A method for growing carbon nanotubes is provided. A reactor including a reactor chamber and a substrate located in the reactor chamber is provide. The substrate is a hollow structure including a sidewall and a bottom. The hollow structure also defines an opening. The sidewall includes a carbon nanotube layer and catalyst particles dispersed in the carbon nanotube layer. A mixture of carbon source gas and carrier gas is introduced into the reactor chamber so that the mixture of carbon source gas and carrier gas flows into the hollow structure from the opening and out of the hollow structure through the sidewall. The hollow structure is heated.

An offshore installation or offshore vessel is provided which comprises a reactor system for carrying out steam reforming of a feed gas comprising hydrocarbons.

A reactor for producing a solid carbon material comprising at least one reaction chamber configured to produce a solid carbon material and water vapor through a reduction reaction between at least one carbon oxide and at least one gaseous reducing material in the presence of at least one catalyst material. Additional reactors, and related methods of producing a solid carbon material, and of forming a reactor for producing a solid carbon material are also described.

A reactor includes a reactor chamber and a substrate. The reactor chamber having an inlet and an outlet. The hollow structure is received in the reactor chamber, wherein the hollow structure includes a sidewall, a bottom, and a opening opposite to the bottom, the sidewall defines a number of apertures, gases in the reactor chamber flow penetrate the hollow structure through the number of apertures.