Abatement of 3-methylbutanal and trimethylamine with combined plasma and photocatalysis in a continuous planar reactor

International audienceThis paper deals with the 3-methylbutanal ((CH3)2CHCH2COH) removal with the help of a nonthermal surface plasma discharge coupled with photocatalysis. The capability of this process for gas treatment was studied. A planar reactor system was developed in order to perform the effect of adding photocatalytic material in plasma surface discharge barrier dielectric (SDBD) zone on (i) 3-methylbutanal removal, (ii) selectivity of CO2 and CO, (iii) byproducts formation such ozone formation. It was found that the influence of the UV light generated by SDBD reactor was very low. The activation of the photocatalyst media could be negligible. Whereas, the introduction of external UV light to the process improves significantly the removal efficiency of 3-methylbutanal (3MBA) and the mineralization. A synergetic effect was observed by combining plasma SDBD and photocatalysis from all experiments and with other pollutant such as trimethylamine (N(CH3)3). Moreover, the byproducts of 3MBA were identified and evaluated with plasma SDBD, photocatalysis and plasma SDBD/photocatalysis combination

A tool for predicting the dynamic response of biotrickling filters for VOC removal

This article presents the development of a MATLAB® computer program to simulate the performance of biotrickling filters. Since these filters behave differently during spraying and nonspraying cycles, the presented simulation tool is built on top of a mathematical description of each situation. The resulting variable-structure model is then used as the basis for simulation experiments. The model presented herein represents the first attempt to take into account the variable spraying pattern usually found in industrial installations. Overall, the software is flexible and easy to use, allowing the user to specify the emission concentration pattern, the gas concentration pattern, as well as the spraying cycle periods for up to two different emission patterns per day. The model is able to predict experimental data from a biotrickling filter treating isopropanol under intermittent conditions of loading and spraying. Simulation examples are then provided to study the effect of variable inlet concentrations and gas flow rates

Dynamic Mathematical Modelling of the Removal of Hydrophilic VOCs by Biotrickling Filters

A mathematical model for the simulation of the removal of hydrophilic compounds using biotrickling filtration was developed. The model takes into account that biotrickling filters operate by using an intermittent spraying pattern. During spraying periods, a mobile liquid phase was considered, while during non-spraying periods, a stagnant liquid phase was considered. The model was calibrated and validated with data from laboratory- and industrial-scale biotrickling filters. The laboratory experiments exhibited peaks of pollutants in the outlet of the biotrickling filter during spraying periods, while during non-spraying periods, near complete removal of the pollutant was achieved. The gaseous outlet emissions in the industrial biotrickling filter showed a buffered pattern; no peaks associated with spraying or with instantaneous variations of the flow rate or inlet emissions were observed. The model, which includes the prediction of the dissolved carbon in the water tank, has been proven as a very useful tool in identifying the governing processes of biotrickling filtration

Biotrickling filtration of isopropanol under intermittent loading conditions

This paper investigates the removal of isopropanol by gas phase biotrickling filtration. Two plastic packing materials, one structured and one random, have been evaluated in terms of oxygen mass transfer and isopropanol removal efficiency (RE). Oxygen mass transfer experiments were performed at gas velocities of 104 and 312 m h-1 and liquid velocities between 3 and 33 m h-1. Both materials showed similar mass transfer coefficients up to liquid velocities of 15 m h-1. At greater liquid velocities, the structured packing exhibited greater oxygen mass transfer coefficients. Biotrickling filtration experiments were carried out at inlet loads (IL) from 20 to 65 g C m-3 h -1 and empty bed residence times (EBRT) from 15 14 to 160 s. To simulate typical industrial emissions, intermittent isopropanol loading (16 h/day, 5 16 day/week) and intermittent spraying frequency (15 min/1.5 hours) were applied. Maximum elimination capacity (EC) of 51 g C m-3 h -1 has been obtained for the random packing (IL of 65 g C m-3 h -1 17 , EBRT of 18 50 s). The decrease in irrigation frequency to 15 min every 3 hours caused a decrease in the outlet emissions from 86 to 59 mg C Nm-3 (inlet of 500 mg C Nm-3). The expansion of spraying to night and weekend periods promoted the degradation of the isopropanol accumulated in the water tank during the day, reaching effluent concentrations as low as 44 mg C Nm-3. After a 7 week starvation period, theperformance was recovered in less than 10 days, proving the robustness of the proces

Evaluation of Parallel-Series Configurations of Two-Phase Partitioning Biotrickling Filtration and Biotrickling Filtration for Treating Styrene Gas-Phase Emissions

The removal of styrene from industrial representative gaseous emissions was studied using two reactors connected in series: a two-phase partitioning biotrickling filter (TPPB-BTF) and a conventional biotrickling filter (BTF). The system was operated under industrial conditions, which included steady and transient conditions and intermittent spraying. Silicone oil was used in the TPPB-BTF with a quantity as low as 25 mL L−1, promoting a faster start-up compared to the BTF. By working at a styrene loading of 30 g m−3 h−1, nearly complete removal efficiency (RE) was obtained. In addition, the removal was not adversely impacted by using non-steady emission patterns such as overnight shutdowns (97% RE) and oscillating concentrations (95% RE), demonstrating its viability for industrial applications. After 2 months from inoculation, two additional configurations (reverse series BTF + TPPB-BTF and parallel) were tested, showing the series configuration as the best approach to consistently achieve RE > 95%. After 51 days of operation, high throughput sequencing revealed a sharp decrease in the bacterial diversity. In both reactors, the microorganisms belonging to the Comamonadaceae family were predominant and other styrene degraders such as Pseudomonadaceae proliferated preferably in the first reactor