SOP 4
Pulsed-fluorescence hydrogen sulfide analyzer
(TEI Model 45C)

 

Description and Principle of Operation

 

Hydrogen sulfide is converted catalytically at (200-400 °C) to SO2 with a converter (TEI Model 340) followed by measurement with a pulsed fluorescence SO2 detector (TEI Model 45C) (U.S. EPA. Method EQSA-0486-060) equipped with a high intensity xenon lamp. The analyzer is based on the principle that SO2 molecules absorb ultraviolet (UV) light and becomes excited at one wavelength, decay to a lower energy state, and emit UV light at a different wavelength (Equation 2).

 

SO2 + hv1 ® SO2* ® SO2 + hv2        (2)

 

where * refers to a molecule in an excited state. The emitted UV light is proportional to SO2 concentration and is detected by a PMT. The SO2 analyzer has a range of 0.05 to 100 ppm, a response time of 60 s with a 10 s averaging time, and a sample flow rate of 0.5 L/min. Full scale is adjustable up to 100 ppm. The data averaging time is adjustable up to 60 s. The guaranteed precision is 1% of reading or 1 ppb (whichever is greater) and the linearity is ±1% of full scale (TEI Model 340 H2S Converter Instruction Manual and Model 43C Pulsed Fluorescence SO2 Analyzer Instruction Manual).

 

Calibration

 

1.      Calibration Gases

 

Zero air, sulfur dioxide (SO2) in N2 and H2S [JN1] HHBHin N2 are used to calibrate the instrument. Unless SO2 is one of the target analytes, it is only used to check converter efficiency.

 

2.      Zero and Span Check Procedure for Analyzer Only

 

  • Record the calibration date and time in the lab notebook.
  • Detach the H2S inlet including the filter from the existing sampling manifold. Close the pipe adapter of the sampling manifold with a cap or plug.
  • Attach the H2S analyzer inlet tube to a calibration manifold.

 

Zero Gas Check

 

  1. Close regulator valve on the zero gas cylinder
  2. Open main valve on zero gas cylinder
  3. Insert the 1/8” ID tubing (from gas cylinder) into the calibration manifold connected to the valve; then open the regulator valve to allow gas flow. Zero gas is now flowing from the cylinder to the analyzers.
  4. Adjust regulator valve until airflow is 1 L/min (read from bottom of ball of the vent monitoring flow meter installed in outlet of calibration manifold). This provide a little extra zero air to the analyzers and keep the pressure inside the manifold close to the atmospheric pressure.
  5. Record time and analyzer display in lab notebook after display is stabilized (typically 5 to 10 minutes).
  6. Press MENU button on the SO2 Analyzer

a.   Select calibration press ENTER

b.   Select calibrate zero press ENTER

c.   When readings are stable press ENTER to zero the analyzer

d.   Press RUN

  1. Close regulator and remove tubing from zero gas cylinder

 

Span Gas Check (SO2)

 

1)      Close regulator valve on span gas cylinder

2)      Open main valve on the SO2 cylinder

3)      Insert 1/8” ID tubing (from gas cylinder) into the calibration manifold connected to the valve; then open regulator valve to allow gas flow

4)      Adjust regulator valve until gas flow is 1 L/min (read from bottom of ball of the flow meter).

5)      Record the time and analyzer display on the lab notebook after display is stabilized (typically 5 to 10 minutes).

6)      Press MENU on the SO2 Analyzer

a.       Select calibration press ENTER

b.      Select SO2 press ENTER

c.       Set SO2 value to concentration of the calibration gas

d.      When readings are stable press ENTER

e.       Press RUN

7)      Close regulator and remove tubing from gas cylinder

 

Span Gas Check (H2S)

 

1)      Close regulator valve on the span gas cylinder

2)      Open main valve on span gas cylinder

3)      Insert the 1/8” ID tubing (from gas cylinder) into the calibration manifold then open the regulator valve to allow gas flow

4)      Adjust regulator valve until airflow is 1 L/min (read from bottom of ball of the flow meter).

5)      Wait for 5 to 10 minutes for the display to stabilize, record the time and analyzer display on the lab notebook

6)      Press MENU on the H2S Analyzer

a.       Select calibration press ENTER

b.      Select H2S press ENTER

c.       Set H2S value to the concentration of the calibration gas

d.      When readings are stable press ENTER

e.       Press RUN

7)      Close regulator and remove tubing from gas cylinder

 

Post Calibration

 

Reattach the filters to the existing gas sampling system.

Check and close main valves on all cylinders

Calibration of the H2S analyzer is complete

 

Maintenance (to be completed)

 

 

 

List of Spare Parts (to be completed)

 

Manufacturer Contact Information

 

Thermo Environmental Instruments (www.thermoei.com)

8 West Forge Parkway

Franklin, MA  02038
Tel:  (508) 520-0430 ext. 6812
Fax: (508) 520-1460

Sales: Souphin A. Sithideth, Inside Sales Engineer, e6812, E-Mail:  SSithideth@thermoei.com
Service: Barry Pepin, Service Engineer, e6908, E-Mail:  Bpepin@thermoei.com

Calibration Record for the Hydrogen Sulfide Analyzer

 

Date of Calibration: __________________                                 Calibrated by: __________________

 

Time

Items

Unit =

Notes

:    :

Sample airflow (L/min)

 

 

:    :

Zero air applied

SO2

H2S

Cylinder P: _____ psi

:    :

Reading (ٱ PC, ٱ Analyzer)

 

 

:    :

Reading (ٱ PC, ٱ Analyzer)

 

 

:    :

Reset to zero gas

Yes/No

 

:    :

SO2 ( __ ppm) applied

---

---

Cylinder P: _____ psi

:    :

Reading (ٱ PC, ٱ Analyzer)

 

 

:    :

Reading (ٱ PC, ٱ Analyzer)

 

 

:    :

Reset to span gas

Yes/No

:    :

H2S ( __ ppm) applied

---

---

Cylinder P: _____ psi

:    :

Reading (ٱ PC, ٱ Analyzer)

 

 

:    :

Reading (ٱ PC, ٱ Analyzer)

 

 

:    :

Reset to span gas

Yes/No

:    :

New coefficient saved

Yes/No

:    :

Connect analyzers back to the CEM system.

 

 [JN1] NH3 measurement will be set at 0-50 ppm.