Residual substances in liquid ammonia
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The nitrogen and hydrogen used in our glass factory are produced by the thermal decomposition of liquid ammonia. After the furnace stopped operating yesterday, during the process of purging the system with nitrogen, a large number of sparks were observed at the outlet. May I ask the experienced colleagues: where do these sparks come from? Are they residual particulate natural substances in liquid ammonia, or residual hydrogen (is that possible)? This post was last edited by mingyyan on 2009-1-7 15:18.]
When liquid ammonia is produced, the pressure is generally high as well; at this time, some inert gases are dissolved in the liquid ammonia
Liquid ammonia should not contain any other impurities; they might be inherent to the furnace.
So everyone is wondering, what could be in it? Phosphorus? Iron shavings cannot produce sparks at such a flow rate. Could these substances be present in the catalysts used for hydrogen production via ammonia decomposition?
There’s quite a lot of oil contamination; during maintenance, there was a lot of oil at the bottom of our liquid ammonia storage tank
Catalysts for ammonia decomposition generally use Ni catalysts. In a hydrogen atmosphere, the gases have strong reducing properties; as a result, many metals are reduced to their reduced forms. Consequently, when these substances come into contact with oxygen after being blown out, sparks are generated. It are reduced substances such as K and Fe
What was said upstairs makes a lot of sense. Additionally, I would like to ask whether this substance could be a metallic compound of sulfur?
Replying to floor 7: There is basically no possibility of the existence of metal compounds containing sulfur in liquid ammonia. The situation described on the first floor could also be due to catalyst powder entrained in the liquid; during use, the catalyst loses its strength and becomes powdered, and this powder is carried away by the gas out of the synthesis tower. When the liquid is separated, it too is carried out of the system and ends up in the liquid ammonia.
Liquid ammonia contains some impurities, such as catalyst ash, water, oil, etc. But the nitrogen you use is derived from the catalytic cracking of liquid ammonia; it shouldn’t end up in the nitrogen, right? Could it be caused by particulate matter that has mixed in from other sources?
The analysis on floors 5 and 6 is quite reasonable. I have a set of data that clearly illustrates the oil contamination issue mentioned on floor 5: before maintenance work on our liquid ammonia products, each sample taken was basically of first-class or qualified quality; there were very few samples that were of top-grade quality, and the reason for this was the high oil content in those samples. Take a look at one of our samples: the residue content is 0.04% ； Oil content: 5.51mg/kg ； Grade rate: 99.96% — First-class quality. The compressor has been upgraded and modified, and it’s now in perfect condition!
First, does the gas composition inside your furnace contain hydrogen? Secondly, what is the nitrogen pressure when you perform purging?