I have two questions regarding compressors?
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A few days ago, I had a technical discussion with a compressor manufacturer, focusing on the selection of natural gas compressors for use in recovering vapors from large tanks in oil fields. The gas in question contains a small amount of water vapor, and a small quantity of condensates with molecular weights above C5 are also produced when the temperature drops. It is generally believed that natural gas can dilute the lubricant, causing it to become ineffective and ultimately leading to damage to the compressor; therefore, self-lubricating or oil-free compressors are used. The manufacturer uses oil-injected screw compressors; they believe that only the liquid phase can cause the lubricating oil to become diluted, so gas-liquid separation is implemented at the compressor inlet to ensure that what comes into contact with the lubricating oil contains no liquid ； Moreover, high-viscosity lubricant is used; even if it becomes diluted over a short period of time, this will not affect the quality of the lubricant, allowing it to remain effective. It is said that it can be used for 2 to 3 years. I would like to ask everyone whether this way of expressing it is appropriate?
Choosing a screw compressor is also a good option
Choosing a screw compressor is a good option; it should work fine.
So for this type of oil injection system, that is, the one where lubricating oil comes into contact with natural gas, to what extent does natural gas affect the lubricating oil? Is what the manufacturers say reasonable?
So for this type of oil injection system, that is, the one where lubricating oil comes into contact with natural gas, what is the impact of natural gas on the lubricating oil?
I don’t think it’s good; the medium contains moisture, which can easily cause the lubricant to emulsify
The injection screw is mainly cost-effective; it has an impact on the circulating oil in the compressor, but it’s difficult to determine exactly how much. In my opinion, the gas that forms from the oil and gas mixture has little effect on the lubricating oil (this may not be correct). Of course, oil-free screws can be used to eliminate this concern; the price will be higher, but that’s also fine.
So what if it’s an aqueous gas? Should a gas-liquid separator be installed at the compressor inlet to separate liquids such as water in advance?
Is there any theoretical basis for the idea that only liquid water and hydrocarbon liquids can cause lubricant dilution?
It’s just a speculation; there’s no evidence to support it. Whether the additional water will have an impact on the circulating oil, or how long it will take for such an impact to occur, are all very technical matters – I’m not sure. I feel that over time, it might have some effect, but I have no evidence to back this up
This post was last edited by Bai Yunfan on 2015-9-18 at 13:24. I saw a VRU (Vapor Recovery Unit) developed by a renowned American design firm, used to recover the volatile gases from condensate oil storage tanks. They use a liquid ring compressor with a power rating of 400 HP; the inlet pressure is 95.6 kPa gauge, and the outlet pressure is 630 kPa gauge. Abroad, one can find many animations explaining the working principle on Google, but it seems there aren’t any such things on Baidu.