NEWS

With the deepening of air pollution control, high value of carbon monoxide has become a major factor affecting the improvement of air quality in China, especially in the northern region, carbon monoxide management and control has become the focus of air pollution control this year. In order to conscientiously implement the green development concept, the installation of online monitoring devices at carbon monoxide emission points in iron and steel and coking enterprises is a basic guarantee to identify the carbon monoxide emission base in key industries and to precisely control and manage carbon monoxide, which is an effective measure to reduce the high value of carbon monoxide data.

Based on the independent research and development of TDLAS technology and laser, Shengnuo Instruments has launched iLAS-700 high-performance in-situ laser CO gas analyzer, which adopts the design of counter-fire or single-ended reflection, with fast response time, calculated in seconds in in-situ measurement, and can respond to the measured gas CO concentration online in time, avoiding the time delay brought by picking style measurement; in high temperature, high dust, high moisture, high It has good adaptability under the harsh measurement environment such as high temperature, high dust, high moisture, high corrosiveness, high flow rate, etc.; the gas concentration is not easily distorted, the measurement accuracy is high, and the change of CO concentration is accurately responded in real time, which provides reliable data support for environmental monitoring. The product can be continuously monitored online, in line with HJ75-2017 requirements; explosion-proof level in line with ExdIICT6 GB; functional safety certification in line with SIL2; IP level in line with IP66; can be widely used in metallurgy, petrochemical, cement, electric power, environmental protection and other industries.

TDLAS all-optical design, high sensitivity, good electrical insulation, not subject to electromagnetic interference, easy microcomputer connection, can achieve long-distance transmission, in flammable and explosive material collection and dispersal, high temperature and other extreme environments have unique advantages, is currently a more promising carbon monoxide monitoring sensing technology.

Laser measurement principle: TDLAS technology is essentially a spectral absorption technique that obtains the concentration of a gas by analyzing the selective absorption of the laser by the gas. It differs from traditional infrared spectral absorption techniques in that the laser analyzer uses a single-line spectral principle, thus avoiding cross-interference from other gases. A single gas absorption line is selected in the near infrared region without cross-interference, and a diode laser operating at room temperature scans this single absorption line. The detector in the relative direction of the laser detects the light intensity absorbed by the measured gas molecules and thus calculates the content of the measured gas components.

Main technical features

1. Independent of the background gas

Conventional non-dispersive infrared spectroscopy absorption technology uses a very wide spectral band of the light source, its spectral width range in addition to the measured gas absorption spectral lines, there are many other background gas absorption spectral lines. Therefore, the light emitted from the photogen is absorbed by several absorption spectral lines of the gas to be measured in addition to the absorption spectral lines of some background gases, which leads to inaccurate measurements.

The TDLAS gas concentration analyzer first selects an absorption line of the gas to be measured at a certain frequency, and then scans the laser wavelength across the absorption line by modulating the laser operating current to obtain a single line absorption spectrum as shown in the figure "Tunable semiconductor laser absorption spectroscopy principle". By modulating the operating current of the laser, the laser wavelength is scanned through the absorption line to obtain the single line absorption spectrum data as shown in the figure "Principle of Tunable Semiconductor Laser Absorption Spectroscopy Technology". 2.

2. Independent of dust and window contamination

The concentration of the gas is determined by the ratio of the second harmonic signal of the transmitted light intensity to the DC signal. When the light intensity is attenuated by dust or window contamination in the laser transmission optical path, the two signals decrease in equal proportion, thus keeping the ratio constant. Therefore, dust and window contamination in the process gas have no effect on the measurement results of the instrument.

3. Automatic correction of temperature and pressure effects on measurement

Some industrial process gases may have temperature variations of several hundred degrees Celsius and pressure variations of several atmospheres. Changes in gas temperature and pressure can cause corresponding changes in the amplitude and shape of the second harmonic signal waveform, thus affecting the accuracy of the measurement.

In order to solve this problem, TDLAS technology can add temperature and pressure compensation algorithm, as long as the gas temperature and pressure signals measured by external sensors are input into the compensation algorithm, TDLAS gas concentration analyzer can automatically correct the influence of temperature and pressure changes on gas concentration measurement, ensuring the accuracy of measurement.

Advantages of iLAS series laser gas analyzer of Shengnuo

1)Adopting in-situ laser spectrum measurement technology, it solves the problems of easy plugging and leakage, high maintenance cost and frequent maintenance caused by the pre-processing of the collection style products;

2)The single absorption line of laser single line spectrum for the measured gas, no cross absorption interference of other gases;

3)No interference from dust and water vapor;

4) In-situ monitoring of the system, no need for sample collection, transmission and pre-processing;

5) High measurement accuracy and small drift;

6) The system is not affected by the background gas components, dust particles, light source changes and other factors on the measurement;

7) Laser in-situ measurement, fast response time, high measurement accuracy;

8) Modular design, all functional modules can be replaced on site, easy maintenance;

9) High intelligence and easy operation;

10)Non-contact optical measurement, can directly measure high temperature, strong corrosive gas ;

11)Support automatic compensation of gas temperature and pressure;

12) The vibration of the pipeline has no effect on the laser beam and detection.