Process for fabricating carbon nanotubes and apparatus for implementing the process
AssigneeArkema France
InventorsPatrice Gaillard, Serge Bordere
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Abstract
An industrial process and an apparatus for fabricating carbon nanotubes (CNTs) is provided, comprising synthesis of the carbon nanotubes by decomposing a carbon source brought into contact, in a fluidized-bed reactor, whereby the carbon nanotubes synthesized in the reactor and fixed onto the grains of catalytic substrate in the form of an entangled three-dimensional network, forming agglomerates constituting the CNT powder, are recovered sequentially by discharging them while hot, that is to say at the reaction temperature for synthesizing the CNTs, at the foot of the reactor, the sequence in which the discharges are carried out corresponding to the frequency of filling of the reactor.
Claims18
An industrial process for fabricating carbon nanotubes (CNTs), comprising synthesis of the carbon nanotubes by decomposing a carbon source brought into contact, in a fluidized-bed reactor at a reaction temperature between 500° C. and 1500° C. with a catalyst in the form of substrate grains covered with a metal, the nanotubes produced being recovered, in which the carbon nanotubes synthesized in the reactor and fixed onto the grains of catalytic substrate in the form of an entangled three-dimensional network, forming agglomerates constituting the CNT powder, are recovered sequentially by discharging them while hot at the reaction temperature for synthesizing the CNTs, and discharge taking place beneath the reactor via an outlet of the reactor;
- wherein it comprises the following steps:
- 1) the temperature of the reactor is raised to the value desired for the synthesis, between 500° C. and 1500° C. for an initialization phase and this temperature is maintained with a carbon nanotube powder feedstock in the reactor;
- 2) a CNT synthesis phase for a defined time T1, consisting in:
- pulsingly injecting the catalyst into the reactor by means of an inert gas and
- continuously injecting reactive gases containing the carbon source into the reactor;
- and
- 3) a hot CNT recovery phase for a time T2, consisting in:
- stopping the injection of the catalyst when the reactor reaches a predetermined filling level,
- continuing to inject the reactive gases containing the carbon source, or stopping the injection after having maintained it for a defined time tr,
- discharging the CNT powder beneath the reactor in order to introduce it into a cooling container,
- stopping the discharge and
- recommencing a new phase 2).
An industrial process for fabricating carbon nanotubes (CNTs), comprising synthesis of the carbon nanotubes by decomposing a carbon source brought into contact, in a fluidized-bed reactor at a reaction temperature between 500° C. and 1500° C. with a catalyst in the form of substrate grains covered with a metal, the nanotubes produced being recovered, in which the carbon nanotubes synthesized in the reactor and fixed onto the grains of catalytic substrate in the form of an entangled three-dimensional network, forming agglomerates constituting the CNT powder, are recovered sequentially by discharging them while hot at the reaction temperature for synthesizing the CNTs, and discharge taking place via the bottom of the reactor by means of a bottom outlet of the reactor;
- wherein it comprises the following steps:
- 1) the temperature of the reactor is raised to the value desired for the synthesis, between 500° C. and 1500° C. for an initialization phase and this temperature is maintained with a carbon nanotube powder feedstock in the reactor;
- 2) a CNT synthesis phase for a defined time T1, consisting in:
- pulsingly injecting the catalyst into the reactor by means of an inert gas and
- continuously injecting reactive gases containing the carbon source into the reactor;
- and
- 3) a hot CNT recovery phase for a time T2, consisting in:
- stopping the injection of the catalyst when the reactor is full,
- continuing to inject the reactive gases containing the carbon source, or stopping the injection after having maintained it for a defined time tr,
- discharging the CNT powder at the bottom of the reactor in order to introduce it into a cooling container,
- stopping the discharge and
- recommencing a new phase 2).
An industrial process for fabricating carbon nanotubes (CNTs), comprising synthesis of the carbon nanotubes by decomposing a carbon source brought into contact, in a fluidized-bed reactor at a reaction temperature between 500° C. and 1500° C. with a catalyst in the form of substrate grains covered with a metal, the nanotubes produced being recovered, in which the carbon nanotubes synthesized in the reactor and fixed onto the grains of catalytic substrate in the form of an entangled three-dimensional network, forming agglomerates constituting the CNT powder, are recovered sequentially by discharging them while hot at the reaction temperature for synthesizing the CNTs, and discharge taking place via the bottom of the reactor by means of a bottom outlet of the reactor;
- wherein the CNTs are discharged via the bottom outlet of the reactor, said outlet corresponding to an outlet for draining the reactor, said outlet being provided with a valve-type shutoff system, opened sequentially, the outlet of this system being connected to a cooling/storage container capable of holding the CNT powder;
- wherein it comprises the following steps:
- 1) the temperature of the reactor is raised to the value desired for the synthesis, between 500° C. and 1500° C. for an initialization phase and this temperature is maintained with a carbon nanotube powder feedstock in the reactor;
- 2) a CNT synthesis phase for a defined time T1, consisting in:
- pulsingly injecting the catalyst into the reactor by means of an inert gas and
- continuously injecting reactive gases containing the carbon source into the reactor;
- and
- 3) a hot CNT recovery phase for a time T2, consisting in:
- stopping the injection of the catalyst when the reactor is full,
- continuing to inject the reactive gases containing the carbon source, or stopping the injection after having maintained it for a defined time tr,
- discharging the CNT powder at the bottom of the reactor in order to introduce it into a cooling container,
- stopping the discharge and
- recommencing a new phase 2).
Dependencies are inferred from the claim text.