Successful Start Up of the Worlds Newest FCC

Authors:S. Tragesser - KBR

J. Reeves - KBR

T. Barnreiter - ConocoPhillips Ferndale Refinery

Publication / Presented:KBR-EMRE FCC Licensee Symposium 2003

Date:2003

SUCCESSFUL START-UP OF THE WORLD’S NEWEST FCC

KBR-EMRE FCC Licensee Symposium 2003 Page 1

Successful Start-up of the World’s Newest FCC

S. Tragesser and J. Reeves Kellogg Brown & Root, Inc.

601 Jefferson Ave Houston, TX 77002

and

T. Barnreiter ConocoPhillips

Ferndale Refinery 3901 Unick Road

Ferndale, WA 98248

ABSTRACT

With much of the attention in the refining industry being focused on clean fuels today, it is refreshing to report the startup of the world’s newest FCC unit by ConocoPhillips at the Ferndale refinery in Washington. In 1999, ConocoPhillips Ferndale refinery made a decision to replace their 1950s vin-tage Thermofor Catalytic Cracking Unit (TCC) with a modern KBR Orthoflow™ Fluid Catalytic Cracking Unit (FCC). At the time of the shutdown, Ferndale’s TCC Unit was the last TCC operating in the United States. The basis for this decision was the im-proved reactor yield slate, improved reliability, reduction in catalyst cost, and environ-mental benefits. The new FCC Unit, located in Ferndale, Washington, was commis-sioned in March 2003. As a result of extensive preparation and training by ConocoPhil-lips, the initial startup of the unit occurred very smoothly and without any difficulties. In addition to the new FCC Unit, ConocoPhillips installed new regenerator flue gas cleanup technology including (1) a CO Incinerator for elimination of carbon monoxide and (2) a Flue Gas Scrubber system for removal of sulfur oxides and particulate matter. Also included within the revamp scope was the addition of a new regenerator air blower system and catalyst storage hoppers. The revamp reused the existing TCC main fractionator, wet gas compressor system, and vapor recovery unit. These areas under went fairly modest modifications to sup-port the higher yields of gasoline and LPG that the FCC produces.

DESIGN BASIS ConocoPhillips’ primary goal was to maximize low sulfur gasoline production from feed-stocks consisting of vacuum gas oil and residuum blends with Conradson Carbon values up to 4.0 at a fresh feed rate of 30,000 BPSD. Two unique design cases were consid-ered for the project; (1) 100% ANS Vacuum Gas Oil (VGO) and (2) Blend of Canadian VGO and Canadian Residuum. To achieve these objectives, design operating conditions



were optimized in conjunction with KBR/ExxonMobil Research and Engineering (EMRE) advanced technologies. Included within Ferndale’s Orthoflow™ FCC Unit are Closed Cy-clones riser termination to minimize over-cracking of valuable products, Riser Quench for improved conversion and gasoline yield, ATOMAX-2™ Feed Injection Nozzles for im-proved gasoline and LPG yield, DynaFlux™ Stripper internals for minimizing loss of valuable products to the regenerator, and counter-current catalyst regeneration for minimizing nitrogen oxides. With the wide range of design feedstocks, unit flexibility was extremely important. KBR built flexibility into this unit by designing it to operate in both complete CO combustion, used for lower coke producing feedstocks, as well as in partial CO combustion mode used for higher coke forming feedstocks. The VGO/Residuum blend design feedstock requires a partial CO combustion regenerator mode of operation while the 100% VGO feedstock operates in full CO combustion mode. This paper summarizes the commercial performance data for the unit. Design feed-stock properties and operating conditions are shown in Table 1. Current yields and op-erating conditions are shown in Table 2. It is worthy of note that soon after the startup, ConocoPhillips was able to increase feedrate about 7% above the design rate and gasoline yield was maximized within limits of the Vapor Recovery Unit. PROJECT CONCEPTION When ConocoPhillips decided to replace their TCC with a modern FCC to improve the yield slate from the main refinery conversion unit, KBR and all other FCC licensors were invited to submit proposals for this project. After an exhaustive review by ConocoPhil-lips, they determined that KBR’s FCC technology would be best suited for their needs. Primary reasons for selecting KBR for the FCC licensor were their commercially proven FCC technology, which is discussed in more detail below, their ability to design a single stage low NOx regenerator for both VGO and residuum feedstocks, and the small plot space that their converter requires. CONSTRUCTION One of the unique aspects of this project is that the entire converter was built in a fabri-cation shop in Spain by Fel-guera and then shipped across the Atlantic Ocean, through the Panama Canal to the refin-ery site in northwest Washing-ton state. Figure 1 shows the converter aboard a barge ready to off-load and roll to the refinery site. Being able to build the entire converter in a fabrication shop was a signifi-cant cost saving measure and is unique to the KBR design. Not only did it minimize the cost of construction, but it also

Orthoflow™ FCC

Figure 1 – FCCU CONVERTER IN PORT

Orthoflow™ FCC shipped to site aboard barge

External reactor-riser added once erected

Total length is approximately 160 feet



minimized the amount of work that had to be done in the field. The shipped converter was approximately 160 feet long or high depending on whether it was on the barge or standing up and it weighed over 500 tons. It was off loaded sev-eral miles from the refinery and transported by road to the Ferndale refinery where it was erected. The only items that were not installed in the shipped converter were the cyclones and the external riser. Most abrasion resistant refractory was also installed at the fabrication shop. Gunned refractory for the regenerator and reactor walls was in-stalled at site. TECHNOLOGY FEATURES AND PERFORMANCE This section describes the FCC technology features included within the Ferndale FCC Unit and the performance of the unit. These features, listed in Figure 2, are largely the product of extensive research and develop-ment performed by KBR and EMRE. The Ferndale FCC unit incorporates the latest Or-thoflow design with state-of-the-art KBR/EMRE technology including ATOMAX-2TM feed injection, Riser Quench, Closed Cy-clones, Dynaflux Stripping technology, self aerating spent catalyst distributor and air distribution. Vessel nozzles were added to the regenerator shell for a future catalyst cooler, and support clips were added to the internal regenerator shell for the option of adding RegenMax™ regeneration technology at a latter date. Disengager product vapors are condensed and separated in the Main Fractiona-tor/Vapor Recovery Unit originally designed with the TCC Unit. Modifications to the downstream equipment were made during the installation of the new FCC Unit to ac-commodate the FCC converter products. ATOMAX-2™ Feed Injection The feed injection system of a Fluid Catalytic Cracking unit plays a key role in the yield performance of the unit. A well-designed feed injection system must provide both rapid vaporization and intimate contact between the oil and catalyst. While both of these at-tributes are equally important, sometimes one or the other is overlooked in the design of the feed injection system. The ATOMAX nozzle injects medium pressure steam through annular orifices perpen-dicular to the inner flow of the oil, as shown in Figure 3, for primary oil feed atomiza-tion. The steam orifices are sized to efficiently utilize the energy available in the steam to impact the oil at near sonic velocity, resulting in superior atomization with minimal

Closed CycloneSystem

Riser Cyclone

DisengagerCyclone

Disengager

External Plenum

BaffedStripper withSwirl Vanes

Regenerator

Self AeratedSpent CatalystDistributor

Spent CatalystPlug Valve

Spent CatalystStandpipe

ReverseSeal

RegeneratedCatalystSlide Valve

RegeneratedCatalyst

Standpipe

Atomax-2Fresh Feed

Nozzles

Air Distributor

Reactor-Riser

Riser QuenchNozzles

RegeneratorCyclones

Spent CatalystWell

Figure 2: Ferndale Converter Sketch



oil side pressure drop. The unique 5-slotted tip shapes the spray into an optimal pattern as it is injected into the riser. This design al-lows KBR to customize the spray angle and flux distri-bution for each application. While atomization is a criti-cal consideration in the de-sign of the feed injection system, it is also important to introduce the catalyst into the mix zone at the proper conditions to ensure rapid vaporization and ho-mogeneous mixing. The Ferndale ATOMAX-2 feed nozzles operate with an oil side pressure drop of ap-proximately 50 psi at normal conditions. Riser Quench The Riser Quench system, patented by ExxonMobil, injects vaporizable oil, usually recy-cle heavy naphtha, into the riser above the feed injection nozzles. The recycle material acts as a heat sink as it is vaporized by the catalyst. At constant riser outlet tempera-ture, quench increases the catalyst-to-oil ratio because the riser outlet temperature control point is downstream of the quench location. Introduction of quench oil also in-creases the temperature in the mix zone and lower section of the riser, as shown in Fig-ure 4. The higher initial cracking temperature and higher catalyst-to-oil ratio increases gaso-line yield, olefin production, and gasoline octane. Rapidly lowering the temperature at the optimally located quench point prevents secondary reactions such as saturation of olefins and overcracking to form dry gas. Riser quench is especially useful for residue feedstocks with high boiling ranges. With an elevated mix zone tempera-ture, the fresh feed vaporiza-tion efficiency is improved. Since the desirable catalytic re-actions occur in the vapor phase, vaporization of the fresh feed at the mix zone is very

Orthoflow™ FCC

Distance up Riser

Tem

pera

ture Quenched Profile

25-50°F

NormalProfile

Riser Outlet Temperature

Quench Increases Mix ZoneTemperature by 25-50°F

Figure 4 - Riser Quench Technology

Fresh Feed

Quench

Orthoflow™ FCC

Figure 3 - ATOMAX-2™ NOZZLES

Steam Orifices

Expansion Section

Multi-Slotted Tip

Oil

Steam

Mechanically reliable for years of service

Optimized coverage of riser cross section

Finely atomized feed

26 units in operation



important. Any fresh feed not vaporized generally reacts to form coke and other less desirable products. The Ferndale quench system utilizes a heavy naphtha that is recycled from the main fractionator. Commissioning the riser quench system at Ferndale increased overall con-version by about 2 vol% at the same riser outlet temperature. Closed Cyclone Riser Termination Technology Rapid disengaging of the catalyst and oil at the end of the riser has become imperative for the high cracking temperatures used in modern FCC units. Two goals must be achieved: • Eliminate dilute phase catalytic cracking downstream of the riser to prevent recrack-

ing and to improve coke selectivity. • Minimize post-riser thermal cracking by reducing vapor residence time between the

riser exit and the main fractionator quench zone. The purpose of Closed Cyclone technology is to reduce the backmixing of the hydrocar-bon vapors and hence reduce residence time for non-selective thermal cracking in the reactor. Backmixing in a typical reactor is approximately 40 to 50%. Installing Closed Cyclones reduces the backmixing to less than 2%. Independent laboratory research has confirmed that the hydrocarbon underflow from a Closed Cyclone system is less than 2% of the vapor flow through the cyclones. The benefits of Closed Cyclones are a decrease in dry gas production and LPG and a corresponding increase in gasoline and light cycle oil production. Typically, the average reduction in dry gas make is 30-40%. The average increase in gasoline plus light cycle oil is 2.5 volume %. In addition, butadiene production is reduced by as much as 50%. The reduction in butadi-ene significantly improves the downstream alkyla-tion unit performance. Referring to the sketch of the system (Figure 5), the riser cyclone dipleg discharges the catalyst slightly below the top of the stripper bed. The up-per cyclone diplegs are equipped with trickle valves and are also sealed in the bed above the top of the stripper. The upper disengager cy-clones are connected to the riser cyclones by a conduit, which is open at the circumference so that the steam and hydrocar-

Orthoflow™ FCC

Figure 5 - Closed Cyclone Operability

Excellent stability, confirmed by coldflow tests & commercial experience

22 operating in ExxonMobil FCC’s36 more licensed by KBR-ExxonMobil

Easy startup procedures

Catalyst forced out diplegin upset -- prevents carryovers

No mechanical seals required

Easy to "disengage" for quickstartup

18 years commercial experience



bon vapors from the stripper and disengager can exit to the main fractionator with the products of reaction. The dry gas yield on Ferndale unit is approximately 2.2 wt%, which is about 20% below than design value even with a 20°F higher riser outlet tem-perature than design. Catalyst retention in the closed cyclone system has been excellent. Catalyst content in the fractionator bottoms has averaged 0.08 wt%. The unit has been through several startups since the original startup and has no problems at all with catalyst carryover. Spent Catalyst Stripping The Ferndale FCC includes two-stage stripping, as well as DynaFlux technology, a more recent technology developed by KBR and ExxonMobil to increase catalyst resi-dence time and flux distribution within the stripper. DynaFlux™ stripper baffles incor-porate Lateral Mixing Elements™ to increase the mean residence time, minimize flow short-circuiting, and improve mixing. Steam is introduced through pipe grid distributors at two elevations in the stripper, separated by seven DynaFlux™ baffles. DynaFlux™ stripper baffles solves one of the most significant problems encountered in most commercial strippers, i.e., entrainment of hydrocarbons into the regenerator. In conventional catalyst stripper baffles poor lat-eral mixing is a problem --- they do not force the catalyst and steam to mix well later-ally across the vessel. Consequently, catalyst maldistribution frequently remains a problem in large commercial strippers, even in well-designed units operating within conventional limits. The Ferndale stripper operates with stripping steam rates below normal due to heat balance demands. Even with these low stripping steam rates the stripper is achieving an average hydrogen-in-coke of 6wt%. Regenerator Design Features and Performance In the regenerator, coke is burnt off the catalyst to supply the heat re-quirements of the proc-ess and restore the catalyst's activity. The preferred system for spent catalyst regenera-tion is one which can burn the coke to fairly low residual levels on the catalyst, while avoiding catalyst deac-tivation and after-burning in the regenera-tor dilute phase. The initial burning rate of the coke on the catalyst particles must be con-

Orthoflow™ FCC

Spent Catalyst(high carbon)

+ Low O2

Regen Catalyst(low carbon)

+ High O2

DENSEPHASE

BED

cata

lyst

air

Air Distributor

Spent Cat Distributor

Figure 6 - Counter-Current Regenerator



trolled to prevent premature catalyst deactivation. Key technology features of the Ferndale counter-current regenerator include the pipe grid air distributor and spent catalyst distributor. These are shown in Figure 6. The pipe grid air distribution system provides a uniform combustion air supply across the regenerator cross sectional area. The mixing of catalyst particles within the regenerator bed is rapid, but not instantane-ous. In FCC catalyst regeneration, distribution of spent catalyst is critical since most of the catalyst in the bed has very little coke on it. Incoming coke-laden spent catalyst creates the possibility of coke maldistribution within the bed. If an area of the bed con-tains almost no coke, the combustion air will escape from the bed with most of its oxy-gen intact. At the same time, high CO-content flue gases will be emitted from the ar-eas of the bed which have high concentrations of coke. Afterburning results when these high CO-content flue gases mix with the high oxygen content gases in the dilute phase of the regenerator. In order to ensure a rapid and even radial distribution of spent catalyst within the re-generator bed, the Ferndale design uses a central spent catalyst distributor to evenly distribute spent catalyst across the top of the regenerator fluid bed. The design lifts the coke-laden spent catalyst through a well to the top of the regenerator bed. The cata-lyst then flows through six troughs located at the top of the distributor. These troughs evenly distribute the catalyst over the regenerator cross section. The symmetrical de-sign of the spent catalyst distributor and air distributors results in uniform distribution with no bypassing of catalyst and air, as well as intimate contacting of air and catalyst particles. Counter-current regeneration also reduces NOx emissions compared to other types of regenerators. When the carbon-laden spent catalyst is distributed across the top of the regenerator bed, the following reaction occurs:

XNONCONOC ++→+ 2222 Table 3 shows a typical regenerator temperature profile of the Ferndale FCC. The uni-form distribution of coke and air is evident from the small temperature differences be-tween readings in the bed. The bed temperatures only vary ±7°F from average to low and high readings. The cyclone inlet temperatures only vary ±5°F. The counter current regeneration performance has been excellent with regard to NOx production. The measured NOx values from the stack have been averaging 30-50 ppm. This is even after the CO boiler which is firing auxilary gas and creating additional NOx after the regenerator. This is well below the Ferndale permit, so it will not be necessary for Ferndale to consider installation of other NOx removal technology.



New Orthoflow Converter Features In addition to the technology features discussed above, this section highlights some of the new features of the KBR Orthoflow converter that were not incorporated in earlier Orthoflow designs. Self-Aerating Spent Catalyst Distributor

Unlike earlier designs, which used air or steam for fluidizing the catalyst in the arms, the new self-aerating distributor makes use of the up-ward flowing air in the regenerator for fluidi-zation. Vertical plates extend downward on the bottom of the troughs which trap the upward flowing gas bubbles under the troughs. The gas is the distributed through holes located in the bottom of the trough, which fluidize the catalyst flowing down the troughs.

This eliminates the six aeration pipes for the troughs and the associated valving and in-strumentation that was previously required.

Regenerated Catalyst Standpipe Wye-Piece Configuration

The new KBR Orthoflow design now incorporates a Wye-Piece configuration for the re-generated catalyst standpipe in place of the lateral/boot design. One of the benefits to this design is the simplification of the aeration system without any loss of performance. There is no longer a lateral that requires multiply aeration nozzles at each elevation point along the length of the lateral. The Ferndale FCC only has a single aeration ring located at the bottom of the wye for fluidization and an emergency steam nozzle for startup and shutdown.

Elongated Spent Catalyst Stripper

The new stripper design is elongated and includes seven baffles compared to the previ-ous five baffle design. The advantage to this design is that it increases the residence time for improved stripping of the entrained hydrocarbons and also reduces the re-quired length of the spent catalyst standpipe while maintaining the same static head of catalyst for good pressure buildup above the spent catalyst plug valve. The benefits to

Orthoflow™ FCC

Kellogg Brown & RootA Halliburton Company

Figure 7 - Self-Aerating Spent Catalyst Distributor

Provides simple method for aerating catalyst

Captures gas from ascending bubbles

Eliminates need for 6 small-boreaeration lines and associatedvalving and instrumentation



the refiner are reduced delta coke, increased catalyst circulation and conversion as well as minimization of spent catalyst standpipe aeration piping. Ease of Converter Startup The startup of the Ferndale FCC unit was exceptionally smooth and without incident. The operators had been well trained even though they had no previous experience op-erating a FCC. They completed a rigorous training program, which included the use of a FCC simulator for hands-on training. From the time the unit was handed over to the operations team to the introduction of feed took less than four days. This would have taken even less time since problems with other units in the refinery outside of the FCCU caused delays. The converter was in-ventoried with catalyst in less than three hours and heated to approximately 1250°F with torch oil. The catalyst was then cir-culated with steam to heat-up the disengager and stripper for preparation of starting the oil to the unit. Oil-in occurred on March 11, 2003 and only 16 hours after the start of catalyst loading to the unit. The feed rate was quickly increased to 60% of design and held there until the vapor recovery unit was lined out, which also allowed control loops to be tuned. The DCS printout above shows how uniform the temperatures were in the converter prior to starting feed to the unit with steam circulation of the catalyst. One of the benefits of the closed cyclone system, compared to other riser termination devices, is the high catalyst separation efficiency during steam circulation when velocities are rela-tively low in the cyclones.



Conclusion The ConocoPhillips refinery at Ferndale was the latest to upgrade their FCC capabilities by installing a modern grassroots KBR OrthoflowTM FCC unit. The new unit consists of some of the more recently developed FCC technologies namely ATOMAX-2TM Feed Injec-tion, Riser Quench system, Closed Cyclone riser termination, DynaFluxTM spent catalyst stripping baffles, and counter-current regenerator design. In addition to making the latest technologies available to ConocoPhillips, significant cost savings were realized by transporting the entire FCC converter from the fabrication shop to the job site as on piece, which is only possible with the KBR OrthoflowTM design. Once installed, the new FCC unit started up without a hitch. This successful construction and startup is a direct result of the innovative technologies implemented at ConocoPhillips Ferndale refinery coupled with the refinery’s well trained operations team.



Table 1 DESIGN FEEDSTOCK PROPERTIES AND OPERATING CONDITIONS

100% ANS VGO RESID MIX

Specific Gravity, °API 20.3 23.7 Sulfur Content, wt% 1.36 0.72 Total Nitrogen, wt% 0.207 0.146 Metals, ppmw Iron 0.2 11.6 Nickel 0.8 2.0 Vanadium 1.7 1.6 Aniline Point, °F 173 N/A Refractive Index @ 80°C 1.4943 N/A Conradson Carbon, wt% 0.6 4.0 TBP Distillation, °F IBP 650 650 10 vol% 681 690 30 vol% 752 770 50 vol% 822 866 70 vol% 902 986 90 vol% 987 1170 EP 1050 1258

100% ANS VGO RESID MIX

Feed Rate, BPSD 30,000 30,000 Temperatures Riser Outlet 960 970 Feed Preheat 500 420 Regenerator 1282 1300 Feed Dispersion, wt% 3.0 5.0 Riser Quench, vol% 10 10 Catalyst to Oil Ratio, wt/wt 7.5 8.4

Flue Gas CO2/CO Ratio Compete Combustion 3.5

Excess O2, vol% 1.5 0.2 Carbon on Regen Cat, wt% 0.05 0.15



Table 2 ACTUAL OPERATING CONDITIONS AND YIELDS

Feed Rate, BPSD 31,800 Temperatures Riser Outlet 975 Feed Preheat 505 Regenerator 1315 Feed Dispersion, wt% 2.9 Riser Quench, vol% 10 Catalyst to Oil Ratio, wt/wt 6.6

Flue Gas CO2/CO Ratio Compete Combustion

Excess O2, vol% 1.5 Carbon on Regen Cat, wt% 0.05

Yields

Vol% Wt%

Conversion 72.41 70.2

C2 and Lighter -- 2.4

Total C3’s 9.9 5.5

Total C4’s 13.4 8.6

Gasoline (C5–440°F D2887) 59.0 48.4

LCO (440-650°F D2887) 17.3 17.9

Slurry (650°F + D2887) 10.3 11.9

TOTAL C3+ Liquid 109.9 --

Coke -- 5.0



Table 3

CONOCOPHILLIPS FERNDALE FCC

REGENERATOR TEMPERATURE PROFILE

Orientation Degrees Bed Cyclone Inlet Cyclone Outlet

A 1319 1333 1320

B -- 1336 1342

C 1308 1341 1327

D -- 1339 1348

E 1308 1341 1324

F -- 1338 1324

Successful Start Up of the Worlds Newest FCC

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