Effect of sudden drop in boiler level on bed temperature

Both of the answers mentioned by the original poster are possible; the key in such a situation is whether the temperature control for ammonia cooling is effective or not. (In this case, either insufficient water is used in the water cooler, or enough water is used but there isn’t enough margin in the design, which inevitably leads to an increase in the water cooling temperature and makes it difficult to control the ammonia cooling temperature as well.) If the temperature is managed to be controlled, the second answer might apply; but over time, safety issues, ammonia balance problems, and power consumption problems will arise, causing the catalyst’s reaction to proceed according to the first scenario. If it wasn’t pulled down, then the first answer must be correct.

Hehe :) Has LZ ever seen a dry-bottomed furnace in operation? As the dry-bottomed furnace is about to reach its operating temperature, the temperature of the gas entering the tower increases, as does the temperature of the catalyst bed! There’s also the pressure in the furnace itself—our pressure used to be 1.4 MPa, but it was increased to 1.9 MPa in order to raise the temperature of the gas entering the tower and the temperature of the catalyst bed. As for the first situation, I didn’t pay much attention to it~

This is a good question; it is also a situation that often arises in ammonia synthesis production. When the boiler level drops, the temperature of the hot gas used for heat exchange increases, as does the temperature of the gas entering the tower. Consequently, the temperature of the gas entering the catalyst bed rises, and the temperature of the catalyst bed itself also increases ； The temperature of the syngas entering the water cooling system also increases. If the load on the water cooling system remains unchanged, then the load on the ammonia cooling system at the back will increase as well. This will lead to two scenarios: 1. If ammonia cooling does not provide much operational flexibility, the ammonia content in the gas entering the tower will gradually increase ； Due to the increased ammonia content at the inlet of the synthesis tower, the reaction within the tower is affected; the bed temperature of the synthesis tower rises temporarily before gradually decreasing ； The system pressure will also gradually increase. 2. If ammonia cooling provides sufficient operational flexibility, the ammonia cooling temperature can be maintained, and thus the ammonia content in the gas entering the tower will not increase ； As the temperature of the gas entering the tower increases, the bed temperature in the synthesis tower also rises continuously; at this point, it is necessary to increase the amount of recycled gas in order to carry the heat away from the tower ； If the boiler level is not adjusted to normal as soon as possible at this time, a vicious cycle will arise, which could even lead to the boiler running out of fluid and forcing a shutdown.

Generally, the gas coming out of the preheater in front of the tower passes through a soft water heater as well, where more heat is absorbed. The water heated in this process is then sent to the boiler. In practice, the temperature change after water cooling isn’t very significant; of course, if the temperature remains low for an extended period, the system needs to be shut down. Another scenario involves an increase in the temperature of the incoming gas, which in turn raises the temperature of the catalyst bed and thus the zero-meter temperature as well. As for the first case, increasing the water volume or adding more ammonia to the ammonia cooler can resolve the issue

A sudden drop in the liquid level of the waste heat boiler generally leads to an increase in the bed temperature. The increase in the water cooling temperature is relatively small, and the condensation of ammonia mainly occurs after ammonia cooling; in other words, as long as there are no significant fluctuations in the ammonia cooling temperature, the inlet ammonia concentration will not rise much. For information on the impact of the waste heat boiler’s liquid level on the bed temperature, you can refer to the following two documents, which provide detailed discussions on this topic. (Click to access) Analysis of the importance of maintaining a stable liquid level in the waste heat boiler at the outlet of the ammonia synthesis tower; Discussion on issues related to high synthesis pressure and suggestions for improvement

First, regarding the first issue: the level of the waste heat boiler drops too rapidly, and the temperature at the outlet of the water cooler rises; if possible, reduce the temperature of the circulating water； The ammonia cooling temperature rises; however, as long as the chiller adjusts in a timely manner by increasing the load and keeping the ammonia cooling temperature under control, the ammonia content entering the tower will not increase. Second, the liquid level drops, the temperature at the inlet of the synthesis tower rises, and the temperature of the catalyst bed also increases. A few days ago, the soft water pump stopped working, which prevented water from reaching the waste heat boiler and caused fluctuations in the system. If the level of liquid in the boiler drops rapidly, it is necessary to identify and address the cause as soon as possible. Failing to restore the boiler’s liquid level to normal will lead to a vicious cycle, which may even result in the boiler running out of liquid and forcing a shutdown

If the level of the waste boiler fluid suddenly drops, causing the boiler outlet temperature to rise, this will inevitably lead to an increase in the temperature of the gas entering the tower. The rise in catalyst temperature, combined with the increase in the temperature of the gas entering the tower, in turn causes the temperature exiting the tower to rise, thus creating a vicious cycle. If the liquid level cannot be raised in time, an emergency shutdown should be carried out ； If the boiler outlet temperature has already far exceeded the specified value, water cannot be added at this point; instead, an emergency shutdown is necessary to reduce the temperature, otherwise there is a risk of explosion! ! ! As for ammonia cooling, what impact can it have from a distance of 108,000 miles?