Cryogenic gas plants process natural gas in part to efficiently recover natural gas liquids (NGLs) from raw natural gas. This process of cryogenic separation involves a complicated collection of technology and techniques in order to achieve high percentages of ethane, propane, and butane recovery. Providing the most optimal plant structure, from design to operation, is a challenging task in itself, requiring expertise in many disciplines. Yet we’re now able to push ethane recovery rates to as much as 95 percent thanks to engineers’ dedication to overcoming technological challenges. Two of the biggest challenges in cryogenic gas processing have been improving efficiency and adding flexibility to plants.

Improving the efficiency of a cryogenic gas plant has been a challenge tackled solidly through the development of technology. The idea of cryogenic turboexpansion became a commercial reality in the late 1950s and early 1960s, though those early designs had “minimal heat integration and little or no reflux.” Improvements through the gas subcooled process as well as the addition of dephlemators, residue-reflux systems, improved presaturation and chilling technologies, high-efficiency expander-compressors, and plate-fin exchangers have taken cryogenic gas processing to safer, more efficient levels. Advances in wireless technologies and data management systems are also driving the installation of sensors and software to improve sustained and peak performance of cryogenic gas plants.

Building flexibility into cryogenic plant design has also been challenging, particularly when data regarding gas composition and quality is limited. As new wells are drilled in the nearby area, gas compositions may differ (particularly in shale plays), creating variability in the primary feed to the plant. One way some producers have managed the challenge of developing flexible cryogenic plants is through the use of modular plant design and construction. Modularity can “optimize overall project scheduling and profitability” by allowing standardized, pre-engineered modules to be integrated first without even knowing the specifics of gas composition. As more data is obtained, additional modularized equipment specific to the process can be added and optimized later in the manufacturing and development processes. And as priorities in gas processing shift during operation, additional modules can be swapped in and out for added flexibility.