Chemical Characterization of Coke Fouling From Pipeline Refinery

  • Slides: 28
Download presentation
Chemical Characterization of Coke Fouling From Pipeline, Refinery and Upgrader Process Units. Roxanne Shank,

Chemical Characterization of Coke Fouling From Pipeline, Refinery and Upgrader Process Units. Roxanne Shank, P. Chem. M. Sc. shank. roxanne@cleanharbors. com

Introduction One of the biggest fouling problems in refineries, upgraders and pipelines is coke

Introduction One of the biggest fouling problems in refineries, upgraders and pipelines is coke fouling Little Research Mechanical Methods Better Way?

Coke Fouling Largely misunderstood, often misinterpreted Most of the fouling in the energy sector

Coke Fouling Largely misunderstood, often misinterpreted Most of the fouling in the energy sector is attributed to coke Usually a mixture, iron sulfides likely Sample research may be difficult Feedstock changes Impurities Sulfur Content Asphaltene/Maltene content

Fouling Process A number of models exist for the formation of coke fouling in

Fouling Process A number of models exist for the formation of coke fouling in the process stream. Thermal Conversion Model Asphaltenes converted to ashaltene cores. Concentration < solubility, cores precipitate out as coke. Thermal Cracking Model Hot Spots = thermal cracking = coke particles in fluid Mechanisms of Coke Fouling Free flowing particulates in the fluid, plugging off pipes and tubes Coke precipitates and is deposited on the metal surface Layer of coke forms at the metal surface and grows.

Temperature and Pressure Temperature is a key factor in the process As temperature increase,

Temperature and Pressure Temperature is a key factor in the process As temperature increase, coke formation increases rapidly As the pressure increases, the temperature increases, but the fluid is not uniform Hot Spots arise in the fluid, resulting in spontaneous thermal cracking, and an increase in the formation of coke.

Samples Over 60 samples have been collected over the past 20 years from various

Samples Over 60 samples have been collected over the past 20 years from various pipeline, refinery and upgraded process units worldwide, each deemed to be ‘coke’

Experimental Methods Multi-part Chemical Analysis Organic extraction Inorganic Digestion Instrumental Analysis of Inorganic Components

Experimental Methods Multi-part Chemical Analysis Organic extraction Inorganic Digestion Instrumental Analysis of Inorganic Components X-Ray Fluorescence (XRF) Powder X-Ray Diffraction (XRD) Fourier Transform – Infra. Red (FT-IR)

Chemical Analysis A multi-stage approach is used distinguish the different fractions in the sample.

Chemical Analysis A multi-stage approach is used distinguish the different fractions in the sample. Organic extractions Distinguish between light hydrocarbons, asphaltenes and heavy fractions, paraffin and water. Inorganic Digestion of the inorganic portion in various acids to determine composition.

X-Ray Fluorescence The inorganic portion of the sample is analyzed by qualitative XRF (detects

X-Ray Fluorescence The inorganic portion of the sample is analyzed by qualitative XRF (detects S to Se) X-Ray Fluorescence Spectrum for RD 13 -17 100 90 Background Signal 80 Intensity 70 Fe 60 50 40 V 30 Cr Mn 20 S 10 Ca Cu Zn 0 2 3 4 5 6 7 Energy (ke. V) 8 9 10 11 12

X-Ray Diffraction (Powder) Inorganic Portion is crushed and assessed by XRD to determine composition.

X-Ray Diffraction (Powder) Inorganic Portion is crushed and assessed by XRD to determine composition. Iron Sulfide - 9. 3% Iron Oxide) - 5. 7% Iron Sulphate – 70. 8% RD 23 -17 Iron Oxide – 8. 5% Crystalline Coke – 19. 5% Iron Sulphate – 52. 7% RD 13 -13

FT-IR Samples are assessed by diamond ATR FT-IR analysis before and after organic extraction

FT-IR Samples are assessed by diamond ATR FT-IR analysis before and after organic extraction 0. 4 FT-IR Spectrum For RD 01 -13 0. 35 Before extraction 0. 3 After Extraction 0. 25 0. 2 0. 15 0. 1 0. 05 0 3650 3150 2650 2150 1650 1150 1/cm 650

Results A total of 62 samples were tested Varying levels of amorphous and crystalline

Results A total of 62 samples were tested Varying levels of amorphous and crystalline carbon (coke or graphitic carbon) Nearly 70% of the samples contained sulfur in some form (elemental, iron sulfide, sulfates) Silicates (Sand) is a major contaminate in many samples Asphaltenes remain as a major carbon source in many of the samples.

Coke Foulant Spectrum The samples assessed could be broken up into 5 major categories

Coke Foulant Spectrum The samples assessed could be broken up into 5 major categories Primarily Amorphous Carbon Primarily Asphaltic Primarily Sulfurous Silicate-based Scale Mixture Corrosion Products were also observed Salts and Carbonates may also be present

RD 03 -13 Category 1 – Primarily Amorphous Carbon X-Ray Fluorescence Spectrum for RD

RD 03 -13 Category 1 – Primarily Amorphous Carbon X-Ray Fluorescence Spectrum for RD 03 -17 %wt 140 Lt. Hydrocarbon 0. 44% 120 Paraffin 0. 10% 100 Asphaltenes 0. 78% HCl Acid Soluble 2. 40% Sulfurous 2. 19% 20 Silicates 2. 31% 0 Unreacted Residue 91. 78% Iron – 0. 4% Mereiterite – 14. 6% Cr. S – 6. 6% Quartz – 12. 1% Graphite – 18. 5% Sulfur – 24. 2% 25/62 ~ 40% of samples Intensity Fraction Background Signal 80 Ti Fe 60 V 40 S 2 Ca 4 Cr Mn 6 8 Energy (ke. V) 10 12

Fraction %wt Lt. Hydrocarbon 19. 48% Paraffin 0. 26% Asphaltenes 76. 30% HCl Acid

Fraction %wt Lt. Hydrocarbon 19. 48% Paraffin 0. 26% Asphaltenes 76. 30% HCl Acid Soluble 2. 75% Sulfurous 19. 53% Silicates 0. 00% Unreacted Residue 0. 67% Iron Oxide – 27. 2% Iron Sulfide – 16. 8% Silicate – 34. 8% Salt – 7. 9% 9/62 ~ 15% of samples X-Ray Fluorescence Spectrum for RD 26 -17 140 Fe 120 Intensity RD 26 -17 Category 2 – Primarily Asphaltic 100 Background Signal 80 Ca 60 40 20 0 S 2 Sc Ti V Cr 4 Mn Cu Zn 6 8 Energy (ke. V) 10 12

Fraction %wt Lt. Hydrocarbon 2. 19% Paraffin 0. 51% Asphaltenes 8. 57% HCl Acid

Fraction %wt Lt. Hydrocarbon 2. 19% Paraffin 0. 51% Asphaltenes 8. 57% HCl Acid Soluble 4. 30% Sulfurous 71. 87% Silicates 1. 16% Unreacted Residue 11. 40% Iron Oxide/ Metal Oxide – 15. 7% Iron Phosphate – 11. 7% Sulfur/ Sulphur – 18. 0% 10/62 ~ 16% of samples X-Ray Fluorescence Spectrum for RD 11 -13 Intensity RD 11 -13 Category 3 – Primarily Sulfurous 140 120 100 80 60 40 20 0 Background Signal Fe Cr Mn Ca 2 4 6 8 Energy (ke. V) 10 12

RD 49 -17 Category 4 – Silicate Based Scale Fraction %wt Lt. Hydrocarbon 7.

RD 49 -17 Category 4 – Silicate Based Scale Fraction %wt Lt. Hydrocarbon 7. 56% 60 Paraffin 0. 42% 50 Asphaltenes 5. 54% HCl Acid Soluble 14. 76% 20 Sulfurous 10. 78% 10 Silicates 55. 04% Unreacted Residue 5. 90% Silicate – 63. 3% Silicate – 25. 4% 3/62 ~ 5% of samples X-Ray Fluorescence Spectrum for RD 49 -17 80 Intensity 70 Background Signal 40 Fe 30 V Cr Mn Cl 0 2 4 Ni Cu Zn 6 8 Energy (ke. V) 10 12

Category 5 – Mixture X-Ray Fluorescence Spectrum for RD 22 -17 RD 22 -13

Category 5 – Mixture X-Ray Fluorescence Spectrum for RD 22 -17 RD 22 -13 140 %wt 120 Lt. Hydrocarbon 18. 77% 100 Paraffin 0. 45% Asphaltenes 5. 34% HCl Acid Soluble 13. 95% Sulfurous 21. 74% Silicates 7. 82% Unreacted Residue 31. 93% Iron Oxide – 3. 6% Iron Sulfide/ Metal Sulfide – 25. 2% Iron Sulphate – 49. 7% 7/62 ~ 10% of samples Intensity Fraction Fe 80 Background Signal 60 40 20 S Cr Ca Mn 0 2 4 6 8 Energy (ke. V) 10 12

Conclusions Fouling Coke in refineries is often attributed to Coke Fouling is more complex

Conclusions Fouling Coke in refineries is often attributed to Coke Fouling is more complex Spectrum of coke fouling can be derived It may be possible to map the fouling based on process to some degree Coke Fouling may be dealt with chemically, reducing cost/downtime of maintaining process units.

Future Studies CHNS, LOI, Ash Analysis Elemental Analysis by AES-MP DRIFTS FT-IR Map the

Future Studies CHNS, LOI, Ash Analysis Elemental Analysis by AES-MP DRIFTS FT-IR Map the Foulant Spectrum Chemical Cleaning Laboratory Studies In-field Case Studies

Acknowledgements I would like to thank my colleagues Thomas R. Mc. Cartney, P. Chem.

Acknowledgements I would like to thank my colleagues Thomas R. Mc. Cartney, P. Chem. Samar Gharaibeh, P. Chem. Ph. D. Darcy Granburg, R. Chem. Charlie Clune Thank you to all companies who have provided samples over the years.

Lt Hydrocarbon Sample Name Paraffin RD 69 A RD 58 RD 56 RD 55

Lt Hydrocarbon Sample Name Paraffin RD 69 A RD 58 RD 56 RD 55 A RD 53 RD 51 RD 49 RD 47 RD 45 RD 43 Rd 41 RD 39 RD 37 RD 35 RD 33 RD 31 RD 29 RD 27 RD 25 RD 23 RD 21 RD 19 RD 17 RD 15 RD 13 RD 11 RD 09 RD 07 RD 05 RD 03 RD 01 Weight % Light Hydrocarbon and Paraffin 100. 00 90. 00 80. 00 70. 00 60. 00 50. 00 40. 00 30. 00 20. 00 10. 00

Sample Name RD 69 A RD 58 RD 56 RD 55 A RD 53

Sample Name RD 69 A RD 58 RD 56 RD 55 A RD 53 RD 51 RD 49 RD 47 RD 45 RD 43 Rd 41 RD 39 RD 37 RD 35 RD 33 RD 31 RD 29 RD 27 RD 25 RD 23 RD 21 RD 19 RD 17 RD 15 RD 13 RD 11 RD 09 RD 07 RD 05 RD 03 RD 01 Weight % Asphaltene 100. 00 90. 00 80. 00 70. 00 60. 00 50. 00 40. 00 30. 00 20. 00 10. 00

Sample Name RD 69 A RD 58 RD 56 RD 55 A RD 53

Sample Name RD 69 A RD 58 RD 56 RD 55 A RD 53 RD 51 RD 49 RD 47 RD 45 RD 43 Rd 41 RD 39 RD 37 RD 35 RD 33 RD 31 RD 29 RD 27 RD 25 RD 23 RD 21 RD 19 RD 17 RD 15 RD 13 RD 11 RD 09 RD 07 RD 05 RD 03 RD 01 Weight % Oxides, Salts, Carbonates and Sulfates 80. 00 70. 00 60. 00 50. 00 40. 00 30. 00 20. 00 10. 00

RD 01 RD 02 RD 03 R 04 RD 05 RD 06 RD 07

RD 01 RD 02 RD 03 R 04 RD 05 RD 06 RD 07 RD 08 RD 09 RD 10 RD 11 RD 12 RD 13 RD 14 RD 15 RD 16 RD 17 RD 18 RD 19 RD 20 RD 21 RD 22 RD 23 RD 24 RD 25 RD 26 RD 27 RD 28 RD 29 RD 30 RD 31 RD 32 RD 33 RD 34 RD 35 RD 36 RD 37 RD 38 RD 39 RD 40 Rd 41 RD 42 RD 43 RD 44 RD 45 RD 46 RD 47 RD 48 RD 49 RD 50 RD 51 RD 52 RD 53 RD 54 RD 55 A RD 55 B RD 56 RD 57 RD 58 RD 59 RD 69 A RD 60 B Weight % Sulfurous Content 80. 00 70. 00 60. 00 50. 00 40. 00 30. 00 20. 00 10. 00 Sample Name

Sample Name RD 69 A RD 58 RD 56 RD 55 A RD 53

Sample Name RD 69 A RD 58 RD 56 RD 55 A RD 53 RD 51 RD 49 RD 47 RD 45 RD 43 Rd 41 RD 39 RD 37 RD 35 RD 33 RD 31 RD 29 RD 27 RD 25 RD 23 RD 21 RD 19 RD 17 RD 15 RD 13 RD 11 RD 09 RD 07 RD 05 RD 03 RD 01 Weight % Silicate 60. 00 50. 00 40. 00 30. 00 20. 00 10. 00

Sample Name RD 69 A RD 58 RD 56 RD 55 A RD 53

Sample Name RD 69 A RD 58 RD 56 RD 55 A RD 53 RD 51 RD 49 RD 47 RD 45 RD 43 Rd 41 RD 39 RD 37 RD 35 RD 33 RD 31 RD 29 RD 27 RD 25 RD 23 RD 21 RD 19 RD 17 RD 15 RD 13 RD 11 RD 09 RD 07 RD 05 RD 03 RD 01 Weight % Amorphous Carbon ‘Coke’ 100. 00 90. 00 80. 00 70. 00 60. 00 50. 00 40. 00 30. 00 20. 00 10. 00