MARATHON ASHLAND PETROLEUM LLC

REFINERY ENGINEERING SPECIFICATIONS

SPECIFICATION NO.

SP-99-05

PAGE 1 OF 3

CORE REV. 5 02/21/95

POSTWELD HEAT TREATMENT OF EQUIPMENTHANDLING ALKALINE SOLUTIONS

TABLE OF CONTENTS

SECTION PAGE

1.0 Scope...............................................................................................2

2.0 Summary of Additional Requirements..............................................2

3.0 Equipment Subject to Heat Treatment.............................................2

4.0 Procedures.......................................................................................3

5.0 Testing.............................................................................................3

MARATHON ASHLAND PETROLEUM LLC

REFINERY ENGINEERING SPECIFICATIONS

SPECIFICATION NO.

SP-99-05

PAGE 2 OF 3

CORE REV. 5 02/21/95

POSTWELD HEAT TREATMENT OF EQUIPMENTHANDLING ALKALINE SOLUTIONS

1.0 SCOPE

This specification covers mandatory requirements for determining the need for, and performing postweld heat treatment for the prevention of caustic embrittlement of all welded carbon steel equipment including piping handling alkaline solutions.

2.0 SUMMARY OF ADDITIONAL REQUIREMENTS

Table 1 lists the code and standard which shall be used with this specification.

TABLE 1

Codes, Standards & Specifications

ASME CodeSection VIII Pressure Vessels, Division 1

API StandardsAPI 945-RP A Study of the Effects of High-Temperature, High-

Pressure Hydrogen on Low-Alloy Steels

NACE CodesNACE-RP 0472-87

ANSI StandardB31.3 Petroleum Refinery Piping

3.0 EQUIPMENT SUBJECT TO HEAT TREATMENT

3.1 Caustic Services. The following equipment for handling of caustic solutions shall be postweld heat treated:

a. All equipment provided with steam tracing.

b. All equipment containing heating coils not provided with high temperature alarms, including equipment operating at a temperature below the “Tsr” temperature as determined per subpar.c.

c. All equipment for handling solutions which have a concentration factor greater than two degrees Baume’ and a solution design temperature greater than Tsr as determined by the following formula:

Tsr = 170 - C

where Tsr = caustic solution temperature in degrees F, above which temperature heat treatment is required.

MARATHON ASHLAND PETROLEUM LLC

REFINERY ENGINEERING SPECIFICATIONS

SPECIFICATION NO.

SP-99-05

PAGE 3 OF 3

CORE REV. 5 02/21/95

C = concentration of caustic solution in degrees Baume’.

3.2 Postweld heat treatment is not required for equipment handling caustic solutions in concentrations of two degrees Baume’ or less, or when solutions of any concentration are at atmospheric temperatures.

3.3 All equipment handling potassium carbonate, except Catacarb solution containing inhibitor, having a concentration greater than 2% (by weight) shall be postweld heat treated if:

a. The metal temperature exceeds 200°F, or

b. The equipment contains a heating coil not provided with high temperature alarms.

3.4 All equipment handling monoethanolamine solution in concentrations greater than 2% ( by weight) shall be postweld heat treated if:

a. The metal temperature is 150°F or above and the absorbed acid gas contains at least 80% CO2, or

b. The metal temperature is 200°F or above, regardless of the type of acid gas absorbed.

4.0 PROCEDURES

4.1 For all equipment except field fabricated tanks and piping, the postweld heat treatment procedure outlined in the ASME Code Section VIII, par. UW-40, UW-49 and UCS-56, shall be followed. The exemptions provided for in the notes to Table UCS-56 are not permitted. The minimum holding time at the full postweld heat treatment temperature shall be 45 minutes.

4.2 For large field fabricated tanks, where it is impractical to perform the postweld heat treatment required by par. 4.1, lower temperatures may be employed as permitted by ASME Code Section VIII, Table UCS-56, Note (1), but the requirements of par. 4.1 shall be met in all other respects. Procedures shall be approved by Marathon Engineering, and a copy of continuously recorded postweld heat treatment temperature shall be provided to Marathon Engineering.

4.3 For piping, the postweld heat treatment procedure outlined in ANSI B31.3, par. 331, shall be followed, except that the specifications in Table 331.2.1 are mandatory and the exemptions in par. 331.3.2 (a) and (b) are not permitted. Socket welded and seal welded threaded connections for all pipe sizes shall also be postweld heat treated. The minimum soaking period at the full postweld heat treatment temperature shall be 45 minutes.

4.4 Attachment of clips, brackets, or other devices requiring welding directly to the inside or outside of vessel or piping walls after postweld heat treatment is not permitted unless a reheat treatment is performed on the equipment or material.

5.0 TESTING

MARATHON ASHLAND PETROLEUM LLC

REFINERY ENGINEERING SPECIFICATIONS

SPECIFICATION NO.

SP-99-05

PAGE 4 OF 3

CORE REV. 5 02/21/95

5.1 After postweld heat treatment is performed, the equipment shall not be deformed during handling and erection.

5.2 Hammer testing of postweld heat treated materials and equipment shall not be permitted.