My views on the inlet temperature of reciprocating compressors
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My views on the inlet temperature of reciprocating compressors It is generally believed that the purpose of insulating and heating the compressor inlet is merely to prevent the precipitation of liquids within the gas – including water or hydrocarbons – in order to avoid liquid slugging. I believe this is not entirely accurate. The design of a compressor takes into account parameters such as temperature, pressure, flow rate, and the type of medium used. If these parameters deviate significantly from the specified values, the operating conditions of the compressor change considerably. Maintaining a certain inlet temperature serves to prevent an increase in the density of the gas phase at low temperatures; this would lead to an increased actual suction volume, and as a result, the actual exhaust volume would far exceed the standard value. The increase in exhaust volume also causes greater fluctuations in airflow, which can lead to vibrations in the inlet pipelines and buffer tanks, as well as instability in the process system. Therefore, regarding the issue of vibrations in the pipelines and equipment of reciprocating compressors, I think this factor should be taken into consideration. These are just my preliminary thoughts; I earnestly invite everyone to share their opinions and offer guidance
The OP’s view makes sense, but I don’t think it is the main cause of pipeline vibration: 1. For ordinary media, within the range of variations in inlet temperature (I guess the maximum is only 30-40 degrees), their density does not change to such an extent that the actual exhaust volume would far exceed the standard value. The main ways to increase the air delivery volume of piston compressors are expanding the cylinders in each stage, applying pressure in one specific stage, or modifying the equipment by removing the balance stage. 2. In actual production, many manufacturers nowadays carry out cylinder expansion upgrades or partial pressurization modifications in order to increase their production capacity; this effectively boosts the air injection volume without causing pipeline vibration. 3. When the “actual exhaust volume far exceeds the standard exhaust volume,” the motor current has already far exceeded the rated current, and the equipment can no longer operate.
It is specified that the temperature of the cylinder cooling water should be 5-6 degrees higher than the intake air temperature. The compressor’s air handling capacity is calculated under standard conditions; if the intake air temperature deviates from the designed values, there will be a slight change in the air handling capacity, but this will not cause vibration. If vibration does occur, it means that the temperature deviation is quite large, and other parameters have also changed, resulting in a significant deviation from the designed conditions, which in turn causes vibration
1. In the production of low-nitrogen fertilizers, we strive to keep the compressor inlet temperature as low as possible in order to increase the volume of air entering the compressor and thus boost its pumping capacity. The maximum temperature difference between winter and summer is around 26 or 27 degrees. After seven-stage compression, the pressure can be increased by approximately 2–3 MPa, which corresponds to a rise of about 4%; this doesn’t have any impact on the stability of the system. 2. The company also increases the inlet pressure by expanding the cylinders, in order to boost the volume of air that can be pumped. 3. If the actual air inflation volume is too high, the compressor will trip due to overload.