Could everyone help figure out what is causing the following issue with the system?

Check whether the bottom liquid valve of your synthesis tower is working properly. Also, check whether the valve position of the high-pressure washer vent valve matches the indication on the control panel. Are the ratios of ammonia to carbon and water to carbon appropriate?

Check whether the level gauge of your synthesis tower is functioning properly, and also verify whether the valve position of the high-pressure scrubber vent valve matches the indication on the control panel. Check whether the ratios of ammonia to carbon and water to carbon are appropriate, inspect high-pressure system equipment and pipes for leaks, and verify that there is no short circuit or air leakage involving CO2.

Based on what you’ve described, it’s possible that the liquid seal of the overflow tube is not functioning properly (as indicated in points 2, 3, 5, and 6), which is causing carbon dioxide to bypass the system. Also check whether the discharge valve of the scrubber is closed (as mentioned in point 4). Please give me some advice!

My analysis: 1. A drop in system pressure – does this refer to the pressure in the high-pressure system? If so, it indicates that CO2 is not leaking out of the \"U\"-shaped tube (as a leak would cause a sudden rise in pressure). 2. The stripping tower being under no load (i.e., a decrease in steam flow) suggests that there is a fault with the discharge valve of the synthesis tower, preventing urine from being discharged; as a result, less stripping gas is available, which leads to a decrease in the gas production from the lower vessel. 3. The temperature of the gas exiting the high-stage scrubber decreases, as do the temperatures of the gas and liquid coming from the synthesis process, but this change occurs slowly. It seems that a valve failure has caused the synthesis tower to become filled with liquid. 4. The level of the synthesis liquid first drops and then rises, along with a decrease in system pressure – these are signs that the synthesis tower is about to become filled with liquid, and soon the pressure in the high-pressure system will increase. 5. How is it determined that the synthesis conversion rate has decreased? Original poster, have you identified the cause of this phenomenon? How was it addressed? Could you share this information with other users?

Is the poster a manager? Are the above phenomena occurring simultaneously, or are they topics to be discussed one by one? If it is accompanied by a recommendation to scrap the equipment, and if it occurs separately, it is advisable to ask the operators, as they know how such phenomena arise, occur, and can be optimized.

6# zhtgg A series of phenomena occurred almost simultaneously. What does this friend mean by ‘scraped’?

4# xuminghong-xmh If carbon dioxide really creates a short circuit, the system pressure should increase instead of staying low

The last edit to this post was made by lxq700918 on 2009-12-17 at 09:08. First of all, it should be corrected that a decrease in synthesis conversion rate is a result, and cannot be included in the description of the incident. It is the production disruptions in your system that have led to a decrease in the synthesis conversion rate. All types of accidents in high-voltage systems exhibit distinct visual characteristics. Among the various phenomena you described, the main characteristics have not been identified. I hope you can provide additional information so that everyone can conduct an analysis. Please provide the following information: 1. The liquid outlet temperature of the stripping tower. 2. Changes in pressure in the high-pressure system. 3. The liquid outlet temperature of the high-pressure ammonium methoxide condenser. 4. The steam consumption on the shell side of the stripping tower and any changes in pressure there. 5. Whether the pressure in the low-pressure system is increasing or decreasing. 6. Changes in the liquid outlet temperature and the temperature of the high-temperature water on the shell side of the high-pressure ammonium methoxide washer. 7. Changes in liquid level, temperature, and pressure in the medium-pressure system. The following outlines the criteria for assessing accidents based on each of the characteristics you mentioned: 1. Excess liquid in the reactor: When the liquid level in the synthesis tower becomes too high, an excess of liquid enters the high-pressure ammonium methoxide scrubber. This results in a decrease in the temperature of the liquid exiting the scrubber, a reduction in the temperature difference on the shell side of the scrubber, an increase in the load on the medium-pressure system, and a decrease in the temperature difference. In severe cases, the medium-pressure system may become filled with liquid and experience overpressure. Even if liquid spraying occurs in the medium-pressure system and the pressure in the high-pressure system drops, it will rise again shortly. Once it rises, it can quickly cause overpressure in the high-pressure system, forcing a reduction in load, shutdown of the carbon dioxide system, or even a complete shutdown of the plant. 2. Closure of the liquid outlet valve in the synthesis tower: When material supply to the stripping tower is interrupted, its liquid outlet temperature drops; the steam flow supplied to the shell side decreases sharply, causing the pressure to rise. This is accompanied by low-pressure gas leakage, with the pressure in the low-pressure system first dropping and then rising, potentially leading to overpressure. On the shell side of the high-pressure ammonium methoxide condenser, the low-pressure steam pressure decreases, the flow rate decreases, and the liquid outlet temperature drops. At this point, a situation of full liquid level in the synthesis tower occurs, but carbon dioxide does not flow in a shortcut from the synthesis tower and directly into the upper part of it. 3. Failure of the level gauge of the liquid outlet valve in the synthesis tower leads to a drop in the liquid level within the tower, which results in a disruption of material flow to the stripping tower. The symptoms are similar to those described in point 2; however, carbon dioxide can flow directly into the upper part of the synthesis tower via the overflow pipe, causing an increase in pressure in the high-pressure system and leading to overpressure. This can be determined by checking the temperature of the liquid exiting the synthesis tower as well as the pressure in the high-pressure system. Your issue is the automatic closure of the liquid outlet valve in the synthesis tower. To resolve this problem, you can open the liquid outlet valve of the synthesis tower with confidence. It also strictly refers to the load conditions of the stripping tower, mainly including the gas consumption on the shell side of the stripping tower, the liquid outlet temperature, as well as the liquid level and the pressure in the low-pressure system. (When opening the valve, check on-site whether the liquid outlet valve of the synthesis tower is open.) All types of accidents in high-pressure systems exhibit distinct observable characteristics; the most important ones are relatively few, and so are the steps required to handle them. It is essential to grasp these key points, otherwise the situation will only get worse.

Based on the analysis of the poster’s situation, another possibility is that CO2 has entered the low-pressure system, causing a drop in the pressure of the high-pressure system; the low-pressure pressure should show some reaction as well. When CO2 enters the low-pressure system, it causes a severe imbalance in the ammonia-to-carbon ratio in the high-pressure system, and the liquid level in the synthesis tower becomes difficult to control due to the large amount of ammonia, which is less dense. The liquid outlet valve of the stripping tower can be reduced to control its liquid level, thereby lowering the pressure in the high-pressure drum; first, the liquid level in the synthesis tower should be lowered. Adjust the components properly, reduce ammonia usage, and add CO2 first.

This post was last edited by Durian on 2009-12-18 at 11:35. Hai Na Chuan is absolutely right; the order in which I described the symptoms of the problem was a bit chaotic. Here are the answers based on the issues you mentioned: 1. The temperature of the liquid coming out of the stripping tower first decreases and then increases. 2. The pressure in the high-pressure system continues to decrease. 3. The temperature of the liquid coming out of the high-pressure ammonium methylate condenser increases over time. 4. The steam consumption and pressure on the shell side of the stripping tower both decrease. 5. Does the pressure in the low-pressure system increase or decrease? The load decreases when the low-pressure drops. 6. The temperature of the liquid coming out of the high-pressure ammonium methylate scrubber, as well as the temperature of the water on the shell side, both decrease. 7. As for the level, temperature, and pressure in the medium-pressure system, we don’t have such a system; we only have high-pressure and low-pressure systems.