What is the ratio of mixed refrigerants used in LNG plants for cooling?
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What is the ratio of mixed refrigerants used in LNG plants for cooling? In my plant, the composition is 30% methane, 31% ethylene, 25% propane, 15% isopentane, and 10% nitrogen – all as percentages. Let’s discuss this and see what differences exist in the composition between my plant and your LNG liquefaction plants
That adds up to 111%, how was that calculated?
It cannot be generalized, as the gas composition varies from factory to factory; consequently, the amount of cooling required for liquefaction differs, and so does the ratio of mixed refrigerants used.
The parameters provided by the design institute are only for reference; in practice, the mixing ratio is determined based on the composition, flow rate, and temperature of the feed gas. Stepwise cooling is achieved by taking into account the temperature range in which each refrigerant component operates. It is essential to gradually explore and draw conclusions through long-term experience on the front line
It’s indeed different; first of all, the design objectives of the design institutes are different. Although it is all about cooling, some plants aim to remove heavy hydrocarbons; this allows for an increase in the temperature at which cooling takes place, resulting in a higher proportion of heavier components in the design ； If the SNG is clean and free of other components, the design team will increase the depth of the cryogenic stage to allow more light components to be present ； So the situations are different; each party has to figure out its own ratio. In addition, the heat exchangers estimated and designed by different manufacturers also vary. Consider it all together.