Paste Logo Here Strategies for Maximizing FCC Light Cycle Oil Ann Benoit, Technical Service Representative Refcomm, March 4-8, 2015
LCO and Bottoms Selectivity 90 Bottoms wt% 24 LCO wt% Hi Z/M Low Z/M 80 22 70 60 50 20 18 40 16 30 14 20 12 10 10 0 0 20 40 60 80 0 Conversion wt% 20 40 60 80 Low Z/M catalyst produces more LCO 2
Strategies for Maximizing FCC Light Cycle Oil Operating Strategies Recycle Catalyst Optimization Click to edit text styles 3
Diesel Maximization: Operating Strategies Main Fractionator Adjustments Reduce gasoline endpoint Main tower top temperature limitations Higher LCO endpoint Diesel Hydrotreating constraints FCC Main Column bottoms temperature limits Slurry circuit coking and slurry exchanger fouling Feedstock Removal of diesel range material from the FCC feedstock Operating Conditions Lower reactor temperature Higher feed temperature Additional bottoms Lower volume swell Click to edit text styles 4
Strategies for Maximizing FCC Light Cycle Oil Operating Strategies Recycle Catalyst Optimization Click to edit text styles 5
Recycle Considerations To fully maximize LCO, recycle may be required to maintain bottoms yield as conversion is reduced Which recycle stream is best to recycle? Does the feedstock type play a role? Heavy cycle oil or bottoms? Which specific boiling range is optimal? 6
Lab Simulation of Recycle Operation A two-pass DCR pilot plant+ ACE scheme was adopted to simulate the recycling operation in a commercial unit DCR was used to generate 650+ F material over a conversion range of 75 to 54 wt% with a resid and VGO feedstock 650+ F stream was distilled into desired bottom cuts Bottoms cuts were blended with original resid feed ACE testing used original feeds together with recycle streams Grace s MIDAS premium bottoms cracking catalyst was used Resid and VGO Feedstock DCR 650+F Distillation Blending ACE FCC Products 7
DCR Pilot Plant Used to Generate Recycle Streams Recycle streams at 54% conversion distilled to: 650 750 F 650 800 F 650 F+ 750 F+ 800 F+ 850 F+ Recycle streams at 54%, 58%, 68%, and 75% conversions distilled to 650 750 F Quantity of each recycle stream measured from 1 st pass cracking Properties of each recycle stream determined Click to edit text styles 8
Incremental Yields of 650-750 F Recycle Streams Boiling Range VGO 650-750ºF from VGO Resid 650-750ºF from Resid Dry Gas, wt% 0.7 0.7 1.1 1.2 LPG, wt% 8.4 8.9 8.0 10.1 C5+ Gasoline, wt% 44.0 43.6 40.3 38.2 LCO, wt% 26.0 26.3 24.7 37.0 Bottoms, wt% 19.0 18.7 20.3 8.0 Coke, wt% 1.9 1.8 5.6 5.5 650-750 F fractions from VGO made about the same LCO and bottoms as fresh VGO 650-750 F fractions from resid made more LCO and LPG, less bottoms than fresh resid Click to edit text styles 9
Cracking Path of Hydrocarbon Molecules Percentage 45.0 40.0 35.0 30.0 25.0 20.0 R R Di-aromatics R : hydrocarbons with less than 4 carbon atoms Mono-aromatics + Gasoline R R LCO Tri-aromatics + R Bottoms + R 15.0 10.0 Coke 5.0 0.0 Tetra-aromatics Saturates Mono-aromatics Di-aromatics Tri-aromatics Tetra-aromatics Click to edit text styles 650-750F Recycle Stream from VGO 650-750F Recycle Stream from Resid 10
Recycle Streams at 54% Conversion from Resid Properties API Gravity @60 øf 20 15 Conradson Carbon, wt.% 16 12 8 10 4 5 1000 900 0 50% Vol% F Hydrogen, wt.% 12 Data 800 11 700 10 Fresh Feed 650-750F 650-800F 650-850 F 650F+ 750F+ 800 F+ 850 F+ 650-7 50F 650-800F 650-850 F 650F+ 750F+ 800 F+ 850 F+ 600 Fresh Feed Click to edit text styles 9 Feed ID 11
650-750ºF Recycle Stream vs. Conversion for Resid Properties Click to edit text styles 12
55 wt% conversion vs. % recycle in combined feed - Resid Key Yields 25.8 LCO, wt% 20.4 Bottoms, wt% 25.5 20.1 25.2 19.8 24.9 19.5 24.6 6.00 5.75 Coke, wt% 19.2 40.8 40.4 C5+ Gasoline, wt% 650-750F 650-800F 650-850F 650+ 750+ 40.0 5.50 0% 4% 8% 12% 16% 0% 4% % Recycle in Combined Feed 8% 12% 16% Click to edit text styles 13
Element Tracking Approach Element Tracking Approach can be used to simulate a continuous recycle operation Two-pass cracking can closely simulate steady-state ~0 for Recycle Ratios ~ <= 15% Click to edit text styles 14
Maximum LCO Yields Fresh Feed Basis Resid Max Gasoline Base Base No Recycle 650-750 F 650-800 F 650-850 F 650+ F Conversion 70.0 55.1 61.2 64.2 65.1 64.7 Recycle Ratio 0 0 0.10 0.14 0.16 0.15 Maximun recycle available 0.10 0.14 0.18 0.24 Hydrogen, wt% 0.11 0.09 0.10 0.11 0.12 0.12 Total C1's & C2's, wt% 1.4 1.0 1.1 1.3 1.4 1.4 Propylene, wt% 3.3 2.1 2.4 2.6 2.7 2.7 Total C3's, wt% 3.9 2.4 2.7 2.9 3.1 3.1 Total C4='s, wt% 5.1 3.9 4.5 4.5 4.7 4.8 Total C4's, wt% 8.5 5.6 6.6 6.6 6.9 7.0 C5+ Gasoline, wt% 49.5 40.5 44.7 46.9 47.0 46.5 RON 89.6 89.2 89.4 89.5 89.5 89.7 MON 78.6 77.3 77.7 77.8 77.7 77.9 LCO, wt% 20.5 24.7 28.9 30.2 29.9 29.3 Bottoms 9.5 20.2 9.9 5.6 5.0 6.0 Coke, wt% 6.7 5.6 6.1 6.5 6.7 6.7 Click to edit text Max. styles Coke Allowed Limited by Max. Recycle Stream Limited by Max. Coke 15
Product Selectivity with and without Recycle Resid 650 800/850 F produces the highest LCO selectivity with slight coke penalty Yields on a fresh feed basis 20 Bottoms, wt% 52 C5+ Gasoline, wt% 15 48 10 5 30 25 LCO, wt% 44 40 9 8 7 Coke, wt% No Recycle Recy cle 650-800/850 Recy cle all 650-750F 20 6 55 60 65 70 Click to edit text styles 75 55 Conversion 60 65 70 75 16
Fresh Feed & Recycle Cracking Selectivity Resid 2 nd pass cracking of 650-750 o F fraction at reduced conversion made more LCO than cracking fresh feed with almost no penalty on coke and gasoline Large coke debit at increased conversion Yields of 2nd pass cracking (Recycle Cracking) minus Yields of Fresh Feed Cracking 10 Max Recycle Ratio 0 C5+ Gasoline, wt% 8-10 -20 6-30 4 16 LCO, wt% -40 20 Coke, wt% 12 15 8 10 4 5 0 55 60 65 Click to edit text styles 70 0 75 55 Conversion 60 65 70 75 17
Strategies for Maximizing FCC Light Cycle Oil Operating Strategies Recycle Catalyst Optimization Click to edit text styles 18
Catalyst Strategies for Maximum LCO Maximize Bottoms Cracking to LCO Lower Z/M using a high diffusivity matrix Optimal matrix surface area, pore size, and pore distribution Optimal Ecat MAT Lower within slurry and liquid yield limits with consideration to economics Optimal rare earth for activity and hydrogen transfer Reduced zeolite surface area Minimize LCO conversion via zeolite Maintain or increase liquid yield by increasing LPG ZSM 5 additives Lower zeolite rare earth Catalyst design to increase C4= selectivity 19
Design Concept for ACHIEVE 400 FCC Catalyst ACHIEVE 400 FCC Catalyst delivers higher LCO yield, greater gasoline octane, and improved C 4 = selectivity through: Low Z/M ratio to drive bottoms uplift and decrease hydrogen transfer activity Dual zeolite functionality (USY + pentasil) with tailored acidity to Boost octane via isomerization activity Crack gasoline olefins more selectively to C4= rather than C3= Maintenance of excellent coke selectivity using Grace s proprietary alumina matrix first commercialized in the MIDAS catalyst family 20
Modeling with Optimal Recycle Stream and Catalyst System Full Burn FCC - Residual Feedstock Model yields and operating conditions Base Resid Operation Maximum Gasoline Case 1 Maximum LCO with 650-800 F recycle stream Case 2 Optimized maximum LCO operation Click to edit text styles 21
Base Maximum Gasoline Operation Product Relative Price C3=, $/b - 9.0 C4=, $/b +17.0 Gaso., $/b Base LCO, $/b +21.0 Slurry, $/b -25.0 Resid Feedstock Operation Base Mode Max Gasoline Recycle %FF (650 to 800 F) 0.0 Reactor Temperature, F 975 Air Blower, mscfm Constraint Wet Gas Compressor, scf/b Constraint LPG/Gaso., Vol% 23.8/56.9 RON/MON 92.3/80.4 LCO, Vol% FF 22.3 Slurry, Vol% FF 7.0 C 3+, Vol% FF 110.0 Incremental $/b Base 22
Maximum LCO with ACHIEVE 400 FCC Catalyst Resid Feedstock Operation Base Case 1 Case 2 MIDAS FCC Catalyst ACHIEVE 400 FCC Catalyst Mode Max Gasoline Max LCO Max LCO Recycle %FF (650 to 800 F) 0 7 7 Reactor Temperature, F 975 960 960 Air Blower, mscfm Constraint Constraint Constraint Wet Gas Compressor, scf/b Constraint ~90%Constraint Constraint LPG/Gaso., Vol% 23.8/56.9 21.2/54.3 24.8/51.6 C4=, Vol% 8.9 7.7 9.3 RON/MON 92.3/80.4 91.4/80.0 92.4/80.4 LCO, Vol% FF 22.3 27.0 27.0 Slurry, Vol% FF 7.0 6.7 6.7 C 3+, Vol% FF 110.0 109.2 110.1 Incremental $/b Base $0.08 $1.16 Volume swell is critical to maintaining profitability 23
Summary Maximum FCC LCO operation is challenged by bottoms yield and the need to preserve C3+ liquid yield and octane as conversion is reduced Shifting operating conditions (lower reactor temperature, higher feed temperature) can be adjusted to increase LCO, but this comes at a price Recycle can be employed to fully maximize LCO at reduced conversion 650 to 800 F recycle stream produces the highest LCO when processed against a coke constraint The proper catalyst system, operating conditions and recycle ensure a profitable LCO operation 24
GRACE, ACHIEVE and MIDAS are trademarks, registered in the United States and/or other countries, of W. R. Grace & Co.-Conn. DCR is a trademark of W. R. Grace & Co.-Conn. This trademark list has been compiled using available published information as of the publication date of this brochure and may not accurately reflect current trademark ownership or status. GRACE CATALYSTS TECHNOLOGIES is a business segment of W. R. Grace & Co.-Conn. Copyright 2015 W. R. Grace & Co.-Conn. All rights reserved. 25
Ann Benoit FCC Technical Service Representative Grace Catalysts Technologies Ann.Benoit@grace.com 26