Seal Gas Ejection for Aligned Carbon Nanotube Growth
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Solution Overview
Problem
Existing apparatuses face challenges in uniformly controlling the concentration distribution and flow rate distribution of raw material gas and catalyst activation material on a substrate during the production of aligned carbon nanotube aggregates, leading to turbulence and stagnation in the growth furnace, which hinders the continuous production of aligned CNT aggregates.
Innovation Solution
An apparatus with a growth unit and first gas mixing prevention means, including a seal gas ejection section and exhaust section, is designed to prevent outside air from entering the growth furnace, ensuring uniform control of gas distributions and minimizing gas flow disturbances, thereby facilitating the continuous production of aligned CNT aggregates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seal gas is ejected to prevent outside air from entering the growth furnace, then gas mixing is prevented and production stability is improved, but device complexity increases due to additional ejection and exhaust sections
Solution Approach 1:
The growth furnace system is segmented into distinct functional zones: a seal gas ejection section at the opening to prevent outside air entry, a growth chamber for CNT synthesis, and a separate exhaust section for removing seal gas. This segmentation allows each component to perform its specific function independently, improving overall system reliability while maintaining manageable complexity through modular design
Solution Approach 2:
Seal gas acts as an intermediary substance between the outside environment and the growth furnace interior. The seal gas ejection section introduces this intermediary to create a protective gas barrier that prevents harmful outside air from entering, while the exhaust section removes the seal gas after it has fulfilled its protective function. This intermediary mechanism resolves the contradiction by providing reliable protection without requiring complex sealing structures
2Productivity
If high carbon concentration atmosphere is used to increase CNT production quantity, then productivity is improved, but catalyst deactivation occurs due to carbonaceous impurities covering the catalyst
Solution Approach 1:
The system maintains continuous CNT production by implementing a sealed growth environment that sustains high carbon concentration atmosphere throughout the synthesis process. The seal gas ejection and exhaust sections work continuously to maintain atmospheric stability, allowing the catalyst to operate at high productivity levels without premature deactivation from uncontrolled gas exchange
Solution Approach 2:
The growth furnace is maintained in an inert or controlled atmosphere using seal gas to prevent unwanted reactions and maintain stable carbon concentration. This controlled inert environment allows high carbon concentration to be sustained without catalyst deactivation, as the seal gas barrier prevents outside air (oxygen) from entering and reacting with the catalyst or interfering with the carbon deposition process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus effectively prevents external gas interference, allowing for precise control of gas distributions and maintaining a stable gas flow, resulting in the efficient production of aligned CNT aggregates with enhanced specific surface area and orientation.
Implementation Method 1
first seal gas ejection section for ejecting a seal gas along an opening plane of at least one of (i) an opening of the growth furnace through which opening the substrate is transferred into the growth furnace and (ii) an opening of the growth furnace through which opening the substrate is transferred out of the growth furnace
Implementation Method 2
first exhaust section for sucking and exhausting the seal gas out of the apparatus, so that the seal gas does not flow into the growth furnace through the opening of the growth furnace
Implementation Method 3
a growth unit including a growth furnace for growing therein the aligned carbon nanotube aggregates on a substrate supporting a catalyst on a surface of the substrate
Data Source
AI summary
Provided is a production apparatus (100) for continuously producing aligned carbon nanotube aggregates on a substrate supporting a catalyst while continuously transferring the substrate. The production apparatus (100) includes gas mixing prevention means (12, 13) for preventing gas present outside a growth furnace (3a) from flowing into the growth furnace (3a). The gas mixing prevention means (12, 13) includes a seal gas ejection section (12b, 13b) so that the seal gas does not flow into the growth furnace through the openings of the growth furnace. The production apparatus prevents the outside air from flowing into the production apparatus, uniformly controls, within a range suitable to production of CNTs, a concentration distribution(s) and a flow rate distribution(s) of a raw material gas and/or a catalyst activation material on the substrate, and does not disturb gas flow as much as possible in the growth furnace.