Regarding the issue of anti-surge
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There are currently two anti-surge solutions as follows: Solution A: Solution B: Our company uses compressors of the 2BCL458 model manufactured by Shenyang Gear Pump Co., with 7 compression stages and 1 circulation stage, for producing syngas. We adopt the first solution; please discuss these two options to see which one is better. Some changes have been made to the diagram, mainly after reading the comments on the fourth floor, as we thought it was necessary to make such adjustments to make it more in line with our own solution. Thank you to the person who posted on the fourth floor. I hope everyone will continue to discuss this topic. This post was last edited by hbspider on 2008-2-20 at 18:20.]
I think the first option is also the better one. In Option 1, anti-surge control is achieved through a valve located from the compressor outlet to the inlet. When, in actual production, the pressure and flow rate of the feed material decrease and this could lead to surge in the unit, the opening degree of this valve from the outlet to the inlet can be adjusted to increase the inlet flow rate and thus bring the system out of the surge zone, thereby protecting the unit.
Neither option is good. Option 1: Direct backflow at the outlet of the compression section for anti-surge protection; the absence of a backflow cooler leads to an increase in the temperature of the gas entering the compression section, thereby reducing the compressor’s efficiency. Second option: The outlet of the circulation section flows directly back to the inlet of the circulation section, without passing through a return cooler, which causes the temperature of the gas entering the circulation section to rise and reduces the efficiency of the compressor. In summary, neither of the two solutions for this case is very good; neither represents a typical anti-surge solution for such synthetic cycle compressors.
As mentioned on the 2nd floor, comparatively speaking, the first method is better
Our plant uses the first type for catalysis; however, since the outlet pressure is not very high, there are no outlet condenser, circulation section, or cross-connections for the circulation section as shown in the diagram. But I think we could combine these two options: namely, couldn’t both anti-surge lines be connected to the outlet of the condenser? I haven’t tried it; I wonder if anyone has used it?
What you said upstairs is also worth considering. However, when the compressor in the second scheme experiences surge, it is the outlet flow rate of the circulating compressor that is used for adjustment in order to exit the surge zone. I have never worked in such a synthesis workshop, so I’m not sure whether it’s possible for both compressors to experience surge. If both the main compressor and the cycle compressor experience surge at the same time, it will be necessary to adjust the flow rate at the outlet of the cycle compressor in order to control the surge in both compressors. Isn’t that unsafe? This post was last edited by sunhow on 2008-2-1 14:58.]
Could we consider adding a buffer tank at the condenser outlet, and then connecting it to the outputs of the 2 compressors? Or one of them controlled manually and the other automatically? In practice, when a compressor experiences surge, one reason is a decrease in flow rate, and another is a reduction in the molecular weight of the medium being compressed. I’ve never operated this type of compressor either; I think there is sufficient flow in the compression stage, so the circulation stage should not experience surging, right? Just a guess》
Happy New Year. I’d like to hear the proposal for the fourth floor.
The second method is better in practice; the control synchronization of the first method is not good