Freezing in the exhaust gas scrubber of low-temperature methanol washing

1. The steam heating for the exhaust gas scrubber is not turned on； 2. The temperature interlock is not in service ； 3. On days when exhaust gases are vented, the cooled heat is not recovered and is discharged directly ； 4. Leakage into the desalinated water valve when parking in winter (personal opinion)

The specific reasons are as follows: the heating system for the exhaust gas scrubber was not turned on; the exhaust gas at the top of the hydrogen sulfide concentration tower entered the exhaust gas scrubber without going through any heat exchange first; the temperature control system inside the exhaust gas scrubber was not activated. In actual production, these factors can basically be ignored, as the likelihood of such basic mistakes occurring is very low. The person in charge can check whether the heat exchanger used to exchange heat between the exhaust gas at the top of the hydrogen sulfide concentration tower and lean methanol as well as raw gas is clogged or leaking, which could lead to poor heat exchange and significant loss of cooling capacity. It’s also necessary to check whether the steam heating lines in the exhaust gas scrubber are clogged and whether the valve settings are appropriate

I think the main reasons for icing on this tower are: 1. Water was not drained completely during winter maintenance or water circulation tests； 2. During driving, the nitrogen gas is directly introduced into the exhaust gas scrubber ； 3. The supply of transformed gas is suddenly stopped, causing a large amount of exhaust gas to enter the exhaust gas scrubber!

Rule out equipment issues and presumed operational errors! The main reason is the insufficient recovery of cooling capacity in the carbon dioxide flashing section!

Summarize all the sources of cold input, along with each reason analyzed by everyone; conduct a thorough check one by one using the fishbone analysis method, eliminating them one after another, and the cause will eventually become apparent. This post was last edited by “The Earth keeps spinning every day” on April 17, 2009, at 16:55.]

As mentioned above. This tower is nothing but that. Waste gases generated by the CO2 and C3 towers. . It enters after heat exchange. . The reasons for its freezing. . If breathing stops suddenly. . As airless air enters. . Then heat exchange will not work. We have to take a detour. If it isn’t opened in time. Will it freeze?

The possible reasons can be analyzed as follows: 1. Rule out the possibility that freezing occurred in winter and has not yet melted. 2. It could be caused by the exhaust gas entering the exhaust gas scrubber at too low a temperature; check what the lower limit indicated by the thermometers on the various exhaust pipes leading into the scrubber is Are some already at the lower limit? If so, make adjustments promptly. If the thermometer on the exhaust pipe is damaged, it should be replaced promptly. 3. The steam tracing effect in the exhaust pipeline is not good; check whether there is a possibility of blockage in the steam control valve. By opening the bypass and checking whether the temperature rises, it will be possible to determine the issue. 4. I wonder if the packing in the exhaust gas scrubber is clogged? Make no mistaken judgments; first of all, we need to confirm the correctness of the direction, as freezing and blockage caused by filler are essentially the same phenomenon. The above is for reference only!

Make the steam supplied before the exhaust gas enters the tower self-regulating, and by controlling the temperature of the exhaust gas entering the tower, freezing can be prevented.

I also think there’s a problem with the raw gas heat exchanger; it’s not due to an excess of cooling capacity!

In the nine-tower process designed by Luchi, a steam injection line is installed on the pipeline at the CO2 gas inlet of the exhaust gas scrubber, thereby preventing freezing. The cold energy carried by CO2 cannot be recovered; if there is an excess of this cold energy, it may cause the exhaust gas scrubber to freeze, which is why steam is injected in advance

In the nine-tower process designed by Lu Chi, a steam injection line is installed on the pipeline at the CO2 gas inlet of the exhaust gas scrubber, thereby preventing freezing. The cold energy carried by CO2 cannot be recovered; if there is an excess of this cold energy, it may cause the exhaust gas scrubber to freeze, so steam is added in advance