TLG-837 Tail Gas Analyzer/Air Demand Analyzer main view

Sulfur Pit Analyzer

The TLG-837-SP Analyzer and Applied Analytics DEMISTER Probe is used to monitor the level of H2S that accumulates in the headspace of the sulfur pit.

  • Continuously measures H2S levels using UV-Vis spectrophotometer
  • Totally solid-state build with no moving parts — modern design for low maintenance
  • Additional software benches for up to 4 chemical analytes
  • Ultra-safe fiber optic design with no sample gas inside analyzer unit — world’s safest solution for this application

Request a Quote
Contact Us

Applications: Sulfur Pit Analyzer

Sulfur Storage Pit

A sulfur recovery unit (SRU) serves to remove H2S (and other sulfur-containing compounds) from incoming acid gas and convert it into elemental sulfur. A Claus process is the most common method used for an SRU. Sulfur that is removed during the Claus process is condensed and directed into a sulfur storage pit. The liquid elemental sulfur that is produced in the Claus process can contain upwards of 300 ppmw of dissolved H2S.

Over time, the dissolved H2S will off-gas into the headspace of the sulfur storage pit, creating an equilibrium between the gas and the liquid. The H2S that accumulates in the sulfur storage pit must be monitored. H2S has a lower explosive limit of 4% by volume, and can ignite when in contact with mechanical equipment such as pumps or compressors.

Sulfur Recovery Unit Feed Forward Analysis--Flow-Diagram-SRU

Sampling: Sulfur Pit Analyzer


The DEMISTER sampling probe was designed to be lightweight and compact, so it can easily be installed by a single technician. The probe is inserted into a flange on top of the sulfur pit, and continuously cycles sample gas. Ultraviolet light from the spectrometer inside the TLG-837-SP Analyzer travels to the head of the probe through a fiber optic cable, where it interacts with the sample before being returned to the analyzer via a second fiber optic cable. The light being returned to the analyzer is then analyzed via the ultraviolet absorbance measurement technique, and an H2S reading is displayed.

No sample is removed from the probe and brought into the TLG-837-SP Analyzer enclosure. This ensures that there is no risk of sample leaking inside of the analyzer enclosure, which minimizes the risk to plant operators. The DEMISTER Probe conditions the gas sample to remove any trace elemental sulfur vapor which may plug up the probe. This feature minimizes the required maintenance of the probe.

Tail Gas Demister Probe Demonstration

Specifications: Sulfur Pit Analyzer

Note: All performance specifications are subject to the assumption that the utility control panel and unit installation are approved by Applied Analytics. For any other arrangement, please inquire directly with Sales.

Measurement Principle Dispersive ultraviolet-visible (UV-Vis) absorbance spectrophotometry
Detector nova II™ UV-Vis diode array spectrophotometer
Spectral Range 200-800 nm
Light Source Pulsed xenon lamp (average 5 year lifespan)
Signal Transmission 600 μm core 4 meter fiber optic cables
Other lengths available
Sample Introduction In situ DEMISTER Probe
Analyzer Calibration Calibrated with certified calibration fluids; no re-calibration required after initial calibration; measurement normalized by Auto Zero
Reading Verification Simple verification with samples
Human Machine Interface Industrial controller with touch-screen LCD display running ECLIPSE™ Software
Data Storage Solid State Drive
Analyzer Environment Indoor/Outdoor (no shelter required)
Ambient Temperature Standard: 0 to 35 °C (32 to 95 °F)
With optional temperature control: -20 to 55 °C (-4 to 131 °F)
To avoid radiational heating, use of a sunshade is recommended for systems installed in direct sunlight.
Standard Outputs 1x galvanically isolated 4-20mA analog output per measured analyte
5x digital relay outputs for indication and control
1x K type ungrounded thermocouple input
Optional Outputs Modbus TCP/IP; RS-232; RS-485; Fieldbus; HART
Wetted Materials Stainless Steel 316/316L, Kalrez
Other materials available
Analyzer Enclosure wall-mounted NEMA 4X stainless steel type 304 Enclosure
Other enclosures available
Probe Material Stainless Steel 316/316L
Other materials available
System Dimensions Analyzer: 24” H x 20” W x 8” D (610mm H x 508mm W x 203mm D)
Probe (Average): 36” length x 12“ widest diameter (914mm x 305mm)
System Weight Analyzer: 32 lbs. (15 kg)
Probe (Average): 29 lbs. (13 kg)
Accuracy/Repeatability Analyte Typical Range Accuracy Repeatability
H2S 0-4%  ± 1% full scale  ± 0.4%
SO2 (optional) 0-2%  ± 1% full scale  ± 0.4%
Response Time 1-5 seconds
Sensitivity  ±0.1% full scale
Noise  ±0.004 AU at 220 nm
Standard Design General Purpose
Available Options ATEX, IECEx, EAC, PESO, JPN
Please inquire with your sales representative for additional certifications (CSA, FM etc.).
Request a Quote
Newsletter Signup