Reasons for internal leakage in the methanol water cooler

How many years has the equipment been in use? It’s impossible that a blowout occurred; overpressure in the process is also unlikely – it’s probably a defect in the equipment. Just my own guess

1. Corrosion. 2. An excessive pressure difference between the tube and shell sides, along with high flow rates that cause severe wear, leading to leaks at the welds.

1. Problems or defects with the quality of the pipes; 2. Issues with the quality of the welds; 3. Slight corrosion present in the syngas itself – our company uses stainless steel pipes, and the pipe sheet flanges are also lined with stainless steel; 4. Gas-liquid shock causes vibration of the pipes, and friction against the baffle plates leads to pipe perforation.

1. Problems or defects with the quality of the pipes; 2. Issues with the quality of the welds; 3. Slight corrosion present in the syngas itself – our company uses stainless steel pipes, and the pipe sheet flanges are also lined with stainless steel; 4. Gas-liquid shock causes vibration of the pipes, and friction against the baffle plates leads to pipe perforation.

The original poster did not specify where the leakage occurred or provide any other information about it, making it difficult to make a judgment. The people above have already analyzed the issue from the perspectives of material quality, manufacturing processes, and methanol synthesis processes, which is quite comprehensive. Here, I would like to add one more point: poor quality of circulating water leads to the accumulation of dirt, which ultimately causes pitting in the pipes.

1. If the material of the equipment is not stainless steel, it is prone to corrosion; corrosion may occur. 2. If expansion joints are not used during the fabrication of the water cooler, cracks may appear at the tube sheet. I’m adding these two possible issues; other conditions have been mentioned above

In the case of a reciprocating compressor, it is also necessary to determine whether the pressure of the cooling water or that of the gas is higher: 1. If the water pressure is higher, it is very dangerous, as liquid slugging can easily occur, leading to serious consequences. 2. If the gas pressure is higher, air will end up in the water, causing air blockages; this results in poor cooling effects and an increase in the inlet temperature； If there is a sight glass on the cooling water pipe, air in the water can be clearly seen.

It’s probably due to the high gas velocity, as well as the corrosion caused by some by-products

I’d like to add that I don’t know where the leaks are or any other details about them; I also know that water coolers often develop wax buildup, and steam is used to remove this wax. I wonder if there’s a causal relationship between these two phenomena

The usual reason is a corrosion issue. The original poster’s description is too vague; without detailed information, it’s difficult to make a judgment. I hope more details will be provided in the future, as that will help everyone assist in identifying the cause!

1. The quality of the circulating water is poor, causing severe corrosion to the heat exchangers. 2. There is an issue with the selection of the material for the heat exchange tubes. 3. Severe wax formation in the water cooler leads to uneven heating of the heat exchange tubes, resulting in thermal stress corrosion.

1. First, consider whether the water cooler has reached the end of its useful life (if it’s a newly established project at the moment, this need not be considered). 2. Material quality. Regarding products these days, people generally have an understanding of their quality, but some manufacturers, in order to cut costs... Also, there are people in the procurement departments at your company who buy things at lower prices in order to save money for their bosses. 3. Improperities caused during use. Things like an increase in the pressure difference inside and outside the equipment, rising operating temperatures, and rough handling during cleaning.

The main cause of internal leakage in the methanol water cooler is likely issues with the quality of the circulating water, which leads to external corrosion； Water coolers generally do not suffer from internal corrosion. This post was last edited by Idyllic Poet on 2009-2-13 19:15]

Let me add something: the original poster must have worked at our factory. On the afternoon of the 13th, there was a leak in the methanol water cooler at our factory. The water cooler is made of stainless steel, and the problem occurred in one of the tubes inside it. Everything is operating normally in our plant; the system pressure never exceeds the specified limits, nor does the temperature. However, when there are fluctuations in the gas composition, the pressure can vary, with the difference reaching around 1 MP at its maximum. The circulating water is a bit dirty, but the pressure difference between the inlet and outlet of the water cooler is generally less than 0.15 MP. When the problem occurred, the system pressure rose rapidly; the current drawn by the compressor and the inlet temperature increased sharply. The inlet temperature of the compressor reached around 110 degrees, prompting the shutdown of the system. After releasing pressure, nitrogen was used to cool down the system.

1. Severe corrosion, with poor control of circulating water quality. 2. The large pressure difference between the inside and outside has caused damage to the welds of the equipment, resulting in internal leakage. 3. There are problems with the manufactured heat exchangers: the welding is poor, or the material quality is low.

May I ask if the methanol water cooler you are using has internal leakage? Is it of the U-tube type? If it is indeed a U-tube type, I believe the reason could be a large temperature difference between the inlet and outlet, which leads to significant internal stresses and ultimately results in cracking and internal leakage.