Production of ammonia from plasma-catalytic decomposition of urea: Effects of carrier gas composition
| Autor: | Xing Fan, Tianle Zhu, Danqi Qiu, Jian Li |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Environmental Engineering
Inorganic chemistry 02 engineering and technology Dielectric barrier discharge 010402 general chemistry 01 natural sciences Catalysis Ammonia production Ammonia chemistry.chemical_compound Urea Environmental Chemistry Gas composition General Environmental Science Air Pollutants General Medicine 021001 nanoscience & nanotechnology Decomposition 0104 chemical sciences Models Chemical chemistry Yield (chemistry) Nitrogen Oxides 0210 nano-technology |
| Zdroj: | Journal of Environmental Sciences. 66:94-103 |
| ISSN: | 1001-0742 |
| DOI: | 10.1016/j.jes.2017.05.033 |
| Popis: | Effects of carrier gas composition (N 2 /air) on NH 3 production, energy efficiency regarding NH 3 production and byproducts formation from plasma-catalytic decomposition of urea were systematically investigated using an Al 2 O 3 -packed dielectric barrier discharge (DBD) reactor at room temperature. Results show that the presence of O 2 in the carrier gas accelerates the conversion of urea but leads to less generation of NH 3 . The final yield of NH 3 in the gas phase decreased from 70.5%, 78.7%, 66.6% and 67.2% to 54.1%, 51.7%, 49.6% and 53.4% for applied voltages of 17, 19, 21 and 23 kV, respectively when air was used as the carrier gas instead of N 2 . From the viewpoint of energy savings, however, air carrier gas is better than N 2 due to reduced energy consumption and increased energy efficiency for decomposition of a fixed amount of urea. Carrier gas composition has little influence on the major decomposition pathways of urea under the synergetic effects of plasma and Al 2 O 3 catalyst to give NH 3 and CO 2 as the main products. Compared to a small amount of N 2 O formed with N 2 as the carrier gas, however, more byproducts including N 2 O and NO 2 in the gas phase and NH 4 NO 3 in solid deposits were produced with air as the carrier gas, probably due to the unproductive consumption of NH 3 , the possible intermediate HNCO and even urea by the abundant active oxygen species and nitrogen oxides generated in air-DBD plasma. |
| Databáze: | OpenAIRE |
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