How many waves does it take for your converter to heat up when the car is running?
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After the system is shut down, the conversion temperature generally decreases somewhat, sometimes by a significant amount. Taking into account factors such as heat storage in the catalyst layer, the ignition temperature of the catalyst, and heat losses, the catalyst temperature rises first after the system is restarted, then drops, before rising again. Usually, after 1 to 2 such cycles, the temperature returns to normal; I believe everyone has seen this phenomenon before. But with our converter, it’s not normal for there to be fewer than 4 waves when driving; once, when driving at low temperatures, there were as many as 7 large waves, and these waves propagated from the front to the back, one after another, causing the heart rate to fluctuate accordingly. There are so many waves; it’s really hard to explain. What about you? Can any expert explain this phenomenon? Explanation: One rotation and one suction process, with four sections in the converter. Before the major overhaul last year, this converter operated smoothly during the heating-up process; generally, the temperature rose in a typical wave-like pattern. During the major overhaul, 50% new catalyst was added to Section 1, and 6% new catalyst was added to Section 4. The catalyst filling was carried out following a top-to-bottom approach, with the principle of replacing the degraded catalyst in each section as well as that in Section 1, while keeping the amount of catalyst filled in each section unchanged. :Handshake :handshake This post was last edited by “Also a chemical industry worker” on March 20, 2009 at 22:22.]
We produce sulfuric acid; there was an issue in Stage 1, with the temperature dropping once before rising again, but it seems there were no such issues in the other stages.
At our plant, fluctuations usually return to normal after one or two adjustments. It’s crucial for the control personnel to make appropriate comparisons; controlling two key parameters is sufficient – the first being the gas concentration, and the second the air volume. The air volume should be kept as low as possible to ensure maximum utilization of heat. Additionally, the boiler’s bypass system should be used to some extent in order to make use of the heat, and water bypass systems such as those in heat exchangers also need to be checked and activated. All of these measures are taken to maximize heat utilization.
Generally, 4-5 waves are sufficient; the temperature rise of the converter is not very strict.
Our process involves two rotations and two absorptions for sulfur-based acid production; the conversion temperature generally fluctuates once before returning to normal, with an initial drop followed by an increase, which in turn causes fluctuations in the subsequent stages.
As the original poster mentioned, there are several fluctuations in the temperature during the conversion process. In our factory, which has been in operation for over a decade, we have never encountered such situations, unless there are fluctuations in the temperature of the boiling furnace, or if the sulfur content in the feed material varies greatly. As long as the boiling furnace operates stably, we have not faced this issue.
Has it never appeared in China? Our factory’s operation is intermittent; looking back, it’s possible that the furnace gas was introduced without sufficient preparation, and its concentration wasn’t adequate.
When we drive, the level drops first and then rises again. Is there a problem with the adjustment of the air volume and sulfur content?
It is easy to understand that fluctuations in gas concentration and air flow volume lead to variations in the conversion temperature. However, our plant has another converter that is started up simultaneously with this one, and it is fed with air by the same fan (so the gas concentration remains constant). The inlet and outlet valves of these two converters generally do not change (as the air flow volume stays relatively stable). As a result, one converter stabilizes quickly, while the other experiences several more fluctuations. I noticed that in the cases of those upstairs, the temperature first drops and then rises. But in my case, the temperature of the catalyst layer first drops slightly (by a few degrees or a dozen degrees), then rises sharply (reaching over 640; if it doesn’t reach 570 on the first attempt, then the converter’s temperature must rise significantly), after which it drops sharply again (reaching around 380), and then gradually rises back up. Sometimes it rises again only to drop once more, and this cycle repeats itself... Is there anyone who can provide an explanation for this phenomenon related to the catalyst? Why are there such fluctuations?