Problems related to the commissioning of ammonia synthesis turbine units
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For the two turbine units in an ammonia synthesis plant – the syngas compressor and the ammonia compressor – what medium is suitable for no-load testing? Air–nitrogen?
1. Since the molecular weight of air is 29 and that of nitrogen is 28, the molecular weight of the gas entering at 103–J is 9; there is a significant difference, and this difference is too large from a design perspective. Refer to the book on large-scale ammonia synthesis compressors
Large-scale ammonia synthesis compressors? Where can I find this book? Please give your advice
The molecular weight of NH3 is 17; how about conducting a trial run with air as the load?
Conduct a no-load test with air, keeping the pressure below 14 MPa.
Does the fifth floor have any experience in this area?
I also have books on this topic, but I’m unable to share them right now
If rotation at low speeds is no problem, the large difference in molecular weight means that using nitrogen as a medium to reach normal speeds will cause the outlet pressure to increase significantly; at the same speed, the outlet pressure can increase by several times. The outlet pressure under different molecular weight conditions can be calculated using the polytropic energy head formula, to see how great the differences are.
The two main turbine units in an ammonia synthesis plant are the syngas compressor and the ammonia compressor. Nitrogen is a good choice for no-load testing, but the rotation speed should not be too high, as there is a risk of equipment oxidation. Since normal operation follows successful no-load testing, there is no need for gas replacement; if any issues arise during testing, replacement is also not necessary.
I thought about it for a long time and researched a lot, and in the test plan I developed I decided to use process media for the testing, that is, hydrogen, nitrogen, and ammonia. The effect is very good, but safety measures must be properly implemented.
The molecular weight of air is similar to that of nitrogen, so using air is more convenient.
Most of our factory uses ammonia, as it is readily available (in the form of ammonia tanks), and no accumulation problems arise once normal production resumes. In contrast, pure nitrogen requires air separation to be produced, and a large amount is needed; any excess must be discharged.