Low-Pressure Dilution Gas Sampling Probe for Sticky Pollutant Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current extractive gas sampling systems fail to accurately measure 'sticky' pollutants like hydrogen cyanide (HCN) that adhere to internal ducts or piping, necessitating a system capable of precise monitoring of such emissions from fossil fuel power plants and other stationary sources.
Innovation Solution
A low-pressure, low-flow dilution extraction gas probe end assembly and system that includes a helical heating element, temperature- and pressure-regulated nozzles, and a manifold for mixing dilution gas with sample gas, allowing for accurate sampling and analysis of pollutants like SO2, HCl, and HCN, with optional filtering and vacuum maintenance to control dew point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional extractive gas sampling systems are used, then the system structure is simple, but the measurement precision of sticky pollutants deteriorates due to adhesion to internal ducts or piping
Solution Approach 1:
The patent changes the pressure parameter by operating at low pressure (vacuum conditions) and changes the flow parameter by maintaining low flow rates. This prevents sticky pollutants from adhering to internal surfaces while being transported through the sampling system, thereby improving measurement precision without requiring complex additional components
Solution Approach 2:
The patent introduces a membrane interface that acts as an intermediary between the stack gas and the sampling system. The membrane allows gas permeation while preventing contact between sticky pollutants and internal duct surfaces, thus maintaining measurement accuracy without increasing overall device complexity
2Reliability
If high pressure high flow sampling is used, then the sampling speed is fast, but the dew point of the sample gas increases causing condensation of pollutants
Solution Approach 1:
The patent changes the pressure parameter to low pressure operation, which directly lowers the dew point of the sample gas according to thermodynamic principles. This prevents condensation of pollutants during transport while maintaining reliable analysis, without requiring additional heating or cooling mechanisms
3Reliability
If dilution gas is added to sample gas, then the dew point is reduced preventing condensation, but the concentration of pollutants decreases
Solution Approach 1:
The patent changes the pressure parameter to low pressure operation, which lowers the dew point without requiring dilution. This maintains pollutant concentration while preventing condensation, thereby preserving both reliability and quantity of analyte
Solution Approach 2:
The membrane interface acts as a selective mediator that allows gas transport while maintaining sample integrity. The low pressure gradient across the membrane enables sufficient gas flow without dilution, preserving pollutant concentration while preventing condensation
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 accurate monitoring of 'sticky' pollutants by forming a dilute mixture that maintains a low dew point, effectively capturing and analyzing emissions from fossil fuel sources, improving compliance with environmental regulations.
Implementation Method 1
a helical heating element positioned in a cavity within the outer probe housing
Implementation Method 2
transporting the mixture to at least one analyzer and maintaining vacuum on the mixture sufficient to maintain a dew point of the mixture below a predetermined threshold
Implementation Method 3
forming a dilute mixture by passing a dilution gas through a dilution nozzle... and through a through hole connecting the dilution nozzle tap with the sample tap
Implementation Method 4
The manifold is connected to the second end of the inner probe housing and is operably connected to the sample nozzle and the dilution nozzle, allowing the manifold to direct the dilution gas to mix with the sample gas
Implementation Method 5
The temperature- and pressure-regulated sample nozzle... The temperature- and pressure-regulated dilution nozzle
Data Source
AI summary
Disclosed is a system and method for low-pressure, low-flow dilution extraction. The system includes an outer housing, an inner housing partially within a heating element, and a manifold connected to the inner housing, having taps for a sample nozzle and dilution nozzle, and a through hole connecting the sample and dilution nozzle taps to allow a sample gas from, e.g., a stack to mix with a dilution gas before being drawn at a low pressure towards a gas analyzer.