Deadly Freeze at -20°C: The "Frozen Mystery" Hidden Behind a Waste Gas Regenerative Thermal Oxidizer Heating Project
In October, the bitter wind had already begun to howl across the northern region. The equipment for the low-concentration waste gas Regenerative Thermal Oxidation (RTO) heating project had just been put into operation, and everything seemed to be proceeding as planned. However, as temperatures plummeted, a "frozen mystery" lurking deep within the pipelines quietly unfolded...
Chapter 1: Anomaly in the Cold Night
At first, the equipment ran smoothly, and minor issues during commissioning were quickly resolved. But by November, temperatures suddenly dropped to -10°C, and some pipelines began to freeze. The technical team sprang into action, applying comprehensive heat tracing and insulation to all vulnerable water and gas lines. Everyone thought the "freezing crisis" had been contained.
Chapter 2: The Unexpected Freeze
Yet, the situation was far from resolved. One late night, when temperatures plunged to nearly -20°C, a critical component—the high-temperature valve actuator—suddenly froze. The puzzling part? The area around the valve wasn’t particularly cold. Why would the actuator freeze? Upon urgent inspection, the team traced the root cause to the compressed air line inside the actuator.Emergency heating measures restored normal operation, and the next day, technicians insulated all pneumatic actuators. Yet, despite these efforts, freezing incidents persisted. Each occurrence was like a silent "assassination," threatening the entire heating system’s safety without warning.
Chapter 3: The Hidden Culprit
After repeated discussions, the team finally pinpointed an inconspicuous device—the compressed air dryer. The real culprit was excessive moisture in the compressed air. The original refrigerated dryer, while effective under standard conditions, performed poorly in extreme cold.
Refrigerated dryers work by cooling compressed air to condense and drain moisture. But when ambient temperatures drop below 0°C, residual moisture in the lines can still freeze—enough to block actuators in subzero conditions.
Chapter 4: Solving the "Frozen Mystery"
To eliminate the issue, the team replaced the dryer with an adsorption-type unit. This new system used desiccant beds to adsorb moisture, achieving pressure dew points as low as -40°C. Post-replacement, actuator freezing ceased entirely, and the heating system regained stable operation. The "frozen mystery" was finally laid to rest..
Epilogue: Wisdom in Extreme Cold
This incident revealed the complexities of operating equipment in extreme cold, where even minor oversights can trigger a "deadly freeze." Through systematic troubleshooting, the team cracked the case by upgrading the compressed air drying system, ensuring the project’s heating system ran safely.
Waste Gas Heating & Power Island
This real-world case occurred at Xi’an Yurcent’s Cuijiagou Coal Mine ultra-low-concentration waste gas RTO project in Shaanxi, China. The project successfully applied Yurcent’s advanced "Waste Gas Heating & Power Island" technology to utilize coal mine gas with concentrations below 8% for CCER carbon offsets.
The Cuijiagou project employs two 80,000 Nm³/h RTO units paired with a 16-ton boiler, destroying 6.3 million m³ of methane annually and reducing CO₂ emissions by 260,000 tons—achieving economic and environmental benefits.
Across multiple Yurcent projects in heating applications, winter temperatures often plunge below -10°C, with extremes reaching -20°C or lower. Thus, anti-freezing measures for equipment and pipelines are critical. Selecting the right compressed air dryer for low-concentration waste gas RTO heating systems is paramount to ensuring uninterrupted operation.