Failures of reactor effluent air cooler

Failure of Reactor Effluent Air Cooler (REAC) in Hydrocracker Units.

A Literature Search Muhammad Ramli Ahmad Bahri/ Syed Sham Ariff Muhammad Amani/ Noraini Dahlan/ Mohd Faiz Md Izani 19th March 2018 Pengerang

http://www.totalenergy.com/SNGPlant/Section100Exchangers.htm#PhotoE102

Fion Zhang/ Charlie Chong

Reactor Effluent Air Cooler (REAC)

REAC

Reactor Effluent Air Cooler (REAC)

NH3 + H2S →NH4HS

https://www.honeywellprocess.com/library/marketing/whitepapers/CorrosionNACE06_Paper_06577.pdf

Reactor Effluent Air Cooler (REAC)

Reactor Effluent Air Cooler (REAC)

https://www.osha.gov/dts/hib/hib_data/hib19940729.html

Reactor Effluent Air Cooler (REAC)

https://www.nickelinstitute.org/~/media/Files/KnowledgeBase/Presentations/20151126Duplex%20Stainless%20Steel%20Congress%20ChinaGary%20CoatesEnglish.ashx

Reactor Effluent Air Cooler (REAC)

https://www.nickelinstitute.org/~/media/Files/KnowledgeBase/Presentations/20151126Duplex%20Stainless%20Steel%20Congress%20ChinaGary%20CoatesEnglish.ashx

Reactor Effluent Air Cooler (REAC)- Macrostructural Examination of the Failed Weld Joints of REAC fire at Indian Refinery of DSS Construction.

https://store.nace.org/492e2a5c-a5ba-e311-a396-0050569a007e

Reactor Effluent Air Cooler (REAC)- EDS at Ductile Fracture Location of REAC fire at Indian Refinery Energy Dispersive X-Ray Spectroscopy (EDS) EDS was carried out at the ductile fracture location, at the ductile-brittle (mixed mode) fracture location, and at the brittle fracture location during SEM examination. The presence of Chlorides (0.26% to 2.68%) along with Sodium (0.32% to 1.61%), Magnesium (0.11% to 0.48%), Aluminum (0.13% to 0.65%), Silicon (0.22% to 1.40%), Sulfur (0.58% to 2.17%), Calcium (0.23% to 0.37%) are reported. EDS reports are shown in Figures 14 (a), (b), (c).

https://store.nace.org/492e2a5c-a5ba-e311-a396-0050569a007e

Reactor Effluent Air Cooler (REAC) - Fire at ConocoPhillips Refinery

https://www.nickelinstitute.org/~/media/Files/KnowledgeBase/Presentations/20151126Duplex%20Stainless%20Steel%20Congress%20ChinaGary%20CoatesEnglish.ash

01 O

bjective

Initiated by the bulletin1 from one REAC licensor on the possible failure of REAC with DSS construction, literature search was conducted to investigate the possible root cause of REAC tube explosion. From the literature search there have been several fire incidences of REAC failure2,3,4 with 8 publically reported serious incidents worldwide with significant impact3.

Root cause analysis was conducted based on this literature search; summary and recommendations were suggested. Detailed manufacture data book MDR reviews were performed. Conclusion on the quality of equipment fabrication and reliability of equipment was make.

1 2 3 4 5

CLG’s bulletin to Petronas on DSS REAC failures.

Failure Analysis of Reactor Effluent Air Cooler (REAC) in a Hydrocracker Unit https://www.nace.org/cstm/PaperTrail/Authors/Submission.aspx?id=a32f252b-9da1-e211-ac5b-0050569a007e SURVEY OF CORROSION IN HYDROCRACKER EFFLUENT AIR COOLERS. https://www.researchgate.net/publication/282387247_SURVEY_OF_CORROSION_IN_HYDROCRACKER_EFFLUENT_AIR_COOLERS Corrosion of Reactor Effluent Air Coolers https://www.onepetro.org/conference-paper/NACE-97490 Nickel Institute article Special Considerations for Welding of Thick Duplex Stainless Steel by Gary Coates https://www.nickelinstitute.org/~/media/Files/KnowledgeBase/Presentations/20151126Duplex%20Stainless%20Steel%20Congress%20ChinaGary%20CoatesEnglish.ashx

02 D

amage Mechanism for REAC

REAC Failure

For REAC failure, depending on the material of construction, there were two kinds of failure at the tube to tube-sheet welding (1) Ammonia bisulfide corrosion for carbon steel 6 and (2) Stress corrosion cracking 5,7 (Sulfide stress corrosion) for corrosion resistance alloys including duplex stainless steel DSS.

3 6 7

Ammonia Bisulfide Sour Water Corrosion: Thinning/ Erosion

Carbon Steel

Stress Corrosion Cracking SCC/ Sulphide Stress Cracking

Corrosion Resistance AlloyDuplex Stainless Steel & Stainless Steel

For DSS REACSulphide Stress Cracking is the principle failure mechanism. 2,3

Nickel Institute article Special Considerations for Welding of Thick Duplex Stainless Steel by Gary Coates https://www.nickelinstitute.org/~/media/Files/KnowledgeBase/Presentations/20151126Duplex%20Stainless%20Steel%20Congress%20ChinaGary%20CoatesEnglish.ashx API571 Chapter 5.1.1.2 Ammonium Bisulfide Corrosion (Alkaline Sour Water) CLG Bulletin https://www.cbi.com/getattachment/b93f3734-f9f4-4263-97db-de12fa77cd8f/Reactor-Effluent-Air-Cooler-Safety-through-design.aspx

03 C

ASE STUDY

Case Study 1: Failure Analysis of Reactor Effluent Air Cooler (REAC) in a Hydrocracker Unit https://www.nace.org/cstm/PaperTrail/Authors/Submission.aspx?id=a32f252b-9da1-e211-ac5b-0050569a007e

A major fire incident took place in Reactor Effluent Air Cooler (REAC, 04-EA-001 D) of the Hydrocracker Unit (HCU) on April 07, 2012 evening at 18.35 hrs. in one of the Indian refineries. The cooler had failed after a period of 2 years in operation. Among four air coolers (04-EA-001 A, B, C & D), 04-EA-001 C & D were severely damaged. The damage in air cooler (04-EA-001C) was less in comparison with air cooler (04-EA-001D). Cracks were observed on the welding joints between top plate & tube sheet, bottom plate & tube sheet of the floating header of air cooler (04-EA-001D). The reactor effluent air coolers (04-EA-001A/B/C/D) were designed by the hydrocracker process licensor for the process fluid (HHPS vapour - H2+H2S+NH3+HC+ Water).

The material of construction was Duplex Stainless Steel (DSS) conforming to UNS S32205. The documents related to fabrication of the air cooler (04-EA-001D) were reviewed. Visual inspection, liquid penetrant testing and ultrasonic thickness measurement were carried out on the failed portion of the air cooler (04-EA-001D). A systematic metallurgical investigation such as Scanning Electron Microscopy (SEM), Energy Dispersive x-ray Spectroscopy (EDS), mechanical testing was conducted on the failed samples as a part of a failure analysis.

High hardness and low charpy impact energy indicted a very less ductile weld metal. Porosities and slag inclusions at weld root were acceptable in radiography examination, but their presence was in favour of localized corrosion (crevice and pitting) for the intended service. The higher percentage of chlorides was reported in EDS results. DSS material had suffered crevice and pitting corrosion as the metal temperature was about 100°C. Localized corrosion at weld root was corroborated the ductile fracture (dimples) by SEM. Once crack was initiated at weld root by localized corrosion mechanism, there was continuous charging of the weld by high pressure process fluids during operation. A complete failure was attributed to the reactor effluent air cooler (04EA- 001D) by a combination of low ductile and hard weld metal at very high pressure of process fluid. The sudden failure of the weldment was characterized by brittle mode of fracture (cleavage).

 Case Study 2: CUSTOMER BULLETIN: Failures in Duplex Stainless Steel Reactor Effluent Air Coolers in High Pressure Hydrogen Service November 2017 Chevron Lummus Global bulletin to Owner.

Summary This Bulletin is to notify CLG licensees of reports of failures of duplex stainless steel (DSS) 2205 reactor effluent air coolers (REACs) in high pressure hydro processing service in the refining industry, and to advise them of recommendations where these DSS REACs are in service. For those licensees with existing DSS REACs in operation, CLG recommends that a risk assessment and mitigation plan be promptly implemented to validate that any DSS REACs were fabricated rigorously to CLG's DSS standards by qualified vendors and to perform additional inspections on existing DSS REACs. Going forward, CLG will specify either Carbon Steel or Alloy 825 (see below) as options for hydroprocessing REAC service in our future designs. Based on service conditions, licensees should also consider replacing their existing DSS REACs in high pressure service (1000 psi hydrogen partial pressure and higher) with Carbon Steel or Alloy 825.

History Duplex 2205 has been widely recommended throughout the industry for use in REACs over the last twenty years. However, licensees and others have reported failures of DSS REACs in high pressure, hydro processing services. For example, a published report concerning this topic can be found in the paper PVP2016-63927, Proceedings of the ASME Pressure Vessels and Piping Conference, July 17- 21, 2016, Vancouver, British Columbia, Canada . In addition, API RP 932-B, Design, Materials, Fabrication, Operation, and Inspection Guidelines for Corrosion Control in Hydroprocessing Reactor Effluent Air Cooler (REAC) Systems, 2"d Edition 2012, Section 7.2.2 (API RP 932-B), discussed duplex stainless steel failures and attributed those failures to improper fabrication and hydrogen embrittlement cracking. At the 2013 AFPM annual meeting, and at its 2014 Licensee symposium, CLG presented an industry paper titled "Reactor Effluent Air Cooler (REAC}: Safety Through Design" which highlighted CLG's stricter fabrication and welding practices which are above and beyond those specified in API TR 938C and explained select design considerations that are incorporated in a basic engineering package for licensees.

Initial problems associated with Duplex 2205 appeared to be controlled through CLG's stricter fabrication protocols. However, preliminary review of recent failures has shown that variations in fabrication practices can cause DSS REACs to be vulnerable to failure.

 Case Study 3: Quality-controlled replacement of carbon steel with Duplex 2205 for revamps can increase the service life and reliability of the REAC in the high-pressure loop Chevron Lummus Global https://www.cbi.com/getattachment/b93f3734-f9f4-4263-97db-de12fa77cd8f/Reactor-Effluent-Air-Cooler-Safety-through-design.aspx

…………….. Duplex 2205 REAC failure can be attributed to not respecting the

guidelines specific to duplex material. ………………………. …. Hardness values in the heat-affected zones (HAZ) and at the weld of failed specimens were higher than those recommended (in the range of 313359 HV10 vs 310 HV10 maximum). As a result, CLG concluded that REAC failure in this case was due to sulphide stress cracking (SSC).

 Case Study 4: Special Considerations for Welding of Thick Duplex Stainless Steel The 5th China International Duplex Stainless Steel Congress Gary Coates Beijing, China , 26 Nov. 2015 https://www.nickelinstitute.org/~/media/Files/KnowledgeBase/Presentations/20151126Duplex%20Stainless%20Steel%20Congress%20ChinaGary%20CoatesEnglish.a shx

REAC vessels – scope of the problem  There have been 8 publically reported serious incidents worldwide  This resulted in a joint MTI (Materials Technology Institute) and API (American Petroleum Institute) activity to identify the root cause and prevent other failures.  Many 2205 REACs were operating without any problems  A REAC is used in hydroprocessing which involves hydrogen at high temperature and pressure.  Sulphur and nitrogen compounds are converted by a catalyst in the first stage reactor to hydrogen sulphide and ammonia. As the effluent stream from the reactor cools down, the ammonia and hydrogen sulfide combine to form solid ammonia bisulfide.  In the absence of liquid water, the ammonia bisulphide condenses directly from the vapor phase to form a crystalline solid which can result in rapid plugging.  To prevent this plugging, water is injected ahead of the REAC. This prevents fouling, however, a highly corrosive ammonium bisulphide solution is created. High rates of carbon steel failures led the industry to select duplex 2205 (S31803 or S32205) for REAC and associated piping as the most economical alloy choice meeting the corrosion requirements.

REAC vessels – history and investigation  Higher ferrite and high hardness in the 2205 welds were noted in many of the failures reported. Sometimes only one weld pass had the high ferrite, but it was the weld exposed to the corrosive conditions.  Sulphide Stress Cracking is the principle failure mechanism.  Some REACs are made of Ni-Cr-Mo Alloy 825 (N08825), and have not reported any issues. 825 is not susceptible to the same issues as the 2205 duplex alloy. However 825 is more expensive and not as strong as 2205.

Case Study 5: Failure Analyses: In Retrospect Nurul Asni Mohamed PETRONAS Group Technical Solutions asnimo@petronas.com Co-authors: Norhariti Hassan and Naimah Azizan Malaysian Refining Company Sdn Bhd (MRCSB) Failure Analyses: In Retrospect Corrocon Paper No.11851 http://www.nace-malaysia.org/docs/corcon2017/corcon2017-nurul-asni-full-paper.pdf

During the commissioning of the DSS 2205 in 2002, leak of one air-fin cooler bundle was detected along with the smell of H2S. Snoop or bubble leak test was performed and leaks were observed to have occurred at various tube to tube sheet welds of all four REAC tube bundles. A detailed root cause failure analysis was conducted with tube samples sent to a third party failure analysis laboratory in the UK. The results revealed that the tube to tubesheet weldments failed due to sulphide stress cracking (SSC) which occurred during the introduction of H2S containing hydrocarbon gas along with the presence of water. ….. At the point of the investigation conclusion, the principal causes of the observed failures were the initiation of Sulphide Stress Cracking at the weld surface, due to the limited tolerance of the localised ferrite content of the tube to tubesheet weldments of DSS 2205 to the process environment.

 Case Study 6: Prediction And Assessment Of Ammonium Bisulfide Corrosion Under Refinery Sour Water Service Conditions https://www.honeywellprocess.com/library/marketing/whitepapers/CorrosionNACE06_Paper_06576.pdf

Abstract This paper summarizes results of a joint industry program (JIP) to address ammonium bisulfide (NH4HS) corrosion in H2S-dominated alkaline sour waters typically found in refinery services such as the reactor effluent air cooler (REAC) systems of hydroprocessing units. The impacts of several process variables on corrosion were quantified. Key learnings support a paradigm shift from the rules of thumb previously applied to these systems. Data collected were used to develop a software tool to predict the corrosion rate of 14 materials evaluated in the program.

FIGURE 4 – Material Resistance to NH4HS Corrosion

 Case Study 7: Reading on NACE “Corrosion Control in The Refining Industry”

Corrosion Control in The Refining Industry January 2010

7.4.5 Effluent Air Coolers Effluent air coolers are probably the piece of equipment most vulnerable to ammonium bisulfide (NH4HS) corrosion. Most plants initially install carbon steel tubes for effluent air coolers, but some units with high Kp values have installed duplex stainless steel, alloy 800, or alloy 825.

Duplex stainless steels, such as type 2205, are increasingly used for tubes and header boxes, but special requirements should be imposed on the materials as well as the fabrication and welding practices. Welds or HAZs that do not have the proper ratio of austenite/ferrite in their microstructure can be susceptible to hydrogen embrittlement and SSC.

 Case Study 8: Reading on NACE MR0103/ISO 17495-1:2016 ANSI/NACE MR0103/ISO 17495-1:2016 Petroleum, petrochemical and natural gas industries — Metallic materials resistant to sulfide stress cracking in corrosive petroleum refining environments A.7 Duplex stainless steels (identified as material types) A.7.1 Materials chemical compositions Table D.7 lists the chemical compositions of some duplex stainless steel alloys that can, but do not necessarily, meet the restrictions of this materials group. In some cases, more restrictive chemistries than those shown in the Table D.7 are needed.

13.8 Duplex stainless steels 13.8.1 General requirements for duplex stainless steels 13.8.1.1 Wrought and cast duplex stainless steel products shall be in the solution-annealed and liquid-quenched condition. Tubing shall be rapidly cooled by liquid quenching, or by air or inert gas cooling to below 315 °C (600 °F). The ferrite content shall be 35 vol% to 65 vol%.

13.8.1.2 The hardness of grades with PREN ≤ 40,0 % according to Formula (1) shall not exceed 28 HRC. 13.8.1.3 The hardness of grades with PREN > 40,0 % according to Formula (1) shall not exceed 32 HRC. 13.8.1.4 Brinell hardness measurements obtained on duplex stainless steels cannot be converted to Rockwell C hardness values using existing tables in ASTM E140 or ISO 18265. Use of empirically derived tables for this hardness conversion is subject to the approval of the end user.

13.8.2 Welding requirements for duplex stainless steels Fabrication and repair welds in all wrought and cast duplex stainless steels shall be produced using a welding procedure qualified by performing the following tests on specimens taken from the WPQT coupon(s). a)

A hardness survey shall be performed in accordance with Annex C. The average hardness shall not exceed 310 HV, and no individual reading shall exceed 320 HV.

b)

Metallographic ferrite measurements shall be performed in accordance with ASTM E562. The average ferrite content in the weld deposit and HAZ shall be within the range of 35 % to 65 %, with a relative accuracy of 10 % or lower.

Note: 13.7.2 … PREN = %Cr + 3,3 (%Mo + 0,5 × %W) + 16 × %N (https://www.bssa.org.uk/topics.php?article=111)

 Case Study 9: Reading on “A Study of Corrosion in Hydroprocess Reactor Effluent Air Cooler Systems” API PUBLICATION 932-A SEPTEMBER 2002 API PUBLICATION 932-A SEPTEMBER 2002

5.3 REACTOR EFFLUENT AIR COOLERS Where corrosion has been serious and persistent, unit operators have sometimes invested in Alloy 800 or Alloy 825 as a permanent solution. Alloy 800 has been used for at least 17 years with no major failures (Plant B); however, pitting corrosion has been reported (Plants Q and E) so that the long-term reliability has been put in question.

5.9 ALLOY SUBSTITUTION (CS) TO PREVENT CORROSION The alloy solution is costly. A recent study 10 concluded that to upgrade REAC exchanger and piping materials from carbon steel to Alloy 825 would cost $1 million for a hydrocracker unit with 6,160 ft2 of air cooler surface. Alternative solutions, however, carry more risk. This is because the parameters affecting corrosion are not quantitatively well defined and there often is great difficulty predicting the sites where the process parameters may fall outside of the guidelines. Some of the alternative materials selections to replace or upgrade from carbon steel have been discussed by Singh et al.11, and Shargay and Lewis12……..

Another approach to avoiding these problems was to employ duplex alloys which have inherent resistance to both phenomena. 3RE60 has been used successfully (Plant CC) downstream of the water injection point for more than 18 years with no plans to replace it. Alloy 2205 has been used for both air cooler tubes and piping with varying success. Problems can arise if the material is not properly specified and fabricated13. High residual hardness after welding can lead to sulfide stress cracking and must be avoided. In addition one respondent reported selective leaching of the ferrite phase by ammonium chloride.

 Case Study 10: Reading on: “Design, Materials, Fabrication, Operation, and Inspection Guidelines for Corrosion Control in Hydroprocessing Reactor Effluent Air Cooler (REAC) Systems” API RECOMMENDED PRACTICE 932-B SECOND EDITION, MARCH 2012

7.2.2 Duplex Stainless Steels Duplex stainless steels are often successfully used in these systems because they offer advantages of both the ferritic and austenitic stainless steel families. They are often cost effective due to their higher strength and reduced alloy element content compared to other higher alloys.

However, since this material consists of dual phase microstructure, heat-treating, fabrication and welding techniques need to be carefully reviewed and monitored to assure that the balanced microstructure is not compromised.13 In the past, Alloy 3RE60 was successfully used, but it had inferior corrosion resistance and toughness at the welds and is no longer available. The most commonly used grade today is Alloy 2205.

Duplex stainless steels have failed by hydrogen embrittlement cracking in these services, but these problems were attributed to improper fabrication. Specific considerations to minimize the possibility of deterioration are to specify a minimum of 0.14 % N content and a water quench. This helps avoid intermetallic precipitates. Weld procedures should be developed to assure ferrite content in the 35 % to 65 % range (measured by ferrite scope). Higher ferrite content can lead to hydrogen-related cracking and reduced corrosion resistance. There have been a few failures in duplex stainless steel header box welds and duplex stainless tube-to-tubesheet welds the designer or user need to be aware of. Additional guidance on materials and fabrication practices to achieve good corrosion resistance in duplex stainless steels are given in API 938-C. Super duplex stainless steels such as Alloy 2507 are predicted to perform better than Alloy 2205, and hence are promising for resisting severe environments.

 Case Study 11: Reading on: “Use of Duplex Stainless Steels in the Oil Refining Industry” API TECHNICAL REPORT 938-C SECOND EDITION, APRIL 2011

5.3 Hydrogen Stress Cracking/SSC ……..A newer NACE standard (MR0103-2007) [10] is similar to older versions of NACE MR0175 but is targeted for the refining industry. It limits DSS base materials in severe wet sour services are 28 HRC maximum hardness. It also limits ferrite content to 35 to 65 volume percentage for weld procedure qualification, but that was based on earlier versions of this document (API 938-C).

Some welding restrictions are also given including thickness and heat input limits.

SSC susceptibility is dependent on many variables: partial pressure of H2S, pH, chloride content, temperature, microstructure, hardness, cold work, surface finish, etc. In the NACE TM0177 [11] test for SSC, most DSS do not show any cracking until the applied stress is well above the proof strength. Cold work decreases the threshold failure stress. Figure 10 shows suggested chloride and H2S partial pressure limits for S31803 and S32760 based on testing by TWI. [2] There have been SSC failures in refinery applications; however, they have been attributed to improper fabrication. The hardness limit of 310 HV average (320 HV max) for weld procedure qualification given in Annex B, along with the tight control of welding variables to help ensure that the production welding matches the qualified procedures, are the primary means of minimizing the risk of HSC/SSC. The 25 % Cr DSS require a higher limit due to their higher yield strength, and testing indicates they are acceptable to higher values.

04 D

iscussion

Hydrocracking, or hydroprocessing, is a two stage process combining catalytic cracking and hydrogenation. Sulfur and nitrogen compounds are converted by a catalyst in the first stage reactor to hydrogen sulfide H2S and ammonia. As the effluent stream from the reactor cools down, the ammonia and hydrogen sulfide combine to form solid ammonium bisulfide NH3 + H2S →NH4HS. Ammonium bisulfide, also called ammonium hydrogen sulfide (NH4HS).

At REAC the process stream also contained variable amount of uncombined hydrogen sulfide (H2S), ammonia (NH3) and hydrogen chloride (HCl)

NH4HS precipitates out of the gas phase in the reactor effluent stream (REAC) at temperatures below about 150°F (66°C), depending on the concentration of NH3 and H2S, and may cause fouling and plugging unless flushed away with wash water.

NH4HS salt deposits lead to under deposit corrosion and fouling. The salts are not corrosive unless they become hydrated at which point they are very corrosive.

Oxygen and iron in the wash water injected into hydroprocessing reactor effluent can lead to increased corrosion and fouling. Presence of cyanides increases severity of corrosion in FCC gas plants, coker gas plants and sour water stripper overheads by destroying the normally protective sulfide film.

NH4HS concentration, H2S partial pressure, velocity and/or localized turbulence, chloride ions, pH, temperature, alloy composition and flow distribution are all critical factors to consider. Corrosion increases with increasing NH4HS concentration and increasing velocity. Below 2 wt %, solutions are not generally corrosive. Above 2 wt % NH4HS, solutions are increasingly corrosive.

Depending on material of construction, REAC may fail by; Carbon Steel- Ammonia bisulfide corrosion8 DSS Duplex Stainless Steel- Stress Corrosion Cracking (Sulfide stress corrosion) Sulfide stress corrosion is initiated by the H2S in the process stream at REAC, it is a form of HAC Hydrogen Assisted Cracking.9,5,7,10 H2S corrosion in the presence of tensile stress may result in catastrophic failure as a result of hydrogen embrittlement by mechanisms such as Sulfide Stress Cracking (SSC) and Stress Corrosion Cracking (SCC).These failures are often delayed, but happen abruptly with no visible warning and may happen at stresses well below the yield strength. Factors contributing may include partial pressures of H2S and chloride ions concentration (HCL), temperature, pH, and stress.

NACE MR0103 serves as the industry guideline for selection of materials and welding for equipment used in sour service. This has also been specified by CLG bulletin for section dealing with dissimilar metal welding9.

5 Nickel Institute article Special Considerations for Welding of Thick Duplex Stainless Steel by Gary Coates https://www.nickelinstitute.org/~/media/Files/KnowledgeBase/Presentations/20151126Duplex%20Stainless%20Steel%20Congress%20ChinaGary%20CoatesEnglish.ashx 7 CLG Bulletin https://www.cbi.com/getattachment/b93f3734-f9f4-4263-97db-de12fa77cd8f/Reactor-Effluent-Air-Cooler-Safety-through-design.aspx 8 OSHA Hazard Information Bulletins: Corrosion of Piping in Hydroprocessing Units https://www.osha.gov/dts/hib/hib_data/hib19940729.html 9 Evaluation of the Susceptibility of Duplex Stainless Steel 2205 to Hydrogen Assisted Cracking in REAC Systems http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2590542 Download paper: https://etd.ohiolink.edu/pg_10?0::NO:10:P10_ACCESSION_NUM:osu1471554106 10 Evaluation of the Susceptibility of Duplex Stainless Steel 2205 to Hydrogen Assisted Cracking in REAC System https://etd.ohiolink.edu/pg_10?0::NO:10:P10_ETD_SUBID:117471

05 L

iterature search- Summary & Recommended Actions:

The RC Root Cause & conclusion of DS2205 REAC failures; -The failure of REAC with DSS 2205 construction is at the welding area -Appearance or Morphology of Damage - Crack -The Nickel Institute & Licensor CLG point the root cause to sulfide stress cracking SSC -The Licensor attributing the SCC susceptibility to poor welding practices (high hardness & austenite/ferrite ratio) -NACE Publ. “NACE Corrosion Control in The Refining Industry” indicated that improper ratio of austenite/ferrite may lead to SCC -NACE MR0103/ISO 17495-1:2016, specified the requirement of maximum harness and austenite/ferrite ration

Compliances for Reliable and Safe Operation; In addition to Licensor recommendation1,7, REAC equipment shall be checked on compliances with NACE MR0103/ISO 17495-1:2016 to ensure reliable and safe operation.

(Licensor recommendations were checked and were found to be in lined with NACE MR0103 requirements) 1 7

CLG Bulletin CPM-SU-5011-E: Materials & Fabrication Requirements For Duplex Stainless Steel CLG Bulletin https://www.cbi.com/getattachment/b93f3734-f9f4-4263-97db-de12fa77cd8f/Reactor-Effluent-Air-Cooler-Safety-through-design.aspx

 Quality follow-up: (Equipment being delivered) Clarification with Licensor (if necessary): - Check with Licensor the relevancy of NACE MR0103 as a mean of material requirements and welding requirements. With further clarifications on: 1. NACE MR0103 was quoted for dissimilar welding only 2. Why REAC was not specified by Licensor to be meeting metallurgical requirements of MR0103/ISO 17495-1:2016?

- Checks/ reaffirms with Licensor on the suitability of equipment material of construction on the operation conditions and expected variations.

- Check on Licensor recommendations on parent material and welding, whether inline with PTS, NACE MR0103/ISO 17495-1:2016 requirements (The Licensor recommendations on A/F ratio and hardness were found to be inline with NACE MR0103)

MDR Reviews: - Review REAC MDR (manufacturer data record) ▪ MTR ▪ Welding ▪ Tube bending infor.

▪ Fabrication records

Site Verification: (if necessary) -Performed hardness & ferrite testing on the adjacent parent metal & finished weld accessible to testing near tube sheet.

-Performed internal assessment with respect to PTS, NACE MR0103/ISO 17495-1:2016 & Licensor parent metal & weld recommendation; (Licensor: Hv310 max/ 40-60% in the base metal and 35-60% in the weld metal. These were inline with NACE MR0103/ISO 17495-1:2016)

-Feed back to the Licensor the hardness survey data for advice on the reliability of equipment.

-Only weld cap hardness could be performed

06 C

ompliance Check

Based on the literature search summary recommendations; compliance check on equipment actually fabricated, was performed by MDB (Manufacturer Data Book) reviews for compliances with; - NACE MR0103/ISO 17495-1:2016 - Licensor welding recommendation CLG; CPM-SU-5011-E

Compliance Check Code/ Specification

MR0103/ISO 17495-1:2016

CLG CPM-SU1 5011-E

Base Metal

Weldment & HAZ

Heat Treatment

A/F Ratio

Hardness

PREN

Heat Treatment

A/F Ratio

Hardness

Consumable

Solutionannealed and liquidquenched condition

The ferrite content shall be 35 vol% to 65 vol%.

PREN ≤ 40,0 % HRC≤ 28 (286 Hv) PREN > 40,0 % HRC ≤ 32 (318 Hv)

PREN ≤ 40,0 % HRC≤ 28 (286 Hv) PREN > 40,0 % HRC ≤ 32 (318 Hv)

As weld

The average ferrite content in the weld deposit and HAZ shall be within the range of 35 % to 65 %.

The average hardness shall not exceed 310 HV, and no individual reading shall exceed 320 Hv.

Not Specified

Materials shall be furnished in the annealed and water quenched condition

Ferrite content at these locations shall be 40-60% in the base metal

Post weld heat treatment (PWHT) is prohibited unless specified by the Company

Ferrite content at these locations shall be 35-60% in the weld metal.

Hardness shall not be above Hv310.

Sandvik 22.8.3L or Sandvik 25.1 0.4.L or 25.1 0.4.LR 22.9.3.LR Avesta 2507/P100 Avesta 2205

As weld

Note 3 A1: Within Range A5: Within Range D1: Within Range B1: Within Range

Note 4 A1: 245/256/268/246/235 A5:262/266/275/243/252 D1:247/277/260/254/251 B1:243/255/270/265/263

Avesta 2205 Sandvik 25.1 0.4.L

Actual 11,12 (Weld)

Actual (Material) 2016083116289002

Cold finished, solution annealed & pickled

Within Range

248/248 246/248

35.376 35.497

BM / HAZ / W / HAZ / BM

1

CLG CPM-SU-5011-E: 2.0 MATERIALS b. Each heat of material shall be tested in accordance with ASTM A923 Test Methods A and C. c. The corrosion rate determined in Test Method C shall not exceed 10 mdd and the results specified in the Certified Materials Test Report (CMTR).

(ASTM A923 - 14 Standard Test Methods for Detecting Detrimental Intermetallic Phase in Duplex Austenitic/Ferritic Stainless Steels) 11 Project REPORT NO: FCR-2016-519-2 Sample: TF10 12 Project REPORT NO: 21C15519-16-09-13 Sample: TF10

07 M

anufacturing Data Book Reviews

Finding Summary of Review on Part II Vendor’s MDB (Manufacturing Data Book) for REAC’s Duplex Stainless Steel from Package 2 No 1 2 3 4 5 6 7 8

Item

Comment

Qualification Certification Inspection Release Certificate Certificate of Conformity Manufacturer Data Report Certificate of Inspection Authority Nameplate Copy Material Welding i. Weld Map ii. Joint Configuration iii. WPS & PQR

No Comment No Comment No Comment No Comment No Comment No Comment No Comment

9 10 11 12

NDT Test Report of Production Test Plate Hardness Testing PMI Testing

13 14 15 16

Ferrite Check Report Surface Protection Dimensional Inspection Report Hydrostatic Test

17 18 19 20 21 22 23 24 25

Air Leak Test Report Approved Drawings Steel Sructure Motor Fan Vibration Transmitter Shop Running Test Inspection Test Plan Vendor Concession Request

No Comment No Comment Mechanical Test Reports were not attached however all the information had been included in PQR with stamped and reviewed by 3rd Party Inspector (HSB GS).

No Comment No Comment No Comment PREN Calculation (Production weld sampling), complied.

No description provided on reference point.

No Comment No Comment a. There is no Water Analysis Report attached. b. There is no copy of Pressure Gauge Calibration Report attached.

There is no copy of Pressure Gage Calibration Report attached.

No Comment No Comment No Comment No Comment No Comment No Comment No Comment No Comment

08 Operation Consideration: From the literature search there were insufficient corrosion data to fully understand and predict the corrosiveness of REAC over a wide range of concentration and velocity encounter during operations to avoid REAC failure13,14. The effect of other parameters such as pH, temperature, partial pressures of H2S and NH3, and solution contaminants such as oxygen, chlorides, and cyanides need to be quantified for safe operations. It is recommended the operation condition15,16, corrosion monitoring and inhibition shall be within the IOW integrity operating window as specified by the equipment licensor 7.

From the literature search, it sheds lights on corrosion tendency in REAC. It is therefore important that the Operation to develop a comprehensive inspection program and perform regular inspection monitoring of REAC plus the inlet and outlet piping during operation 17,18,19, detecting general corrosion, erosion, thinning and stress cracking in the early stages to avoid early equipment failure.

Inspection and continuous monitoring data (corrosion rates and damage mechanism )may be used to justify resistant materials upgrades such as Alloy 825 1, 7, 20 .

7

CLG bulletin https://www.cbi.com/getattachment/b93f3734-f9f4-4263-97db-de12fa77cd8f/Reactor-Effluent-Air-Cooler-Safety-through-design.aspx 13 API Publication 932-A, “A Study of Corrosion in Hydroprocess Reactor Effluent Air Cooler Systems”, (Washington, DC: American Petroleum Institute, 14 Prediction And Assessment Of Ammonium Bisulfide Corrosion Under Refinery Sour Water Service Conditions September 2002). https://www.honeywellprocess.com/library/marketing/whitepapers/CorrosionNACE06_Paper_06576.pdf 15 Aramco SAES-L-133: Corrosion Protection Requirements for Pipelines, Piping and Process Equipment, Clause 7.3.5 16 NACE Publication 01543 Design Considerations To Minimize Ammonium Chloride Corrosion In Hydrotreater Reac's https://store.nace.org/01543-design-considerations-to-minimize 17 Failure Analyses: In Retrospect Corrocon Paper No.11851 http://www.nace-malaysia.org/docs/corcon2017/corcon2017-nurul-asni-full-paper.pdf 18 API 574 Inspection Practices for Piping System Components 19 NACE Corrosion 97: Paper 490 Corrosion Of Reactor Effluent Air Coolers https://store.nace.org/2964ca67-dfca-4574-b034-df2c720e63e3 20 Prediction And Assessment Of Ammonium Bisulfide Corrosion Under Refinery Sour Water Service Conditions https://www.honeywellprocess.com/library/marketing/whitepapers/CorrosionNACE06_Paper_06576.pdf

09 CONCLUSION: On random checks on the MDB of 1211-E-107 & 1211-E-207, 1212-E-107 & 1212-E-207; checks were conducted on the material of construction and welding against CLG CPM-SU-5011-E and NACE MR0103/ISO 17495-1:2016 requirements. The equipment were found generally to be satisfactory with respect to Licensor welding recommendations and generally satisfy the NACE MR0103/ISO 17495-1:2016 requirements with comments a, b.

a For equipment to comply with MR0103/ISO17495-1:2016; WPS/PQR to be developed in accordance with Clause 13.8.2 with hardness survey

shall be performed in accordance with Annex C. For equipment to comply with MR0103/ISO17495-1:2016; On the fabricator’s WPS 11.04, PQR and other WPS, the welding procedure qualification hardness survey layout in accordance with MR0103/ISO 17495-1:2016, Annex C need to be submitted for review.

b

References: Ref No

Titles

Links

1

CLG’s bulletin to Petronas on DSS REAC failures.

Internal document.

2

Failure Analysis of Reactor Effluent Air Cooler (REAC) in a Hydrocracker Unit.

https://www.nace.org/cstm/PaperTrail/Authors/Submission.aspx?id=a32f252b-9da1-e211-ac5b0050569a007e

3

Survey Of Corrosion In Hydrocracker Effluent Air Coolers.

https://www.researchgate.net/publication/282387247_SURVEY_OF_CORROSION_IN_HYDRO CRACKER_EFFLUENT_AIR_COOLERS

4

Corrosion of Reactor Effluent Air Coolers.

https://www.onepetro.org/conference-paper/NACE-97490

5

Nickel Institute article Special Considerations for Welding of Thick Duplex Stainless Steel by Gary Coates.

https://www.nickelinstitute.org/~/media/Files/KnowledgeBase/Presentations/20151126Duplex%2 0Stainless%20Steel%20Congress%20ChinaGary%20CoatesEnglish.ashx

6

API571 Chapter 5.1.1.2 Ammonium Bisulfide Corrosion (Alkaline Sour Water)

https://www.techstreet.com/standards/api-rp-571?gclid=CjwKCAjws6jVBRBZEiwAkIfZ2sOgcvbnXzQqLcrigt6ZfFg5ZcLpmWqhONucPXS9xA28xF5ut48ERoCzg0QAvD_BwE&sid=goog&pro duct_id=1785786

7

CLG Bulletin

https://www.cbi.com/getattachment/b93f3734-f9f4-4263-97db-de12fa77cd8f/Reactor-EffluentAir-Cooler-Safety-through-design.aspx

8

OSHA Hazard Information Bulletins: Corrosion of Piping in Hydroprocessing Units

https://www.osha.gov/dts/hib/hib_data/hib19940729.html

9

Evaluation of the Susceptibility of Duplex Stainless Steel 2205 to Hydrogen Assisted Cracking in REAC Systems

http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2590542 https://etd.ohiolink.edu/pg_10?0::NO:10:P10_ACCESSION_NUM:osu1471554106

10

Evaluation of the Susceptibility of Duplex Stainless Steel 2205 to Hydrogen Assisted Cracking in REAC System

https://etd.ohiolink.edu/pg_10?0::NO:10:P10_ETD_SUBID:117471

11,12

Project MDR Project Report

Project MDR Project Report

References: Ref No

Titles

Links

13

API Publication 932-A- A Study of Corrosion in Hydroprocess Reactor Effluent Air Cooler Systems

https://www.techstreet.com/standards/api-tr-932-a?product_id=1035468

14

Prediction And Assessment Of Ammonium Bisulfide Corrosion Under Refinery Sour Water Service Conditions September 2002).

https://www.honeywellprocess.com/library/marketing/whitepapers/CorrosionNACE06_Pap er_06576.pdf

15

Aramco SAES-L-133: Corrosion Protection Requirements for Pipelines, Piping and Process Equipment, Clause 7.3.5

-

16

NACE Publication 01543 Design Considerations To Minimize Ammonium Chloride Corrosion In Hydrotreater Reac's

https://store.nace.org/01543-design-considerations-to-minimize

17

Failure Analyses: In Retrospect Corrocon Paper No.11851

http://www.nace-malaysia.org/docs/corcon2017/corcon2017-nurul-asni-full-paper.pdf

18

API 574 Inspection Practices for Piping System Components

https://www.techstreet.com/standards/api-rp-574?product_id=1936468

19

NACE Corrosion 97: Paper 490 Corrosion Of Reactor Effluent Air Coolers

https://store.nace.org/2964ca67-dfca-4574-b034-df2c720e63e3

20

Prediction And Assessment Of Ammonium Bisulfide Corrosion Under Refinery Sour Water Service Conditions

https://www.honeywellprocess.com/library/marketing/whitepapers/CorrosionNACE06_Pap er_06576.pdf

Charlie Chong/ Fion Zhang

UNS Number N08825 Other common names: Alloy 825, Inconel® 825 Incoloy 825 is a nickel-iron-chromium alloy with additions of molybdenum, copper and titanium. This nickel steel alloy’s chemical composition is designed to provide exceptional resistance to many corrosive environments. It is similar to alloy 800 but has improved resistance to aqueous corrosion.

It has excellent resistance to both reducing and oxidizing acids, to stress-corrosion cracking, and to localized attack such as pitting and crevice corrosion. Alloy 825 is especially resistant to sulfuric and phosphoric acids. This nickel steel alloy is used for chemical processing, pollution-control equipment, oil and gas well piping, nuclear fuel reprocessing, acid production, and pickling equipment.

Alloy 825 (UNS N08825) Chemical Composition, %

Ni

Fe

Cr

Mo

Cu

Ti

C

Mn

S

Si

Al

38.046.0

22.0 min

19.523.5

2.53.5

1.53.0

0.61.2

0.05 max

1.0 max

0.03 max

0.5 max

0.2 max

PREN = %Cr + 3,3 (%Mo + 0,5 × %W) + 16 × %N PREN min = 27.75

https://www.sandmeyersteel.com/images/SSC825-Spec-Sheet.pdf https://www.sandmeyersteel.com/A825.html

Duplex 2205 Duplex 2205 stainless steel (both ferritic and austenitic) is used extensively in applications that require good corrosion resistance and strength. The S31803 grade stainless steel has undergone a number of modifications resulting in UNS S32205, and was endorsed in the year 1996. This grade offers higher resistance to corrosion.

At temperatures above 300°C, the brittle micro-constituents of this grade undergo precipitation, and at temperatures below -50°C the micro-constituents undergo ductile-to-brittle transition; hence this grade of stainless steel is not suitable for use at these temperatures. The properties that are mentioned in the below tables pertain to flat rolled products such as plates, sheets and coils of the ASTM A240 or A240M. These may not be uniform across other products such as bars and pipes Alloy 825 (UNS N08825) Chemical Composition, %

Grade

C

Mn

Si

P

S

Cr

Mo

Ni

N

2205 (S31803)

Min Max

0.030

2.00

1.00

0.030

0.020

21.0 23.0

2.5 3.5

4.5 6.5

0.08 0.20

2205 (S32205)

Min Max

0.030

2.00

1.00

0.030

0.020

22.0 23.0

3.0 3.5

4.5 6.5

0.14 0.20

PREN = %Cr + 3,3 (%Mo + 0,5 × %W) + 16 × %N PREN min = 34.14

https://www.sandmeyersteel.com/A825.html http://www.duplex2205.net/difference-between-duplex-and-super-duplex-steel/

UNS Number N08825/ Duplex 2205 Comparison of DSS 2205 & Alloy 825 (UNS N08825)

Grade

C

Mn

Si

P

S

Cr

Mo

Ni

N

2205 (S32205)

Min Max

0.030

2.00

1.00

0.030

0.020

22.0 23.0

3.0 3.5

4.5 6.5

0.14 0.20

Alloy 8251

Min Max

0.05

1.0

0.5

-

0.03

19.5 23.5

2.5 3.5

38.0 46.0

-

1 Alloy 825 (UNS N08825) Other Chemical Composition not specified in DSS 2205, %

Grade Alloy 8251

Min Max

Cu

Ti

Al

1.5 3.0

0.6 1.2

0.2