fcc catalyst refinery performance

7/27/2019 FCC Catalyst Refinery Performance

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Role of FCC catalyst in refineryprofitability

The FCC unit is the main contributor

(51-52%) to the renery gasoline pool ofthe Lukoil Neftohim Burgas renery in

Bulgaria, with the next largest contributor being

the reformer (about 27%). The gasoline sensitiv-

ity (research octane number minus motor octane

number [RON MON]) from the FCC unit and

reformer is about 12 and 11 numbers, respec-

tively, resulting in an overall MON shortage in

the renery gasoline pool. Considering MTBE

has a MON of 94-97, alkylate a MON of 93 (both

of which are produced from C4olens) and FCC

gasoline a MON of about 82, increasing theproduction of C

4olens at the expense of gaso-

line in the FCC unit will increase the MON of the

overall gasoline pool.

A catalyst selection was

performed with the objective

of increasing MON. Grace

proposed the REsolution cata-

lyst, which was trialled in the

FCC unit and subsequently

led to an increase in gasoline

MON by 0.5 numbers. Thisallowed the renery to

increase the production of

automotive gasoline by 1.3%,

and to increase the share of

premium automotive gasoline

from 68% to 73%. This

resulted in an annual six-g-

ure improvement in renery

economics.

The Reid vapour pressure

Ivan Chavdarov, Dicho Stratiev, Ivelina Shishkova and Rosen Dinkov Lukoil Neftohim Burgas JSCVladimir Jegorov Grace Catalysts TechnologiesPetko Petkov University Prof Dr Assen Zlatarov Burgas

(RVP) of gasoline from the FCC unit correlates

to the content of C4 hydrocarbons in the gaso-

line, with lower RVP values obtained by

producing more C4 at the expense of gasoline.

Optimising the FCC gasoline RVP during the

winter season (RVP was reduced from 60 to 50

kPa) and increasing the C4

olens yield (leading

to a higher MON in alkylate production) resulted

in an additional improvement in renery

economics by a ve-gure number (US $/y).

Lukoil Neftohim Burgass FCC unit

Commercial investigations were carried out onthe FCC unit, which consists of a feed hydro-

treater section, the FCC reactor and regenerator,

as well as the main fractionator

and vapour recovery sections. The

FCC reactor is equipped with the

modern UOP VSS riser termina-

tion device and the UOP Optimix

feed injection system. Typical feed

for the FCC unit is hydrotreated

vacuum gas oil distilled from

Urals crude, of which the physicaland chemical properties are

shown in Table 1.

Optimisation of FCC catalysttechnologyIn response to rapidly inating

rare earth metal prices in 2011,

Grace developed the REpLaCeR

series of rare earth-free FCC cata-

lysts. The REsolution catalyst

www.digitalrefining.com/article/1000896 PTQ Q1 2014 1

By switching to a rare earth-free FCC catalyst, a refiner raised its output ofpremium grade gasoline and increased its operating margin

Density at 20C, g/cm3 0.895Sulphur content, wt% 0.3Total nitrogen, wt ppm 800Content of Ni and V, wt ppm max 1.0Conradson carbon, wt% max 0.1Refractive Index at 20C 1.4994

ASTM D 1160 distillation5 vol% 357

10 vol% 376 50 vol% 438 90 vol% 509 95 vol% 532K-Factor 12.13Molecular weight (Goosens) 369Hydrogen content (ConocoPhillips) 12.5Aromatic carbon content(ConocoPhillips) 17.02Gasoline precursors (LNB) 79.5

Physical and chemical properties ofhydrotreated vacuum gas oil feedstock

for Lukoil Neftohim Burgas FCC unit

Table 1
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belongs to this series and is based on the rare

earth-free Z-21 zeolite. Within each family of

REsolution catalysts, the ability to inde-

pendently adjust the activity and selectivities of

zeolite and matrix, as well as the ratio of

zeolite/matrix activity, enables maximum

formulation exibility. For low metal applica-

tions, REsolution catalysts are proven to match,

and even improve on, the performance of tradi-

2 PTQ Q1 2014 www.digitalrefining.com/article/1000896

tional rare earth based

catalysts. To date, there have

been more than 15 successful

applications of the REsolution

catalyst in the EMEA region.

Based on laboratory, pilot

plant and commercial datausing Catalyst X from Supplier

1, Lukoil Neftohim Burgas

switched to the Grace

REsolution catalyst in 2011,

with the objective of increasing

the FCC gasoline MON. As

Table 2 shows, the REsolution

catalyst differs signicantly

from the previous catalyst,

primarily in terms of rare earth

content, which is 16 timeslower than in the catalyst from

Supplier 1. Even though

REsolution is a rare earth-free

catalyst, the e-cat still contains

a small amount of rare earth,

as the inventory was not 100%

changed out. Typical FCC unit

operating conditions from peri-

ods using Catalyst X and the

Grace catalyst are shown in

Table 3.Table 4 shows the yield struc-

ture for FCC products obtained using Catalyst X

and the REsolution catalyst. The slightly higher

conversion obtained with Catalyst X is due to the

higher catalyst to oil ratio resulting from the

higher outlet temperature and lower feed

temperature used in this period. The catalyst

consumption rate was the same for both

catalysts, at 0.350 kg catalyst addition per ton

of feedstock. Generally, both catalysts

E-cat properties Supplier 1 Grace Catalyst X REsolutionApparent bulk density (ABD), g/cm3 0.85Total surface area, m2/g 159 147Matrix surface area, m2/g 55 51Zeolite surface area, m2/g 104 96

Particle size distribution, %0-20 m 0.1 2 0-40 m 1.8 5 0-80 m 46 45 0-149 m 94Average particle size, mm 83 84Unit cell size, 24.29 24.27Al

2O

3, wt% 40.5 44.2

RE2O

3, wt% 1.35 0.38

Na2O, wt% 1.15 0.28

Fe, wt% 0.61 0.42V, wt ppm 206 208Ni, wt ppm 25 63Cu, wt ppm 25 8

Physical and chemical properties of e-cats used in the study

Table 2

Operating conditions Supplier 1 Grace Catalyst X REsolutionFlow rates

Hydrotreated feed, t/h 220 229 Unhydrotreated feed, t/h 11 7 Recycle, t/h 2 5 Dispersion steam, kg/h 3000 3435

Riser steam, kg/h 2000 2000 Stripping steam, kg/h 5881 6200 Air flow rate, kNm3/h 134 118 Fresh catalyst flow, t/d 2 2Catalyst to oil ratio 8.1 7.9Temperatures, C

Combined feed temperature 317 331 Riser temperature 535 533 Regenerator dense phase temperature 668 668 Regenerator dilute phase temperature 678 677 Air temperature 179 184 Steam temperature 262 247

Operating conditions in Lukoil Neftohim Burgass FCC unit

Table 3

Product, wt% Supplier 1 Grace Catalyst X REsolutionDry gas (C

2-) 3.8 3.5

Total C3s 8.0 8.2Total C4s 14.0 13.8Gasoline (C

5-195C) 51.1 51.2

LCO (195-296C) 9.8 10.3HCO (296-360C) & slurry 9.0 8.9Coke 4.3 4.1Conversion 81.2 80.8

Yield structure in Lukoil NeftohimBurgass FCC unit

Table 4


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displayed very similar product

selectivities.

Table 5 shows the FCC prod-

uct properties from Lukoil

Neftohim Burgas. Compared to

Catalyst X, the REsolution cata-

lyst provided FCC gasoline with

an increased MON of 0.5

numbers. This can be explained

with the increased aromatics in

gasoline. It is well known that

increased hydrogen transfer

activity results in the increased

conversion of olens and naph-

thenes to parafns and

aromatics. Conventional under-

standing of typical FCC catalysts

would explain that a lower rare

earth content and smaller unit

cell size (as found in theREsolution catalyst) should

result in decreased hydrogen

transfer activity. However, the

data shown in Table 5 demon-

strate that the REsolution

catalyst displayed higher hydro-

gen transfer activity, resulting in

a lower olen content of FCC gasoline, as well as

the C4 and C

3fractions. This is due to the Z-21

technology utilised in this catalyst.

Figure 1 shows how the proportion of differentgrades of automotive gasoline within the gaso-

line pool changed when switching from Catalyst

X to the REsolution catalyst. The REsolution

catalyst increased the proportion of premium

gasoline A-95 from 68% to 73% at the expense

of the regular grade.

Figure 2 highlights the structure of the gaso-

line pool using Catalyst X and the REsolution

catalyst. Catalyst X produced FCC gasoline with

a RON of 94 and a MON of 81.7, resulting in a

gasoline pool with a RON of 95 and a MON of84.2, which complies with the requirements of

standard EN228:2012 for RON but not MON.

Switching to the REsolution catalyst increased

the MON of FCC gasoline from 81.7 to 82.2,

resulting in a nal MON of 84.5 for the gasoline

pool with the RON unchanged. Since FCC gaso-

line accounts for the majority of the gasoline

pool (over 50 vol%), the FCC catalyst clearly has

a signicant impact on the octane number of the

total gasoline pool.


Based on operational data

from the FCC unit, the economic

efciency of using both catalysts

from different suppliers was

determined by applying a ren-

ery model, which uses software

for linear programming by

Honeywell (RPMS). The results from RPMS

demonstrate that replacing Catalyst X with the

Grace catalyst results in an increased prot of

4% for the overall oil rening operations ofLukoil Neftohim Burgas. This demonstrates the

important role that the FCC catalyst plays in

rening operations protability.

Optimisation of FCC gasolineReid vapour pressure

A signicant parameter of FCC gasoline is Reid

Vapor Pressure (RVP),1 which increases linearly

with an increasing amount of C4

components.

Lukoil Neftohim Burgas performed a commer-

cial test operating with two different RVP valuesof FCC gasoline. Table 6 shows how the yield of

FCC products changed when switching from an

RVP of 60 kPa to 50 kPa, with the yield of C4s

increasing by 0.6 wt% at the equal expense of

gasoline.

The effect of operating with two different RVP

values on the renery gasoline grades produced

is shown in Figure 3. The total amount of auto-

motive gasoline produced by the renery

decreased by 0.18 wt%, while overall LPG

Product, wt% Supplier 1 Grace Catalyst X REsolutionGasolineMON 81.7 82.2RON 94.0 94.0RVP, kPa 55.1 57.9

FIA hydrocarbonComposition, vol%Saturates 37.8 41.7

Olefins 39.2 32.5 Aromatics 23.0 25.8C3s, wt%:Propylene 80.8 78.8

Propane 17.9 20.9C4s, wt%:i-butane 33.5 39.5

i-butylene 17.3 16.0 n-butane 6.7 7.6 Total olefins 56.3 53.3

Product properties in LukoilNeftohim Burgass FCC unit

Table 5

Regular A-92

Gasoline A-93

Premium A-95

Super A-98

Catalyst X

2%

1%

29%

68%

REsolution

2%

25%

73%

Figure 1 Refinery gasoline gradesproduced by Lukoil Neftohim Burgasusing Catalyst X and the REsolutioncatalyst


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production increased by 3.7 wt%. This resulted

in an increase of Premium A-95 production from

71% to 73% at the expense of the Regular A-92

grade. Reducing the RVP from 60 kPa to 50 kPa

improved renery protability by about 2.5%.

SummaryIt has been demonstrated that the FCC catalyst is

an excellent tool for improving overall renery

protability. Optimising FCC technology by

switching to the Grace

REsolution catalyst led to an

increase in the FCC gasoline

MON by 0.5 points, which

allowed the renery to produce

5% more premium gradegasoline.

The overall renery margin

was improved further by opti-

misation of the FCC gasoline

RVP. A reduction in the RVP

from 60 to 50 kPa resulted in

an increase in LPG production

by 3.7% at the expense of

gasoline pool reduction. The

higher FCC C4 yield led to

higher production of alkylate, which resulted in

the production of 2% more premium grade

gasoline.

References

1 Watanbe K, Nagai K, Aratani N, Saka Y, Chiyoda N, MizutaniH, Techniques for octane enhancement in FCC gasoline, 20thAnnual Saudi-Japan Symposium, Dhahran, December 2010. 17.Montgomery J A, Guide to Fluid Catalytic Cracking, Part 1, 1993.

Ivan Chavdarovis a Chemical Engineer in theProcess Engineering department of LukoilNeftohim Burgas, Bulgaria. His activities arefocused on guiding the operation of the unitsof the FCC complex, troubleshooting support

and optimisation of the performance of theFCC complex.Email: [email protected]

Dicho Stratievis Chief Process Engineer withLukoil Neftohim Burgas. He holds a MS inorganic chemistry engineering, and a PhDand a DSc in petroleum refining from theBurgas University Assen Zlatarov. He hasauthored more than 130 papers.Email: [email protected]

Ivelina Shishkova is R&D DepartmentManager with Lukoil Neftohim Burgas.

4 PTQ Q1 2014 www.digitalrefining.com/article/1000896

FCC gasolinePrime-G

unitPrime-G

unit

Reformate

Alkylate

Straight-runnaphtha

Methyl tertiarybutyl ether

Bioethanol

Gasoline pool

RON 95.0MON 84.2

Gasoline pool

RON 95.0MON 84.5

1.9 vol%; RON 94.0; MON 81.7 7.0 vol%; RON 94.0; MON 82.2

51.7 vol%RON 93.1MON 81.7

53.6 vol%RON 94.0MON 81.7

26.7 vol%; RON 99.9; MON 89.0

11.1 vol%; RON 97.2; MON 93.2

4.2 vol%; RON 63.2; MON 60.2

4.4 vol%; RON 112.0; MON 93.0

0.01 vol%; RON 108.0; MON 93.0

51.7 vol%RON 94.0MON 82.2

44.7 vol%RON 93.1MON 82.2

27.7 vol%; RON 99.9; MON 89.0

10.9 vol%; RON 96.8; MON 93.1

5.1 vol%; RON 63.2; MON 60.2

4.2 vol%; RON 118.0; MON 94.0

0.1 vol%; RON 108.0; MON 93.0

Catalyst X REsolution

Figure 2 Structure of gasoline pool at Lukoil Neftohim Burgas using CatalystX and the REsolution catalyst

Regular A-92

Premium A-95

Super A-98

RVP = 60kPa

1%

28%

71%

RVP = 50kPa

1%

26%

73%

Figure 3Effect of changing the RVPon refinery gasoline grades producedduring the Resolution catalyst period

Product, wt% RVP

60 kPa 50 kPaDry gas 5.32 5.30C

3s 7.10 7.15

C4s 12.65 13.25

Gasoline 50.61 50.01LCO 11.01 11.04HCO 5.10 4.92Slurry 4.00 4.10Coke 4.21 4.23Conversion 79.89 79.94

FCC yields at different gasolineRVP values

Table 6


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She holds a MS in organic chemistry engineering and a PhDin petroleum refining from Sofia Chemical and Technologicaland Metallurgical University, and has authored more than 20technical papers.

Email: [email protected]

Rosen Dinkov is the Quality Manager in the Process Engineeringdepartment of Lukoil Neftohim Burgas. His research interestsinclude crude oil characterisation, bio/conventional fuels blendscharacterisation and modelling of refinery distillation processes.He holds a MS in organic chemistry engineering from BurgasUniversity and a PhD in the technology of fossil and syntheticfuels from the University of Chemical Technology and Metallurgy,Sofia. Email: [email protected] Jegorov is the Sales Development Manager for Gracein the CIS region. Prior to joining Grace, he was an FCC processengineer at the Mazheikiai refinery in Lithuania.

Petko Petkovis a full professor and rector of the Burgas UniversityAssen Zlatarov. He teaches in the social science department inthe field of oil refining and lubricants, and has authored morethan 180 scientific papers and five books.Email: [email protected]


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