Can hydrothermal ammonia be directly fed into a normal-pressure ammonia tank?
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Hello everyone: I am currently facing a tricky problem. I have just started a new 180,000-ton synthetic ammonia production project. When the urea production line is shut down, 25 t/h of cold ammonia at -33°C is generated. There are two 5,000 m3 atmospheric-pressure ammonia tanks available for storing this ammonia. Meanwhile, the old plant still produces 14 t/h of hot ammonia at 20°C and 2.4 MPaA; this hot ammonia used to be sent to the pressurized ammonia tanks, but those tanks are now to be removed, so this hot ammonia also needs to be stored in the atmospheric-pressure tanks. I’m concerned that directly sending this hot ammonia into the atmospheric-pressure tanks might pose the following problems: 1. The selection of valves before the ammonia enters the tanks, as well as the operating requirements for such valves, are quite stringent, and the pressure difference across the valves is high； 2. Ammonia being fed directly due to improper control, valve failure, and other reasons can very easily cause overpressure in the ammonia tank ； 3. Moreover, after thermal ammonia is depressurized, it has a certain temperature, which differs significantly from that of the cold ammonia formed upon injection; continuous injection ensures that the cold and hot ammonia remain in contact with each other, and the expansion and contraction due to temperature changes can also cause the ammonia tank to rupture ；
The most fundamental aspect of your question is whether the load on the large chiller is sufficient. It is possible to consider synthesizing it and sending it over after directly cooling it to -33°C. If hot ammonia is directly fed into the low-temperature tank in a continuous operation mode, it certainly won’t work; in that case, the cooling load on the chiller in the atmospheric-pressure ammonia tank will not be sufficient. I’ll calculate it for you. Let’s discuss the details in a private message.
I have a question: For a liquid ammonia storage tank operating at a temperature of 4 degrees and a pressure of 4.92 MPa(A), what values are appropriate for the design pressure and temperature? Are there any relevant standards or guidelines that can be referred to? Thank you!