Feasibility study on the use of LNG in natural gas purification and liquefaction processes
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Hello, respected colleagues. I’m a newcomer to the natural gas industry. My boss has asked me to develop a process that uses the cold energy of LNG for the purification and liquefaction of natural gas. After searching online for relevant information, I couldn’t find any precedents for such a process, so I would like to ask if this approach is feasible Operating condition background: Raw natural gas at 4.0 MPa and 20°C (containing acids, sulfur, water, mercury, and various heavy hydrocarbons)
Could you explain it in a bit more detail? I’d like to learn about it as well. Do you intend to use LNG to liquefy or solidify the impurities in the feed gas so that they can be separated?
Our preliminary idea is to use the cooling power of liquid nitrogen or LNG to liquefy or even condense the acidic gases in the feed gas, thereby carrying out rough impurity removal. However, given that such a process requires a large amount of energy and its impurity removal efficiency is likely to be poor, such processes are virtually non-existent in China
At present, relatively mature process solutions for the pretreatment of LNG already exist in China, including acid removal, water removal, and the separation of various C3 and C4+ compounds
Using cooling to remove acidic gases from the feed gas requires high standards for the equipment, and it’s also costly. In my opinion, cooling can only be used for removing water and heavy hydrocarbons.
The main issue is that there are basically no opportunities to commercialize this process: the recovery of cold energy from LNG takes place during the gasification of LNG; in other words, any demand for such recovery exists only in cases where gaseous natural gas needs to be supplied； And now, the cooling capacity from the gasification process is used to liquefy and purify pipeline natural gas, but such \"niche\" applications are hardly to be found. The process of using LNG cooling energy to re-liquefy BOG is quite mature, and it finds application in LNG receiving stations.