a pre-growth tube configured for an early pre-reaction of raw materials before generation of carbon nanotubes;

an atomizer configured to atomize the raw materials for the generation of the carbon nanotubes and then to spray the atomized raw materials into the pre-growth tube; wherein the atomizer is provided at a front end of the pre-growth tube and has a spray output tube that extends into the pre-growth tube;

a growth tube configured to generate and continuously grow the carbon nanotubes; wherein the front end of the growth tube is hermetically connected to a rear end of the pre-growth tube; and

a gas curtain generator configured to form a gas curtain enclosing the atomized raw materials around an outlet of the spray output tube, wherein the gas curtain extends parallel to an extension direction of the pre-growth tube and the gas curtain generator is provided inside the pre-growth tube,

wherein the gas curtain generator comprises at least one gas curtain forming plate which is provided with a plurality of gas holes,

the gas curtain forming plate has a ring shape, and the spray output tube is located at a hollow center of the gas curtain forming plate; an outer wall of the spray output tube is in contact with an inner wall of the gas curtain forming plate; and the gas holes are radially distributed on the gas curtain forming plate, and

an edge contour of the gas curtain forming plate matches an inner wall of the pre-growth tube.