Failing to distinguish between primary and secondary matters results in losses that outweigh the gains!
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Recently, due to the favorable conditions in the fertilizer market, our branch plant has stopped decarburization and started carburization. Carbonization index: CO2 ≤ 0.02% ； Transformation index: 0.8≤CO≤1.3%, but due to abnormalities in the refining section, there are significant minor fluctuations (as reflected mainly in CO values in the table)! When the CO2 level in the carbonization main tower exceeds the limit, the control system notifies the converter to reduce CO levels in order to maintain proper carbonization! I wonder, is it meaningful to do this? ! The low-temperature conversion catalyst is originally designed to operate under low-sulfur conditions; so what’s the point of artificially increasing the steam-to-gas ratio in order to raise the conversion rate? ! There is a certain sense of achievement in having carbonized fertilizers piled up in the field, but what about the costs associated with the conversion? What about the cost per ton of ammonium? How to counteract the negative effects caused by reverse desulfurization? The guiding principle behind scheduling is: “Isn’t transformation a purification process? Why wait until the level of impurities rises significantly before taking action?” ”I’m speechless! I become Genghis Khan! ! !
:O How should this be put? It’s the conflict between short-term and long-term benefits, right? If production increases, his rewards will be high, right? But who is responsible if the equipment breaks down? Haha
Even without considering costs and consumption, purely from a principle standpoint, the mechanisms for removing carbon monoxide and removing carbon dioxide are entirely different. When carbon dioxide levels are high, no matter how low carbon monoxide levels are kept, it has little impact on reducing the trace amounts present in the refined gas. By the way, what is the refining process used by the original poster?
I haven’t been involved in the carbonation process in production, but I know that carbonation involves using ammonia to absorb CO2. When the CO2 level in the main tower for carbonation rises, it means that the absorption capacity of ammonia has decreased. Is that correct? At this point, requiring a reduction in CO means increasing the CO2 concentration at the carbonization inlet – how is this supposed to help with carbonization? I think what LZ means is: the CO2 output at the carbonization stage is above the specified level, so the control system requires that the CO level be reduced in order to maintain the refining process (since it was mentioned earlier that minor fluctuations are mainly caused by CO), right? As mentioned on the third floor, the principles behind removing CO and CO2 are different; reducing CO has little impact on maintaining low levels of CO2, but it can help reduce the overall trace amounts in the refined gas. The scheduling requirement to reduce CO should be within the process parameters (after all, scheduling doesn’t have the authority to change those parameters, right?) I think the process parameters for a company aren’t set arbitrarily. In situations where there are frequent minor fluctuations in CO levels during the refining process, it doesn’t seem reasonable to require a reduction in the amount of CO converted under those parameters. If it can be said that such actions are counterproductive, it shouldn’t be based on assumptions alone; concrete data is needed to prove it. The data related to conversion consumption, ammonia consumption per ton, and the desulfidation of conversion catalysts mentioned by the original poster are all easy to obtain. If the data shows that the scheduling instructions are incorrect, it’s possible to report this to the higher-level authorities. Of course, if scheduling demands changes to the process parameters, it constitutes illegal instructions, and it is the operator’s right to refuse such illegal instructions. Note: I am a dispatcher; criticism is welcome!
Not many people these days think deeply about production issues; please keep doing so. Using short-term methods to reduce the CO content in the conversion gas as a way to lower the refining load is not a good approach; the key is to properly control the carbon dioxide levels. Reducing CO in the conversion gas often takes some time, and as you mentioned, it also leads to increased consumption. Increasing the steam usage is a factor that contributes to reverse sulfidation, but it does not necessarily lead to the occurrence of this phenomenon. It is common for dispatchers to focus on production volume, often paying insufficient attention to cost control; it ultimately depends on how the management guides them. I believe your dispatchers will also employ other methods to increase the output of fertilizers. Also, a carbonization gas value of 0.02 might be incorrect; why should the CO value in the shift gas be greater than 0.8? Is it to prevent too much steam from being added?
It’s clear that the approach taken in scheduling is wrong; reducing CO does not mean reducing the amount of impurities present during copper cleaning. This is especially illogical when the level of CO in those impurities is already low. CO2 is absorbed by the free ammonia present in the copper melt, while CO is absorbed by copper in its higher-valent form – these are two completely different concepts
Since the refining section is already not operating properly, the conversion section must control its process parameters even more carefully, in fact, trying to keep them as low as possible. The CO2 level in the carbonization main tower is too high; adjustments should be made to the production conditions for carbonization, the process operations, and the ammonia concentration levels. CO2 is absorbed by the free ammonia in the copper melt, while CO is absorbed by low-valent copper. The conversion consumption, ammonia consumption per ton, and desulfidation of the conversion catalyst mentioned by the poster are all data that can be easily obtained; if such data prove that the control instructions are incorrect, it is possible to report this to the higher-level authorities. During the CO conversion (H2O/CO=4-5), both CO2 and H2, the raw material gas required for ammonia synthesis, are obtained simultaneously. The CO index of the transformed gas is greater than 0 because the increase in the refined copper ratio is achieved through the reducing action of CO. Please give me your guidance
The original poster is considering the situation of one specific production unit, while scheduling focuses on maintaining overall production. It’s clear that an imbalance in the copper content in the refining process is causing a slight increase in levels; it seems that the refining process cannot be adjusted quickly, which is why adjustments are made to reduce those levels. This is a temporary measure. Is the loss resulting from a short shutdown of the synthesis process smaller than that? I’m also a scheduler, but we’ve switched to a dual-A process; refining it is too complicated and difficult to adjust
In fact, for any fertilizer plant, it is essential for its production and technical departments to conduct a thorough analysis and adjust the process parameters, identify which stage of the process represents a weak point based on those parameters, and then carry out improvements. If one cannot even do this, then they are not a competent technician. From what the original poster has asked, it seems that your factory’s copper washing system needs to be upgraded. Generally speaking, for copper washing, the CO value of imported materials should be within 2%, and there should be no excess of trace amounts of copper in the washing process ； The fact that your plant cannot even maintain 1.0% indicates a problem with the copper washing tower, which requires renovation. I’m not sure what the capacity of your factory is, or how large the copper towers are. What is the structure inside the copper tower like? I would appreciate it if you could let me know, so that an appropriate renovation plan can be developed.
CO2 should be <0.2； CO＞0.8 is to control the steam-to-gas ratio during light-load operation, as well as to extend the catalyst's service life.
I agree with the view from floor 8; you are considering one work section, while scheduling requires taking the entire system into account – the focus is different
This post was last edited by mn197601 on 2013-4-26 at 16:31. I disagree with what some friends said, about considering only the work sections or only the overall situation. This is not a criterion for judgment. Standards should be based on operating methods and operational indicators. This is the foundation of a chemical plant. Although I don’t understand this old craft. But the principles of managing a chemical plant should be the same.