Waste Heat Steam Generator Leak Detection via Exhaust Moisture Sensing
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Solution Overview
Problem
Conventional acoustic detection systems for identifying leaks in heat exchanger tubes of heat recovery steam generators require extensive sensor deployment, which is costly and complex.
Innovation Solution
Utilizing moisture sensors or optical detection systems to measure the moisture content of exhaust gas for detecting leaks in heat exchanger tubes, allowing for localized sensor placement and reducing the number of sensors needed, with optional redundancy and leak localization through sensor positioning and pattern recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acoustic sensors are distributed over the entire heat recovery steam generator to detect leaks, then leak detection capability is improved, but device complexity and cost increase significantly
Solution Approach 1:
The invention extracts the leak detection function from the complex acoustic sensor network and concentrates it in a single moisture sensor positioned at the exhaust gas outlet. This extracts only the essential detection capability (moisture content measurement) while eliminating the need for distributed acoustic sensors throughout the heat recovery steam generator.
Solution Approach 2:
The invention introduces moisture content as an intermediary parameter to detect leaks. Instead of directly detecting acoustic signals from leaks, the system measures the moisture content of exhaust gas, which changes when steam leaks from heat exchanger tubes. This intermediary measurement simplifies the detection system while maintaining reliability.
2Measurement precision
If multiple acoustic sensors are deployed to enable leak localization, then detection precision is improved, but manufacturing cost and installation complexity increase
Solution Approach 1:
The invention extracts leak localization capability from the complex multi-sensor acoustic network by using a single moisture sensor combined with flow direction knowledge. The system determines leak position based on the exhaust gas flow direction and moisture detection timing, eliminating the need for multiple sensors while maintaining localization precision.
Solution Approach 2:
Instead of using multiple sensors to detect acoustic signals from different positions, the invention inverts the approach by using a single sensor to detect moisture changes and inferring leak position from the exhaust gas flow direction and temporal patterns. This inversion simplifies the system while achieving the same localization function.
3Reliability
If distributed acoustic sensors are used for leak detection, then detection reliability is improved, but maintenance costs and operational complexity increase
Solution Approach 1:
The invention extracts the essential detection function from the complex distributed sensor system and consolidates it in a single moisture sensor. This extraction maintains detection reliability by focusing measurement at the exhaust outlet where leak effects are most pronounced, while dramatically reducing maintenance complexity by eliminating hundreds of sensors.
Solution Approach 2:
The invention replaces expensive, complex acoustic sensor systems with a simpler, more maintainable moisture sensor system. The single moisture sensor is easier to maintain and replace than a distributed acoustic network, reducing operational complexity and maintenance costs while maintaining adequate detection reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces sensor costs and maintenance complexity while enabling accurate and timely leak detection and localization, minimizing downtime and maintenance efforts.
Implementation Method 1
sensors (18) that measure a measured quantity representing the moisture content of the exhaust gas flow
Implementation Method 2
an optical detection system... the steam flow in the exhaust gas, which forms a steam cloud or steam swathe propagating downstream from the location of the leak, can be recognized by an optical detection system
Data Source
AI summary
A method for monitoring the state of pipelines, which conduct water or steam, of at least one heat exchanger, in particular a heat exchanger designed as a superheater, a heat exchanger designed as an evaporator, and a heat exchanger designed as a feed water preheater. When viewed in the downstream flow direction, the at least one heat exchanger is arranged in the exhaust gas flow of a waste heat steam generator. The presence of steam within the exhaust gas flow is automatically detected using sensors which detect a measurement variable that represents the moisture content of the exhaust gas flow and/or using an optical detection system, and if steam is detected, an alarm is triggered. A waste heat steam generator is designed to carry out the method.