Comparison of MACT CC & NSPS Subpart Ja Requirements - Flares. Presented by: Stephen Walls, P.E. Trihydro Corporation

Transcription

1 Comparison of MACT CC & NSPS Subpart Ja Requirements - Presented by: Stephen Walls, P.E. Trihydro Corporation

2 Agenda Applicability Regulated Pollutants Emissions Limitations Compliance Strategy Monitoring Calibration and QA/QC Data reduction Root Cause Analysis/Corrective Action Analysis (RCA/CAA) Compliance Documents

3 Applicability NSPS Subpart Ja Refinery flare C-M-R after 6/24/2008 New connection or increase flow = modification Regardless of assist type - non-assisted, air, steam, pressure MACT Subpart CC Located at HAP major refinery - 10 tpy / 25 tpy HAPs Control one of nine source categories listed don t forget FCC, CRU, and SRU in MACT UUU Vent gas contains one of 27 HAPs listed in Table 1 = regulated material

4 Applicability (continued) Older flares (C-M-R on or before 6/24/08) excluded Ja, subject to CC Special use flares (e.g., hydrogen) may be subject to Ja, excluded CC (no regulated material) Fuel gas used as purge/sweep could trigger MACT CC Intermittent flares addressed in RTC for CC, not Ja Temporary flares addressed in RTC for both regs.

5 Regulated Pollutants NSPS Subpart Ja (criteria pollutants) Sulfur dioxide (SO 2 ) Reduce vent gas flow/reduce TRS concentration = less SO 2 emissions Other criteria pollutants PM, NO X, CO, VOC Reduce vent gas flow = less emissions of other criteria pollutants

6 Regulated Pollutants (continued) MACT Subpart CC (organic HAPs) 27 Table 1 HAPs and other inadvertent HAPs Continuous smokeless operation Low tip velocity Maintain vent gas heat content Maintain destruction efficiency = lower organic HAP emissions

7 Emissions Limitations NSPS Ja Sulfur dioxide 162 ppmv H 2 S flare vent gas Determined hourly on a 3-hr rolling average basis Sulfur dioxide and other criteria pollutants Baseline flow(s) = magic number(s) Set by refinery after minimization assessment Do not need to include pilot / purge gas (introduced after water seal) Multiple baselines allowed different operating scenarios

8 Emissions Limitations MACT CC Organic HAPs Compliance with enhanced operating standards = improve destruction efficiency Continuous operation of a pilot flame* Operate without visible emissions (VE)* Flare tip velocity < 60 fps or < 400 fps and v max * Combustion zone heat content > 270 Btu/scf* Dilution parameter > 22 Btu/ft 2

9 Emissions Limitations MACT CC (continued) Enhanced operating standards (*) similar to general requirements and not the same Gen. requirements different for different flare types MACT CC consistent for different flare types Only reference non-assisted, air assisted, and steam assisted flares MACT CC not limited to these types EPA feels general requirements inadequate

10 Compliance Strategy NSPS Ja Hard numeric limit H 2 S concentration flare vent gas Exceedance triggers excess emissions reporting Refinery established baseline flow(s) RCA/CAA process Flare SO 2 emissions and elevated vent gas flow (Q vg ) can trigger analyses Identify root cause and implement corrective actions in 45 days Documentation Driving toward flare gas recovery flare minimization assessment/cost-benefit analysis

11 Compliance Strategy MACT CC Enhanced operating standards Continuous pilot light No visible emissions when vent gas below smokeless capacity Actual tip velocity below applicable numeric standard NHV cz above 270 Btu/scf NHV dil above 22 Btu/ft 2 (air assisted flares)

12 Compliance Strategy MACT CC (continued) V max, NHV cz and NHV dil incorporate flare gas composition data (continuous GC, 8-hr sampling, or calorimeter) Pilot light requirements apply regulated material routed to flare VE requirements apply regulated material routed to flare AND Q vg less than smokeless capacity v tip requirements apply regulated material routed to flare for at least 15-min AND Q vg less than smokeless capacity NHV cz and NHV dil requirements apply regulated material routed to the flare for at least 15-minutes

13 Compliance Strategy MACT CC (continued) Smokeless capacity = magic number Single value not dependent upon operating scenarios May require input manufacturer/engineering May need to consider MW of vent gas Emergency flaring provisions and RCA/CAA trigger Driving toward flare gas recovery flare minimization assessment/cost-benefit analysis during S/U and S/D

14 Monitoring NSPS Ja Continuous vent gas flow RCA trigger Does not specifically address volumetric vs. mass flow meters Continuous H 2 S monitoring compliance with the 162 ppmv Continuous sulfur monitoring - SO 2 RCA trigger TRS monitoring not meant to be only H 2 S, COS, and CS 2 (total sulfur (Method 16A) H 2 S monitoring develop total sulfur-to-h 2 S ratio through sampling Representative SO 2 monitoring Single TRS or H 2 S monitor can be used for both meet span requirements Sampling approach approved using AMP

15 Monitoring MACT CC Continuous vent gas flow Ja required Volumetric (standard P and T corrected) Mass converted to volumetric with gas composition data or default Continuous P and T engineering calculation for volumetric flow Continuous assist media (air or steam) and supplemental fuel flow not Ja required Same monitoring options as vent gas flow Convert mass flow using default values gas composition may be required for refinery fuel gas Using fan speed and curve acceptable for air-assisted flares

16 Monitoring MACT CC (continued) Continuous pilot light monitoring Thermocouple, ultraviolet, infrared, etc. Redundancy Gas composition monitoring Continuous GC provide MW and speciation, automatic 8-hour sampling provide MW and speciation, manual Continuous calorimeter (optional H 2 analyzer) no MW or speciation, could rule out mass flow monitoring option

17 Monitoring MACT CC (continued) Visible emissions Method 22 observations Minimum daily for 5-minutes 5-minute when VE routinely observed (even if daily already performed) VE observed 1-min during 5-min observation extend to 2-hrs Video surveillance Continuous one frame every 15 seconds (time and date stamped) Video routed to continuously manned location

18 Monitoring (continued) NSPS Ja requirements apply Any time vent gas is routed to the flare MACT CC requirements apply When regulated material (27 HAPs in Table 1) routed to flare

19 Calibration and QA/QC Vent gas flow meters both regs. Same accuracy and calibration frequency Quarterly visual inspection waived under MACT CC if redundant sensors MACT CC requires additional visual inspection when flow exceeds manufacturer maximum flow rate for 24-hours

20 Calibration and QA/QC (continued) Pressure monitoring devices Different requirements in Ja and CC Ja calibrate quarterly and after manufacturer range exceedance CC calibrate annual and after manufacturer range exceedance CC requires quarterly inspection waived if redundant sensor CC review pressure data to check for monitor blockage

21 Calibration and QA/C (continued) MACT CC Table 13 (nothing in NSPS Ja) Temperature GC/Calorimeters additional GC requirements in (e) Assist media and supplemental fuel flow Sulfur/H 2 S monitoring devices (only NSPS Ja) Span differs by configuration Performance specification and test method differs by type of device H 2 S, TRS/total sulfur, SO 2

22 Data Reduction NSPS Ja Calculate rolling 24-hr flow Compare rolling 24-hr vent gas flow to appropriate BL + 500,000 scf/24-hr (RCA trigger) Calculate 3-hr rolling average H 2 S concentration from hourly data Compare 3-hr rolling average to 162 ppmv limit Calculate SO 2 emissions for each hour using total sulfur/trs data and vent gas flow and sum assume 99 percent conversion Approx. equation - Compare to 500 lbs/24-hr (RCA trigger) Some data may require moisture correction

23 Data Reduction MACT CC Review of pilot light and VE observation data Determine if standards exceeded Calculate volumetric flow, if required Compare volumetric flow to smokeless capacity Sum volumetric flow (vent gas, assist media, and supplemental fuel) for each 15-minute block Calculate NHV vg v tip, and v max for each 15-minute block using vent gas flow and composition data Compare v tip to applicable standard not hard limit, changes Calculate NHV cz, and NHV dil for each 15-minute block Compare to applicable standard Two different methods to calculate (direct and feed-forward) consistent for each flare

24 RCA/CAA RCA/CAA process is basically the same for both regs. 45-days and document MACT CC allows single RCA if both triggering conditions met during same event MACT CC does not exclude planned S/U and S/D events Reporting period Ja (24-hrs), CC (15-min)

25 RCA/CAA (continued) Triggering conditions are different NSPS Ja Emissions 500 lbs SO 2 /24-hr period Vent gas flow 500,000 scf above established baseline flow(s) MACT CC Vent gas flow exceeds smokeless capacity, regulated material is routed to the flare and either VE standard is exceeded or v tip standard is exceeded

26 Compliance Documents Both regs. require flare management plans (FMPs) Ancillary connection list General flare description MACT CC requires more assist media info Minimization assessment NSPS Ja - routine, fuel gas imbalance, and FGRU outage MACT CC - S/U, S/D, and emergency release Magic numbers NSPS Ja baseline flow(s) MACT CC smokeless capacity MACT CC requires detailed CPMS Plan

27 Conclusion Complying with MACT Subpart CC Leverage vent gas flow monitors installed for NSPS Ja Incorporate existing pilot light monitoring Incorporate existing assist media flow monitoring Evaluate current VE compliance and vent gas composition determination procedures Engage engineering early to determine unobstructed area and smokeless capacity Get DCS engaged early for data reduction

28 Presenter Stephen Walls, P.E. Senior Engineer

29 Questions? WHAT WHY WHERE WHEN WHO HOW