Compressor users, take a look at this issue – have you run into scammers?
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The new unit is ready to be fed with fresh hydrogen and recycled hydrogen compressors. The solution provided by the manufacturer doesn’t present any issues regarding fresh hydrogen. For the recycle hydrogen compressor, it is required that the inlet pressure be at atmospheric pressure at the time of startup (the inlet valve should be closed to release pressure), and the inlet valve should then be slowly opened after the machine has started up. Is there such an operation? In the past, I dealt with situations where imports and exports were enabled, and it was sufficient to start the system with no load. But this time, the manufacturer said it would trip if started directly. However, this solution places high demands on the operators on site. I wonder if the manufacturer used motors with insufficient power (they can operate normally, but the current is too high at the moment of startup; the motors chosen were too small to save money?) I hope experts who understand this equipment will kindly offer their guidance! !
Based on your description, it seems you suspect that the manufacturer used motors with insufficient power, and you are concerned that the compressor will trip when the inlet pressure is at atmospheric pressure. First, I recommend that you communicate with the manufacturer to understand their approach and the reasons behind their choice of motor. You can ask them why they took pressure-reduction measures to start the circulating hydrogen compressor, and why they believe starting it directly would cause a trip. They may be able to provide you with a more specific explanation. In addition, you can also consider the following points: 1. Check the electrical system: Ensure that the load of the electrical system can handle the instantaneous current generated when the compressor starts up. If it is suspected that the motor does not have sufficient power, the manufacturer can be asked to provide the technical specifications of the motor to determine whether it meets the requirements. 2. Consider using a soft starter: A soft starter can control the current during motor startup, gradually increasing it to the rated value, thereby reducing voltage spikes and current peaks at the time of startup. 3. Seek opinions from other experts: If you still have doubts about the manufacturer’s proposal, you can consult other equipment experts or engineers and hear their suggestions and opinions. In short, to ensure the safety and proper operation of the equipment, I recommend conducting further discussions with the manufacturer and seeking the opinions of other experts. .
This post was last edited by The wise on 2023-6-16 at 20:09. Follow what the manufacturer says; don’t be overly clever – will you be responsible if something goes wrong while driving?
If it is centrifugal, then this solution seems like a joke; under such a scheme, how can surge be prevented during the startup process?
We have also encountered this situation you mentioned; indeed, it involves shutting off the inlet and outlet and starting the compressor. I don’t know what your circulating hydrogen inlet pressure is? The advantage of turning off the inlet to start the compressor is that the compressor does not start under load; although a unloader is used to keep the compressor running without load, there is still a difference between this and true no-load operation. When increasing the motor power, it is necessary to consider the capacity of the upstream power grid to handle it; if the starting current is too high, can the grid withstand such fluctuations?
Some compressors are designed to start at low pressure, and this is done to protect the motor. The current level is very high immediately when the compressor starts up, but it returns to normal after that.
Thank you for your reply; it’s very detailed! 1. The manufacturer did not specify a motor of sufficient capacity; it was only mentioned that many manufacturers proceed in this way (but to be honest, I have never seen it done). 2. Our compressor is relatively small and of the reciprocating type, with a motor capacity of only 355 KW. The electrical engineer said that since the motor is small, a soft starter is not necessary. 3. We asked a few people, and they all speculated that the manufacturer chose small motors in order to save costs, meeting the functional requirements but complicating the operation process. Thank you again! ! !
Thank you for your reply; it’s very detailed! 1. The manufacturer did not specify a motor of sufficient capacity; it was only mentioned that many manufacturers proceed in this way (but to be honest, I have never seen it done). 2. Our compressor is relatively small and of the reciprocating type, with a motor capacity of only 355 KW. The electrical engineer said that since the motor is small, a soft starter is not necessary. 3. We asked a few people, and they all speculated that the manufacturer chose small motors in order to save costs, meeting the functional requirements but complicating the operation process. Thank you again! ! !
Our compressors are relatively small, with a pressure of 6 MPa; the motors have a power of 350 KW. There is also another dry gas compressor that is even smaller, with an inlet pressure of only 0.5 MPa and a motor power of 15 KW. The situation is the same in that case as well. Thank you for the answer! ! !
This startup procedure is intended for reciprocating compressors. Under normal circumstances, such compressors should be started without load; once they are operating properly, the inlet and outlet valves should be gradually opened. Once these valves are fully open, the two-return-one (or unloader) valve should be closed to allow the compressor to start working under load! If you want to reduce labor and resources, you can choose electric actuators to replace humans in operating valves.
When selecting the equipment at that time, the manufacturer should have been requested to ensure that the main motor is capable of enabling the compressor to start without load under stall conditions, with pressure present (at the normal operating pressure at the inlet).