(AGRU) ACID GAS SOUR SHIFT: CASE STUDY IN REFINERY GAS TREATMENT

Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries

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(AGRU) ACID GAS SOUR SHIFT: CASE STUDY IN REFINERY GAS TREATMENT Case Study: #0978766GB/H

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CONTENTS CASE STUDY OVERVIEW Syn Gas Sour Shift: Process Flow Diagram AGR: Acid Gas to VULCAN SYSTEMS Sour Gas Shift DESIGN BASIS: ACID GAS REACTOR CATALYST SPECIFICATION

SOUR SHIFT CASE SHIFT REACTOR CATALYST SPECIFICATIONS COS REACTOR CATALYST SPECIFICATIONS SWEET SHIFT CASE

SHIFT REACTOR CATALYST SPECIFICATIONS PERFORMANCE SIMULATION RESULTS SOUR SHIFT SECTION 1 Cases Considered 2 Catalyst Used 3 Client Requirements 4 Oxygen and Olefins 5 HCN 6 NH3 7 Arsine 8 Input Data Sour Shift Unit 9 Activity (PROPRIETARY) 10 Results



ADIABATIC SWEET SHIFT SECTION: HTS Reactor followed by LTS Reactor 1 Catalyst Used 2 Inlet Operating Temperature HTS Reactor 3 Feed Flow Rate, Inlet Operating Pressure and Feed Composition

HTS Reactor 4 Inlet Operating Conditions LTS Reactor 5 Client Requirements 6 Results: Standard Case as Presented to the Client 7 Results: Inlet Operating Pressure HTS Reactor = 25.2 bara 8 Results: Addition of 100 kmol/h N2 COS HYDROLYSIS SECTION FOR SWEET SHIFT CASE 1 Total Feed Flow Rate, Feed Composition, Direction of Flow, Inlet

Operating Temperature, Inlet Operating Pressure 2 Inlet H2S and COS Levels 3 Equilibrium H2S and COS Levels (COS Hydrolysis Reaction) 4 Client Requirements 5 Results H2S REMOVAL SECTION AFTER AGR UNIT (2 Absorbent Beds (VULCAN VSG-EZ200) in Lead/Lag Arrangement) 1 Total Feed Flow Rate, Feed Composition, Direction of Flow, Inlet

Operating Temperature, Inlet Operating Pressure 2 Inlet H2S and COS Levels 3 Client Requirements (All Cases) 4 Results



ISOTHERMAL SWEET SHIFT SECTION: Alternative Approach

VULCAN Simulation Input Data 1 Enthalpy method 2 Cases considered 3 Feed stream data 4 Kinetics 5 Catalyst 6 Catalyst Activity relative to standard 7 Catalyst size and packing details 8 Catalyst pressure drop parameters 9 Catalyst Volume 10 Standard die-off rate 11 BFW Rate 12 Vapor fraction 13 Steam Temperature 14 Steam Pressure 15 Boiling Model 16 Volumetric UA Isothermal Shift Simulations Results APPENDIX Characteristics of Acid Gas Removal Technologies



OVERVIEW Gas Treating in gas industries, and in oil and chemical facilities is getting more complex due to emissions requirements established by environmental regulatory agencies. Acid Gas Removal (AGR) Currently, the processes of choice in refinery gas processing facilities for the removal of acid gases are both the chemical solvent AGR processes based on aqueous methyldiethanolamine (MDEA) and the physical solvent-based Selexol process—which uses mixtures of dimethyl ethers of polyethylene glycol.

In most of the refinery acid gas applications now, with both of these AGR processes, the AGR units are preceded by carbonyl sulfide (COS) hydrolysis units to convert most of the COS to H2S. This then enables the AGR units to accomplish deeper total sulfur removal and lower H2S levels. AGR units remove essentially all of the H2S and CO2 from various refinery gas streams.

• Fuel gas treating • Hydrotreater product/fuel gas • Hydrotreater recycle gas • Hydrocracker product/fuel gas • Hydrocracker recycle gas • LPG liq-liq contactor • Thermal/catalyst cracker gases



This case study demonstrates how the VULCAN SYSTEMS S2GP “sour gas shift process” can provide a technically viable process option in the treatment of an AGRU’s acid gas stream, for the generation of Synthesis gas suitable for various downstream refinery and petrochemical processes. The “Shifted” Syngas can be utilized for co-gen (as fuel to existing gas turbines), fuel for existing heaters, producing value added products like hydrogen, substitute natural gas (SNG), carbon monoxide (CO), synthesis gas, etc. ACID GAS: SOUR SHIFT CASE STUDY



Acid Gas to VULCAN SYSTEMS Sour Gas Shift

ACID GAS REACTOR CATALYST SPECIFICATION

DESIGN BASIS: SOUR SHIFT CASE SHIFT REACTOR CATALYST SPECIFICATIONS COS REACTOR CATALYST SPECIFICATIONS SWEET SHIFT CASE

SHIFT REACTOR CATALYST SPECIFICATIONS

4 1. Data marked v to be specified / confirmed by catalyst vendor.56 2. Allowable pressure drop to include catalyst support material.



Job ACME - Sour Shift Case Item No.

Item Name SHIFT REACTOR CATALYST 1 OPERATING DATA Units INLET OUTLET2 Component Flow3 Hydrogen mol % 11.48 v4 Nitrogen mol % 3.23 v5 Carbon Monoxide mol % 23.05 v6 Carbon Dioxode mol % 1.67 v7 Methane mol % 0.01 v8 Argon mol % 0.03 v9 Hydrogen Sulphide mol % 0.63 v10 Carbonyl Sulphide mol % 0.05 v11 Ammonia mol % 0.06 v12 Water mol % 59.79 v13 Hydrogen Cyanide mol % 0.003 v141516 17 Total mol %18 Total Flow kmol/h 1443819 Total Flow kg/h 27965620 Actual Volume Flow m3/h21 Normal Volume Flow Nm3/h22 (at 0°C, 1 bar a)23 Stream Temperature oC 21524 Operating Pressure bar a 37.525 Stream Viscosity cP 0.0252627 Bed 1 Bed 228 Allow able Pressure Drop bar29 Maximum Temperature oC30 Design Temperature oC31 Heat Loss kW/m2

32 33 Catalyst Vendor34 Catalyst Type35 Catalyst Size / Shape36 Catalyst Life years37 Bulk Density kg/m3

38 Bed 1 Bed 239 Bed Height mm40 Bed Diameter mm41 Bed Volume m3

42 Bed Weight te4344 LHSV / VHSV45 Flow Direction Downwards4647484950

v

v

100.00

v

100.0014438279656

-40 min

vv

0.34 (Note2)

v

v

v

v

vv

v



Job ACME - Sweet Shift Case Item No.

Item Name COS REACTOR CATALYST OPERATING DATA Units INLET OUTLET

Component Flow Hydrogen mol % 21.98 v Nitrogen mol % 6.20 v Carbon Monoxide mol % 44.17 v Carbon Dioxode mol % 3.10 v Methane mol % 0.01 v Argon mol % 0.05 v Hydrogen Sulphide mol % 1.20 v Carbonyl Sulphide mol % 0.10 v Ammonia mol % 0.005 v Water mol % 23.18 v Hydrogen Cyanide mol % 0.005 v

Total mol % Total Flow kmol/h Total Flow kg/h Actual Volume Flow m3/h Normal Volume Flow Nm3/h

(at 0°C, 1 bar a) Stream Temperature oC Operating Pressure bar a Stream Viscosity cP

Bed 1 Bed 2 Allow able Pressure Drop bar Maximum Temperature oC Design Temperature oC Heat Loss kW/m2

Catalyst Vendor Catalyst Type Catalyst Size / Shape Catalyst Life years Bulk Density kg/m3

Bed 1 Bed 2 Bed Height mm Bed Diameter mm Bed Volume m3

Bed Weight te

LHSV / VHSV Flow Direction Downwards

v

v

v

v

vv

v

-40 min

vv

0.34 (Note 2)

37.80.024

201

100.007535

155091

100.007535

155091

v

v

v



Job ACME - Sweet Shift Case Item No.

Item Name SHIFT REACTOR CATALYST 1 OPERATING DATA Units INLET OUTLET2 Component Flow3 Hydrogen mol % 11.55 v4 Nitrogen mol % 3.26 v5 Carbon Monoxide mol % 23.22 v6 Carbon Dioxode mol % 1.29 v7 Methane mol % 0.01 v8 Argon mol % 0.03 v9 Hydrogen Sulphide mol % 0.00 v10 Carbonyl Sulphide ppmv < 50 v11 Ammonia ppmv < 0.1 v12 Water mol % 60.65 v13 Hydrogen Cyanide ppmv < 0.1 v141516 17 Total mol %18 Total Flow kmol/h 1432119 Total Flow kg/h 27431620 Actual Volume Flow m3/h21 Normal Volume Flow Nm3/h22 (at 0°C, 1 bar a)23 Stream Temperature oC 21024 Operating Pressure bar a 33.225 Stream Viscosity cP2627 Bed 1 Bed 228 Allow able Pressure Drop bar29 Maximum Temperature oC30 Design Temperature oC31 Heat Loss kW/m2

32 33 Catalyst Vendor34 Catalyst Type35 Catalyst Size / Shape36 Catalyst Life years37 Bulk Density kg/m3

38 Bed 1 Bed 239 Bed Height mm40 Bed Diameter mm41 Bed Volume m3

42 Bed Weight te4344 LHSV / VHSV45 Flow Direction Downwards4647484950

v

v

100.00

v

100.0014321274316

-40 min

vv

0.34 (Note 2)

0.025

v

v

v

v

vv

v



PERFORMANCE SIMULATION RESULTS Sour Shift Section Starting Point: In this document only the Sour Shift option will be considered. The following Cases were considered: 1 Cases Considered Life Inlet Operating

Pressure (bara)

Inlet Operating Temperature (oC)

Standard Case SOR SOR Expected 37.5 (= 36.5 barg)

Bed 1: 300* Bed 2: 280

Standard Case EOR 2 Years Guaranteed

Lower Inlet Operating Pressure SOR

SOR Expected 29.5 (= 28.5 barg) Lower Inlet Operating

Pressure EOR 2 Years Guaranteed

Addition of 100 kmol/h N2 SOR

SOR Expected 37.5 (= 36.5 barg)

Addition of 100 kmol/h N2 EOR

2 Years Guaranteed

*The Inlet Operating Temperature ad specified by the Client (215oC) is too low for sour shift; moreover this temperature is below the dewpoint for water at an Inlet Operating Pressure of 37.5 bara (= 215oC). 2 Catalyst Used: VULCAN VIG-SGS202. The use of this catalyst is allowed here, because the Inlet Operating Pressure is always lower than 40 bara. 3 Client Requirements: Required Guaranteed Maximum Catalyst Life (years): 2 Required Guaranteed Maximum CO Slip EOR (i.e. 2 years, mol%, dry): 1.2 Required Expected Total Maximum Catalyst Bed Pressure Drop after 2 Years EOR (bar):

0.34



4 Oxygen and Olefins

There are no oxygen or olefins present in the feed, which would have resulted in an additional exotherm and a change in the composition of the feed.

5 HCN

The catalyst hydrogenates 90% of the HCN present in the feed. 6 NH3

The NH3 Level present in the feed will not affect the performance of the catalyst.

7 Arsine

No mention is made of the presence of arsine. Arsine is a severe catalyst poison. In view of the fact that coal is the starting point in this process it would be wise to double-check whether there is really no arsine whatsoever present in the feed of the Sour Shift Section.



8 Input Data Sour Shift Unit Lower Inlet

Operating Pressure (29.5 bara)

Addition of 100 kmol/h N2

Standard Case

Feed Flow Rate (kmol/h, wet): 14438 14538 14438 Feed Flow Rate (Nm3/h, wet): 323613 325855 323613 Feed Flow Rate (kmol/h, dry): 5806 5906 5806 Feed Flow Rate (Nm3/h, dry): 130136 132378 130136 Steam Flow Rate (kmol/h): 8632 8632 8632 Steam Flow Rate (Nm3/h): 193478 193478 193478 Steam/CO Ratio (mol/mol): 2.594* 2.594* 2.594* Steam/Dry Gas Ratio (mol/mol): 1.4867** 1.4616** 1.4867** Feed Composition (mol%, dry): H2 CO CO2 N2 CH4 Ar NH3 H2S HCN COS TOTAL

28.5480 57.3198 4.1529 8.0322 0.0249 0.0746 0.1492 1.5667 0.0075 0.1243 100.0000

28.0646 56.3493 4.0826 9.5892 0.0245 0.0733 0.1467 1.5402 0.0074 0.1222 100.0000

28.5480 57.3198 4.1529 8.0322 0.0249 0.0746 0.1492 1.5667 0.0075 0.1243 100.0000

Inerts (mol%, dry): 9.9793 11.5035 9.9793 COS (ppmv, dry): 1243 1222 1243 H2S/COS Ratio (mol/mol): 12.60 12.60 12.60 Inlet Operating Pressure (bara): 29.5

(= 28.5 barg)

37.5 (= 36.5 barg)

37.5 (= 36.5 barg)

Interbed Cooling: Heat Exchanger

Heat Exchanger

Heat Exchanger

Inlet Operating Temperature, Bed 1 (oC):

300*** 300*** 300***

Inlet Operating Temperature, Bed 2 (oC):

280*** 280*** 280***

Required Exit CO Slip (mol%, dry) 1.2 1.2 1.2



*This value for the Steam/CO Ratio is high enough to avoid methanation at the specified Operating Pressure and CO Inlet Level. **This value for the Steam/Dry Gas Ratio is high enough to avoid methanation. ***This value for these Inlet Operating Temperatures is way above the dewpoint for water in all Cases. 9 Activity (PROPRIETARY) For beds 1 and 2 ATE’s of 50 and 30oC, respectively were used in the calculations. 10 Results: Downflow and axial reactors have been assumed. The details are given below: Results: Standard Case as Presented by the Client Bed 1 EOR SOR Expected Exit Operating Temperature (oC): 498.1 499.3 Expected Catalyst Bed Pressure Drop (bar): -* 0.24 Guaranteed Catalyst Life (Years): 2 N.A. Gas Exit Composition (mol%, dry): Inerts**: H2 CO CO2 TOTAL

6.72 51.86 6.00 35.42 100.00

6.71 51.96 5.78 35.55 100.00

Exit Steam: Dry Gas Ratio (mol/mol): 0.6755 0.6721 Catalyst Bed Volume, Bed 1 (m3): 51.00 Catalyst Bed Diameter, Bed 1 D (m): 4.766 Catalyst Bed Height H, Bed 1 (m): 2.859 H/D (-): 0.60 Bed 2 EOR SOR Expected Exit Operating Temperature (oC): 309.2 308.6 Expected Catalyst Bed Pressure Drop (bar): -* 0.18 Guaranteed Catalyst Life (Years): 2 N.A.



Gas Exit Composition (mol%, dry): Inerts**: H2 CO CO2 TOTAL

6.42 54.04 1.20 38.35 100.00

6.41 54.08 1.09 38.41 100.00

Exit Steam: Dry Gas Ratio (mol/mol): 0.5996 0.5980 Guaranteed Maximum CO Slip (mol%, dry): 1.20 N.A. Catalyst Bed Volume, Bed 2 (m3): 51.00 Catalyst Bed Diameter, Bed 2 D (m): 4.766 Catalyst Bed Height H, Bed 2 (m): 2.859 H/D (-): 0.60 *Due to build-up of particulates it is impossible to give a value for the Catalyst Bed Pressure Drop EOR. **Inerts = N2 + CH4 + Ar + H2S + COS + NH3 + HCN. Results: Inlet Operating Pressure = 29.5 bara Bed 1 EOR SOR Expected Exit Operating Temperature (oC): 496.4 500.7 Expected Catalyst Bed Pressure Drop (bar): -* 0.30 Guaranteed Catalyst Life (Years): 2 N.A. Gas Exit Composition (mol%, dry): Inerts**: H2 CO CO2 TOTAL

6.76 51.57 6.63 35.03 100.00

6.71 51.93 5.83 35.52 100.00





6.43 53.97 1.36 38.25 100.00

6.41 54.08 1.12 38.40 100.00

Exit Steam: Dry Gas Ratio (mol/mol): 0.6021 0.5983 Guaranteed Maximum CO Slip (mol%, dry): 1.36 N.A. Catalyst Bed Volume, Bed 2 (m3): 51.00 Catalyst Bed Diameter, Bed 2 D (m): 4.766 Catalyst Bed Height H, Bed 2 (m): 2.859 H/D (-): 0.60 *Due to build-up of particulates it is impossible to give a value for the Catalyst Bed Pressure Drop EOR. **Inerts = N2 + CH4 + Ar + H2S + COS + NH3 + HCN. Results: Addition of 100 kmol/h N2 Bed 1 EOR SOR Expected Exit Operating Temperature (oC): 497.0 498.4 Expected Catalyst Bed Pressure Drop (bar): -* 0.24 Guaranteed Catalyst Life (Years): 2 N.A. Gas Exit Composition (mol%, dry): Inerts**: H2 CO CO2 TOTAL

7.79 51.26 5.94 35.01 100.00

7.78 51.37 5.69 35.16 100.00





7.44 53.44 1.19 37.92 100.00

7.44 53.49 1.08 37.99 100.00

Exit Steam: Dry Gas Ratio (mol/mol): 0.5931 0.5914 Guaranteed Maximum CO Slip (mol%, dry): 1.20 N.A. Catalyst Bed Volume, Bed 2 (m3): 51.00 Catalyst Bed Diameter, Bed 2 D (m): 4.766 Catalyst Bed Height H, Bed 2 (m): 2.859 H/D (-): 0.60 *Due to build-up of particulates it is impossible to give a value for the Catalyst Bed Pressure Drop EOR. **Inerts = N2 + CH4 + Ar + H2S + COS + NH3 + HCN. Amount of Catalyst to be Ordered (m3): 2 x 51 x 1.03 = 105 m3. Comments In all Cases both beds show an Expected Exit Operating Temperatures of less than 550oC, which is acceptable. Of course the steam content must always stay below dew point level. This is true for all Cases in both beds. The Catalyst Bed Pressure Drop is acceptable for sour shift design, but is slightly higher than the value specified by the Client (= 0.34 bar). Please also note that the Catalyst Bed Pressure Drops calculated here are for SOR expected only. The Required Guaranteed Maximum CO Slip EOR (2 years) of 1.2 mol% (dry) can be achieved for the Standard Case and for the Addition of 100 kmol/h N2 Case. In all Cases Desulfiding of the catalyst will not occur. A Catalyst Bed Height of 2.859m is acceptable (less than 5 m). H/D = 0.60 is acceptable.



A decrease in the Inlet Operating Pressure results in a slightly worse performance in terms of Catalyst Bed Pressure Drop and in terms of CO Slip compared to the Standard Case. Slightly larger Catalyst Bed Volumes would be required here. The addition of 100 kmol/h N2 results in virtually the same performance as the Standard Case in terms of Catalyst Bed Pressure Drop and in terms of CO Slip. The linear velocities are acceptable in the Standard Case and in the Addition of 100 kmol/h N2 Case (less than 0.35 m/s). However, the Lower Inlet Operating Pressure Case shows linear velocities of 0.43 and 0.36 m/s for Bed 1 and 2, respectively. Increasing D could decrease these linear velocities, which would be acceptable because (see above) in the Lower Inlet Operating Pressure Case slightly larger Catalyst Bed Volumes would be required anyway to meet 1.2 mol% (dry) CO Slip criterion specified by the Client. In all Cases the linear velocities are less than 1.5 x the fluidization threshold velocity (the criterion used to prevent milling of catalyst at the top of the bed in downflow), which is acceptable. The wet GHSV is always less than 10000 h-1, which is fine.



ADIABATIC SWEET SHIFT SECTION: HTS Reactor followed by LTS Reactor Starting Point: The calculations were carried for 0 years expected and 2 years guaranteed for the standard case presented by the Customer. Moreover the impact of the following changes were evaluated: An 8 bar lower Operating Pressure and the addition of 100 kmol/h N2. The direction of flow is downflow throughout. Axial reactors are used. The following data were used in the calculations: 1 Catalysts Used: HTS Section: VULCAN VSG-F101 LTS Section: VULCAN VSG-C111/112 2 Inlet Operating Temperature HTS Reactor Inlet Operating Temperature (oC): Optimized Calculation Type: OPTIMIZATION 3 Feed Flow Rate, Inlet Operating Pressure and Feed Composition

HTS Reactor: Lower Inlet

Operating Pressure (25.2 bara)

Addition of 100 kmol/h N2

Standard Case

Feed Flow Rate (kmol/h, wet):

14321 14421 14321

Inlet Operating Pressure (bara):

25.2 33.2 33.2

Feed Composition (mol%, wet): Hydrogen Nitrogen Carbon Monoxide Carbon Dioxide Methane Argon Water TOTAL

11.550 3.260 23.220 1.290* 0.010 0.020 60.650 100.000

11.470 3.931 23.059 1.281 0.010 0.020 60.229 100.000

11.550 3.260 23.220 1.290* 0.010 0.020 60.650 100.000



*Please note that the carbon dioxide seems to have been diluted more by the steam added than the other components. The Carbon Dioxide Component Feed Flow Rate is here 184.7 kmol/h, whereas the Carbon Dioxide Component Feed Flow Rate for the H2S Removal Section is 241.1 kmol/h. There is something not quite right here. 4 Inlet Operating Conditions LTS Reactor: Inlet Operating Temperature (oC):

Optimized

Inlet Operating Pressure (bara):

To be calculated

Feed Flow Rate (kmol/h, wet): 14321 Feed Composition (mole %, wet):

= Exit Composition HTS Reactor (to be calculated)

Calculation Type: OPTIMIZATION 5 Client Requirements: Guaranteed Minimum Catalyst Lives: 2

(Assumed) Maximum CO Slip Exit Adiabatic Sweet Shift Section after 2 Years Guaranteed (mol%, dry):

1.2

Expected Maximum Catalyst Bed Pressure Drop across Adiabatic Sweet Shift Section after 2 Years (bar):

0.34

6 Results: Standard Case as Presented to the Client: HTS Catalyst: VULCAN VSG-F101 LTS Catalyst: VULCAN VSG-C111/112

0 Years Expected (SOR)

2 Years Guaranteed (EOR)

Bed 1: HTS Reactor Guaranteed Catalyst Life (Years): 2 Required Catalyst Bed Volume (m3): 42.0 (Order: 43.3) Catalyst Bed Diameter D (m): 4.47 Catalyst Bed Height H (m): 2.68 H/D (-): 0.6 Expected Optimum Inlet Operating Temperature (oC):

310.0 310.0

Expected Exit Operating Temperature (oC):

507.4 507.4



Expected Catalyst Bed Pressure Drop (bar):

0.123 0.133

Inlet Operating Pressure (bara): 33.2 Expected Exit Operating Pressure (bara): 33.1 GHSV (h-1): 7642.6 Exit Composition (mol%, dry): Hydrogen Nitrogen Carbon Monoxide Carbon Dioxide Methane Argon TOTAL

52.960 5.520 5.870 35.600 0.020 0.030 100.000

52.920 5.520 5.960 35.540 0.020 0.030 100.000

Exit Steam/Dry Gas Ratio (mol/mol) x 100:

69.2 69.4

Exit WGS Approach–to–Equilibrium (oC): 0.0 3.3 Reduction Potential (-): 0.717 Bed 2: LTS Reactor Guaranteed Catalyst Life (Years): 2 Required Catalyst Bed Volume (m3): 42.0 (Order: 43.3) Catalyst Bed Diameter D (m): 4.47 Catalyst Bed Height H (m): 2.68 H/D (-): 0.6 Expected Optimum Inlet Operating Temperature (oC):

208.4 219.6


240.4 251.3


0.145 0.164


55.390 5.230 0.380 38.940 0.020 0.030 100.000

55.240 5.250 0.740 38.720 0.020 0.030 100.000


60.5 61.0



Exit WGS Approach–to–Equilibrium (oC): 3.7 16.7 Guaranteed Maximum CO Slip Exit LTS Reactor after 2 Years (mol%, dry):

1.2

Total Expected Catalyst Bed Pressure Drop across Adiabatic Sweet Shift Section (bar):

0.268 0.297

7 Results: Inlet Operating Pressure HTS Reactor = 25.2 bara HTS Catalyst: VULCAN VSG-F101 LTS Catalyst: VULCAN VSG-C111/112




310.0 310.0


510.0 509.6


0.161 0.173


52.920 5.520 5.960 35.550 0.020 0.030 100.000

52.810 5.530 6.220 35.390 0.020 0.030 100.000


69.3 69.8

Exit WGS Approach–to–Equilibrium (oC): 0.0 3.2 Reduction Potential (-): 0.544 Bed 2: LTS Reactor Guaranteed Catalyst Life (Years): 2



Required Catalyst Bed Volume (m3): 42.0 (Order: 43.3) Catalyst Bed Diameter D (m): 4.47 Catalyst Bed Height H (m): 2.68 H/D (-): 0.6 Expected Optimum Inlet Operating Temperature (oC):

207.5 218.9


241.3 252.6


0.192 0.217


55.390 5.230 0.390 38.94 0.020 0.030 100.000

55.200 5.250 0.820 38.670 0.020 0.030 100.000


60.5 61.1


1.2


0.353 0.390



8 Results: Addition of 100 kmol/h N2 HTS Catalyst: VULCAN VSG-F101 LTS Catalyst: VULCAN VSG-C111/112




310 310


506.6 506.5


0.125 0.135


52.35 6.62 5.77 35.20 0.02 0.03 100.00

52.30 6.63 5.89 35.13 0.02 0.03 100.00


68.4 68.5

Exit WGS Approach–to–Equilibrium (oC): 0.0 3.5 Reduction Potential (-): 0.717 Bed 2: LTS Reactor Guaranteed Catalyst Life (Years): 2 Required Catalyst Bed Volume (m3): 42.0 (Order: 43.3) Catalyst Bed Diameter D (m): 4.47 Catalyst Bed Height H (m): 2.68 H/D (-): 0.6 Expected Optimum Inlet Operating Temperature (oC):

208.7 219.9


240.4 251.4




0.147 0.166


54.78 6.28 0.38 38.51 0.02 0.03 100.00

54.61 6.30 0.75 38.28 0.02 0.03 100.00


59.8 60.4


1.2


0.272 0.301

Comments: For all Cases the value for the Reduction Potential R is so low that over-reduction of the HTS Catalyst can be safely ruled out (R is always less than 1.9). The dew point of the bulk gas inlet the HTS and LTS Reactors is always at least 15oC lower than the corresponding Inlet Operating Temperature, so there is no risk of water condensation. All Operating Temperature regimes encountered are acceptable. An H/D Ratio of 0.6 is acceptable for HTS and LTS Reactors. The GHSV of the HTS Reactor is < 8000 h-1, which is OK. The Total Expected Catalyst Bed Pressure Drop across the Adiabatic Sweet Shift Section after 2 Years (bar) was found to be 0.297 bar for the Standard Case, which meets the Pressure Drop requirement. On the other hand their figure of 0.34 bar is to include catalyst support, which could mean that there might be an opportunity for VULCAN DPOPTIMIZOR System here.



The Required Guaranteed Maximum CO Slip Exit Adiabatic Sweet Shift Section after 2 Years is achieved for all Cases (= 1.2 mol%, dry). The Required Guaranteed Minimum Catalyst Lives are achieved for all Cases. A decrease in the Inlet Operating Pressure of the HTS Reactor of 8 bar results in a slightly worse performance in terms of Catalyst Bed Pressure Drop and in terms of CO Slip compared to the Standard Case. However, the CO Slip requirement is still met. On the other hand, the Total Expected Catalyst Bed Pressure Drop across the Adiabatic Sweet Shift Section is a bit too high ( 0.353 and 0.390 bar for 0 years expected and 2 years guaranteed, respectively). The addition of 100 kmol/h N2 results in virtually the same performance as the Standard Case in terms of Catalyst Bed Pressure Drop and in terms of CO Slip. Both the CO Slip requirement and the requirement for the Total Expected Catalyst Bed Pressure Drop across the Adiabatic Sweet Shift Section are still met.



COS Hydrolysis Section for Sweet Shift Case (1 Bed of VULCAN A2ST 99) Starting Point: 1 Total Feed Flow Rate, Feed Composition, Direction of Flow, Inlet

Operating Temperature, Inlet Operating Pressure Total Feed Flow Rate (kmol/hr): 7535 Total Feed Flow Rate (Nm3/hr): 168889 Feed Composition (mol%): Hydrogen Nitrogen Carbon Monoxide Carbon Dioxide Methane Argon Hydrogen Sulphide Carbonyl Sulphide Ammonia Water Hydrogen Cyanide TOTAL:

21.980 6.200 44.170 3.100 0.010 0.050 1.200 0.100 0.005 23.180 0.005 100.000

Direction of Flow: Downflow Inlet Operating Temperature (oC): 201 or 125 (See

below) Inlet Operating Pressure (bara): 37.8 Inlet Stream Dynamic Viscosity (cP): 0.024 2 Inlet H2S and COS Levels* H2S (ppmv as S): 12000 COS (ppmv as S): 1000 *As specified by the Customer. 3 Equilibrium H2S and COS Levels (COS Hydrolysis Reaction) Operating Temperature (oC):

201 125

H2S (ppmv as S): 13000 13000 COS (ppmv as S): 0.38 0.10



From the above calculated equilibrium H2S and COS levels it can be concluded that if an exit COS Level of 0.1 mol% is required the Operating Temperature will have to be decreased from 201 to 125oC. An Operating Temperature of 125oC will kinetically still be acceptable for VULCAN A2ST 99, the COS Hydrolysis Catalyst recommended here. 4 Client Requirements Required Guaranteed Catalyst Life (VULCAN A2ST 99) (years): 2

(Assumed) Required Guaranteed Maximum Exit COS Level (ppmv, expressed as S):

Unknown

Required Expected Maximum Total Catalyst Bed Pressure Drop across HDS Section and H2S Removal Section after 2 Years (bar):

Unknown

5 Results The Absorbent Bed Pressure Drop: Exit Operating Temperature (oC): 201 125 Expected Exit Operating Pressure after 2 Years (bara): 37.6 37.6 Exit Stream Dynamic Viscosity (cP): 0.024 Calculated Required Bed Volume of VULCAN A2ST 99 (m

3):

43.6* (Order: 44.9)

Catalyst Bed Diameter D (m): 3.81 Catalyst Bed Height (m): 3.81 H/D (-): 1.0 Guaranteed Minimum Catalyst Bed Life (VULCAN A2ST 99) (years):

2

Guaranteed Maximum Exit Total COS Level (ppmv): 0.38 0.10 Expected Catalyst Bed Pressure Drop after 2 Years (bar): 0.247 0.201



Exit Composition (mol%): Hydrogen Nitrogen Carbon Monoxide Carbon Dioxide Methane Argon Hydrogen Sulphide Carbonyl Sulphide Ammonia Water Hydrogen Cyanide TOTAL:

21.980 6.200 44.170 3.200 0.010 0.050 1.300 0.000 0.005 23.080 0.005 100.000

*This Bed Volume is determined by the minimum acceptable contact time of 20 s. Please note that our HTS Catalyst (VULCAN VSG-F101) can cope with H2S levels up to 200 ppmv. The Client has stated that the AGR Unit will remove 99.95 % of all the H2S present (= 13000 ppmv). This means that after the AGR Unit there will still be 0.0005 x 13000 = 6.5 ppmv H2S present in the feed of the HTS Unit, which should be OK. However, if an LTS Section is required the H2S Level must be reduced to 0.1 ppmv, which means that at a temperature of 220oC a bed of VULCAN EZ200 Zinc oxide will be required.



H2S Removal Section after AGR Unit (2 Absorbent Beds (VULCAN EZ200) in Lead/Lag Arrangement Starting Point: 1 Total Feed Flow Rate, Feed Composition, and Direction of Flow, Inlet

Operating Temperature, And Inlet Operating Pressure: Total Feed Flow Rate (kmol/hr): 7535 Total Feed Flow Rate (Nm3/hr): 168889 Feed Composition (mol%): Hydrogen Nitrogen Carbon Monoxide Carbon Dioxide Methane Argon Water TOTAL

21.980 6.210 44.170 3.200 0.010 0.050 24.380 100.000

Direction of Flow: Downflow Inlet Operating Temperature (oC): 220 Inlet Operating Pressure (bara): 33.2 2 Inlet H2S and COS Levels: H2S (ppmv as S): 6.5* COS (ppmv as S): 0.0* *These values are the equilibrium values of the COS Hydrolysis reaction. 3 Client Requirements (All Cases): Required Guaranteed Absorbent Life per Bed (VULCAN EZ200) (months):

6 (Assumed)

Required Guaranteed Maximum Exit Total S Level (ppmv, expressed as S):

0.1

Required Expected Maximum Total Catalyst Bed Pressure Drop across H2S Removal Section after 1 Year (bar):

Unknown



4 Results: The Absorbent Bed Pressure Drops: Calculated Required Bed Volume of VULCAN EZ200 per Reactor (m

3):

64.6* (Order: 133 for 2 reactors)

Absorbent Bed Diameter D (m): 4.35 Absorbent Bed Height H (m): 4.35 H/D (-): 1.0 Guaranteed Minimum Bed Life per Absorbent Bed (VULCAN EZ200) for the Calculated Required Bed Volume (months):

8.5**

Guaranteed Maximum Exit Total S Level (ppmv): 0.1 Calculated Total Expected Absorbent Bed Pressure Drop for 2 VULCAN EZ200 Reactors after 1 Year (bar)***:

0.304

*This Bed Volume is determined by the minimum acceptable contact time of 25 s. **It is assumed that the sulfur slip from the first bed is allowed to increase to 90% of their inlet levels. ***These absorbents will be changed after 6 months.



ISOTHERMAL SWEET SHIFT SECTION: Alternative Approach

Simulation Input Data 1 Enthalpy method: 0 (Ideal gas) 2 Cases considered: Case 1A: Standard Case, 0 years expected (SOR). Case 1B: Standard Case, 2 years guaranteed = 4 years expected (EOR). Case 2A: Lower Inlet Operating Pressure, 0 years expected (SOR). Case 2B: Lower Inlet Operating Pressure, 2 years guaranteed = 4 years expected (EOR). Case 3A: Addition of 100 kmol/h N2, 0 years expected (SOR). Case 3B: Addition of 100 kmol/h N2, 2 years guaranteed = 4 years expected (EOR). 3 Feed stream data Cases 2A and

2B: Lower Inlet Operating Pressure

Case 3A and 3B: Case Addition of 100 kmol/h N2

Cases 1A and 1B: Standard Case

Inlet Temperature (oC): 210 Inlet Pressure (bara): 25.2 33.2 33.2 Inlet CO (kmol/h): 3325.3 3325.3 3325.3 Inlet CO2 (kmol/h): 184.7 184.7 184.7 Inlet H2 (kmol/h): 1654.1 1654.1 1654.1 Inlet N2 (kmol/h): 466.9 566.9 466.9 Inlet CH4 (kmol/h): 1.4 1.4 1.4 Inlet H2O (kmol/h): 8685.7 8685.7 8685.7 Inlet Ar (kmol/h): 2.9 2.9 2.9 TOTAL (kmol/h, wet): 14321.0 14421.0 14321.0 Inlet CO (mol%, wet}: 23.220 23.059 23.220 Inlet CO2 (mol%, wet}: 1.290 1.281 1.290 Inlet H2 (mol%, wet}: 11.550 11.470 11.550 Inlet N2 (mol%, wet}: 3.260 3.931 3.260 Inlet CH4 (mol%, wet}: 0.010 0.010 0.010 Inlet H2O (mol%, wet}: 60.650 60.229 60.650 Inlet Ar (mol%, wet}: 0.020 0.020 0.020 TOTAL (mol%, wet}: 100.000 100.000 100.000



4 Kinetics PROPRIETARY

5 Catalyst

PROPRIETARY 6 Catalyst Activity relative to standard

PROPRIETARY 7 Catalyst size and packing details

Default values were used. 8 Catalyst pressure drop parameters

PROPRIETARY (No pressure drop could be calculated, because reactor geometry is unknown).

9 Catalyst Volume

A typical GHSV of 5000 Nh-1 (wet) was assumed, which with a maximum Total Wet Inlet Flow Rate of 14421 kmol/h = 323232 Nm3/h, results in a Catalyst Bed Volume of 64.6 m3 (Order: 66.5 m3).

10 Standard die-off rate

PROPRIETARY 11 BFW Rate

A value of 300.000 t/h was assumed. This is much higher than the default value, because the process flow rates are very high. The Client provided no value.

12 Vapor fraction: 0 13 Steam Temperature = 220oC.

The value is lower than the default value of 250oC, because we need to avoid excessive process temperatures in the catalyst bed.

14 Steam Pressure.

A Steam Pressure of 23.201 bara was used, which is the Saturated Steam Pressure at 220oC.



15 Boiling Model: The default value PROPRIETARY

16 Volumetric UA:

0.03 MW/(m3K). this value is higher than the default value of 0.02 MW/(m3K), because we need to avoid excessive process temperatures in the catalyst bed.



Isothermal Shift Simulations Results Table 1: Exit Composition (kmol/h): Case 1A Case 1B Case 2A Case 2B Case 3A Case 3B CO 22.9 35.8 22.9 38.4 22.9 35.6 CO2 3487.1 3474.2 3487.1 3471.6 3487.1 3474.4 H2 4956.5 4943.6 4956.5 4941.0 4956.5 4943.8 N2 466.9 466.9 466.9 466.9 566.9 566.9 CH4 1.4 1.4 1.4 1.4 1.4 1.4 H2O 5383.3 5396.2 5383.3 5398.8 5383.3 5396.0 Ar 2.9 2.9 2.9 2.9 2.9 2.9 TOTAL 14321.0 14321.0 14321.0 14321.0 14421.0 14421.0 Table 2: Required Catalyst Type, Required Catalyst Bed Volume, Expected Approach-to-Equilibrium (WGS Reaction) and CO Slip:

Case 1A Case 1B Case 2A Case 2B Case 3A Case 3B Required Catalyst Type:

PROPRIETARY VULCAN SERIES CATALYST

Required Catalyst Bed Volume (m3):

64.6 (Order: 66.5)

ATE (oC): 1.0 22.5 1.2 26.2 1.0 22.2 CO Slip (mol%, dry):

0.26 0.40 0.26 0.43 0.25 0.39

Table 3: Maximum Catalyst Bed Temperature and Position: Case 1A Case 1B Case 2A Case 2B Case 3A Case 3B Maximum Bed Temperature (oC):

298.8 300.5 296.8 298.4 298.4 300.0

Position (Catalyst Bed Volume m3):

8.7 44.8 8.7 44.8 8.7 44.9



Comments:

• We can guarantee that the CO Slip after 2 years will always be less than the value indicated by the Client (= 1.2 mol% (dry)). We could perhaps at a later stage even offer a smaller catalyst volume. The CO profile found in the worst case (Case 2b) suggests that we could go as low as 55 m3.

• Catalyst Life: 2 years guaranteed.

• Catalyst Bed Pressure: At this stage it is impossible to calculate the pressure drop, because we know nothing about the geometry of this multi-tube reactor.

• There is very little difference in performance between the 3 Cases.



APPENDIX

(AGRU) ACID GAS SOUR SHIFT: CASE STUDY IN REFINERY GAS TREATMENT

Technology

Transcript of (AGRU) ACID GAS SOUR SHIFT: CASE STUDY IN REFINERY GAS TREATMENT