Regarding compressors Compressors
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In a continuously variable control system, how should adjustments be made if the intake pressure of the compressor changes? In the absence of infinite control, I would like to ask: do the control valves for one-in-one or two-in-two operation on the secondary compressor regulate the inlet pressure or the outlet pressure of the compressor? I personally think it is meant to control the inlet pressure, mainly to stabilize the compression ratio of the compressor. If that’s the case, I would like to ask what effects a decrease in the inlet pressure of the compressor would have on it I’ve never been able to figure this out; I hope the experts can give me some guidance! ! Also, a wind-shut interlock valve has been installed at the inlet of the new hydrogen compressor in the hydrogenation unit; I wonder if it should be a wind-open valve instead
If you install a wind opening valve, it will put the system in an emergency shutdown mode, thereby cutting off the source of cold hydrogen gas in that emergency situation.
In other words, in the event of an accident, the new hydrogen cannot be cut off, right?
If the supply of new hydrogen is interrupted, the reactor is at risk of overheating.
The questions you ask are quite profound, which shows that you know how to think! But some foundations need to be strengthened; keep it up! Operators who ask questions and think for themselves see their skill levels improve very quickly!
Inlet pressure is an important parameter; it’s difficult to understand it thoroughly without referring to the book. This involves the compression ratio and energy; assuming that a decrease in inlet pressure makes it difficult at the outlet, a large amount of energy should be generated, resulting in an increased load
When the intake pressure changes, if the Hölbig manual controller is set to manual mode, the exhaust pressure will also decrease; in such cases, you need to apply a load. Regarding the 1:1 and 2:2 ratios, the pressure under such conditions is as follows: if a 1:1 ratio is used, the inlet pressure at stage 1 will increase while the exhaust pressure at that stage will decrease, resulting in a lower compression ratio. I believe this is not a matter of controlling the inlet pressure; rather, it’s about balancing the compression ratio, exhaust temperature, and system pressure. As is well known, when controlling the exhaust pressure of a compressor, one needs to take into account the compression ratio, temperature, the set pressure value of the safety valve, and the pressure specified by the hydrogen supplier’s guidelines. If the pressure at the compressor inlet drops, and if you do nothing, the system pressure will also drop. The impact on the compressor is reflected in the exhaust temperature and in the compression ratio. There’s also the air shut-off valve at the inlet of your compressors; we don’t have one here. I guess it’s there to prevent the system from overheating in case the instrument air supply is interrupted, while still allowing the fresh hydrogen to keep flowing. It doesn’t matter if it exists or not.
I’m sorry for my ignorance, but I really don’t understand what secondary compression, namely stage one and stage two, is used for It should be to control the outlet pressure. Thus, two approaches arise. The first is to act like a centrifugal pump: by reducing the amount of fluid returning, that is, by decreasing the flow returning from the compressor outlet, less fluid returns, and naturally, the outlet pressure increases ； Another way to think about it is that I can activate the return line; if there are more return inlets, then if the pressure at those inlets increases, wouldn’t the pressure at the outlets also increase naturally? Well, then there is another question: for a compressor with single-stage compression, a return valve is installed at the outlet. What is the purpose of this valve? If I want to increase the load on the unit, and with the unloader fully closed, it goes without saying that I need to raise the load by increasing the amount of feed gas entering the buffer tank at the compressor inlet. So, does this return valve need to be adjusted? If so, how should it be adjusted?
During normal operation, if the return valve is opened wider, the outlet pressure is low while the inlet pressure is high; you can try this on the DCS interface. The second situation you mentioned does exist as well, but I think the amount of return flow has a greater impact. If you click on compression, to increase the load, I think it’s better to set it lower; I remember reading that the return valve can only handle up to 30 percent of that amount.
In our hydrogen production plant, the load on the equipment is adjusted according to the pressure indicated on the hydrogen-related website. When the pressure on that website is low, the load on the equipment increases; I observed that the amount of feed gas entering the plant increased, as did the pressure at the compressor outlet. The return valve did not move, as it operates automatically