The vent flow of the high-pressure washer is high; I hope experts can help analyze this
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The CO2 stripping unit is designed for a capacity of 400,000 tons, but the current production rate is around 350 tons. The opening degree of the control valve in the high-pressure washer is 85% too high; otherwise, the pressure in the high-pressure system becomes too high, preventing an increase in production volume. The remaining indicators are described as follows; experts and specialists are requested to assist with the analysis: System CO2 volume: 21,000 m3/h; temperature of the gas exiting the synthesis tower: 182.5°C, and temperature of the liquid exiting the tower: 182.7°C℃ ； The outlet gas temperature of the high-efficiency washer is 146°C–150°C, while the outlet liquid temperature is 165–169°C. The temperature difference in the high-efficiency washer is around 20°C (the washer is equipped with packing) ； The cold liquid outlet temperature for Gaojia is 168.7–169℃ ； Stirred tank effluent 168-172℃ ； The temperature of the low-pressure temperature-controlled water is 60°C for the inlet water and 63.5–64°C for the return water; the temperature of the ammonium methoxide solution is 77°C. Other parameters: The temperature difference in the dehydrogenation reactor is 45–50°C, and the oxygen content in the raw gas fed into the system is 0.55–0.6%. Additionally, when the CO2 flow rate in our system is 21,000 m3/h, approximately 8,000 m3 of this CO2 comes from the gas produced by another set of aqueous solution compressors, without going through the dehydrogenation process. There is essentially no temperature difference between the inlet temperature of the distillation tower and the outlet gas temperature; the ammonium methyl sulfate solution contains 8-14% (W) urea, and the level of the distillate is 10%. This post was last edited by lxq700918 on 2009-3-12 13:54.]
Analyze it from a conventional perspective: 1. The purity of CO2 is low, especially when it comes from CO2 gas from another system; sampling for analysis can help identify this issue. 2. High-washer filler issue: Add absorbent solution to the high-washer to see if the system performance improves ； Inspection during shutdown ； 3. Problems with the distillation tower: The distributor in the upper part of the packing layer is malfunctioning, and the packing is severely contaminated by oil and scale
There is a malfunction in the distributor on the packing layer, and the packing is severely contaminated with oil and scale. Issues with the packing in the high-pressure washer: When an absorbent solution is added to the high-pressure washer, the purity of CO2 decreases; this is especially true regarding the amount of CO2 gas coming from another system. Sampling and analysis can help identify this problem.
The inert gas components in the carbon dioxide zone have a high content and occupy a large volume. The scrubber is not absorbing effectively; consider the concentration of ammonium methoxide in the low-temperature liquid level tank. The distillation tower is also not performing well – are both the liquid output and the gas output at over 130 degrees? The gas phase temperature is a bit high. Last edited by lxq700918 on 2009-3-6 08:34.]
Both the inlet liquid temperature and the outlet gas temperature of the distillation tower are around 115 degrees. This post was last edited by lxq700918 on 2009-3-8 at 22:36.]
1 Is the packing in the high-level washer clogged? Does the 2-methylammonium solution also contain 8-14% (W) of urea? Is there a problem with the packing in the distillation tower as well? Is there liquid present there? The problems in points 3 and above are similar; could it be that the synthetic chiller is leaking oil? Check the filter at the inlet of the synthetic cold ammonia pump, and analyze the oil content in the urea-ammonia tank. Since your ammonia-to-carbon ratio isn’t high, try adding some ammonia to see if there are any changes in the situation. 5 The stripping tower does not seem to be operating well, with a low conversion rate. 6 The pressure in the low-pressure drum can be reduced slightly.
System CO2 volume: 21,000 m3/h; temperature of the gas exiting the synthesis tower is 182.5°C, and that of the liquid exiting is 182.7°C℃； The outlet gas temperature of the high-efficiency washer is 146°C–150°C, while the outlet liquid temperature is 165–169°C. The temperature difference in the high-efficiency washer is around 20°C (the washer is equipped with packing) ； Stirred tank effluent 168-172℃ ； The temperature of the low-pressure temperature-controlled water is 60°C for the inlet water and 63.5–64°C for the return water; the temperature of the ammonium methoxide solution is 77°C. What are the N\C and H\C values of the system? What about the conversion rate? What are the control pressures for low packages and high packages? Take an exhaust sample from your high-efficiency scrubber and analyze it; it seems that there is quite a lot of liquid in the exhaust gas coming from your scrubber. 1. The temperature of the cold output liquid from the Gaojia unit is 168.7–169°C. The temperature control seems too high under this load; there might be a lack of ammonia in the system. 2. I wonder if the gas production volume under your lower guaranteed output quota has also increased? 3. What are the N\C and H\C values of the ammonium solution that enters the high-pressure system? 4. Analyze whether the levels of CO and H2 in the feed gas entering your system are above the specified limits ? 5. What is the decomposition pressure at low pressure? What about the distillation bottom temperature? 6. Slightly increase the liquid level in the stripping tower to drain the shell-side condensate from it. In short, if the purity of the raw gas fed into the system is not sufficient, the conversion rate will decrease, and thus the efficiency of the gas processing will also drop. The load on the low-pressure system increases as a result. Additionally, there seems to be a problem with your distillation tower – why is there so much urea in the ammonium methylate solution? This post was last edited by lxq700918 on 2009-3-11 12:39.]
It is recommended that the original poster analyze this: the ammonium solution contains 8-14% (W) urea, and its urea content is relatively high; where does this come from? Is the liquid carryover in the gas phase of the distillation column more severe, or is it more serious in the gas phase of the evaporation system? To find out the reason, it might be useful to analyze the problem.
It’s probably severe liquid carryover in the gas phase of the distillation column, right? ? If there is severe liquid in the gas phase of the evaporation system, then operating the hydrolysis system will be quite difficult. The original poster hasn’t replied either – could it be that the system is short of water? ? Either the structured packing in the distillation column has been blown over, or its arrangement is uneven?
The information provided by the poster is limited, so when analyzing the issue, all possible options must be considered. Of course, the possibility of liquid presence in the gas phase of a distillation column is greater. However, the evaporation system may also carry liquid, thereby resulting in urea being present in the methylammonium solution. I hope the original poster will follow up and discuss this further!
It is recommended to investigate the cause from the following aspects: 1. The urea content in the ammonium methylate solution is significantly too high; check whether there is liquid carryover in the distillation tower, and then analyze the ammonium methylate solution. 2. The oxygen content in CO2 is not high; check whether the analytical purity is normal. 3. Check whether the exhaust gas control valve of the high-pressure washer is functioning properly and free from blockages. 4. An output of 350 tons per 2100 hours is too low; it should be over 400 tons per 8 hours. There is a high likelihood that the distillation tower is carrying liquid. It should be difficult to operate a distillation column at low pressure with liquid carryover.
Is the urea content in the ammonium hydroxide solution too high? Is there liquid carried over in the distillation tower?； Is the purity of CO2 normal? ； The yield is low, so it’s likely that there is liquid in the distillation tower.
Looking back at previous request posts now