Weekly Topic 10.12.06, Issue 6: How to determine tube leaks in shell-and-tube synthesis towers.
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This post was last edited by fossil-zhang on 2011-1-11 at 14:00. How to determine if there is a leak in the tubes of a shell-and-tube synthesis tower?
This post was last edited by Shouhou on 2010-12-5 20:47: Tube leakage causes high pressure in the shell side! With the drum set to automatic mode, won’t the pressure get high? ? ?
The steam pressure increases. There are flammable gases in the steam. Water is discharged from the gas pipeline when parking
The temperature of the synthesis tower is difficult to control; combustible gases have been detected in the drum steam, and the pressure of the drum remains high under full load.
In the case of a leak in a tubular synthesis tower, the leakage definitely occurs from an area with higher pressure to one with lower pressure. During normal operation, this leads to high pressure in the shell side, making it difficult to control the pressure in the drum; as a result, the temperature of the synthesis tower is also hard to regulate. This causes gases to be entrained in the steam, reducing its quality. The temperature of the synthesis tower ends up being lower than the corresponding saturated steam pressure, and gas detectors can detect the presence of gases such as CO in the steam； Especially when pressurizing the synthesis tower, it can cause overpressure in the drum. When the pressure in the synthesis tower drops to its lowest level, water from the shell side can flow into the catalyst inside the tubes, which in turn affects the temperature difference and leads to catalyst deactivation. The fastest way to address this is to monitor the conditions of the fluid in the tube side; if there are differences at the shell side inlet, it indicates a possible leak
Check what materials flow through the shell and tube. If the pH values of these materials differ, it is possible to measure the pH value of the shell in order to determine whether there is a leak.
When the leakage is small, it is generally difficult to detect. The phenomenon is an alarm for combustible gases in the steam. As for the temperature of the synthesis tower, it basically has no impact; in plants equipped with steam turbines, the vacuum level decreases. The method of parking involves first releasing pressure in the steam system, replacing the contents of the system through this pressure release, and then cooling it down to achieve passivation. Handle it after unloading.
The steam produced in the synthesis process is saturated steam, and plants equipped with steam superheaters will experience a decrease in the vacuum level of their turbines. If steam is used for heat exchange, it will be found that the heat exchange efficiency of the heat exchanger decreases, and the amount of non-condensable gas inside increases.
In methanol synthesis, there is generally a pressure difference of about 4 MPa between the pressure in the drum and the pressure in the synthesis tower; if the tubes in the shell-and-tube synthesis tower leak, the pressure in the drum will rise rapidly. Moreover, the pressure and temperature in the synthesis tower decrease.