(188c) Metallurgy for Opportunity Crudes

To process more "opportunity crudes" through the sour crude unit at the ConocoPhillips Sweeny Complex, many equipment modifications have been made during the past 10 years. The unit has been in the process of debottlenecking over its entire lifetime but during the last 10 years, a stronger emphasis has been made to process more crude. During the period of 1995-2000, the Top Pump-Around exchangers were experiencing severe corrosion due to chloride salt deposition. These were upgraded to 2507 duplex stainless steel bundles. Installed new Desalter internals during the 2000 T/A. In August 2000, a new Coker was brought online. With the Coker came the "opportunity crudes" and the problem associated with them ? increased corrosion. The Crude Tower was revamped in 2001 to be able to process even more crude. This revamp included tray, packing and metallurgy modifications. With the increased charge rate and the "opportunity crudes" came equipment failures due to corrosion. During the 2004 T/A, the O.H. line and Top Pump-Around lines were replaced with Inconel 625 overlaid pipe. In 2005, a VAT (Vulnerability Assessment Team) was formed to study the increased corrosion problems, to identify equipment vulnerabilities throughout the entire crude processing system and develop procedures to reduce the corrosion and eliminate the vulnerabilities.

History

I. Top Pump-Around Exchangers (10: E-2's and 10: E-5's)

A. Failures

1. Tube Failures from increased chloride attack

2. Fouling ? iron sulfide, amine-chlorides

1. Experience - repairs

2. Still had failures in the carbon steel tubes.

4. Have seen pitting on 2507 Duplex Stainless Steel

2. Top Pump-Around Pumps (P-4's)
3. Failures

1. Severe Erosion-Corrosion of the "Cutwater"

2. Hole in pump case

3. Nipple failures

B. Experience ? repairs

1. Inconel 625 overlay on "registered fits"

2. Belzona

3. Corrosion coupons in pump discharge to determine best metallurgy for new pump case and discharge line.

4. Monel impeller

1. Through wall corrosion on body of valve
2. Sealing surfaces of the block valve

3. Through wall corrosion of downstream piping

4. DMV through wall corrosion

B. Experience - repairs

1. Furmanite/Belzona

2. Plug

3. Installed Hastelloy C-276 overlaid pipe

4. Furmanite

1. 18" elbow
2. Amine-Chloride (molasses)
3. Tray 8 corrosion (Top Pump-Around Draw tray)
4. Tell-Tale Hole leak on Top Pump-Around line ? Product saturated the insulation and caused a fire.

B. Experience - repairs

1. Furmanite

2. Carbon composite wrap (Diamond Wrap)

3. Inconel 625 clad pipe

4. Weld Cap and Hastelloy C-276 overlay

1. Installed weld neck flanges

2. Repaired with monel nozzles

3. Replaced with Inconel 625 clad pipe and 316 S.S. clad pipe

VI. Top Head of Crude Tower

1. Failures

1. Repaired Monel cladding

2. Installed Inconel 625 strip clad

3. Applied Belzona

2000 ? Started up Coker Unit to start processing Venezuelan crudes. Currently processing Maya and Merey.

2000 - Started using Baker-Petrolite as chemical vendor.

2001 ? Revamped the Crude Tower: added AL6XN packing and trays, added new AL6XN nozzles.

We have water wash injection in the O.H. line and at each of the O.H. fin fans.

2004 ? Increased charge from 160,000 bpd to 230,000 bpd.

May 2005 ? Organized VAT (Vulnerability Assessment Team) - decided that the Hamaca crude with MEA (used as a H2S scavenger) was forming Amine-chlorides. These Amine-chlorides were the mechanism to most of our corrosion.

October 2005 ? Started using G.E. BETZ as chemical vendor with their LoSalt technology. Injecting Citric acid/emulsion breaker into the desalter water, LoSalt into the Crude Tower O.H.

Set a new monthly crude throughput record of 255,711 B/D in July 2005 and then broke it again with 261,877 B/D in August!