Dual-functional Materials for Combined CO2 Capture and Non-Thermal Plasma-Assisted Conversion
Kaikkonen, Tero (2023)
Kaikkonen, Tero
2023
Materiaalitekniikan DI-ohjelma - Master's Programme in Materials Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2023-01-30
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202301061155
https://urn.fi/URN:NBN:fi:tuni-202301061155
Tiivistelmä
As industrialization and population are on the rise, CO2 gas emissions are still the number one greenhouse gas (GHG) emission in the world. A multitude of ways to remove it from the air and utilize is being researched. One of the promising methods is direct air capture and utilization via non-thermal plasma-assisted conversion. The energy of the plasma is enough to induce the conversion of CO2 to useful chemicals as low temperature as room temperature.
In this master’s thesis, dual-functional material’s applicability to decrease the amount of CO2 in the air via direct air capture (DAC) and conversion with non-thermal plasma-assisted conversion was researched. The dual-functional materials are referred to as materials that can adsorb CO2 and be used as a base for reverse water-gas shift (RWGS) reaction where CO2 is converted to CO and H2O with H2 as a co-reactant. Commercial organic and inorganic materials' adsorption and conversion capabilities were tested and compared to synthesized PEI snow materials. The materials’ behavior and durability in non-thermal plasma were also tested.
The literature part contains a review of plasma and its applications, focusing on the non-thermal DBD plasmas theory, plasma formation, and efficiency. The dual-functioning materials’ adsorption properties will be reviewed as their effect on plasma-assisted conversion. Also, a benchmark test for CO2 splitting will be reviewed which will work as a starting point for the experiment testing the used equipment and DBD plasma.
The thesis experimental work consists of testing the commercial inorganic and organic material’s capabilities to adsorb and convert CO2 to CO in a DBD reactor. The experiments were conducted by saturating the materials with CO2 gas, after which the adsorbed CO2 was converted with H2 gas via plasma-assist. The experimental part consists of DBD reactor parameters testing with commercial hydrotalcite and hydrocell®-resin, to ascertain experiments plasma optimal power (W) and CO2 conversion efficiency of the materials in question were calculated. Afterward, the hydrotalcite, zeolite, and PEI snow were experimented on RWGS reaction to produce CO with H2 as a co-reactant. The RWGS reaction was verified by qualitative analysis. The possible changes in organic materials and of synthesized PEI snows were verified with mass spectrometer analysis and FTIR spectrometer.
The adsorption capacities of the dual-functional materials were calculated and compared: hydrocell®-resin (1.230 mmol/g) > zeolite (0.995 mmol/g) > hydrotalcite (0.427 mmol/g). The PEI snow did not adsorb any CO2 in the experiments done. The RWGS reaction was verified in tested materials, excluding zeolite and PEI snow. For zeolite and PEI snow materials a platinum catalyst was inserted to induce the RWGS reaction. The PEI snow started to degrade in the plasma area producing ammonia and hydrocarbons. Because of said degradation, the PEI snow was moved upstream and downstream of the (platinum alfa-alumina as a catalyst) plasma area reducing the degradation only to the boundary between the PEI snow and the catalyst. The synthesized PEI snow does not work as a dual-functional material with these experiment parameters, significant changes should be made to improve the material itself.
In this master’s thesis, dual-functional material’s applicability to decrease the amount of CO2 in the air via direct air capture (DAC) and conversion with non-thermal plasma-assisted conversion was researched. The dual-functional materials are referred to as materials that can adsorb CO2 and be used as a base for reverse water-gas shift (RWGS) reaction where CO2 is converted to CO and H2O with H2 as a co-reactant. Commercial organic and inorganic materials' adsorption and conversion capabilities were tested and compared to synthesized PEI snow materials. The materials’ behavior and durability in non-thermal plasma were also tested.
The literature part contains a review of plasma and its applications, focusing on the non-thermal DBD plasmas theory, plasma formation, and efficiency. The dual-functioning materials’ adsorption properties will be reviewed as their effect on plasma-assisted conversion. Also, a benchmark test for CO2 splitting will be reviewed which will work as a starting point for the experiment testing the used equipment and DBD plasma.
The thesis experimental work consists of testing the commercial inorganic and organic material’s capabilities to adsorb and convert CO2 to CO in a DBD reactor. The experiments were conducted by saturating the materials with CO2 gas, after which the adsorbed CO2 was converted with H2 gas via plasma-assist. The experimental part consists of DBD reactor parameters testing with commercial hydrotalcite and hydrocell®-resin, to ascertain experiments plasma optimal power (W) and CO2 conversion efficiency of the materials in question were calculated. Afterward, the hydrotalcite, zeolite, and PEI snow were experimented on RWGS reaction to produce CO with H2 as a co-reactant. The RWGS reaction was verified by qualitative analysis. The possible changes in organic materials and of synthesized PEI snows were verified with mass spectrometer analysis and FTIR spectrometer.
The adsorption capacities of the dual-functional materials were calculated and compared: hydrocell®-resin (1.230 mmol/g) > zeolite (0.995 mmol/g) > hydrotalcite (0.427 mmol/g). The PEI snow did not adsorb any CO2 in the experiments done. The RWGS reaction was verified in tested materials, excluding zeolite and PEI snow. For zeolite and PEI snow materials a platinum catalyst was inserted to induce the RWGS reaction. The PEI snow started to degrade in the plasma area producing ammonia and hydrocarbons. Because of said degradation, the PEI snow was moved upstream and downstream of the (platinum alfa-alumina as a catalyst) plasma area reducing the degradation only to the boundary between the PEI snow and the catalyst. The synthesized PEI snow does not work as a dual-functional material with these experiment parameters, significant changes should be made to improve the material itself.