Ball Valves Material Compatibility

[Seba93]

Hi Guys -
I currently have a floating ball valve that operates in a Mono Ethylene Glycol (MEG) Regeneration Package. The piping spec that it is on is B1E (Carbon Steel, Pressure Class 300, Corrosion Allowance 3mm). I would like to replace it with a new design and am stuck with two options. If you can help me identify which one would be the best option and why. Appreciate your help.

Current Design
Design Standard: API 6D / API 608
Body Material: CS - ASTM A216 WCB
Valve Dim/Pattern: ASME B16.10 (Long)
Ball Material: 316 SS
Stem Material:316 SS
Seat Material:316 SS
Seat Seal: RPTFE
Stem Seal: RPTFE
Body Seal: RPTFE
Port/Bore; Full Bore

Shell: API 598 / API 60

FireSafe Design: API 6FA / API 607

Option #1 Graphite Seat

Design Standard: EB12 ASME B16.34
Body Material: CS - ASTM A216 WCB
Valve Dim/Pattern: ASME B16.10
Ball Material: CF8M
Stem Material: B29SS
Seat Material: Graphite
Seat Seal: Graphite
Stem Seal: Graphite
Body Seal: Graphite
Port/Bore; Full Bore

Shell: API 598

FireSafe Design: API 607

Option #2 Metal Seat

Design Standard: EB12 ASME B16.34
Body Material: CS - ASTM A216 WCB
Valve Dim/Pattern: ASME B16.10 (Long)
Ball Material: 431 SS w coating
Stem Material: 431 SS
Seat Material: 431 SS
Seat Seal: Metal
Stem Seal: Grafoil
Body Seal: AS2637 - 630
Port/Bore; Full Bore

Shell: MSS SP61

FireSafe Design: API 6FA