The solvent and the dissolved CO2 concentrations are two essential properties of CO2 absorption processes. Currently, they are typically monitored using time-consuming offline analytical techniques. Initial development efforts aiming at a cost-effective and reliable inline monitoring system are described. Using a fractional factorial experimental design covering six solvent properties and five analytical techniques, it is demonstrated that the CO2 and solvent concentrations correlate well with the density and refractive index. Applying a simplistic multivariate model to solvent samples from an industrial pilot plant indicated good potential for predictive use. Future work should focus on the development of a more accurate multivariate model, on the modeling of more solvents, and on combining the results with available process data.@en

Electrochemical processes are a promising technology for industrial production of chemicals. One of the major drawbacks of electrochemical systems is the low mass transfer of reactants toward the active surface area of the electrode. In this paper, an approach is presented to enhance the mass transfer and increase the overall performance of the reactions. The strategy comprises introduction of a pulsed electrolyte flow in the electrochemical flow cell. This pulsating behavior results in an improved mass transfer of electroactive species due to a higher instantaneous velocity driven by the pulsations. Though the net residence time of the reactants will not be altered due to the pulsation, the resulting enhancement of mass transfer leads to an increase of the conversion. The oxidation of 1,2-propanediol to lactic acid and pyruvic acid mediated by 4-Acetamido-(2,2,6,6-Tetramethylpiperidin-1-yl) oxidanyl (ACT-TEMPO) was chosen to study the influence of the pulsed flow. Under the pulsating regime, a yield increase of lactic acid of a factor of two and a 15-20% gain in selectivity to a total of 95% toward lactic acid can be achieved by tuning the process parameters.@en

One possible way to reduce our carbon footprint is using postcombustion capture (PCC) processes to remove CO2 from flue gases. Because of the highly dynamic characteristics of such processes, real-time performance monitoring is a very complex task. This paper presents a method for monitoring the concentrations of CO2, SOx, and a CO2 capturing agent (β-alanine) during a process in a PCC pilot plant. A partial least-squares (PLS) model was built to estimate these concentrations from Fourier transform infrared (FTIR) spectra of the capturing solvent during processing in a model PCC plant. The model predicts the species concentrations to within 0.05 mol/L, provided that the concentrations stayed within the calibration window of the model. Next to that, it is paramount that the solutions used for model calibration consist of the same solution matrix as the real process medium. The model was eventually used to monitor an emulated PCC process online during 24 h of processing. This demonstrated that events such as saturation of the capturing agent with CO2, water replenishment, and switching to safety protocols can be followed accurately. The combination of an FTIR spectrometer and a PLS model can be used to extract process information in real-time.@en