In-line LOI Measurement System for Coal Plants

The system divides the LOI measurement process into distinct functional modules: a sampling module that extracts fly ash from the flue gas, a weighing module that measures sample mass, a combustion module that burns the sample, and a calculation module that determines LOI values. This segmentation enables continuous automated operation while keeping each module relatively simple and maintainable.

The patent introduces an intermediary sampling system that extracts small amounts of fly ash from the flue gas and delivers it to the measurement chamber. This intermediary approach allows continuous measurement without requiring direct access to the high-temperature combustion zone, simplifying the overall system design while enabling real-time monitoring.

The system replaces manual laboratory weighing and combustion procedures with automated electronic weighing sensors and controlled combustion heating elements. This substitution eliminates the need for manual sample handling and calibration by standard laboratory equipment, while the automated system performs measurements continuously without operator intervention.

The measurement system is designed to perform its own calibration and maintenance functions through automated baseline measurements and self-diagnostic routines. The system automatically zeroes the balance, performs reference measurements, and adjusts for drift, reducing the need for external calibration services and manual intervention.

The system performs measurements in periodic cycles rather than truly continuous operation. Each cycle involves sampling fly ash, weighing the sample, combusting it at high temperature, cooling it, and calculating LOI. The measurement chamber is heated to combustion temperature only during the combustion phase of each cycle, not continuously, thereby reducing overall energy consumption while maintaining continuous measurement capability.

The system uses partial combustion of small fly ash samples rather than complete continuous combustion of large amounts of fuel. By measuring LOI on small representative samples extracted from the flue gas, the system achieves continuous monitoring capability with minimal energy input compared to combusting the entire fuel stream.