How can a novice control the hydrogen ratio well?~

The main thing is to contact the front section... to adjust the hydrogen, but pay attention to the content of the inert gas. Our company has a total of 3 towers. The hydrogen-to-nitrogen ratio of the 3 towers should not deviate too much! For example, No. 3 is 2.7, No. 4 is 2.8, and No. 5 is 3.1. At this time, we should pay attention. The hydrogen entering the three towers is the same, but the circulating gas is not necessarily the same~ If the hydrogen is raised, the No. 5 may be too high and unqualified. If the hydrogen is lowered, the No. 3 may be unqualified~ So you can consider whether there is too much inert gas in No. 3, and you can blow out more, or whether there is a little less inert gas in No. 5, and you can report a little more inert gas~ Mainly to achieve overall planning~~ This post is finally written by * Edited by aoye613 on 2009-3-10 23:35 ]

The hydrogen-to-nitrogen ratio is mainly adjusted by gas production. Because this indicator is related to the nature of the raw materials of the gas furnace, load size, whether the steam fluctuates, and furnace conditions, etc., as a novice, first of all, when taking over the shift, you must ask more colleagues about how much recycling (or nitrogen addition) can be stabilized. Only when you have a psychological base can you make adjustments. Second, pay attention to check whether the air volume (wind pressure) entering the furnace during the shift has changed. Generally, if the air volume of a normally operating furnace becomes smaller, the recovery cannot be increased. Third, if the steam entering the furnace changes, if it suddenly increases, the hydrogen content of the semi-water gas will increase within a certain period of time, but this will not be the case for a long time. The condition of the furnace is even more important. If there are phenomena such as crossing the furnace, recycling will definitely not be possible. These are just casual remarks. If the raw materials are relatively stable, you can use the automatic adjustment system, which will save a lot of trouble.

The hydrogen content should be controlled by gas generation and hydrogen regulation. Our company introduces the synthetic hydrogen content data to the gas generation to adjust the hydrogen content in time. However, changes in the content of CO and decarbonized CO2 at the conversion outlet will also affect the hydrogen content. The gas supply hydrogen meter installed at the synthetic inlet can also reflect the changes in hydrogen in a timely manner. Normally regulating the hydrogen content is a long time process. However, when the difference is large, it can also be controlled by venting after the tower. Remember that argon must be subtracted from the nitrogen in the circulating gas, otherwise, the calculated hydrogen-to-nitrogen ratio will be low. Affects output and system pressure.

The principle of hydrogen-to-nitrogen ratio adjustment is very simple. In actual operation, because different methods of ammonia synthesis processes vary greatly, and the level of self-control has developed to this day, most hydrogen-to-nitrogen ratio adjustments cannot realize self-adjustment. It is not that it is impossible, but self-adjustment is not as stable as manual adjustment. Generally speaking, there are two types: gas head adjustment and syngas adjustment. Gas head adjustment means adding nitrogen in the gas production process. Fixed-bed intermittent furnace gas production, oxygen-rich continuous gas production and hydrocarbon steam conversion gas production all belong to gas head adjustment. If it is pure oxygen pressurized gas, because nitrogen is not used in the gas production process, nitrogen is usually added to the syngas, such as the low-temperature liquid nitrogen washing process. As a novice in ammonia synthesis, no matter which position you are in, it is recommended that in addition to being familiar with the operations of this position, you should also have an understanding of the entire ammonia synthesis process of the factory and understand the position and role of this position in the ammonia synthesis production line. There are many good posts in the forum that you can refer to for the specific method of adjusting the hydrogen-to-nitrogen ratio. You can look for it yourself. My experience is: The key to hydrogen regulation is not a technical issue, but a matter of responsibility.

I don’t know what process you are using (your front part) or what process you are doing. If it is synthesis, like our synthesis, we adjust the hydrogen-to-nitrogen ratio ourselves, and some units adjust it in the front process. Let me talk about my own experience. Our front process is liquid nitrogen washing, which is relatively easy to adjust, mainly when the coarse nitrogen in the front process is stable (usually they don’t need to adjust this, because it will affect their temperature control, which is generally quite stable). We adjust the amount of fine nitrogen, and generally the increase or decrease is not very large, it is about 200~~~300kg/h. The specific situation depends on the actual situation. If you are a synthesis operator, you need to adjust it according to the actual situation of your synthesis system. You cannot see that if the compressor inlet line is high, increase it, and if it is low, decrease it. You need to observe your system pressure, circulation volume, compressor inlet pressure, flow rate, bed temperature, etc. to determine your hydrogen-to-nitrogen ratio control. Generally, when the circulation volume is large, the temperature drops, and the inlet pressure drops. If the system pressure rises, it means there is too much nitrogen. If there is too much nitrogen, the inlet pressure will rise due to poor reaction. The rest is up to you to observe slowly and sum up your experience.

The hydrogen-to-nitrogen ratio is mainly adjusted. The amount of air in the front system is adjusted by adjusting the air-to-carbon ratio to stabilize the hydrogen-to-nitrogen ratio. Generally speaking, there is a lag of 5 minutes. We control the air-to-carbon ratio to be around 3.3-3.5. Very stable! ! !

If the hydrogen-to-nitrogen ratio is adjusted by gas production, the hydrogen content of the circulating gas is generally pre-adjusted based on the amplitude of the hydrogen content of the refined gas, and is achieved by adding or subtracting recovery (nitrogen addition). The conditions of the gas generator, air volume and pressure, steam consumption, and changes in coal type can directly affect the composition of semi-water gas. The inert gas content of the synthesis tower, indicators after the purification process, etc. can all affect the hydrogen-to-nitrogen ratio. Observe more, adjust frequently, control the amplitude to be small, keep in touch with relevant positions, look for patterns, sum up experience, and gradually you will have your own set of operating methods.

Adjusting the hydrogen-to-nitrogen ratio is a relatively important operation. The stability of the hydrogen-to-nitrogen ratio during operation is very important to the stability of the system. Adjust the hydrogen to nitrogen ratio: 1. First, the amount of air added to the second-stage furnace must be adjusted properly. In the natural gas steam reforming process, the most direct way to adjust the hydrogen-to-nitrogen ratio is to stabilize the hydrogen-to-nitrogen ratio. The stability and appropriateness of the air volume is the basis for stabilizing the hydrogen-to-nitrogen ratio. When other conditions are stable, the furnace temperature rises and there is more air. On the contrary, there is 2 less air. Judging by the speed of the synthesizer compressor, when the steam is stable, an increase in the speed indicates that there is less air. On the contrary, there is more air. 3. If the hydrogen recovery returns more hydrogen, there will be more air, and conversely, there will be less air. 4. Judging from the tower difference of the synthesis tower, fluctuations in the tower difference indicate that the hydrogen-to-nitrogen ratio is inappropriate, and we need to pay more attention to it. 5. The adjustment of the hydrogen-to-nitrogen ratio, many changes in single variables, are usually caused by several factors interacting and restricting each other. Careful judgment, adjustment in advance, and fine-tuning are required.

If you are adjusting the hydrogen-to-nitrogen ratio by making gas, the most important thing is to grasp the effective time of the adjustment, that is, how long it will take for your current adjustment to be reflected, so that you can know how much recovery volume there is. In addition, you should make small adjustments when you first start working and be diligent in making adjustments. You must also have a clear mind to remember the adjustment records of each period of time, and gradually master the recycling amount.

Adjusting hydrogen and nitrogen is easier said than done, and it has something to do with the adjustment of the back-end work section. It is mainly controlled by the gas production side. My experience is that you must first have a general understanding of the furnace conditions, and make appropriate adjustments according to the amount of nitrogen added to each furnace, including the amount of air blowing and steam. You must be able to control the large-scale operation of the three lines. trend (with a lag of about 10 minutes), the key is to be patient and responsible. If there are abnormal ups and downs, you need to contact the dispatcher to see if the instrument is broken or the valve in the back section is opened and closed incorrectly, which will also cause the instability of hydrogen and nitrogen. When the furnace conditions in our factory are stable, the circulating hydrogen is basically a straight line.