What should be the appropriate actual control level for circulating hydrogen?
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In the ammonia synthesis process, the active adsorption of nitrogen is the controlling step in this reaction; increasing the proportion of nitrogen appropriately is beneficial for the ammonia synthesis reaction. However, too high a nitrogen level causes the bed temperature to drop, the system pressure to rise, and it also leads to an increase in the power and current consumption of the circulation pump. What is an appropriate level of circulating hydrogen content under actual control by Haiyou Company? Please provide the actual percentage, the value obtained from the hydrogen meter analysis (excluding methane). In our company, it’s 63% (excluding methane), and I think this is too high
Based on kinetic experiments and the H:N ratio of 2.7-2.9 in actual production, the optimal value during production is 2.7-2.8. The amount of fresh gas, the amount of recycled gas, the amount of off-gas, and the hydrogen-nitrogen ratio can be calculated using formulas or determined through analytical instruments
The actual content of recycled hydrogen is related to the type of tower, that is, it is related to the actual methane content in the synthesis tower. Although the ratio is theoretically 3:1, as the methane content in the recycle gas increases, its partial pressure rises accordingly according to Dalton’s law, which in turn increases its ability to hinder nitrogen adsorption; therefore, to achieve a better ammonia synthesis reaction, more nitrogen must be added. However, when the methane content in the recycle gas is around 10%, the recycle gas volume can be maintained at around 64%, with a hydrogen-to-nitrogen ratio of approximately 3:1 at this point ； However, when the methane content reaches around 25%, the hydrogen-to-nitrogen ratio should be kept between 2.0 and 2.4.
Our company uses cold box purification; it contains no methane, and the hydrogen-to-nitrogen ratio is generally maintained between 2.8 and 3.2
Our company also uses liquid nitrogen to purify the gas, but it hasn’t been put into operation yet. I hope more sea friends will sign up.
Maintain the hydrogen-to-nitrogen ratio between 2.2 and 3.0, with the optimal range being 2.6 to 2.8. Our factory generally keeps the hydrogen level at around 54%
The control of the cyclic hydrogen content is related to two factors: one is the methane content in the recycle gas. When the methane content is high, the cyclic hydrogen level needs to be kept low; whereas when the methane content is low, the cyclic hydrogen level should be kept high. In this process, it is important to maintain an appropriate hydrogen-to-nitrogen ratio in the recycle gas； Another factor is the duration of catalyst use; when the catalyst is used for a short period, the circulating hydrogen level can be kept low, while if the catalyst is used for a longer time, the circulating hydrogen level needs to be kept higher.
The hydrogen-to-nitrogen ratio should be maintained at 2.2–2.8. I wonder what level the original poster has their methane controlled at?
The circulating hydrogen-to-nitrogen ratio should actually be considered from several aspects: 1. Tower type--the heat and mass transfer dynamics of the tower structure determine the range of the circulating hydrogen-to-nitrogen ratio. 2. Regarding the age of the catalyst – new catalysts have high activity, which means they are more sensitive to the hydrogen-to-nitrogen ratio. Generally, this ratio is kept within a certain deviation range in order to suppress reactions in the first bed layer, allowing the reactions to proceed further downstream and become more dispersed. After being used for a period of time, the catalyst will age; therefore, an appropriate HN ratio needs to be adjusted to improve the utilization rate of its activity. 3. The HN ratio also changes depending on the type (composition) of the catalyst.
Hehe, I wonder what the H:N ratio of the synthetic ammonia produced via low-pressure synthesis at 15 MPA, with purification using liquid nitrogen, is controlled to be I hope all fellow sailors can share more information. Studying*. . . .
Here, the hydrogen-to-nitrogen ratio is generally kept between 3.0 and 3.2, with 65% being recycled hydrogen.