The effect of forced periodic modulation of several input parameters on the rate of pho-tocatalytic decomposition of formic acid over a TiO2 thin film catalyst has been investigated in a continuously stirred tank reactor. The kinetic model was adopted based on the literature and it includes acid adsorption, desorption steps, the formation of photocatalytic active sites and decomposition of the adsorbed species over the active titania sites. A reactor model was developed that describes mass balances of reactive species. The analysis of the reactor was performed with a computer-aided nonlinear frequency response method. Initially, the effect of amplitude and frequency of four input parameters (flowrate, acid concentration, temperature and light intensity) were studied. All single inputs provided only a minor improvement, which did not exceed 4%. However, a modulation of two input parameters, inlet flowrate and the acid molar fraction, considerably im-proved the acid conversion from 80 to 96%. This is equivalent to a factor of two increase in residence time at steady-state operation at the same temperature and acid concentration.
Bibliographical noteFunding Information:
Funding: The authors greatly appreciate the funding support from the Russian Science Foundation (grant number 20-69-46041). Thomas Ellwood and Evgeny Rebrov also acknowledge support from the ERC Synergy Grant “Surface-Confined fast modulated plasma for process and energy intensification” (SCOPE) from the European Commission with the Grant No. 810182.
- Forced periodic modulation
- Formic acid decomposition
- Non-stationary CSTR
- Process intensification