oil are the typical byproducts,

lower-oil-content waxes can be produced by using additional dewaxing  and/or “warm-up deoiling” stages.

Description: DILCHILL is a novel dewaxing technology in which wax  crystals are formed by cooling waxy oil stocks, which have been diluted  with ketone solvents, in a proprietary crystallizer tower that has a num-

ber of mixing stages. This nucleation environment provides crystals that filter more quickly and retain less oil. This technology has the following  advantages over conventional incremental dilution dewaxing in scraped- surface exchangers: less filter area is required, less washing of the filter cake to achieve the same oil-in-wax content is required, refrigeration duty is lower, and only scraped surface chillers are required which means that unit maintenance costs are lower. No wax recrystallization is required for deoiling.

 Warm waxy feed is coo led in a pre chi lle r bef ore it ent ers t he DILCHILL crystallizer tower. Chilled solvent is then added in the crys- tallizer tower under highly agitated conditions. Most of the cr ystalliza- tion occurs in the crystallizer tower. The slurry of wax/oil/ketone is fur- ther cooled in scraped-surface chillers and the slurry is then filtered in rotary vacuum filters. Flashing and stripping of products recover solvent.  Additional filtration stages can be added to recover additional oil or pro-

duce low-oil content saleable waxes.

Economics: Depend on the slate of stocks to be dewaxed, the pour point targets and the required oil-in-wax content.

Utilities: Depend on the slate of stocks to be dewaxed, the pour point targets and the required oil-in-wax content.

Installation: The first application of DILCHILL dewaxing was the conversion of an ExxonMobil affiliate unit on the U.S. Gulf Coast in 1972. Since that time, 10 other applications have been constructed. These applications include both grassroots units and conversions of incremen- tal dilution plants. Six applications use “warming-up deoiling.” Licensor: ExxonMobil Research & Engineering Co.

Deoiling filters (2 stages) Waxy feed Cold-wash solvent Cold-wash solvent Warm-up deoiling heater Dewaxing filters 1 or 2 stages Wax slurry Fresh solvent Refrigeration system Solvent   Solvent recovery Solvent recovery Solvent recovery “ Foots oil” Dewaxed wax Dewaxed oil START Precoolers Dichill crystallizer(s) Scraped surface chillers

Lube t reating

Application: Process to produce lube oil raffinates with high viscos- ity index from vacuum distillates and deasphalted oil.

Feeds: Vacuum distillate lube cuts and deasphalted oils.

Products: Lube oil raffinates of high viscosity indices. The raffinates contain substantially all of the desirable lubricating oil components pre- sent in the feedstock. The extract contains a concentrate of aromatics that may be utilized as rubber oil or cracker feed.

Description: This liquid-liquid extraction process uses furfural as the selective solvent to remove aromatics and other impurities present in the distillates and deasphalted oils. Furfural has a high solvent power for those components that are unstable to oxygen as well as for other unde- sirable materials including color bodies, resins, carbon-forming con- stituents and sulfur compounds. In the extraction tower, the feed oil is introduced below the top at a predetermined temperature. The raffinate phase leaves at the top of the tower and the extract, which contains the bulk of the furfural, is withdrawn from the bottom. The extract phase is cooled and a so-called “pseudo raffinate“ may be sent back to the extrac- tion tower. Multi-stage solvent recovery systems for raffinate and extract solutions secure energy efficient operation.

Utility requirements, (typical, Middle East Crude), units per m3

of feed:

Ele ct ricit y, kWh 10 St e a m , MP, kg 10 St e a m , LP, kg 35 Fue lo il,kg 20 Wat er, cooling, m3 ₂₀

Installation: Numerous installations using the Uhde Edeleanu pro- prietary technology are in operation worldwide. The most recent is a com- plete lube-oil production facility licensed to the state of Turkmenistan,  which successfully passed performance testing in 2002.

Licensor: Uhde Edeleanu GmbH.

Extraction tower Raffinate mix buffer Extract mi x settler Feed deaerator Feed Stm Stm Stm Stm Stm Sewer Water stripper Decanter Solvent drying system Extract flasher stripper Extract Raffinate Furfural stripper buffer Extract flash system Raffinate flasher stripper

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Lube t reat ing

Application: Unconverted oil from a fuels hydrocracker is used to pro- duce higher quality lube base stocks at lower investment and operating  costs than either solvent refining or lube oil hydrocracking utilizing the SK UCO Lube Process.

Description: The base oils manufactured by the SK UCO Lube Pro- cess have many desirable properties as lube base stocks over those produced by conventional solvent-refining or lube hydrocracking processes.

Unconverted oil from the existing fractionator in a fuels hydrocracker is processed and separated into grades having the desired viscosity, which are then cooled and sent to intermediate storage. The various grades of base oil are then catalytically dewaxed and isomerized in blocked operation. Excess distillates are sent back to the hydrocracker.

Since the withdrawn UCO can usually be replaced with an equal amount of additional fresh vacuum distillate feed, the hydrocracker fuels production is maintained. The hydrocracking and catalytic dewaxing  steps are not included in the SK UCO Lube Process, but are readily avail- able from others.

Properties:

Lube SK So lv en t h yd ro - U CO Lu be Test it em Test m et hod refining cracking Process Viscosity @100°C, cSt ASTM D 445 5.2 5.1 6.0 Viscosity index ASTM D 2270 97 99 130 Pour point, °C ASTM D 97 – 12 – 12 –12 CCS vis @–20°C, cP ASTM D 2602 2,100 2,000 1,440 Flash point, °C ASTM D 92 218 220 234 NOACK volatility, w t% DIN 51581 17.0 16.6 7.8 Arom atics, w t% ASTM D 2549 27.7 3.5 1.0 Sulfur content, w t% ANTEC 0.58 0.03 0.00

Economics: Investment (Basis: 5,000 bpd of lube base oils excluding  fuels hydrocracker, 1998 U.S. Gulf Coast) $80 million.

Installation: 5,000 bpd of VHVI lube base oils at SK Corporation’s Ulsan, Korea refinery.

Reference: Andre, J. P., S. H. Kwon and S. K. Hahn, “Yukong’s new  lube base oil plant,” Hydrocarbon Engineering,November 1997.

“An economical route to high quality lubricants,” NPRA 1996 Annual Meeting, March 1996.

Licensor: The Badger Technology Center of Washington Group Inter- national, under exclusive arrangement with SK Corp.

START

Unconverted oil (UCO) Distillation Intermediate storage Hydrogen Catalytic dewaxing Lube products Lights to refinery Excess distillates

NO_x abatement

Application: Flue gases are treated with ammonia via ExxonMobil’s proprietary selective noncatalytic NOx reduction technology— Thermal

DeNOx . NOx plus ammonia (NH3) are converted to elemental nitrogen

and water if temperature and residence time are appropriate. The tech- nology has been widely applied since it was first commercialized in 1974. Products: If conditions are appropriate, the flue gas is treated to achieve NOx reductions of 40% to 70%+ with minimal NH3slip or leak-

age.

Description: The technology involves the gas-phase reaction of NO  with NH3(either aqueous or anhydrous) to produce elemental nitrogen

if conditions are favorable. Ammonia is injected into the flue gas using  steam or air as a carrier gas into a zone where the temperature is 1,600°F to 2,000°F. This range can be extended down to 1,300°F with a small amount of hydrogen added to the injected gas. For most applications, wall injectors are used for simplicity of operation.

Yield: Cleaned flue gas with 40% to 70%+ NOx reduction and less than

10-ppm NH3slip.

Economics: Considerably less costly than catalytic systems but rela- tively variable depending on scale and site specifics. Third-party studies have estimated the all-in cost at about 600 U.S.$/ton of NOx removed.

Installation: Over 135 applications on all types of fired heaters, boil- ers and incinerators with a wide variety of fuels (gas, oil, coal, coke, wood and waste).

Reference: McIntyre, A. D., “Applications of the THERMAL DeNOx 

process to utility and independent power production boilers,” ASME Joint International Power Generation Conference, Phoenix, 1994.

McIntyre, A. D., “The THERMAL DeNOx process: Liquid fuels

applications,” International Flame Research Foundation’s 11th Topic Oriented Technical Meeting, Biarritz, France, 1995.

McIntyre, A. D., “Applications of the THERMAL DeNOx process

to FBC boilers,” CIBO 13th Annual Fluidized Bed Conference, Lake Charles, Louisiana, 1997.

Licensor: ExxonMobil Research & Engineering Co.

Heater Combustion air Fuel Injectors NOx analyzer NH₃flow controller NH₃ vaporizer Anhydrous NH3 storage Pressure controller Flow controller Heater load Heater load Carrier supply

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Olefins

Application: Separation of pure C4olefins from olefinic/paraffinic C4

mixtures via extractive distillation using a selective solvent. BUTENEX  is the Uhde technology to separate light olefins from various C4feedstocks,

 which include ethylene cracker and FCC sources.

Description: In the extractive distillation (ED) process, a single- compound solvent, N-Formylmorpholine (NFM), or NFM in a mixture  with further morpholine derivatives, alters the vapor pressure of the components being separated. The vapor pressure of the olefins is lowered more than that of the less soluble paraffins. Paraffinic vapors leave the top of the ED column, and solvent with olefins leave the bottom of the ED column.

The bottom product of the ED column is fed to the stripper to sepa- rate pure olefins (mixtures) from the solvent. After intensive heat exchange, the lean solvent is recycled to the ED column. The solvent, which can be either NFM, or a mixture including NFM, perfectly satisfies the sol- vent properties needed for this process, including high selectivity, thermal stability and a suitable boiling point.

Economics:

Consumpt ion pe r to n of FCC C4fraction feedstock:

St e a m ,t /t 0.5–0.8 Wat er, coo ling (T= 10° C), m3_{/t 15.0}

Elect ric po w er, kWh/t 25.0 Product purity:

n-But e ne co nt ent 99.+ w t .–% m in. So lve nt co nt e nt 1 w t .– ppm m a x.

Installation: Two commercial plants for the recovery of n-butenes have been installed since 1998.

Reference: Preusser, G., “Separation of n-Butanes and Butene-2 by  extractive distillation,” Achema, June 1986, Frankfurt.

Licensor: Uhde GmbH.

Solvent Solvent + olefins Extractive distillation column Stripper column C₄ olefins C₄ fraction C₄ paraffins

Olefins

Application: Dehydrogenation of C4or C3paraffins to pure olefins

using steam-active reforming over a noble metal catalyst. STAR, the steam active reforming process, is the Uhde technology to dehydrogenate light paraffins into olefins.

Description: Fresh paraffin feed is combined with internally gener- ated steam and passed after preheating to the reactor—a fixed-bed, tubu- lar top-fired reformer type. Dehydrogenation reactions occurs at 4 to 6 bar at 500°C to 580°C. In a subsequent fixed-bed reactor, oxygen (or air) is admixed to enhance olefins yield by partial combustion of the hydro- gen generated in the upstream reactor. The reaction section operates in sequential mode (7 hours on-stream, 1 hour regeneration). Product flow  is balanced by a parallel reactor arrangement for continuous production.

 After heat recovery, the gas is compressed, and the pure olefin product is separated from non-converted paraffins and light ends. Apart from fuel gas, which is used within the unit, high-purity olefin is the only product. Economics:

Consumption per ton of propylene product based on standard grade propane feedstock:

Fe e d st o ck,t /t 1.20 Fue l,G ca l/t 1.18 Wat er, cooling (T= 10 °C), m3_{/t 200}

Ele ct ric po w e r, kWh/t 170 Product purity:

Pro pylene 99.70 w t .–% m in.

Installation: Two commercial plants for the dehydrogenation of  butane have been commissioned since 1992.

Reference: Thiagarajan, N., Ranke, U. and Ennenbach, F., “Propane /butane dehydrogenation by steam active reforming,” Achema, May 2000, Frankfurt. Licensor: Uhde GmbH. Reaction section Product Fuel gas Process steam Fresh

feed Gas com - pression Recycle

Gas

separation tionationFrac- Heat

recovery

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