Compressor dry gas seal
Thread Content
It concerns the dry gas sealing system of compressors. I would like to ask whether the flow rate of the sealing gas provided by the compressor manufacturer (volumetric flow rate) changes during the process from startup to normal operation of the compressor (the relationship between flow rate and compressor speed). Assume that the flow rate of the sealing gas provided by the manufacturer is 900 Nm3/h (this flow rate is based on an on-site process gas pressure of 10 Mpa). When the compressor is shut down, the pressure in the inlet pipeline is approximately 3.0 Mpa; when the compressor is running, the maximum outlet pressure is 10 Mpa. My understanding is that when the compressor outlet pressure reaches 10 Mpa (which means the compressor is operating normally), the required flow rate of sealing gas is 900 Nm3/h ； However, during the period from startup to normal operation, the flow rate remains below 900 Nm3/h, while the compressor’s demand for seal gas gradually increases ? Is this the correct way to understand it? ?
Don’t overthink it for now; carefully read the operating instructions, the compressor manual, and the installation and operation guidelines for dry gas seals, and verify the on-site procedures as well as the control processes. Then ask the captain and team leader, and also ask the equipment process engineer
The problem is that I’m not from the using unit, so in practice I have no opportunity to work with this area. The project our company has undertaken involves the renovation of the compressor dry gas seal system; therefore, we would like to ask whether there is a relationship between the flow rate of the sealing gas and the speed of the compressor
Bro, can you help answer this?
I’ve checked it. The post you sent earlier has already received a reply. October 29th.
That means the mass flow rate will also change, right?
The reason for the decrease in flow rate during startup is that the pressure difference between the primary sealing gas and the balance tube decreases at this stage (as the unit starts to operate, the pressure in the sealing chamber increases). It is normal for the flow rate to drop when this pressure difference decreases. During startup, it is essential to maintain a certain flow rate; this value should be in accordance with what the manufacturer specifies. Otherwise, the moving and stationary rings will not be able to separate from each other, no air cushion will be formed, and dry friction will occur, which can damage the seal
Our unit is equipped with reference pressure difference regulation, which applies to both the pressure difference between the primary sealing gas and the cylinder body, and this can be adjusted by the main controller. A small portion of the primary seal gas leaks through the primary seal face, where it merges with the secondary seal gas and passes through a flow meter. Normally, we focus on monitoring the discharge flow rate and the pressure difference of the primary seal.
A reference value for the design criteria of dry gas seals: an adequate flow rate of sealing gas (precharge gas) ensures proper purging of the seal chamber and the first stage of the seal, thereby creating an environment suitable for the operation of the dry gas seal. This is why the gas must be filtered through the system first. \"For the best dry gas seal technology, contact Datang at 18980866098 in Chengdu for technical consultation services.\"“”