Title: Data Associated with, "Methane Emissions from Gathering and Boosting Compressor Stations in the U.S. Supporting Volume 2: Compressor Engine Exhaust Measurements

Abstract: The in-stack tracer method was used during the field campaign to measure unburned methane entrained in the exhaust of natural gas compressor engines (combustion slip). Combustion slip was estimated by injecting a tracer gas into the exhaust stream at a known flow-rate and measuring concentrations of both the tracer gas and methane at the exhaust stack exit. The total exhaust flow was estimated from the diluted tracer gas concentration measured at the exhaust stack exit.

Contact: Dan Zimmerle, dan.zimmerle@colostate.edu

Format: .csv

Location: Natural gas production basins in Colorado, New Mexico, Texas, Arkansas and West Virginia

Time Period: 07/17/2017 through 05/08/2018

File and Variable Information:
A .csv file containing results and supporting data for combustion slip measurements at natural gas gathering and boosting stations throughout the United States.

Data columns are as follows:

StudyID - A unique identifier assigned to each gathering an boosting station by the study team.

UnitID - A unique, sequential number assigned to compressor units by the study team.

Make - Manufacturer of the engine tested.

Model - Model of the engine tested.

RPM - Engine revolutions per minute during testing (if available).

EngType - Engine type according to US EPA AP-42 classifications. 
	4SLB = four-stroke, lean-burn. 
	4SRB = four-stroke, rich-burn.

RatedHP - Manufacturer or site rated horsepower of the engine tested.

Load - Fractional load on the engine during testing (if available).

LoadSource - Source of fractional load on the engine during testing. 
	Panel = electronic panel attached to the engine. 
	GERP = gas engine rating pro, a software tool for Caterpillar brand engines. 
	StackTester = emissions testing personnel present during testing. 
	Mechanic = personnel present during testing.

DistanceEstimateFt - Estimated distance along the exhaust flow in feet between the point of tracer gas injection and exhaust gas sampling.

NumSamples - Average number of samples during tests on a unit. Samples (measurements) were reported by instruments at 0.1 Hz.

StackSLPM - Average total wet exhaust stack flow predicted by the in-stack tracer measurements in standard liters per minute, referenced to 1 atmosphere and 25 degrees Celsius.

StackSLPMStd - Standard deviation of total wet exhaust stack flow during a test, or pooled standard deviation for multiple tests on a unit.

StackSLPMErr - Error of total wet exhaust stack flow during a test, or pooled error for multiple tests on a unit (see text for description).

CH4kgh - Mass flowrate of unburned methane entrained in the engine exhaust (combustion slip) in kilograms per hour, referenced to 1 atmosphere and 25 degrees Celsius.

CH4kghStd - Standard deviation of methane mass flowrate during a test, or pooled standard deviation for multiple tests on a unit.

CH4kghErr - Error of methane mass flowrate during a test, or pooled error for multiple tests on a unit (see text for description).

CH4ppm - Average measured methane concentration in the exhaust gases in parts per million.

CH4ppmStd - Standard deviation of methane concentration during a test, or pooled standard deviation for multiple tests on a unit.

CH4ppmErr - Error of methane concentration during a test, or pooled error for multiple tests on a unit (see text for description).

CO2Prcnt - Average measured carbon dioxide concentration in the exhaust gases in percent.

CO2PrcntStd - Standard deviation of carbon dioxide concentration during a test, or pooled standard deviation for multiple tests on a unit.

CO2PrcntErr - Error of carbon dioxide concentration during a test, or pooled error for multiple tests on a unit (see text for description).

H2OPrcnt - Average measured water concentration in the exhaust gases in percent.

H2OPrcntStd - Standard deviation of water concentration during a test, or pooled standard deviation for multiple tests on a unit.

H2OPrcntErr - Error of water concentration during a test, or pooled error for multiple tests on a unit (see text for description).

StratPass - Result of tracer stratification checks. 
	Pass = pass
	Fail = fail
	N/A = test not performed

TrrPass - Result of tracer recovery ratio checks. 
	Pass = pass
	Fail = fail
	N/A = test not performed

AP42_CH4kgh - Mass flowrate of unburned methane entrained in the engine exhaust estimated using US EPA AP-42 emission factors.

GHGI_CH4kgh - Mass flowrate of unburned methane entrained in the engine exhaust estimated using US EPA GHGI emission factors.

SubC_CH4kgh - Mass flowrate of unburned methane entrained in the engine exhaust estimated using US EPA Subpart C emission factors.































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































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