The vertical fluidized bed reactor makes use of gas flow rates to “fluidize” the solid gas particles in the reactor. The gas travels from the bottom up through the reactor. If the gas flow rate is high enough, it will lift the solid catalyst up. This is done to improve contact with all surfaces of the catalyst and the gas flowing through it. A great advante of fluidized bed reactors is that they permit continuous addition and removal of solid particles from the reactor, without stopping the operation.
The compact tube furnace is equipped with a multi-segment programmable controller, allowing precise control of temperature (up to 1000 ˚C) versus time.
The split hinge permits convenient placement of reactor tubes and a quicker cool down rate with the cover lifted up. Connected with the furnace is a multi-line flow rate controller box, through which a variety of gases flow. The controller box also allows measurement and control of the pressure inside the reactor tube.
The role of water in carbon feed on the surface-guided growth of horizontally aligned single-walled carbon
nanotubes (HA-SWCNTs) was investigated. It is shown that the amount of water can be optimized to favor HA-SWCNT growth, which is proposed to be due to selective etching of carbon deposits at carbon–metal interface. Without water, nanotube–nanotube interaction and carbon accumulation at the interface are disproportionately large compared to the rate of nanotube growth, leading to catalyst deactivation. With excess water, suppression of nanotube growth occurs, resulting in reduced carbon yield on the surface.
Intermediate carbon/water feed ratios achieve cleaner growth with high efficiency.