Improving Furnace Coil Outlet Temperature Measurement: Comparative Performance of Dual-Wavelength Pyrometer and Type-K Thermocouple

In the rigorous environments of industrial furnaces, accurate measurement of Furnace Coil Outlet Temperature (COT) is crucial for maintaining efficiency, safety, and product quality. Traditional thermocouple, while commonly used, suffer from degradation and drift due to harsh conditions, leading to inaccurate measurements and frequent maintenance needs. This paper presents a comparative study of the performance of advanced dual-wavelength pyrometer versus traditional Type-K thermocouple in measuring COT. It explores the response time, accuracy, stability against thermal cycles, and maintainability of these measurement technologies. The study reveals that dual-wavelength pyrometer not only provide faster response times in conditions of rapid temperature changes, but also offer superior accuracy and stability under thermal cycling, reducing the need for frequent recalibration. The pyrometer exhibited response times approximately 2 minutes faster than the thermocouple in reaching temperature stabilization. Over extended periods, the thermocouple showed deviations up to 18°C of average difference, especially after thermal cycling events. Despite its higher cost and the increased complexity in setup, due to the need for external power supplies and precise alignment, the pyrometer demonstrates significant benefits in high-temperature industrial settings. These findings are pivotal for industries where precise temperature control is essential, recommending a shift toward non-contact pyrometry for reliable, long-term temperature monitoring in challenging furnace operations.