During the operation of the synthesis tower, the tower pressure is generally related to the level of methane; sometimes, even when methane levels are low, it is not possible to recover the gas that is vented
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During operation of the synthesis tower, when the methane level is high, pressure builds up in the system; as a result, the methane level before compression also increases accordingly. This is a phenomenon that occurs under normal conditions; by venting, the methane level drops even below the usual levels. At this point, it’s basically impossible to recover the loss. But sometimes the methane level in the system is even higher than this value, and there is no pressure buildup; in such cases, the methane level before compression is slightly lower than in the previously mentioned conditions. Why do these two phenomena occur? (This is due to the phenomena in the actual process, and since the load is basically the same, the output of the latter is slightly higher than that of the former.) The various data analyzed are also roughly similar. ）
Does \"compression\" refer to the cycle gas compressor?
It left me completely confused and bewildered
Reply to 2# jinpingwang_69: There is an analysis point between the methanation unit and the hydrogen and nitrogen compressor. This is based on practical experience, and there is no theoretical basis for it. It seems a bit cutting-edge; it would be better to have some insights, but it’s okay if not – everyone is still learning, right? Perhaps each factory also has its own special features. Just experience it and see. This topic isn’t either a common one. Perhaps the consideration is being too realistic. So it shouldn’t be brought out to put everyone in a difficult situation. Since this question is not usually included in standard test questions, it is rather extreme. Just be careful.
The synthesis pressure depends on the reaction conditions in the synthesis tower, and these conditions are influenced not only by methane but also by factors such as the ammonia content at the inlet, the hydrogen-to-nitrogen ratio, the circulation rate, the hotspot temperature, the temperature difference across the cross-section, and the radial temperature difference.
This issue is essentially a matter of quantity conversion; the two situations are fundamentally the same. In principle, when the operating conditions of the ammonia synthesis tower remain the same and the output volume is consistent, if the methane content in the fresh gas increases, the amount of gas vented through recycling should be increased accordingly. This ensures a stable methane content, and as a result, the system pressure remains stable as well. In summary, the total amount of inert gases carried away by liquid ammonia dissolution and gas venting must be roughly equal to the amount of fresh gas introduced into the system in order for the conditions in the ammonia synthesis tower system to remain stable over a long period of time. So, in the first scenario: as the methane in the fresh gas increases, the system pressure gradually rises as well. It is necessary to increase the venting rate in order to control the methane level, thereby regulating the system pressure. As for the methane level being controlled at a lower level than before and the vent flow not being able to be reduced, this is due to the operational procedures failing to keep up with the changes in methane content in the fresh gas; the delay in adjustment results in a significant increase in pressure. When more venting is required, the vent flow increases accordingly, leading to an increased amount of methane being released. Once the methane level drops back to normal levels, the higher vent flow combined with the lower methane content ensures that the amount of methane released balances out that brought in by the fresh gas – and naturally, the vent flow can no longer be reduced. If it is to be reduced, adjustments to the bed layer must be made, and the reduction should be gradual, so as to keep the total amount of methane removed roughly constant. The second scenario represents good performance in ammonia synthesis production. The methane content in the new trout gas is not high, while the methane content in the recycled gas is kept at a high level; as a result, the amount of gas released is low. With less effective gas loss during each cycle, the output volume is relatively high. This is exactly the result required by process management. I believe that in order for the operators of ammonia synthesis towers to have truly competent skills and to fully understand the relevant process principles, it is only then that they can make timely adjustments in a targeted manner, thereby ensuring optimized and stable production. . .
In response to 6# fuzhouping, I was inspired; I really didn’t have any good ideas before. After reading it, I felt the analysis was good. The thing is that when a large amount of methane is added, the amount of gas released also increases. Even if the methane level drops a bit, the large amount of methane added means that the system’s methane level remains lower than usual, and the gas released cannot be recovered. Only then can a balance be achieved between methane injection and release to stabilize the system pressure. Of course, when the concentration of fresh methane is low, the methane level in the system may be a bit higher due to the stability of the system, which makes it easy to understand.