Method of preparing a cooled hydrocarbon stream and an apparatus therefor

Abstract

A partially condensed hydrocarbon feed stream is sent to a column. An overhead vapour hydrocarbon stream from the column is then partially condensed by indirect heat exchanging against an expanded cooling fluid flowing through a first section of a cold side heat exchanging channel. The cooling fluid consists of a mixed refrigerant composition, and liquid from the expanded cooling fluid is continuously transformed to vapour thereby forming a residual liquid portion of not evaporated expanded cooling fluid. The residual liquid is used to progressively condense the hydrocarbon feed stream to produce the partially condensed hydrocarbon feed stream that is sent to the column, by allowing the hydrocarbon feed stream to lose heat to the residual liquid passing through a second section of the cold side heat exchanging channel. The liquid component that is condensed out of the overhead vapour hydrocarbon stream is used as reflux for the column.

Description

[0001]This application claims the benefit of Indian Application No. 1022 / CHE / 2012 filed Mar. 20, 2012, which is incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention relates to a method and apparatus for preparing a cooled hydrocarbon stream from a hydrocarbon feed stream. The cooled hydrocarbon stream may be cooled to such an extent that the hydrocarbon stream is in a fully condensed condition.BACKGROUND OF THE INVENTION[0003]An example of a hydrocarbon feed stream that in the industry often requires to be cooled is natural gas. Natural gas is a useful fuel source, as well as a source of various hydrocarbon compounds. It is often desirable to liquefy natural gas in a liquefied natural gas (LNG) plant at or near the source of a natural gas stream for a number of reasons. As an example, natural gas can be stored and transported over long distances more readily as a liquid than in gaseous form because it occupies a smaller volume and does not need to be st...

AI Technical Summary

Benefits of technology

The present invention provides a method and apparatus for preparing a cooled hydrocarbon stream by cooling a hydrocarbon feed stream using a mixed refrigerant composition. The cooling process involves circulating the refrigerant through a loop, which includes an expander, a cold side heat exchanging channel, and a warm side heat exchanging channel. The cooling fluid is then compressed and partially condensed as it passes through the warm side heat exchanging channel, resulting in a residual liquid portion and a vaporized residual liquid. The residual liquid is then separated from the vaporized residual liquid and fed back into the cooling loop. The invention has the technical effect of providing a more efficient method for cooling hydrocarbon feeds, which can help to improve the overall performance and efficiency of the process.

Problems solved by technology

The process and apparatus described above has an inherent less than optimal efficiency, because the reflux is produced with the same refrigerant composition and pressure as are used for pre-cooling the natural gas.

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