Follow-ups on P&R1 Questions

robert.j.morehouse to: Nick Parsons 02/25/2011 01:00 PM

Cc: Ken Hustvedt, Penny Lassiter

History: This message has been replied to and forwarded.

Nick:

As a follow-up to questions from last week's meeting I've included some

additional information below:

Flare systems for Butyl Rubber Source Category :

 Baytown Butyl Rubber: Control device for front-end Group 1 vents is

 FS-12, a dedicated flare with no flare gas recovery . [some safety

 devices would route, if a failure occurs, to the Chemical plant Flare

 Loop, which does have flare gas recovery ]

 Baton Rouge Halobutyl Rubber: Control device for front-end Group 1 vents

 is a primary flare (with a backup) that bypasses two interconnected

 loops with 4 flares so gases are not sent to the flare gas recovery

 system. (36" diameter on the main riser

Startup/Shutdown Considerations

 Recommended Procedures for Handling Group 1 Front-end Process Vents

 During Startup and Shutdown

Background: At some point in the startup and shutdown of Butyl Rubber and

Ethylene Propylene Rubber source category units the requirements to achieve

98% organic HAP removal and, additionally for halogenated vents 99% HCl

removal, cannot be met because the vents have inadequate heat content or

pressure. On shutdown, where the equipment is to be gas-freed, these

instances occur after feed forward has stopped and thus the vent streams

will contain only the organic HAP and halogen that is trapped in the

process equipment being vented. On startup of equipment that has been

gas-freed, flow-through of process gas must occur to displace the nitrogen

in the equipment. It may take several equipment volumes of process gas to

remove the nitrogen to the point where the Group 1 vent may be routed to

the thermal oxidizer/scrubber.

Proposed shutdown procedure: Keep halogenated Group 1 front-end process

vents aligned to the thermal oxidizer /scrubber until equipment to be

shutdown is isolated (i.e., no additional hydrocarbon or halogen is

entering the equipment) and depressured to the point where it can no longer

safely be routed to the thermal oxidizer /scrubber. Then either route the

vent to the flare or demonstrate by engineering analysis that the vent

contains <50 ppmv organic HAP. Route to the flare halogenated Group 1

front-end process vents that have been diverted from the thermal

oxidizer/scrubber and any Group 1 non-halogenated process vents that are

normally routed to the flare until either 1) the vent pressure is too low

to go to the flare, or 2) the vent contains <50 ppmv organic HAP as

demonstrated by engineering analysis . Then, the vent may be routed to the

atmosphere.
Proposed startup procedure (from point where equipment is under nitrogen

pressure): Align the Group 1 front-end process vent to the flare and begin

displacing nitrogen to the flare with process gas . For Group 1 front-end

process vents that are routed to the thermal oxidizer /scrubber for

compliance, route the vent to the thermal oxidizer /scrubber when the vent

composition is acceptable and 98% organic HAP destruction in the thermal

oxidizer/scrubber, based on engineering assessment.

Surge Control Vessels

 Baytown Butyl Rubber: 2 front-end surge control vessels both meet the

 Group 1 storage vessel criteria.

 Baton Rouge Halobutyl Rubber: 3 front-end surge control vessels meet the

 Group 1 storage vessel criteria.

Also, as I mentioned last week EPA's cost estimate has several fundamental

errors that we highlighted. I'd be glad to arrange a meeting with our cost

estimators to provide additional information if necessary .

Thanks,

Bob

Bob Morehouse

ExxonMobil

Office: 281-870-6524; Cell: 281-384-5390

robert.j.morehouse@exxonmobil.com