Why is urea slightly yellow?
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Oil contamination in liquid ammonia and CO2 is the fundamental cause of urea discoloration. What good methods do everyone have to solve this problem? Strengthen the oil drainage operation. Reduce oil injection in the four or five cylinders. The oil-free lubrication modification was not very successful either. Short service life. It’s completely impossible to pump oil out from the bottom of the spherical tank. Urea yellowing has always been a very troublesome issue that plagues us.
Check the amount of lubricating oil consumed by your compressors on a monthly basis, to see whether it is the oil filler that uses up the most oil or the thin oil station. Find ways to solve specific issues.
All the oil in the oil filler has been used up； The lubricating oil in the light oil station is in a circulating system, with only losses occurring.
The oil injection for stages 4 and 5 of the CO2 compressor has now been controlled to below 25 drops. The color of the urea is gradually improving.
The number of drops of oil applied in paragraphs 1, 2, and 3 should also be controlled appropriately. Enhance oil and water drainage, and make sure that the drainage in each section is unobstructed. Especially, the spherical tank you mentioned should be a five-stage separator; is the issue caused by a blockage that prevents the separation of oil and water, or is it just excessive exhaust gas? If it gets blocked, be sure to clear it out while the compressor is shut down.
Oil cannot be discharged from the bottom of the ammonia tank; only gaseous ammonia is released.
This post was last edited by WJHSWSW on 2015-9-6 at 10:34. 1·The oil in the liquid ammonia sphere tank floats on the surface; make sure to keep the liquid level in the tank at a high level. What is the liquid level control set for your ball tanks? If there is too much oil, it is recommended to maintain a liquid level of 70–80%; operating at a low liquid level should be avoided to prevent oil bubbles from entering the system. 2. Coordinated by the head plant, it is recommended that the ammonia synthesis system pay attention to the presence of oil in the system, and strive to minimize oil droplets entering the liquid ammonia storage tanks ； That is, to properly control the oil level in the nitrogen-hydrogen compressor.
Oil has a higher density than liquid ammonia, so it should be at the bottom of the spherical tank. I opened the ammonium carbonate solution tank today. Ammonium carbonate solutions are all yellow. Oil must have gotten mixed in. The urea turns white after the desorption amount is reduced. Isn’t the amount of oil added to the CO2 compressor mentioned upstairs a bit too little? In our factory, the oil injection volume is three times higher than what you mentioned. 30–40 drops. I’m not sure what impact reducing the amount of oil applied will have on the equipment.
In addition to oil leakage from the compressor, our finished particles turn yellow; we attribute this to coal residues and the high sulfur content in the CO2 fed into the compressor. Furthermore, the low desulfurization temperature of the compressor causes the finished particles to turn yellow
“And what does “the compressor’s desulfurization temperature is low” mean? Please explain in detail! A high sulfur content in CO2 should be detectable, right?