HEAT TRANSFER TUBE FOR LNG VAPORIZER, ITS PRODUCTION METHOD, AND LNG VAPORIZER USING SUCH HEAT TRANSFER TUBES

摘要

The present invention heat transfer for LNG vaporizer to prevent effectively that the surface is heavily cooled damaged by surface corrosion of the Al alloy substrate even when used in the lower or bottom header of the panel, which is thought to be formed less the oxide-coated tube ( It discloses a heat transfer tube). ; These heat transfer tubes are lower each connected to the panel in the Al comprising a panel consisting of multiple aligned columns (row) of the curtain shape (curtain form) the heat transfer tube alloy panel unit (panel unit), and its lower end and the upper end header (lower header) and a top header (upper header), the device is that LNG vaporizer to be used and, where LNG is the panel's surface along the panel unit of the upper from the lower to the flowing water and the heat transfer tube for through flowing LNG between the heat exchanger to be vaporized by. In such LNG vaporizer, at least that surface roughening the outer surface of the heat transfer tube and the outer surface of the lower header in the lower end of the panel by blasting and then, to 1 to 80 containing Mg in an amount in the range of% by weight and 100 to 1000㎛ was formed by thermal spraying of a coating of Al-Mg alloy (thermal spraying) with a thickness implements a victim way (protection by sacrificial corrosion). A scheme layer Zn and / or contained in the 0.3 to 3.0% by weight content of Mn (However, (Zn + Mn) content is in the range of 0.3 to 3.0% by weight of), and Mg in 0.3 to 5 mass% of the content of to form an Al-containing alloy coating to be also effective.