System and method for hybrid refrigeration gas liquefaction

Abstract

In an embodiment, a method includes cooling a fluid along a fluid path using a vapor compression refrigeration cycle; cooling the fluid along the fluid path using at least one cryocooler of a cryogenic cooling phase; expanding the fluid during cooling within the cryogenic cooling phase, after cooling in the cryogenic cooling phase, or a combination thereof, such that a temperature and pressure of the fluid are reduced to generate a fluid stream having both a vapor phase and a liquid phase; and condensing the vapor phase. The fluid may be a natural gas.

Description

BACKGROUND[0001]Natural gas, when isolated from natural sources (e.g., underground in naturally occurring reservoirs), generally includes a mixture of hydrocarbons. The major constituent in these hydrocarbons is methane, which is generally referred to as natural gas in commerce. Natural gas is useful as a source of energy because, among other things, it is highly combustible. One particularly desirable characteristic of natural gas is that it is generally considered to be the cleanest hydrocarbon for combustion. Because of this, natural gas is often used as fuel in a wide variety of settings, including heaters in residential homes, gas stoves and ovens, dryers, water heaters, incinerators, glass melting systems, food processing plants, industrial boilers, among numerous others. Generally, natural gas (e.g., untreated or raw natural gas) removed from reservoirs is processed and cleaned prior to entering pipelines that eventually feed the gas to homes and industrial plants. For exampl...

AI Technical Summary

Benefits of technology

The patent describes different embodiments of a system and method for liquefying gas. The system includes a flow path, an initial cooling phase using a vapor compression refrigeration cycle, a second cooling phase using a cryocooler, and an expander. The method involves cooling the gas using the vapor compression refrigeration cycle and the cryocooler, followed by expansion to reduce temperature and pressure and condensation of the vapor phase. The technical effects include improved efficiency and a simpler process for liquefaction of gas.

Problems solved by technology

Unfortunately, pipeline networks can represent a significant investment, and are generally used only in situations where the natural gas is traveling a relatively short distance.

Natural gas condenses to its liquid state at about −260° F., or approximately −162° C. Accordingly, it should be appreciated that reaching such a low temperature on a large scale, while also maintaining these temperatures during transport, can be challenging.

However, these techniques can often involve significant capital investment, such as in refrigerant, compressors, and so forth.

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