Why do the waste boiler tubes in Luzzi furnaces leak frequently?

Conduct a water quality analysis to check if the pH level is too low, and ensure the quality of the chemicals used

Analyze the sulfur content in the fuel gas (oil) as well

A thorough analysis should be conducted on the underlying causes of leakage, such as water quality management and whether the system is overheating.

A thorough analysis should be conducted on the underlying causes of leakage, such as water quality management and whether the system is overheating.

This post was last edited by pyp222 on 2017-7-19 at 14:39. There are two main causes of tube leakage: corrosion or wear. Personally, I think leaks caused by corrosion are more likely. The waste boiler in the Ruhr process is a low-pressure steam waste boiler. A large amount of heat from the wet gas exiting the furnace is lost in the previous venturi scrubber; by the time it reaches the low-pressure steam waste boiler, not much heat can be recovered. Therefore, the sensible heat of the wet gas alone is insufficient. As a result, in this waste boiler, in addition to utilizing the sensible heat of the dry gas, the latent heat of some of the steam present in the gas is also utilized, causing some of the water vapor in the gas to condense. Thus, in the Ruhr process, after the gas exits the low-pressure steam waste boiler, it passes through a gas-water separator to separate the condensed water from the gas. Because the water vapor in the wet gas undergoes phase change in the low-pressure steam generator, condensate is produced. Hydrogen sulfide in the gas can dissolve in water to form a corrosive liquid; if the tubes in the low-pressure steam generator are not made of corrosion-resistant austenitic material, even high-temperature steels are not resistant to corrosion. The poster can take a look at the distribution of the leaks. If there are fewer leaks the closer to the gas inlet, and more leaks the further away from it, then it’s very likely that corrosion is the cause.

The water quality is fine; regular tests and analyses are conducted

Conduct a water quality analysis first; it’s very likely that the problem lies with the water.

The water quality shows a slightly higher level of dissolved oxygen; everything else is fine. When a single tube from the tube bundle is taken out, there is no sign of oxygen corrosion

It is usually welding leaks in the tube sheet and tube bundle. 1. The design of the waste heat exchanger does not meet your process requirements. 2. The manufacturing quality is inadequate, especially regarding the welding of the tube sheets. 3. The water hardness is high; as a result, the structure is compromised, heat exchange is poor, the temperature of the tube bundle is high, and damage occurs due to restricted expansion or stress. 4. The alkalinity of the water is high, leading to localized concentration of sodium hydroxide and causing caustic corrosion. 5. In terms of the manufacturing process, preheating was inadequate before operation, resulting in low temperatures. After aeration, the temperature difference between the process gas and the waste heat exchanger is large, causing excessive expansion of the tube sheet in the waste heat exchanger tubes or thermal stress-induced damage due to this temperature difference. The water quality is fine; if the process is no problem, then consider manufacturing; if manufacturing is no issue, then check whether the design is suitable and matches the requirements. There must be a problem somewhere