Online multi-component analysis of flue gas and vent gas

The term ‘flue gas’ does not refer solely to combustion products; any complex mixture of gases released as a result of heating, chemical reactions or cracking can be collectively termed ‘emission gases’ or ‘process exhaust gases’, the composition of which varies in real time depending on temperature, atmosphere and the state of the material. Breaking down such dynamic gases into a multi-component list through ‘real-time measurement as they are generated’ is precisely where online mass spectrometry excels; the New Ceyuan ProC-1S flue gas multi-component dynamic analysis system has been designed specifically to meet these requirements.

The traditional approach involves sampling followed by offline chromatographic analysis; this process is time-lagged and struggles to capture the transient changes during the release process. The ProC-1S takes a different approach: it performs online, multi-component monitoring of the released vapour, providing real-time concentration curves for each component over time, thereby transforming the situation of ‘qualitative data available but quantitative data unknown’ into a quantifiable and comparable release profile. Compared to the time-lagged process of offline sampling followed by chromatography, online mass spectrometry can capture the interplay between components—where one increases whilst another decreases—providing a more accurate representation of the actual process.

There are three key analytical considerations. Firstly, time-varying curves provide more information than single-point averages; differences in release between the heating and isothermal phases can reflect the reaction process. Secondly, both particulate and gaseous phase components must be covered simultaneously to avoid underestimating the total amount by focusing on only one segment. Thirdly, quantification relies on internal standards and calibration; otherwise, it is difficult to compare gases from different batches or under different operating conditions.

For both research and development and regulatory compliance, release gas fingerprints can be used for formulation or process comparisons, verification of specific marker release levels, and demonstrating differences between various process routes. Online mass spectrometry monitoring compresses this process from ‘submitting samples and waiting for reports’ to ‘observing as it happens’, making it a highly efficient analytical tool during process iteration.

When demonstrating differences, a common approach is to compare the emission spectra of different materials or processes under the same operating conditions, followed by clustering or principal component analysis of the emission fingerprints to quantify ‘where the differences lie and to what extent’. It is important to emphasise that the role of mass spectrometry is to ‘clarify’ the released substances, rather than to draw value-based conclusions. For regulatory compliance, key indicators include upper limits for heating or reaction temperatures, and the release levels of specific markers (such as carbonyl compounds and characteristic volatiles). The ProC-1S’s online multi-component capability provides continuous feedback on these indicators as early as the R&D stage, thereby shortening the ‘process–validation’ cycle.