Taken from SRA_AUG_Exp355
The primary purpose of this guide is to provide essential information to the onboard laboratory specialist to maintain the instrument. This document introduces characteristics, site preparation, and maintenance procedures for the SRA. Instrument set-up and operation procedures are presented in the SR Analyzer User Guide.
The SRA system consists of the following main components (Figure 1):
Figure 1. Main Components of the SRA System.
The Agilent autosampler can handle up to 100 samples (Figure 2). The tray is divided into quarter trays that hold 25 samples each. Each sample hole is numbered; these numbers must match the weighing container numbers.
confirm the relationship between the autosampler and pedestal (see
Autosampler Tray Arm Adjustment) and ensure the autosampler is connected to the main control unit with the serial cable connector (Figure 4).
Figure 2. Autosampler Tray.
Figure 4. Serial Cable Connector to the Main Control Unit.
Gas flow controllers and temperature control units are located inside the main control unit (Figure 5). Gas flow procedures and a flow circuit diagram are available in the Flow Control & Calibration section.
Figure 5. Internal View of the SRA Main Control Unit.
Four gas connections are available on the rear panel (Figure 6). Each tube is a different color and/or size to differentiate the gases:
White numbers on the connections indicate the appropriate flow rate for the different gases. The four gas tubes connect to the gas ports on this panel. To adjust gas flows, review the Flow Control & Calibration section.
Figure 6. Gas Flow Control Knobs on Rear Panel of Main Control Unit.
The IR section (Figure 7, Figure 8) contains CO and CO2 detectors in series, pump, tubing, and power supply. The pump pulls a split of sample gases from the oven to the IR absorbance detectors. A pressure controller in the IR unit maintains a constant gas pressure between the oven and IR detectors. The CO and CO2 detectors function as infrared detectors with maximum sensitivity set to detect the wavelengths of CO and CO2, respectively. Results from these detectors are used to determine S3 and S4 parameters.
Figure 7. CO and CO2 Detectors without Insulating Covers.
Figure 8. Internal View of the SRA IR Section.
The FID detector combusts pyrolysis products in a hydrogen/air flame (Figure 9, Figure 10). Both the energy released upon combustion and the temperature at which the pyrolysis products are generated reveal hydrocarbon characteristics. Results from this detector are used to determine S1, S2, and Tmax parameters.
WARNING! During operation keep the FID unit covered to avoid injuries (the FID temperature is 325°C; be careful when handling to prevent serious burns—even when the unit is covered).
Figure 9. Internal View from Side of SRA FID Unit.
Figure 10. Internal View from Top of FID Unit.
Combustion gases for the FID, electric cables for oven and FID control, cooling air tube for oven, and sample gas transport pipes with hydrocarbon filter are located at the back of the FID (Figure 11). The filter needs to be replaced periodically when it turns brown (see Maintenance). The FID cover panel must be in place during operation.
Figure 11. Back of SRA FID Unit.
Configuration options for the SRA software are organized in 6 tabs within the Configuration screen:
The Factory tab contains settings for hardware controls (Figure 12).
Figure 12. SRA > Configuration > Factory Tab.
The General tab specifies the instrument name, data path, analysis type, and gas settings (Figure 13).
Figure 13. SRA > Configuration > General Tab.
In the Report(s) tab (Figure 14), sample reports (CO, CO2, FID, TEMP) are selected and .CSV File Creation is selected for Individual Sample Report and Sequence Report. Make sure Printer is not selected.
Figure 14. SRA > Configuration > Report(s) Tab.
The Pedestal tab configures the seal and purge position numbers and the purge delay time (Figure 15). Generally, these positions do not need to be adjusted. Default Purge Delay (Seconds) is set to 150. To light the FID flame, on the Pedestal tab reseal the oven by completing the following:
Figure 15. SRA > Configuration > Pedestal Tab.
If the autosampler is disconnected, reconnect and click on the AS Tray tab to adjust the pedestal and calibrate the autosampler (Figure 16; see instructions in Autosampler Tray Arm Adjustment).
Figure 16. SRA > Configuration > AS Tray Tab.
The Temperatures tab controls oven and FID detector temperatures (Figure 17). To protect the detector, FID gases must be flowing when the detector temperature is >150°C. If gases are not on and FID temperature is >150°C, type a lower temperature in the Detector (FID) Standby Temperature field and select Send Temperatures Immediately to reset detector temperature. Standard Temperatures tab settings are as follows:
Figure 17. SRA > Configuration > Temperatures Tab.
The Method Editor screen has three active tabs:
In the Acquisition tab (Figure 18), an SRA acquisition method can be defined, comments about the method entered, and FID gain (attenuation) set.
Figure 18. SRA > Method Editor > Acquisition Tab.
In the Temperatures tab (Figure 19), the oven temperature program and FID temperature setting are specified. The oven program determines the rate at which S1 and S2 fractions are pyrolyzed and sent to the detectors.
Figure 19. SRA > Method Editor > Temperatures Tab.
Any time a new standard material is used to calibrate the SRA, it must be documented in the Standard tab, where the standard name and known values are recorded (Figure 20).
Figure 20. SRA > Method Editor > Standard Tab.
To measure a high TOC sample, the following method settings are recommended:
Gas flow and gas pressure are set by hand on the SRA system. These gas flow systems must be checked:
Carrier gas (He) and oxidation gas (O2) flow into the oven from the bottom of the pedestal. Adjust these gas flows as follows.
Figure 21. Gas Flow Measuring Equipment.
Figure 22. Main Menu Screen.
Figure 23. Gas Flow Settings on General Tab.
FID gas flow can be measured either from the front or back of the SRA. To measure gas flow in the front (Figure 24), the FID cover must be removed. However, the stainless steel gas tube from the joint to the FID has little flexibility, so FID gas should be measured from the back of the instrument (Figure 25).
Figure 24. Gas Terminals Connected to the Front.
Figure 25. Gas Terminals Connected to the Back.
To measure and adjust gas flow from the rear of the instrument, follow these steps.
Figure 26. Gas Flow Measurement.
At the end of the sample gas line, a small vacuum pump brings sample gases from the oven to the IR detectors. The pressure controller keeps constant pressure between the oven and IR detectors. The pressure controller is in the IR section of the SRA (Figure 27).
Figure 27. Pressure Controller (yellow).
This gas line does not need to be measured with the flowmeter; simply adjust the gas pressure to ensure that the gas pressure is ~40 psi on the pressure meter (Figure 29). To adjust gas pressure, turn the dial on the rear panel of the IR section of the SRA unit (counterclockwise for higher flow or clockwise for lower flow; Figure 28).
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Routine maintenance of the SRA includes the following. Additional troubleshooting information (i.e., encountered problems) is available in the binder and log books.
Maintenance | How Often | See |
Calibrate IR detectors | Once per year | IR Calibration |
Adjust autosampler tray arm | After autosampler tray is disconnected | Autosampler Tray Arm Adjustment |
Change filter behind FID back panel | When it turns brown | FID Unit Filter |
Warm up 6 hr | After power shutdown | SRA Instrument Preparation section in the |
Calibrate with Calibration Standard | After power shutdown With each batch or 1 per day | Quality Assurance/Quality Control section in the SR Analyzer User Guide |
The IR must be calibrated at least once a year. Turn the instrument on at least 2 hr before calibrating. Calibration history records are located on the side panel of the instrument. Use the following standardized gases to calibrate the SRA (method error is 5% [~500]).
Figure 30. Shortcut to IR Calibration.
Figure 31. IR Calibration Screen.
The position of the autosampler can seriously affect measurement results. After movement or installation of the autosampler unit, use the following procedure to confirm the positional relationship between the autosampler and the pedestal.
Figure 32. AS Tray Tab.
The hydrocarbon filter on the back of the FID unit is filled with a white powdery substance (Figure 11). When the material in the hydrocarbon filter turns brown, replace the filter by disconnecting tubing from top and bottom.
Warning! Burn hazard—replace FID protective cover before operating the FID.
Humble Geochemical Services
Weatherford Core Evaluation Services
218 Higgins Street Humble, TX 77338
Tel: 281-540-6050
Fax: 281-540-2864
Web: www.humble-inc.com
E-mail: sales@humble-inc.com
The following vendor support documents can be downloaded from Cumulus:
FID lab air -> CO2 trap -> moisture trap -> unit
CO2 : proprietary formulation
Moisture trap
SRA User Guide: 29th September 2022
LMUG-SRAAdvancedUserGuide-230220-1925-170.pdf