2018 Fiscal Year Annual Research Report
Concurrent development and assessment of emerging technology: a case study on carbon nanotube production
|Allocation Type||Single-year Grants |
|Research Institution||Waseda University |
ティア ヘンイ 早稲田大学, 理工学術院, 次席研究員(研究院講師) (70822485)
|Project Period (FY)
2018-08-24 – 2020-03-31
|Keywords||Carbon nanotube / Life cycle assessment / Emerging technology / Cleaner production|
|Outline of Annual Research Achievements
Leveraging the experience in lab syntheses, this study aimed to evaluate the prospective environmental impact of CNT synthesized via three selected catalytic CVD methods. First, the CO2-assisted growth on flat substrates [Carbon, 136 (2018): p.143-149], represented the established millimeter long CNT growth. Second, the fluidized-bed growth on spherical beads with sputtered catalysts [Carbon, 50(4) (2012): p. 1538-1545], contrasted the effect of 3D CNT growth to previous 2D growth. Third, the fluidized-bed CVD with chemical vapor deposited catalysts [Carbon, 49(6) (2011): p. 1972-1979], showed a repeatable single-reactor production. We quantified the global warming potential impact of 1 g CNT production with life cycle assessment (LCA). The results for the three syntheses were 28.55, 9.94, and 2.10 kg-CO2equiv/g-CNT, accordingly. By comparing the three syntheses, we showed that the strikingly high impacts could be mitigated through increasing CNT yield with fluidized bed and replacing the energy-intensive sputtering process. A scenario to substitute the remaining hotspot, argon (purging gas), with nitrogen could reduce the impact to 0.48 kg-CO2equiv/g-CNT. When considering scale-up from lab-scale (reactor diameter of 22 mm, productivity of 5 g per day) to industrial scale (diameter >30 times, productivity >3 to 104 times), the CNT production would be comparable to industrialized carbon fiber production (about 0.02 kg-CO2equiv/g-CF).
|Current Status of Research Progress
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
1. The inventory analysis progressed well with the support of experimental data accumulated from the collaborator's lab in the past.
2. Active support from the collaborator and students were received, which helped to overcome the knowledge barriers.
3. The selected CNT synthesis were changed to on-substrate CVD and fluidized-bed CVD for a better comparison of technologies.
|Strategy for Future Research Activity
In the second year, the LCA of CNT synthesized via on-substrate and fluidized-bed CVD will be wrapped up; presentation and publication will be made as research output.
Further life cycle assessment on floating catalyst CVD will be conducted. Floating catalyst has the advantage of producing high-yield single-wall CNT in a single reactor. The experiments on floating catalyst are partially completed and on-going.
In addition, current assessment focuses only on a cradle-to-gate scope that ends at the CNT synthesis. An expansion of scope to include CNT purification, processing, and application will be considered using assumptions based on secondary data.
Research Products (1 results)