What is the oil content in urea hydrolysis wastewater?
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In the urea process that uses reciprocating compressors, what is the oil content in the urea hydrolysis wastewater? Please, Haiyou, share your thoughts. Incidentally, I would like to learn about the current methods for reusing hydrolysis wastewater. Understanding this content is important in order to figure out how to make full use of this wastewater so that it meets the standards for desalinated water. The criteria for desalinated water are as follows: pH value between 8.8 and 9.2 at 25°C; conductivity ≤5μS/cm at 25°C; iron content <30μg/L; oil content ≤0.3μg/L; fouling thermal resistance of 0.00025 m2.K/W. This post was last edited by ch1967 on 2009-4-17 at 10:58
The oil content in the urea hydrolysis waste liquid is related not only to the CO2 gas introduced but also to the oil content in liquid ammonia; I estimate that most urea plants have not conducted any relevant analyses. Those who are aware of the situation please share more information and give more details about it.
There is no standard for this; it mainly depends on the oil leakage rate of the piston compressor. If the high-pressure ammonia pump is a piston pump, then the oil leakage rate of that pump also needs to be taken into consideration, along with various other factors such as the oil content in the raw materials.
I haven’t analyzed this yet, but the content should be low. Why is the original poster concerned about this issue?
Large units using centrifugal compressors have very low oil content, while CO2 compressors using reciprocating compressors have higher oil content. Urea production plants for medium and small-scale nitrogen fertilizers in China all face this problem. Is the raw material for ammonia synthesis on the 1st floor coal or natural gas? If coal is used as the raw material, is it atmospheric-pressure gas generation or pressurized gasification?
Leakage of lubricating oil from the moving equipment in the synthetic urea production section, and oil from the ammonium carbonate liquid containment tanks is strictly prohibited from entering the ammonia tank, yet it still ends up in the system. It is required to regularly raise the liquid level in the sealed discharge tank for ammonium carbonate solutions in order to carry out oil skimming
It is pressure gasification using coal as raw material, with a reciprocating CO2 compressor being used for urea production