Real-time O2 Measurement at Garbage Incinerators Improves Combustion Efficiency and Reduction in NOx and CO

Introduction

Considering safety and environmental issues such as combustion efficiency and decreasing NOX and CO in exhaust gas, it has become important to control O2 concentration in garbage incineration processes. Conventionally, zirconia sensors are commonly employed in process control to measure O2 in exhaust gas. With this method, it takes time to react correspondingly to changes in the combustion environment because sensors are installed at a post-combustion stage, and control configurations are selected more for safety than combustion efficiency. In other words, priority is given to suppressing flammable CO gas, and operation is designed for large safety margins of O2. Also, large quantities of high temperature dust present in the exhaust gas introduce maintenance issues. Yokogawa's garbage incinerator solution featuring TDLS series of laser gas analyzers provides real-time and direct measurement of O2 concentration, even with high level of high temperature dust contamination. Because the sensor never comes into contact with the exhaust gas, it can greatly reduce maintenance costs. These solutions are already fully operational at garbage incinerators in Japan.

What is the TDLS Series?

By irradiating the exhaust gas directly with a laser, the TDLS can measure not only concentrations of O2, CO, CH4, NH3, and H2O, but also various gases that have absorption in the near-infrared region.
The TDLS8000 is smaller and more advanced than its predecessor, the TDLS200. It features a touch panel with intuitive operation.

Customer's Benefits

• Measures O2 Concentrations at up to 1500°C
• Autogain Function Stays Accurate, Even in the Dust
• No Consumable Parts. Incredible Cost-Performance

Solution and Benefits

Measures O2 Concentrations at up to 1500°C
As conventional zirconia sensors have a temperature limit of 700°C they are installed at a post-combustion stage, thus their response is not ideal. There is also a time lag from the pre-process where dust is removed, making it difficult to track rapid fluctuations in O2 quantities. The TDLS series can directly measure gas reaching approximately 1000°C in the vicinity of the burner. It measures safely at up to 1500°C.

Autogain Function Stays Accurate, Even in the Dust
When the exhaust gas contains large amounts of dust, the measuring laser can be attenuated. The TDLS series includes an Autogain function that automatically boosts the signal from the laser to compensate. Even with attenuated laser light, the TDLS maintains good reliability. 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 surrounding air while stopped.

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

Yokogawa Solutions Raise Affinity with Control Systems

Yokogawa offers solutions that have high affinity with control systems. Moreover, we design comprehensive production process solutions that incorporate our control system lineup with additional advanced measuring instruments. Yokogawa also contributes greatly to cost reductions and environmental safety in non-manufacturing sectors, including garbage incineration processes.