Accurate, Maintenance-free Monitoring of H2S Quantities in a Black Liqor Recovery Boiler


H2S management of exhaust gas in black liquor recovery boilers is required to meet an environmental regulations. Previously this component was measured through sampling, but suction tubes would clog, filters needed replacement, and other maintenance was required. Additionally, sensors in contact with gases would corrode. Centered around the TDLS series of laser gas analyzers, Yokogawa's H2S measurement application for black liquor recovery boilers can directly measure high temperature gases and therefore requires no suction tubes or other sampling equipment. And because sensors never come into contact with exhaust gas, deterioration of parts is not a concern. All of these features greatly reduce maintenance costs.

What is the TDLS Series?
By irradiating the exhaust gas directly with a laser, the TDLS can measure not only H2S, O2, CO, HCI, CH4, NH3, and H2O, but also concentrations of various gases that have absorption in the near-infrared region. As the successor to the TDLS200, the TDLS8000 has improved functionality through smarter design, featuring a touch panel for greater ease of use.

Customer's Benefits

  • No Consumable Parts. High Cost-Performance
  • Autogain Function Gives Accurate Values, Even with Dust
  • Measures H2S Concentrations at Up to 500°C

Solution and Benefits

No Consumable Parts. Incredible Cost-Performance
With the TDLS series the process line is partitioned behind a solid glass window, therefore the sensor never contacts the gas and does not deteriorate. The TDLS has the advantage that once installed, there are almost no maintenance costs. If by chance parts need replacing, you can safely and easily swap units out right on site with the analyzer still installed.

Autogain Function Gives Accurate Values, Even with Dust
Large amounts of dust present in exhaust gas can attenuate the measuring laser. But the TDLS series includes an Autogain function that automatically boosts the signal received from the laser to compensate. Even with attenuated laser light, the TDLS stays reliable. Also, the TDLS series uses the peak area method to accurately measure the oxygen concentration in exhaust gas during combustion (without correction), and in the air while stopped.

Measures H2S Concentrations at Up to 500°C
The TDLS series can directly measure gas even at high temperature and in high corrosive fuel gas. It can safely measure H2S, at up to 500°C, in real time.

Accurate, Maintenance-free Monitoring of H2S Quantities in a Black Liqor Recovery Boiler

Yokogawa Solutions Support a Paper Plant on the Move

Yokogawa offers a fast and reliable solution that directly measures process gas, setting a new standard of safe oxygen instrumentation. Many interfaces are available for output of measured data, enabling connection with a wide variety of instruments in systems. By combining products that conform to functional safety standards such as the ProSafe-RS "safety PLC" and EJX/YTA field instruments with CENTUM and other process control systems, we meet our customers' diverse needs by offering a comprehensive solution for efficient and safe operation of the entire plant.

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Have Questions?

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