CEM 2020

CEM 2018 - Abstract

Abstract Title: Novel CEM gas detection system for SO2, NOx and CO/CO2 monitoring based on small size NDIR- and NDUV - technology
Abstract Type: Seminar
Session Choice: Innovative Measurement Technology
Presenter Name: Prof Gerhard Wiegleb
Co-authors:Mr Sebastian Wiegleb
Company/Organisation: University of Applied Sciences Dortmund
Country: Germany

Abstract Information :

Continuous emission monitoring (CEM) is a rapidly growing market worldwide. Especially in developing countries the demand of low cost equipment, with sufficient measurement performance, is significant. Another important application is the mobile/portable flue gas analysis. In this case small size and low power operation are required. For both applications we developed a novel CEM gas detection system based on photometric absorption technique.

The detection of Sulfur dioxide SO2 and Nitrogen dioxide NO2 in the UV range is a well-known method to measure these components at a low level (<ppm) and without water vapor interference. Selective radiation sources are used for this purpose at λ≈285nm (SO2) and λ≈400nm (NO2). Typical ranges are 50ppm SO2 and 100ppm NO2 with a detection limit 4.α < 250ppb. The detection of both gases takes place simultaneously in the same photometric device (ULTRA.sens®). This design saves cost and space for the different applications. By using the NO2 gas concentration (direct measurement) it is possible to substitute the costly catalytic NO2?NO converter (indirect measurement) in regular CEM systems.

In the infra-red range a broad band micro machined IR-Source is used for the gas detection. It is possible to modulate the IR-Source up to 10 Hz in order to get low noise signals and fast response concentration readings. By using multiple wavelengths IR detectors up to 3 gases could be measured simultaneously in one arrangement (INFRA.sens®). Based on this technique a combination of Nitrogen monoxide NO, Carbon monoxide CO and Carbon dioxide CO2 at different concentration levels is feasible ( e.g. 1000ppm NO, 1000ppm CO and 20 Vol.-% CO2).

The individual modules are sealed by O-ring connections. With this modular design, sample cell lengths from 1 mm to 250 mm can be achieved for optimal adaptation to the required measuring range. Optionally, the system can be equipped with coated aluminum or stainless steel sample cells. With corresponding pressure-resistant window materials, working pressures of up to 16 bar can be achieved (Option). The signal conditioning main board could run both technologies (INFRA.sens® and ULTRA.sens®) simultaneously with a 16bit resolution. The data interface is based on RS232 and CANopen. The operation voltage is 24VDC with a power consumption of less than 1Watt. Furthermore a pressure sensor and humidity sensor (HUMI.sens) could be connected to the main board. Using the HUMI.sens signal it is possible to compensate the residual water vapor interference in the INFRA.sens®.