Flue Gas SO3 Monitoring via Particle Conversion and Light Scattering

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Solution Overview

Problem

Current methods for monitoring sulfur trioxide (SO3) in flue gas are offline, prone to errors, time-consuming, and lack accurate, fast online monitoring solutions, especially in the context of stringent environmental regulations.

Innovation Solution

An online monitoring device and method that converts gaseous SO3 into solid barium sulfate particles using an absorption and precipitation process, followed by light scattering measurement to determine concentration, ensuring high accuracy and fast measurement speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If offline measurement methods are used to monitor SO3 concentration, then measurement accuracy can be maintained through manual sampling and analysis, but measurement speed is slow and real-time monitoring cannot be achieved

Engineering Contradiction:
ImproveSO3 concentration measurement accuracyVSAvoidmeasurement speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical manual sampling and analysis system with an automated online monitoring system that uses UV absorption spectroscopy. The automatic sampler collects flue gas samples continuously, and the UV detector measures SO3 concentration in real-time, eliminating manual operations and achieving both high accuracy and fast measurement speed simultaneously

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements continuous online monitoring by establishing an automatic sampling system that continuously collects flue gas and a UV detection system that continuously measures SO3 concentration. This continuous action replaces the discrete offline measurement approach, enabling real-time monitoring while maintaining measurement accuracy through automated procedures

Inventive Principle:
Principle #20Continuity of useful action

2Device complexity

If manual sampling and analysis methods are used, then equipment complexity is low, but measurement accuracy is reduced due to human error and time-consuming procedures

Engineering Contradiction:
Improvemonitoring system complexityVSAvoidSO3 concentration measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces manual sampling and analysis operations with automated equipment including an automatic sampler, UV detector, and data processing system. This substitution eliminates human error in sampling and measurement while automating the complex analytical procedures, thereby improving measurement accuracy without requiring excessively complex manual operations

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If offline measurement methods are used to monitor SO3, then device complexity remains manageable with simple sampling devices, but reliability is compromised due to large errors and inability to provide real-time data

Engineering Contradiction:
Improvesampling device complexityVSAvoidmonitoring reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements continuous online monitoring by establishing an automatic sampling system that continuously collects flue gas and a UV detection system that continuously measures SO3 concentration. This continuous action replaces the discrete offline measurement approach, enabling real-time monitoring while maintaining measurement accuracy through automated procedures

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent replaces the mechanical manual sampling and analysis system with an automated online monitoring system that uses UV absorption spectroscopy. The automatic sampler collects flue gas samples continuously, and the UV detector measures SO3 concentration in real-time, eliminating manual operations and achieving both high accuracy and fast measurement speed simultaneously

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables high-accuracy, repeatable, and rapid online monitoring of SO3 concentrations, overcoming the limitations of offline methods by providing a reliable and efficient monitoring solution.

Implementation Method 1

an absorption device connected to the sampling gun, comprising at least one absorption bottle containing an absorption liquid, for preventing oxidation of sulfur dioxide and absorbing sulfur trioxide in the flue gas

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

a mixing box connected to the absorption device, wherein a stirrer is arranged inside the mixing box for mixing the absorption liquid and a precipitating agent to obtain a mixed solution

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 3

an atomizer connected to the mixing box through a peristaltic pump, for atomizing the mixed solution

Methodology Applied
Scientific EffectAtomization:

Implementation Method 4

an evaporation chamber connected to the atomizer, for drying the mixed solution droplets to form a dry particle airflow

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 5

a light scattering measurement chamber connected to the evaporation chamber, for light scattering measurement of the dry particle airflow to obtain a mass concentration of particles

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP4685465A1Online monitoring device and monitoring method for sulfur trioxide in FLUE gas
Publication Date: 2026.01.28 HUADIAN ELECTRIC POWER SCI INST CO LTD
  • EP4685465A1 patent drawingFigure 1~2
  • EP4685465A1 patent drawingFigure 3
  • EP4685465A1 patent drawingFigure 4

AI summary

Provided is an online monitoring device for sulfur trioxide in flue gas, which relates to the technical field of gas detection and comprises: a sampling gun, for collecting flue gas; an absorption device, for preventing oxidation of sulfur dioxide and absorbing sulfur trioxide in the flue gas; a mixing box for mixing the absorption liquid and a precipitating agent to obtain a mixed solution; an atomizer for atomizing the mixed solution; an evaporation chamber connected to the atomizer, for drying the mixed solution droplets to form a dry particle airflow; a light scattering measurement chamber connected to the evaporation chamber, for light scattering measurement of the dry particle airflow to obtain a mass concentration of particles; and a control device for determining the concentration of sulfur trioxide in the flue gas according to the mass concentration of particles. The present application converts the gaseous sulfur trioxide into solid, measures the concentration of sulfur trioxide using a light scattering method, and has the advantages of high accuracy, good repeatability, fast measurement speed and online monitoring. It solves the current problem that sulfur trioxide monitoring can only be achieved by offline monitoring method.