Application: Upgrade or convert atmospheric and vacuum residues using the Hyvahl fixed-bed process.
Products: Low-sulfur fuels (0.3% to 1.0% sulfur) and RFCC feeds (removal of metals, sulfur and nitrogen, reduction of carbon residue). Thirty percent to 50% conversion of the 565°C+fraction into distillates.
Description: Residue feed and hydrogen, heated in a feed/effluent exchangers and furnace, enter a reactor section—typically comprising of a guard-reactor section, main HDM and HDS reactors.
The guard reactors are onstream at the same time in series, and they protect downstream reactors by removing or converting sediment, met- als and asphaltenes. For heavy feeds, they are permutable in operation (PRS technology) and allow catalyst reloading during the run. Permuta- tion frequency is adjusted according to feed-metals content and process objectives. Regular catalyst changeout allows a high and constant pro- tection of downstream reactors.
Following the guard reactors, the HDM section carries out the remain- ing demetallization and conversion functions. With most of the con- taminants removed, the residue is sent to the HDS section where the sul- fur level is reduced to the design specification.
The PRS technology associated with the high stability of the HDS catalytic system leads to cycle runs exceeding a year even when processing VR-type feeds to produce ultra-low- sulfur fuel oil.
Yields: Typical HDS and HDM rates are above 90%. Net production of 12% to 25% of diesel + naphtha.
Economics:
Investments(ba sis: 40,000 bp sd, AR to VR fee ds, 2002 Gulf co a st ), U.S.$/b psd 3,500 –5,500
Utilities,per bbl feed:
Fue l, e q uiv. fue l o il, kg 0.3 Po w e r,kWhr 10 St e a m pro d uct io n, MP, kg 25 St e a m co nsum pt io n, HP, kg 10 Wat er, coo ling , m3 1.1
Installation: Two units are in operation (one on atmospheric-residue feed, the other on vacuum residue) and a third unit using VR feed will come onstream at the end of 2002; thus, the total installed capacity will reach 134,000 bpsd.
References: “Option for Resid Conversion,” BBTC, Oct. 8–9, 2002, Istanbul.
“Maintaining On-spec products with residue hydroprocessing,” 2000 NPRA Annual Meeting, March 26–28, 2000, San Antonio.
Licensor: Axens, Axens NA.
HDM-HDS reaction section Guard reactors Product Feed
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H Y D R O C A R B O N P RO C E SS IN G NOVEMBER 2002I129
Isomerization
Application: Converting n-butane to isobutene using the Lummus butane isomerization process. Isobutane is typically the feedstock for down- stream alkylation units or MTBE complexes.
Products: Isobutane, fuel gas. The Lummus butane isomerization process has high per pass conversion (>60%) and selectivity (>99%), which provides the highest total yield of isobutene.
Description: The Lummus butane process uses Akzo Nobel’s AT series catalyst to isomerize n-butane into isobutene. The high-activity chlo- rided alumina catalyst allows operation at low temperature, which increases both conversion and selectivity while minimizing capital costs. The reaction is vapor phase at mild temperatures with the presence of a small amount of hydrogen. The high stability of the catalyst at low H2:HC ratios allows operation without a recycle compressor.
The n-butane feed and makeup hydrogen streams are dried over molec- ular sieves (1), combined, heated to reaction temperatures in feed/efflu- ent exchangers followed by a trim heater and sent to two reactors in series (2). The two reactors are used to allow operational flexibility and lower the temperature in the second reactor for higher conversion. The reactor effluent is sent to a stabilizer column to remove hydrogen and light ends (3). The stabilizer overhead is directed to fuel gas via a caustic scrubber (4). The stabilized bottoms is sent to the deisobutanizer which produces the final isobutene product, recycles n-butane back to the reactors, and removes any C5+material that entered the unit in the feed (5).
Economics:
Investment(b asis 10,000 b psd unit ) $/b psd 1,900
Installation: 12,000 bpd DUGAS Dubai, United Arab Emirates. Licensor: ABB Lummus Global Inc.
C5+ to blend C4 feed n-Butane Isobutane product Dryer Circulating caustic Scrubber Stabilizer
Deisobutanizer Isomerizationreactors
Isomerate (iC4 /n C4 mix)
Makeup H2 (via guard dryer)
Fluel gas Spent caustic 1 2 2 4 5 3
Isomerization
Application: C5/C6paraffin-rich hydrocarbon streams are isomer-
ized to produce high RON and MON product suitable for addition to the gasoline pool.
Description: Several variations of the C5/C6isomerization process are
available. With either a zeolite or chlorinated alumina catalyst, the choice can be a once-through reaction for an inexpensive-but-limited octane boost, or, for substantial octane improvement, the Ipsorb Isom scheme shown above to recycle the normal paraffins for their complete conversion. The Hexorb Isom configuration achieves a complete normal paraffin conversion plus substantial conversion of low (75) octane methyl pentanes gives the maximum octane results. The product octanes from five process schemes for treating a light naphtha feed ( 70 RON) containing a 50/50 mixture of C5/C6paraffins are:
Chlorinated Zeolit e alum ina Process conf igurat ion cat alyst cat alyst Once -t hro ug h 80 83 De iso pe nt a nize r a nd o nce-t hro ug h 82 84 De iso he xa niz e r a nd re cycle 86 88 No rm a l re cycle -Ipso rb 88 90 No rm a l a nd d e iso he x. re cycle -He xo rb 92 92
Operating conditio ns: The Ipsorb Isom process uses a deisopen- tanizer (1) to separate the isopentane from the reactor feed. A small amount of hydrogen is also added to reactor (2) feed. The isomerization reaction proceeds at moderate temperature producing an equilibrium mix- ture of normal and isoparaffins. The catalyst has a long service life. The reactor products are separated into isomerate product and normal paraf- fins in the Ipsorb molecular sieve separation section (3) which features a novel vapor phase PSA technique. This enables the product to consist entirely of branched isomers.
Economics: (basis: Ipsorb “A” Isomerization unit with a 5,000-bpsd 70 RONC feed needing a 20 point octane boost):
Investment*, m illio n U.S.$ 13 Utilities: St e a m ,HP,t ph 1.0 St e a m ,MP,t ph 8.5 St e a m ,LP,t ph 6.8 Po w e r,kWh/h 310 Cooling w at er, m3/h 100
* M id-2002, Gulf coast, excluding cost of noble metals.
Installation: Of 24 licenses issued for C5/C6isomerization plants, 11
units are operating including one Ipsorb unit. Licensor: Axens, Axens NA.
START C5 /C6feed Hydrogen Offgas Isomerate Recycle CW 2 3 1
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130 IH Y D R O C A R B O N P RO C E SS IN G NOVEMBER 2002
Isomerization
Application: Convert normal olefins to isoolefins. Description:
C4olefin skeletal isomerization (IsomPlus)
A zeolite-based catalyst especially developed for this process provides near equilibrium conversion of normal butenes to isobutylene at high selectivity and long process cycle times. A simple process scheme and moderate process conditions result in low capital and operating costs. Hydrocarbon feed containing n-butenes, such as C4raffinate, can be pro-
cessed without steam or other diluents, nor the addition of catalyst acti- vation agents to promote the reaction. Near-equilibrium conversion lev- els up to 44% of the contained n-butenes are achieved at greater than 90% selectivity to isobutylene. During the process cycle, coke gradually builds up on the catalyst, reducing the isomerization activity. At the end of the process cycle, the feed is switched to a fresh catalyst bed, and the spent catalyst bed is regenerated by oxidizing the coke with an air/nitro- gen mixture. The butene isomerate is suitable for making high purity isobutylene product.
C5olefin skeletal isomerization (IsomPlus)
A zeolite-based catalyst especially developed for this process provides near-equilibrium conversion of normal pentenes to isoamylene at high selectivity and long process cycle times. Hydrocarbon feeds containing n-pentenes, such as C5raffinate, are processed in the skeletal isomeriza-
tion reactor without steam or other diluents, nor the addition of catalyst activation agents to promote the reaction. Near-equilibrium conversion levels up to 72% of the contained normal pentenes are observed at greater than 95% selectivity to isoamylenes.
Economics: The Lyondell isomerization process offers the advan- tages of low capital investment and operating costs coupled with a high yield of isobutylene. Also, the small quantity of heavy byproducts formed can easily be blended into the gasoline pool. Capital costs (equipment, labor and detailed engineering) for three different plant sizes are:
Total in stalled cost: Feedrate,Mbpd ISBL cost ,$MM 10 8 15 11 30 30
Utility costs:per barrel of feed (assuming an electric-motor- driven compressor) are:
Po w er,kWh 3.2 Fue l g a s, MMBt u 0.44 St e a m , MP, MMBt u 0.002 Wa t er, co o ling , MMBt u 0.051 Nit ro g e n, scf 57–250
Installation: One plant is in operation. Three licensed units are in various stages of design.
Licensor: CDTECH and Lyondell Chemical Co.
3
4 2
5
MTBE unit raffinate
C4s to MTBE unit
C5+
Isomerization
Application: Hydrisom is ConocoPhillips Co.’s selective diolefin hydrogenation process, with specific isomerization of butene-1 to butene- 2 and 3-methyl-butene-1 to 2-methyl-butene-1 and 2-methyl-butene-2. The Hydrisom process uses a liquid-phase reaction over a commercially available catalyst in a fixed-bed reactor.
Description: The Hydrisom process is a once-through reaction and, for typical cat cracker streams, requires no recycle or cooling. Hydrogen is added downstream of the olefin feed pump on ratio control and the feed mixture is preheated by exchange with the fractionator bottoms and/or low-pressure steam. The feed then flows downward over a fixed bed of commercial catalyst.
The reaction is liquid-phase, at a pressure just above the bubble point of the hydrocarbon/hydrogen mixture. The rise in reactor temperature is a function of the quantity of butadiene in the feed and the amount of butene saturation that occurs.
The Hydrisom process can also be configured using a proprietar y cat- alyst to upgrade streams containing diolefins up to 50% or more, e.g., steam cracker C4steams, producing olefin-rich streams for use as chem-
ical, etherification and/or alkylation feedstocks.
Installation of a Hydrisom unit upstream of an etherification and/or alkylation unit can result in a very quick payout of the investment due to:
• Improved etherification unit operations • Increased ether production
• Increased alkylate octane number • Increased alkylate yield
• Reduced chemical and HF acid costs • Reduced ASO handling
• Reduced alkylation unit utilities
• Upgraded steam cracker or other high diolefin streams (30% to 50%) for further processing.
Installation: Ten units licensed worldwide, including an installation at ConocoPhillips Refinery, Sweeny, Texas.
Licensor: Fuels Technology Division of ConocoPhillips Co.
START Hydrogen Olefin Olefin feed pump Reactor feed heater Reactor
HF alkylation or etherification unit feed Reboiler Reflux pump Drain Vent Light-ends separator Overhead condenser
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H Y D R O C A R B O N P RO C E SS IN G NOVEMBER 2002I131
Isomerization
Application: Paraffin isomerization technology for light naphtha offers a wide variety of processing options that allow refiners to tailor per- formance to their specific needs. Applications include octane enhance- ment and benzene reduction. The Penex process is specifically designed for continuous catalytic isomerization of pentanes, hexanes and mixtures of the two. The reactions take place in a hydrogen atmosphere, over a fixed catalyst bed, and at operating conditions that promote isomerization and minimize hydrocracking.
Products: A typical C5/C6light naphtha feedstock can be upgraded to
82-84 RONC in hydrocarbon once-through operation. This can be increased to about 87-93 RONC by recycling unconverted normal pen- tane, normal hexane and/or methylpentanes. Some systems for separating the components for recycle are: vapor phase adsorptive separation (IsoSiv process), liquid phase adsorptive separation (Molex process), fractionation in a deisohexanizer column or a combination of fractionation and selec- tive adsorption. The Par-Isom process is a lower cost isomerization option. It provides a 1–2 lower octane-number product with regenerable catalyst. Dryers are not required; recycle hydrogen is needed. The metal oxide cat- alyst is an ideal replacement for zeolitic catalyst. This process is a cost-effec- tive revamp option.
Description: Hydrogen recycle is not required for the Penex process, and high conversion is achieved at low temperature with negligible yield loss. A fired heater is not required. The flow diagram represents the Hydrogen-Once-Through (HOT) Penex process. A two reactor in series flow configuration is normally used with the total required catalyst being equally distributed between the two vessels. This allows the catalyst to be fully utilized.
Feed and makeup hydrogen are dried (1) over adsorbent and then mixed. The mixture is heated against reactor effluent and sent to the reac- tors (2). Reactor effluent passes directly to the stabilizer (3) after heat exchange. Stabilizer bottoms are sent to gasoline blending in a once- through operation or to separation (adsorption or fractionation) in a recy- cle operation. The light ends are sent to a caustic-scrubber column and then to fuel.
Economics: The typical estimated erected costs for 2Q 2002 ISBL, U.S. Gulf Coast for a 10,000-bpsd unit are:
Flow scheme EEC, $M M Pe ne x 10.1 Pe ne x/Mo le x 25 Pe ne x/DIH 17.1
Installation: UOP is the world’s leading licensor in C5/C6isomer-
ization technology. The first Penex unit was placed on stream in 1958. Over 188 UOP C5/C6isomerization units have been commissioned as
of 2Q 2002.
Licensor: UOP LLC.
START Penex isomer ate
Makeup hydrogen Gas to scrubbing and fuel C5 /C6charge 2 2 3 1 1
Isooctane
Application: Conversion of isobutylene contained in mixed-C4feeds
to isooctane (2,2,4 tri-methyl pentane) to produce a high-quality gaso- line blendstock. The full range of MTBE plant feeds can be processed— from refinery FCC, olefin-plant raffinate and isobutane dehydrogenation processes. The NExOCTANE process is specifically developed to min- imize conversion costs of existing MTBE units and offers a cost-effective alternative to MTBE production.
Products: Isooctene and isooctane can be produced, depending on the refiner’s gasoline pool. Typical product properties are:
Isooct ene Isooct ane RONC 101–103 99–100 MONC 85–87 96–99 Spe cif ic g ra vit y 0.701–0.704 0.726–0.729 Va po r pre ssure , psia 1.8 1.8 ASTM EP, ° F 380–390 370–380
Description: In the NE xOCTANE process, reuse of existing equip- ment from the MTBE unit is maximized. The process consists of three sections. First, isobutylene is dimerized to isooctene in the reaction sec- tion. The dimerization reaction occurs in the liquid phase over an acidic ion-exchange resin catalyst, and it uses simple liquid-phase-fixed-bed reac- tors. The isooctene product is recovered in a distillation system, for which generally the existing fractionation equipment can be reused. The
recovered isooctene product can be further hydrogenated to produce isooc- tane. A highly efficient trickle-bed hydrogenation technology is offered with the NExOCTANE process. This compact and cost-effective tech- nology does not require recirculation of hydrogen. In the refinery, the NEx- OCTANE process fits as a replacement to MTBE production, thus asso- ciated refinery operations are mostly unaffected.
Economics:
Investmentcost for revam ps depend on t he existing MTBE plant design, capa city and feed stock composition. Typical ut ility req uire- ments per bbl product:
St ea m , 150-psig , lb 700 Elect ricit y, kWh 2.3 Wat er, coo ling , ft3 1.2
Installation: Process has been commercially demonstrated.
Licensor: Kellogg Brown & Root, Inc., and Fortum Oil and Gas OY.
TBA recycle Hydrogen Isobutylene dimerization Hydrogenation Isooctane Isooctene Isooctene product recovery C4 feed/ isobutylene C4 raffinate to alky or dehydro
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132 IH Y D R O C A R B O N P RO C E SS IN G NOVEMBER 2002