Cooling of urea finished product particles
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Gentlemen! Urea granules are subject to high temperatures in summer, and they tend to clump together over time when stored for long periods. We are planning to add an ammonia cooler that will use liquid ammonia at -35°C and 2.5 MPA pressure to cool the urea granules; after heat exchange with a liquid ammonia heater, the cooled urea can then be used. Does anyone have experience with similar technical modifications, and what were the results? We would also appreciate any opinions or suggestions regarding this modification.
Particle cooler: We successfully carried out technical upgrades on the 3052 model, reducing the temperature from 70 degrees to below 50 degrees.
Are you a manufacturer or an equipment producer? Do you also use ammonia cooling? Could ammonia cooling cause the particle temperature to drop sharply, leading to particle fragmentation?
Shanghai Gaowei has coolers specifically designed to cool urea; it’s Canadian technology, but it’s just too expensive. I think I can figure it out on my own too :)
There are also manufacturers in China now, but they all use water coolers. What I want to do is utilize the low-temperature liquid ammonia in the ammonia tank for heat exchange; this way, not only can the temperature of the particles be reduced, but steam can also be saved (during normal production, the liquid ammonia in the ammonia tank needs to be heated to 15°C using steam before it can be used to produce urea)
This is indeed a good way to save energy; it requires proper control of temperature, as without such control, urea tends to absorb moisture and form clumps. See if other urea manufacturers use something similar. Let’s take a look.
Well, if there are manufacturers that use ammonia coolers and would be willing to share their insights, I have several concerns. First, whether rapid cooling of the particles could cause them to crack. Second, whether extremely low temperatures in the heat exchanger could lead to frosting, thereby sticking the particles to it. Third, the potential for the particles to cause wear on the heat exchanger, with a risk of thinning over time, as this is difficult to detect.
We have used the liquid ammonia-cooled fluidized air process for cooling large particles, reducing the temperature from 70 degrees to 45 degrees; however, since 6 tons of liquid ammonia were required for cooling, this system was removed. Currently, we use water cooling, which is sufficient to maintain particle cooling
Air cooling can be used; liquid ammonia is employed to cool the air and remove moisture, after which a fan is used to blow the cold air onto the urea belt
Have you ever worked on similar heat exchangers? The main concern is that air entering the system can cause frosting, which in turn leads to blockages. Additionally, during summer, the temperature of urea particles is high; using air to blow on the belt only reduces the temperature on the surface, while it’s difficult to lower the temperature inside. If it blows towards the discharge port, it will increase the dust amount and the dust removal load
Does your company use instrument air? The ammonia tank itself supplies liquid ammonia to the urea production process; then why was it removed just because of 6 tons of liquid ammonia?