SOW_cyliners and gases_12405B24Q0040.docx

BACKGROUND:

Airgas USA, LLC is the compressed gas company that has been providing this product to the Delta Water Management Research Unit, Jonesboro, AR location. Rental tanks and different gases are installed for our research unit’s specific needs in the laboratories. The tanks that the compressed gases come in are the property of Airgas USA, LLC.

Research requires the highest purity of specialty gases (99.998%). Needs to blend wider ranges of atmospheric gases needed for calibrating the three gas detectors of our GC2014 and GC2030 model gas chromatograph. Additionally, needs to provide near ambient concentrations of methane, nitrous oxide and carbon dioxide balanced with N2 gas with standard of deviation of <3%. This is critically important in our measurements of soil trace gases in agricultural fields. Ultra high pure carrier gases have the lowest impurity in the market which prolonged the use of all our gas filters and mole sieves.

OBJECTIVE:

1. To quantify total area- and yield-scaled N2O, CO2, and CH4 emissions from row crop fields using vented chamber method and fully automated gas chromatography system.

SCOPE – MINIMUM TECHNICAL REQUIREMENTS:

The regular purchase of high-quality special blend and carrier gases is crucial to support research projects on greenhouse gas emissions (GHG) from row crops. The vented flux chamber method coupled with gas chromatography will be used to quantify emissions of CO2, N2O, and CH4 from soil trace gas collected at weekly intervals throughout rice crop cycle in various experimental fields. Analyses of atmospheric gases such as CO2, N2O and CH4 concentrations will be conducted using the GC2014 and GC2030 automated gas chromatography (GC) systems equipped with ECD, FID, TCD detectors. Ultra-high-quality helium, zero-grade air gas, P5 and hydrogen gases in 300 and 200 tank sizes with 99.999% purity will be used to continuously run the GC. Standard certified special blend of gases are also needed to calibrate the GC instruments. Table 1 summarizes the description and frequency of support gases and calibration gases needed for the analyses of CO2, N2O and CH4 throughout the rice crop cycle (annual measurements). In emergency situations the Contractor may be required to provide same day delivery.

Table 1. Summary of required carrier gases and calibration gases needed to analyze atmospheric gases from experimental fields.

DELIVERABLES: Base Year, Option Year 1, Option Year 2, Option Year 3 and Option Year 4

Continuous supply of high-purity support gases and high accuracy calibration gases ensure the high quality GHG emission datasets. The same high purity gases are needed to maintain the high sensitivity and accuracy of GC detections from all three detectors.

This work provides high quality GHG emissions with minimum error of estimates from chamber method and GC instrument. It ensures high repeatability and the lowest coefficient of variance within each range of calibration gases and during span calibration.