May 18, 2012

MEMORANDUM

SUBJECT: Meeting notes for the May 17, 2012 Conference Call with AF&PA & Industry 

Representatives

FROM: John Bradfield

Kelley Spence

TO: Docket EPA-HQ-OAR-2007-0544

This memorandum summarizes the conference call between the American Forest and Paper Association 

(AF&PA), pulp and paper industry representatives, and the U.S. Environmental Protection Agency (EPA)

on May 17, 2012. This meeting was requested in response to the risk and technology review (RTR) of the 

national emission standards for hazardous air pollutants (NESHAP) for the pulp and paper industry. The 

agenda for the meeting is provided in Attachment 1.

Meeting Attendees:

Mark Aguilar-Georgia-Pacific John Bradfield-EPA/SPPD

Amy Artmeier-Kapstone Debra Dalcher-EPA/SPPD

Corey Brandt-RockTenn Robin Dunkins-EPA/SPPD

Mike Curtis-Georgia-Pacific Bill Schrock-EPA/SPPD

Russ Frye-Counsel for AF&PA Kelley Spence-EPA/SPPD

Rich Garber-Boise Inc. Nick Swanson-EPA/SPPD

Tim Hunt-AF&PA

Rob Kaufman-KCPS Katie Hanks-RTI

Duane Mummert- Kapstone Tom Holloway-RTI

John Piotrowski-Packaging Corp. of America Corey Gooden-RTI

Jeff Shumaker-International Paper

Vipin Varma-NCASI
Discussion Points:

• Discussions during the meeting followed the industry handout in Attachment 2 regarding industry 

responses to the NCASI survey on noncondensible gas (NCG) venting.

• Final discussions focused on the next steps (as shown in Attachment 1), including a follow-up 

meeting (date TBD).
Attachment 1

Agenda for EPA-AF&PA Subpart S RTR SSM Issues
Agenda for EPA-AF&PA Subpart S RTR SSM Issues

May 17 from 1 to 3 PM

(call info: 919-541-4332)

Introductions – Call Objective 

 Deepen EPA understanding of events occurring in pulp mill processes and 

pollution control systems (and their interrelationships) 

 Explore application of current and proposed excess emission allowances and 

SSM provisions to anticipated and unanticipated pulp mill events 

 Discuss process for considering SS&M issues in light of July 31 schedule 

Startup and Shutdown 

 Examples of Start-up or Shutdown events that trigger NCG system venting 

 If EPA drops SS&M language in venting allowance, how would it work? EPA

Malfunctions 

 Distinguish transport system equipment breakdowns from process equipment or 

final control device failures 

 Review understanding of distinction between reportable malfunctions and 

anticipated operating scenarios 

 How and when would affirmative defense work? EPA

Next Steps 

 Identify additional information needs 

 Clarify process for considering SS&M issues 

 Confirm additional meetings 
Attachment 2

Preliminary Summary of Industry Responses to NCASI Survey on Noncondensible Gas (NCG) 

Venting (May 17, 2012)
Page	1	

Preliminary Summary of Industry Responses to NCASI Survey on Noncondensible Gas (NCG) Venting

(May 17, 2012)

Pulp and paper manufacturing involves an intricate network of interconnected processes.  Unit

operations are tied together by virtue of raw material and intermediate product flows, as well as

through energy and chemical recovery loops.  Steam generated in the boilers is returned back to the

process to meet system heat/energy demands.  Recovered chemicals are brought back to the pulping

and causticizing systems through the recovery cycle.  The collection and transport of potentially

explosive noncondensible gases (NCG) occurs in a complex and interconnected system, parts of which

are under pressure while others are under vacuum.  “Fail‐safe” venting systems, interlocks, and

permissives1 ensure that these gases are transported safely to the thermal destruction device.

The NCASI Survey on NCG venting was distributed to NCASI and AF&PA members on April 30,

2012.  A total of 45 facilities have responded to the survey as of May 15, 2012.  This document

summarizes the key takeaways from the responses received and reviewed to date.  The interim

findings provided in this document will be further updated and potentially modified to reflect

additional responses, further considerations, and analyses.

As discussed below, intermittent venting episodes can be driven by a multitude of SSM and

non‐SSM events.  There is considerable heterogeneity in what triggers these venting episodes and

subsequently a lot of variability in how events are classified.  This survey attempts to differentiate the

drivers of these events and provides more information on the same.  

 Intermittent venting can be caused by Startup, Shutdown, and Malfunction (SSM) events.  In the

context of the NCG system, SSM conditions are unlike normal operation, create unique operating

conditions, and can trigger intermittent venting.

 Intermittent venting can also be caused by non‐SSM events that occur during normal operation

and are related to inherent process variability, transient conditions in the collection, transport, and

conditioning equipment, and the resulting tripping of interlocks.  These are currently reported as

part of the 1% and 4% venting allowances.

 In the context of the NCG collection and transport system, equipment malfunctions can also

include inoperability of transport and conditioning equipment including sensors, gas conditioning

equipment, and fiber/liquor separation equipment.  These devices can be rendered inoperable

due to transient process swings during daily operations.  This category  could include a broader

class of events than those ‘infrequent and reasonably preventable’ failures of process equipment

or the final control device.  

 

1

“Fail‐Safe Systems and Interlocks – A control logic that results in an alarm and/or an automatic venting event, when

monitored parameter falls outside acceptable ranges.   Non control logic / non computer controlled fail safe systems such

as rupture disks, water loop seals, and P/V breakers, are also designed to vent if electronic systems fail.  

Permissives – A set of active conditions that need to be satisfied before NCG gases are introduced into the

collection/transport system OR to the control device, e.g., steam flow into steam ejectors, complete steam purge before

introducing LVHC gases into transport system and control device.
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Page	2	

 Intermittent venting is a consequence of “Fail‐safe” systems, interlocks, and system permissives.  

These interlocks and the resulting intermittent venting are an essential “first line of defense”

against system failures and potential hazardous conditions, including catastrophic explosions.

 Interlocks and permissives are required components of any NCG system.  Insurance companies

consider these as ‘prerequisites of insurability’ and can refuse coverage for systems designed with

inadequate protection.

1. Intermittent NCG Venting can be caused by Startup and Shutdown (SS) events  

The industry survey has identified several unique operating scenarios, occurring during Startup and

Shutdown, that result in the temporary loss of permissives or that trip control interlocks.  These

scenarios are unlike those observed during normal operation and are typically not encountered when

the mill is operating in normal production mode.  Over 90% of the 45 facilities responding to this

survey have identified the following unique SS scenarios:

 Requirement to purge LVHC2 line before pulp mill start‐up to prevent air from entering the LVHC

system and control device and potentially causing an explosion.

 Transient venting of LVHC and HVLC2 sources due to slow "warm up" of a boiler where these gases

will be burned because of low process steam demand.  Overloading the boiler with combustible

gases when the boiler is not “ready” can cause explosive, unsafe conditions.

 Isolated venting of process equipment before achieving steady state operation.

 Intermittent venting of isolated sections of the transport system due to flow balancing, and

 Inability to resolve interlocks due to process variability during start‐up and shutdown.

Other unique scenarios identified by 15+ facilities as being applicable only to startup and shutdown

periods include:

 Low total NCG flow as systems are either going offline or coming online

 Control device instability during startup and shutdown

 Transient pressure swings when the digester and evaporators startup or shutdown, and

 High moisture resulting from reduced flows during startup and shutdown

Survey responses indicate there are unique operating scenarios pertaining only to SS that trigger

intermittent venting events.  In the preamble to the rule proposal, EPA stated there was no

information in the record indicating that operations (and attendant emissions) during startup and

shutdown conditions would differ from those during normal operations.  However, the information

being gathered in the survey indicates that SS conditions are not similar to normal operations with

respect to LVHC and HVLC control systems.  Therefore, further consideration of startup and shutdown

conditions is necessary.

2. Intermittent NCG venting can also be caused by non‐SSM events that occur during normal

operation due to inherent process variability  

 

2 LVHC – Low Volume High Concentration; HVLC – High Volume Low Concentration
3 

Page	3	

Another reason for intermittent venting events is normal process variability and operational swings

(both production related and individual sub‐system related).  Given the complexity and integrated

nature of the manufacturing process, process swings in one end of the system are expected to (and do)

cause ripple effects in other parts of the system.

Survey responses have identified several unique operating scenarios that arise due to inherent

process variability and result in transient tripping of control interlocks and intermittent venting

episodes.  All of the 40+ facilities responding thus far to the survey have identified three or more of the

following scenarios as being pertinent:

 Flow balancing issues among the various branches of the transport system

 Pressure or Temperature Parameters on Process Equipment outside normal operating ranges

 Flow Interlocks at or near Process Equipment (low flow to secondary blow heat condenser, etc.)

 Pressure, Temperature, Flow Interlocks at the Steam Stripper

 Pressure or Temperature Interlocks in Gas Transport System (overall system pressure, frequent

digester blows, variability, etc.)

 Temperature interlocks in Gas Conditioning System (condenser exit temp., cooling water

temperature,

 Flow Interlocks in Gas Transport System (overall system flow, cooling water flow, etc.)

 Steam Interlocks in Gas Transport System (Steam flow in Ejectors)

 Primary combustion device becomes unavailable (low steam rate, temporary loss of burner

permissive, flame‐out etc.)

 Back‐up combustion device also unavailable

 Switching between incineration points, and

 Low levels in chip bin due to disruption in chip feed

Other unique non‐SSM intermittent venting events, as identified by 15+ facilities include:

 Periodic testing of interlocks and safeguards

 Unplanned maintenance activity on isolated conditioning equipment

 Short duration pressure swings due to blow tank level variation, and

 Temporary plugging of flow meter lines

Unlike the events listed in Section 1, these interlocks and intermittent venting episodes all occur

during normal operation (These events can be differentiated from those occurring during Startup and

Shutdown, in part, by using the threshold parameters used by facilities to define SS conditions).

   
4 

Page	4	

3. Malfunctions can also result in intermittent venting episodes.  Four categories of malfunctions

can trigger venting, viz.; (a) those related to process equipment, (b) those related to the

thermal destruction device, (c) those related to equipment in the transport system portion,

including sensors, gas conditioning equipment, and fiber/liquor separation equipment, and (d)

those driven by uncontrollable events.

The industry survey has provided more information on the above four categories of events.  

Facilities responding to the survey identified the following types of malfunctions of process

equipment:

 Failure of control valves, accumulator circulation pumps, liquor heaters, pressure relief

devices etc.

 Malfunctioning condensers in the digester system or turpentine recovery system that either

overload the NCG system, trip flammability interlocks in the transport system or

temperature interlocks in the thermal destruction device  

 Foaming and level control variability in steam stripper due to liquor carryover or other

contamination in condensate feed caused by malfunctioning evaporator set

Malfunctions of the thermal destruction device are typically due to boiler tube leaks, flame‐outs,

burner plugging, or other major issues.  Malfunctioning components in the final pollution control

device like electrostatic precipitator (ESP) plates or induced draft (ID) fans are also identified in this

group. These malfunctions usually require venting of the system, followed by steps to carry out

troubleshooting and the unplanned shutdown/maintenance of the control device.

Malfunctions of transport and conditioning equipment, as identified in the survey, include the

following:

 Fans, ducting, mist eliminators, flame arrestors, dampers, or any other associated in‐line

equipment plugged or plugging

 Control logic malfunctions, distributed control system card failures, computer system failures

etc., and

 Sensors (Pressure relief valves, temperature / flow / pH / pressure sensors etc.) failing, which

renders the NCG system (or sub‐system) inoperable without fixing these devices

Other Malfunctions identified in the survey include those caused by uncontrollable events like loss

of power, water supply, instrument air, etc.