Reactor for the synthesis of melamine from urea, in accordance with the high-pressure non-catalytic process, comprising: a vertical reactor body (1), at least one inlet (2) for the urea melt, a set of heating elements (3), and a central duct (7), said set of heating elements (3) being arranged inside said central duct.

The present invention discloses a hydrogen sulfide reactor vessel with an external heating system that is conductively and removably attached to an exterior portion of the reactor vessel. Also disclosed are processes for producing hydrogen sulfide utilizing the reactor vessel.

The invention provides a curing system that is useful for curing materials that consume carbon dioxide as a reagent. The system has a curing chamber that contains the material to be cured and a gas that contains carbon dioxide. The system includes apparatus that can deliver carbon dioxide to displace ambient air upon loading the system, that can provide carbon dioxide as it is needed and as it is consumed, that can control carbon dioxide concentration, temperature and humidity in the curing chamber during the curing cycle and that can record and display to a user the variables that occur during the curing process. A method of curing a material which requires CO.sub.2 as a curing reagent is also described.

The present disclosure provides devices and systems that utilize concurrent and countercurrent exchange platforms to produce purified silicon.

A direct contact heat exchanger for a molten media reactor can include a plurality of trays or stages disposed in a vessel, a molten media flow path configured to pass a molten media through the plurality of trays or stages, and a gas pathway disposed through the plurality of trays or stages. The gas pathway is configured to directly contact a gas phase fluid with the molten media on the plurality of trays or stages.

Provided is a decompression heat-insulating pipe structure that can be used in the system operating at high temperatures. A decompression heat-insulating pipe structure of the present disclosure includes: an outer tube and an inner tube each having a flange; and a seal member between the flanges, the seal member being configured to keep a space between the outer tube and the inner tube in a decompression state, and a shifting means configured to shift the outer tube and the inner tube relatively so as to selectively dispose the tubes at a pressing position to press the seal member between the flanges and at a cancellation position to cancel the pressing of the seal member.

The present invention discloses a hydrogen sulfide reactor vessel with an external heating system that is conductively and removably attached to an exterior portion of the reactor vessel. Also disclosed are processes for producing hydrogen sulfide utilizing the reactor vessel.

Described herein are processes and apparatus for the large-scale synthesis of boron nitride nanotubes (BNNTs) by induction-coupled plasma (ICP). A boron-containing feedstock may be heated by ICP in the presence of nitrogen gas at an elevated pressure, to form vaporized boron. The vaporized boron may be cooled to form boron droplets, such as nanodroplets. Cooling may take place using a condenser, for example. BNNTs may then form downstream and can be harvested.

The invention provides a curing system that is useful for curing materials that consume carbon dioxide as a reagent. The system has a curing chamber that contains the material to be cured and a gas that contains carbon dioxide. The system includes apparatus that can deliver carbon dioxide to displace ambient air upon loading the system, that can provide carbon dioxide as it is needed and as it is consumed, that can control carbon dioxide concentration, temperature and humidity in the curing chamber during the curing cycle and that can record and display to a user the variables that occur during the curing process. A method of curing a material which requires CO.sub.2 as a curing reagent is also described.

High quality, catalyst-free boron nitride nanotubes (BNNTs) that are long, flexible, have few wall molecules and few defects in the crystalline structure, can be efficiently produced by a process driven primarily by Direct Induction. Secondary Direct Induction coils, Direct Current heaters, lasers, and electric arcs can provide additional heating to tailor the processes and enhance the quality of the BN-NTs while reducing impurities. Heating the initial boron feed stock to temperatures causing it to act as an electrical conductor can be achieved by including refractory metals in the initial boron feed stock, or providing additional heat via lasers or electric arcs. Direct Induction processes may be energy efficient and sustainable for indefinite periods of time. Careful heat and gas flow profile management may be used to enhance production of high quality BNNT at significant production rates.