What are the various treatment options available when a quench tower becomes clogged? Precautions?

The treatment of blockages in quench towers is usually due to sulfur blockages. The process gas can be diverted before the quench tower, the circulation in the quench tower can be stopped, and once it has been confirmed that the quench tower can withstand temperatures of up to 180 degrees, the process gas can be slowly introduced into the quench tower and vented from the top. Use the temperature of the process gas to slowly melt the accumulated sulfur. Key point: Some water must be reserved at the bottom of the tower, so that as the sulfur melts, it can drip into the water to form spherical droplets. Easy to clean.

Introducing process gas is one method; steam stripping can also be used for treatment. That is, stop the quench water circulation, supply steam behind the inlet valve of the process gas in the quench tower, vent from the top of the tower, add a large amount of steam to the tower, and then wash it with water to remove S

There are various methods for dealing with blockages in the quench tower, and the appropriate approach depends on the specific situation: 1. If signs of a tower blockage are detected in advance, such as an increase in system pressure, we can adjust the operations prior to the quench tower to remove or reduce the amount of sulfur vapor in the gas flowing into it； Key operation points: Strengthen the air distribution adjustment for sulfur generation, enhance control of the outlet temperature of the final cooling stage, and check for any leakage points in the system. 2. If the blockage in the tower is severe to the point that normal operation can no longer be maintained, we can divert the quench water out of the quench tower and maintain a certain liquid level in the tower to proceed with sulfur recovery. The process gas can then be directly introduced into the tower (within the allowable temperature range) to carry out high-temperature sulfur melting operations. Key operating points: The temperature must not exceed the allowable limit of the tower, and there should be a certain water level at the bottom of the tower. 3. We can also remove all of the quench water and process gas, then open the vent of the quench tower to carry out steam desulfurization, followed by a washing operation to remove sulfur particles through wastewater discharge. Key operating point: During the water washing cycle, enhance the filtering action of the filter. 4. We can also remove all of the quench water and process gas, then open the vent of the quench tower and inject nitrogen at the inlet of the exhaust gas heater to carry out high-temperature nitrogen sulfur stripping. Key operating points: The temperature must not exceed the allowable limit of the tower, and there should be a certain water level at the bottom of the tower.

I’ve learned it. But the possibility of the quench tower getting clogged is pretty low, right? In the sulfur production section, there are various sulfur collectors; therefore, very little sulfur makes it to the exhaust gas treatment section, so I believe the likelihood of blockages is extremely low

The suggestion for the fourth floor is quite good. But I wonder if it has been proven through practice. At the same time, I believe it is difficult to melt sulfur using steam, as when the steam enters the quench tower it undergoes flashing, resulting in a decrease in pressure and temperature, which prevents the temperature required for melting sulfur from being reached.

Tests have been conducted using superheated steam for sulfur melting; of course, it is possible to blow away the sulfur, but it requires a lot of steam and the results are not very satisfactory； Using a hot air stream for sulfur blowing is a good approach. The experiment was carried out as follows: a DN25 iron pipe was used, with a layer of sulfur adhered to its inner wall; then steam was introduced at one end to use high-temperature steam for blowing away the sulfur, and after some time, the sulfur inside was also completely removed. The experiment works, and some refineries in various places have used this method; some say it’s okay, while others claim it’s not good. Of course, it still depends on the actual circumstances. I think it would be better to introduce the hot air flow from the top of the quench tower and exhaust it from the bottom of the tower – that way the results would be better! What are everyone’s thoughts?

Everyone shared very good opinions, which are truly worth learning from*. The tower has been dealt with; what about the cooling of the emergency cooling water pumps and the related pipeline coolers by air cooling?

We cut off the quench tower, introduced steam from the top of the tower, opened the vent at the bottom, and controlled the temperature of the quench tower between 140 and 160°C (the design pressure for this tower is 0.5 MPa; if the temperature is too low, sulfur cannot be removed, while if it’s too high, the tower’s pressure exceeds the designed level). After about 2 hours of purging, the effect was very noticeable.