Am I a Peaking Unit? – Part 75, Appendix E An Alternative to CEMS Analyzers

Lucas L. Schneider, Senior Environmental Scientist

November 14, 2017

Presentation Overview

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• Appendix E – Does this apply to my unit(s)?

• Appendix E – How to comply with Appendix E.

• Appendix E – Q & A

What is a Peaking Unit?

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For a unit that reports emissions data year-round, peaking unit qualification depends on the annual capacity factor of the unit.

According to 40CFR-Part 72, a combustion unit is a peaking unit if it has:

- An average capacity factor of 10.0 percent or less over the past three years

- And, an annual capacity factor of 20.0 percent or less in each of the those three years

Definitions

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• Capacity Factor –

• (1) The ratio of the unit’s actual annual electrical output to the nameplate capacity times 8,760 hours.

• (2) The ratio of the unit's actual annual heat input to the maximum design heat input times 8,760 hours.

Appendix E Methodology

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• What is Appendix E?

• Pertains only to the monitoring of NOx emission rate

• Alternative methodology to monitor NOx emission rate, in lieu of installing CEMS.

Appendix E Methodology

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• What is required to use Appendix E?

• A correlation curve of NOx emission rate vs heat input rate must be derived from emission testing.

• The hourly unit heat input rate must be measured using the Appendix D methodology

• Hourly NOx emission rate must be determined from the correlation curve

Appendix E Methodology

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• When may Appendix E be used?

• If a unit is in one of the following program(s):

• Acid Rain Program

• CSAPR NOx Trading Program

• And, meets the definition of a “peaking unit”

• And, qualifies as oil-fired or gas-fired

What's Required for Appendix E?

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• Appendix D methodology must be used to measure hourly unit heat input

• Heat Input Rate (mmBtu/hr) = Fuel Flow Rate x Fuel GCV x Unit Conversion Factor

• Emission testing must be performed at four different loads to develop a correlation curve of NOx Emissions Rate to Heat Input Rate

Correlation Curve

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• Derived from emission test results

• Use Reference Method & 7E for combustion turbines

• Four-load NOx emission rate test for each type fuel combusted

• Four evenly-spaced load points ranging from minimum to maximum unit operating load

• Three runs performed at each load level

• Two years historical data used to establish minimum and maximum operating loads

Correlation Curve

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• Heat input rate must be determined using the fuel GCV and readings from a fuel flowmeter

• Fuel flowmeter must meet the requirements of Part 75, Appendix D

• Four parameters indicative of the unit’s NOx formation characteristics are monitored and acceptable ranges established during testing.

• If the unit uses water injection for NOx control, then water-to-fuel ratio must be one of the monitored parameters

Correlation Curves

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• NOx emission and Heat input rate are averaged at each load level

• Correlation curve of NOx emission rate vs heat input rate is constructed

• Curve segments are programmed into the data acquisition system

How are Hourly NOx Emissions Determined?

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• NOx emission rate (lb/mmBtu)

• Following data must be collected

• Fuel flow rate must be continuously monitored using an Appendix D fuel flowmeter

• And, periodic fuel sampling is required to determine GCV according to Appendix D

• Perform the following calculations

• Use measured fuel flow rates and GCV to determine hourly heat input rate

• Select from the correlation curve the NOx emission rate that corresponds to the measured hourly heat input rate

How are Hourly NOx Emissions Determined?

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• NOx mass emissions (lb)• Following data must be collected

• Fuel flow rate must be continuously monitored using an Appendix D fuel flowmeter

• And, periodic fuel sampling is required to determine GCV according to Appendix D

• Unit operating time must be monitored

• Perform the following calculations• Use measured fuel flow rates and GCV to determine hourly heat

input rate

• Select from the correlation curve the NOx emission rate that corresponds to the measured hourly heat input rate

• Multiply hourly heat input rate, NOx emission rate from the correlation curve and the unit operating time

Fuel Sampling Requirements

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• Pipeline Natural Gas• Annual sampling of total sulfur content

• Monthly determination of GCV

• Fuel Oil• Daily Sampling

• Or, composite sampling for up to 168 hours, using hourly flow-proportional sampling or continuous drip sampling

• Or, sampling after each addition of oil to the storage tank

• Or, sampling each delivery or Lot of fuel ( Sample may be taken from supplier’s storage tank or from the shipment tank upon receipt

Quality Assurance Requirements

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• Parameter Monitoring

• Hourly monitoring of the parameters that were monitored during the baseline emission testing.

• Missing data substitution must be used for NOx emission rate when:

• Any parameter is missing

• Any parameter is invalid

• Any parameter is outside the acceptable ranges established during the baseline emission testing

Data Acquisition System Console View

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Quality Assurance Requirements

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• Re-Testing

• Periodic Re-Testing

• Required once every 5 years (20 calendar quarters) to determine new correlation curves

• Unscheduled Re-Testing

• Required if any of the parametric data is outside the acceptable ranges determined during baseline emission testing for more than 16 consecutive unit operating hours

Appendix E Testing

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Quality Assurance Requirements

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• QA Plan

• Owner or Operator is required to develop and implement a quality assurance plan. Contents of the plan are specified in section 1.3.6 of Part 75, Appendix B and section 4 of Appendix E

Quality Assurance Requirements

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• QA Plan• Minimum requirements

• Include data and results from the initial and most recent NOx emission rate testing, including parametric data

• Include written record of the procedures used to perform the NOx emission rate testing

• Include quality-assurance parameters that are monitored and the acceptable values and ranges

• Include records of the monitored parametric data for each unit operating hour

• Fuel flowmeter must meet the on-going QA requirements of Appendix D

Loss of Peaking Status

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• A unit will lose its peaking status if the capacity factors have not been met for an Appendix E unit

• Loss of peaking status requires installation and certification of a NOx -diluent monitoring system by December 31 of the calendar year following the year in which peaking status is lost.

• A unit which has lost peaking status may qualify again for peaking status in a subsequent year only if capacity factor data for a three year period following the loss of peaking status show that the unit once again meets the requirements stated earlier.

Testing Requirements (2 units)

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• 4 Loads

• 3 Test Runs Required

• 3 Hours / Run

• ~ 2 Hour for Tester Calibrations and Other Work

• ~12 - 14 Hours / Test

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Questions?