Programmed Temperature Ramp and Online Dynamic Monitoring (Temporal Resolution)

Temperature programming refers to the continuous or stepwise increase in temperature at a set rate during an experiment, in order to observe the evolution of products across different temperature ranges. In pyrolysis and catalytic studies, many products only appear within specific temperature windows; a fixed temperature allows observation of only a specific cross-section, whereas temperature programming enables the plotting of a complete ‘temperature–product’ profile. The New Ceyuan ProC series and systems all support “online monitoring of products at fixed temperatures and during temperature-programmed pyrolysis”.

‘Online dynamic monitoring’, on the other hand, emphasises the temporal dimension. With a sampling frequency of up to 30,000 Hz, the instrument can capture the complete spectrum of all substances under test within seconds and further plot dynamic curves showing ‘concentration versus time’. This is crucial for studying kinetic processes that evolve over time: for example, the rise and fall of product concentrations during the induction, active and deactivation phases of a catalytic reaction; the fluctuations in the concentration of each component during sequential flue gas sampling; and the sequential release of pyrolysis products as the temperature rises. These processes are difficult to characterise using ‘offline, single-point sampling’ methods and must be recorded continuously online.

Here, mass resolution, sampling rate and wide dynamic range collectively support dynamic monitoring: high sampling frequency provides ‘temporal resolution’ (the ability to distinguish how rapidly changes occur); high resolution ensures that spectra at every instant are clearly distinguishable; and wide dynamic range ensures that both strong and weak signals are captured within the same frame. The combination of these three factors enables an online mass spectrometer not only to answer the question ‘what is present’, but also ‘when it appears and how it changes’.

Take the application example provided by New Ceyuan: during the catalytic pyrolysis of polyethylene, the selectivity of certain products changes significantly following the addition of HZSM-5 catalyst; this change can only be continuously observed through the combination of a temperature programme and real-time sampling. Similarly, in coal pyrolysis, the formation of a large number of hydrocarbon products evolves with temperature, requiring dynamic curves rather than single-point data. By combining the horizontal dimension of ‘programmed temperature ramping’ with the vertical dimension of ‘online dynamics’, researchers obtain a two-dimensional ‘temperature/time–product’ panorama—precisely the raw data most essential for mechanistic and process research.