NDIR Gas Analyzer with Narrowband Filters for Coal Gas
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for measuring coal gas components and calorific value are inaccurate, slow, and unable to perform real-time online analysis, particularly due to interference between gases, which prevents precise measurement of CH4, CnHm, CO, and H2, essential for energy contribution, and calculating the calorific value of coal gas.
Innovation Solution
The method optimizes NDIR narrowband filter parameters to simultaneously measure various gas components, including CH4, CnHm, CO, and CO2, using specific filter wavelengths to reduce interference, and converts other hydrocarbons into C3H8 for calorific value calculation, resulting in a more cost-effective and faster analysis compared to traditional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If chromatographic analysis technique is used to analyze gas concentration, then multiple components can be analyzed through one-time sample injection, but it needs carrier gas, can only achieve intermittent measurement, and cannot achieve site measurement
Solution Approach 1:
The patent combines multiple detection functions (TCD for H2, ECD for O2, NDIR for CO/CO2/CH4) into a single integrated detector system that shares common gas channels and sample injection pathways, enabling simultaneous real-time measurement of multiple gas components without requiring separate instruments or carrier gases
Solution Approach 2:
The detector system is designed with multi-functional capabilities where a single instrument can perform thermal conductivity detection, electrochemical detection, and infrared detection simultaneously, allowing one device to replace multiple specialized instruments and achieve universal gas component analysis
2Productivity
If NDIR method with narrowband filter is used to measure CH4 and CnHm, then gas concentration can be detected, but mutual interference between CnHm and CH4 prevents accurate measurement
Solution Approach 1:
The patent segments the infrared detection into multiple independent detection channels, each equipped with narrowband filters targeting specific wavelength ranges for different gases (CO at 4.6μm, CO2 at 2.3μm, CH4 at 3.3μm, CnHm at 3.4μm), allowing simultaneous detection while minimizing spectral interference through wavelength separation
Solution Approach 2:
Each gas detection channel uses customized narrowband filters with specific center wavelengths and bandwidths optimized for the target gas, creating locally optimized detection conditions for each component while maintaining overall system performance
3Quantity of substance
If TCD is used to measure H2 concentration, then hydrogen can be detected, but interference from CO2 and CH4 prevents accurate measurement without revision
Solution Approach 1:
The system implements feedback correction where TCD measurements of H2 are automatically adjusted based on simultaneous CO2 and CH4 concentration data from ECD and NDIR detectors, compensating for thermal conductivity interference and delivering accurate H2 measurements without manual intervention
Solution Approach 2:
The patent introduces intermediate correction mechanisms where data from CO2 and CH4 detectors serve as mediators to correct the H2 measurement from TCD, using the known thermal conductivity characteristics of these gases to calculate and remove their interference effects from the H2 reading
4Measurement precision
If multiple independent instruments are used to measure different gas components, then each component can be measured with dedicated method, but system complexity and cost increase significantly
Solution Approach 1:
The patent merges TCD, ECD, and NDIR detection technologies into a single integrated instrument with shared sample handling systems, gas channels, and data processing units, maintaining the measurement precision of each individual method while reducing the system from multiple separate instruments to one unified device
Solution Approach 2:
The instrument is designed as a multi-functional platform capable of performing thermal conductivity detection, electrochemical detection, and infrared detection simultaneously through different detection channels, replacing multiple specialized instruments with a single universal analyzer
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
This approach allows for accurate, simultaneous measurement of multiple coal gas components, reduces interference, and calculates the calorific value efficiently, with a significantly lower manufacturing cost and analysis speed 30 times faster than conventional chromatographs.
Implementation Method 1
non-dispersive infrared technology
Implementation Method 2
infrared gas analyzer
Implementation Method 3
principle of thermal conductivity
Implementation Method 4
measured with ECD
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A coal gas component and calorific value measurement method, comprising the following steps: utilizing a non-dispersive infrared technology, and selecting narrowband optical filters with the center wavelength (CWL)/half width bandwidth (HWBP) proportions of 4.66±0.05µm/90±5nm, 4.26±0.05µm/120±5nm, 7.85±0.05µm/180±5nm, and 3.46±0.05µm/120±5nm respectively to measure the volume concentrations of CO, CO2, CH4 and CnHm in the coal gas; utilizing a thermal-conductive gas sensor to measure the volume concentration of H2; utilizing an electro-chemical sensor to measure the volume concentration of 02; utilizing the measured CH4 value to correct the measured CnHm result; and utilizing the measured CO2 and CH4 values to correct the measured H2 result, thus obtaining the accurate CO, CH4, CnHm, H2, 02 content of the coal gas; and utilizing the measured CO and CH4 values and the corrected H2 and CnHm volume concentrations to calculate the calorific value of the coal gas. The present method achieves rapid and accurate measurement of the components and calorific value of multi-component coal gas with one apparatus.