Analysis of the most common GR1 titanium tube heat exchanger leakage problems

Due to the high price of titanium, the traditional stuffing box type titanium tube heat exchanger in the heat exchanger tube selection of titanium, and GR1 tube plate selection of titanium steel composite plate. Due to titanium and steel with non-weldable properties, resulting in titanium tube heat exchanger manufacturing difficulties, so the stuffing box type heat exchanger tube box usually do not use titanium steel composite plate, but the use of carbon steel or low alloy steel tube box overall lining program, which saves costs and reduces the processing difficulty. In order to reduce manufacturing costs and reduce the processing and manufacturing difficulties, in the traditional stuffing box type titanium tube heat exchanger design program, where not in contact with seawater are not used in the part of the Chin material, so the heat exchanger floating tube plate at the tube plate skirt is usually made of carbon steel, which can be avoided to avoid the welding of titanium and carbon steel, but also to reduce costs. Although the traditional stuffing box type titanium tube heat exchanger structure design program to reduce the cost and manufacturing difficulties, but also with a serious equipment leakage problems.

Currently the most common leakage phenomenon occurs in the floating tube plate seal leakage, according to user feedback, the traditional structure of the stuffing box type titanium tube heat exchanger in the floating tube plate at the serious corrosion. Analyze the reason, mainly due to the packing in the process of being pressed, resulting in floating tube plate carbon steel partially exposed in the packing outside, in the sealing of the floating tube plate and inserted into the gap between the tube box, seawater and carbon steel part of the direct contact, resulting in the rapid corrosion of seawater, resulting in heat exchanger leakage, and carbon steel is extremely intolerant of seawater corrosion. Part of the information shows that when seawater directly in contact with carbon steel, floating tube plate carbon steel part in a very short period of time will be corroded off, in serious cases, the corrosion of the remaining only thin titanium part. Once the above leakage appears, it is very difficult to repair, even if the equipment corrosion at the beginning of the maintenance can be found in time through the maintenance and repair of corrosion at the patch welding repair, but due to various conditions and the characteristics of the metal welding, after repairing the operation of the equipment will be in a short period of time again a large area of corrosion, the equipment at any time there will be a risk of leakage. Packing box type titanium tube heat exchanger once the carbon steel part is corroded because of leakage, in order to eradicate the danger, must be replaced by the equipment.

Another common leakage is caused by the rupture of titanium tubes, and the rupture of titanium tubes is usually because the heat exchanger tube is scratched, bruised and other reasons. Because of the high price of titanium, in order to reduce costs, titanium tube heat exchanger selected by the heat exchanger tube wall thickness is usually thin, generally take 0.5mm or so. In such leakage cases, often found in the heat exchanger tube box there are a large number of large particles of sand and gravel or even shells and so on, analyze the reasons, mainly in practice, containing a large number of debris seawater in the heat exchanger tube flow, very easy to cause scratching or abrasion of titanium tubes, in addition to affecting the effect of heat transfer, the heat exchanger life is also greatly reduced, so that the very thin titanium tubes ruptured prematurely, resulting in leakage. Due to structural reasons and difficult to clean up and other environmental conditions, through the patch welding repair is more difficult, only through the sealing of the leaking tube orifice to solve the leakage problem, seriously affecting the heat exchanger heat transfer effect.

The third common leak is mainly caused by titanium pipe joints and tube sheet connection problems, the main reason for this leak is the welding quality problems or heat exchanger tube vibration caused by the destruction of the pipe joints, its repair is very difficult.

In actual use, titanium welding deformation, calibration difficulties, especially when Chin cold working, easy to produce cracks; and bending deformation, elastic rebound, not easy to get the right shape, the degree of strengthening of its cold hardening tendency with the speed of deformation and aggravation, and the speed of deformation of the processing parts of the limit of the degree of quality have a great impact. Due to the existence of many defects in titanium, making titanium equipment is more unfavorable to rework, and sometimes even produce the more rework, the worse the actual results of the situation. For these characteristics of titanium, in order to ensure its process performance, the technical conditions of titanium equipment is extremely strict, in addition to the composition of raw materials, manufacturing, assembly, testing methods and other requirements, but also in accordance with the category of titanium equipment to put forward special manufacturing requirements, and in strict accordance with the manufacturing process regulations for processing and manufacturing.