(100d) Rating Model for Plate-Fin Exchangers for NGL Recovery Units

Rating Model for Plate-fin Exchangers for NGL Recovery Units

Danielle Goldbeck* , Kathy Bigger, and Thomas Walter

Linde Process Plants, Inc., Tulsa, USA

*Corresponding Author: danielle.goldbeck@lppusa.com

The production of cryogenic liquid recovery units for natural gas liquids is a continuously growing industry. As natural gas liquids become more valuable, the technology to process these liquids to produce higher value products will continue to advance.  In this highly competitive industry, it becomes important to design such facilities to be thermally efficient and cost effective.  Additionally, as standardization of cryogenic recovery units becomes more common place, plants are more likely to be exposed to feed conditions for which they were not originally designed. Therefore, it has become crucial to be able to predict plant performance in the most accurate way possible.

Cryogenic plate-fin exchangers are commonly used in natural gas liquefaction processes. These complex exchangers are the "heart" of the cryogenic unit. If the performance capabilities of these units are known, a more accurate prediction of the performance of the entire cryogenic unit is possible leading to better confidence in plant component recoveries. However, the ability to accurately predict the performance of these units has proved to be a challenging task as the design information of the plate-fin exchanger must be available and the process engineer must have a solid understanding of the thermal design of the unit. Many process simulation tools commonly used throughout the industry have moved towards developing rigorous rating tools for these exchangers. Effective use of these tools allows more accurate predictions about the entire plant performance.

A rating model for plate-fin exchangers for NGL recovery units is highly useful in this competitive industry.  The rating model consists of inputting the exchanger geometry details into the chosen rigorous rating tool. Incorporating the geometry of the exchanger into the simulation allows the outputs of the exchanger to now reflect how the exchanger will actually perform given specified inputs.  This exchanger can then be fully integrated into the entire process simulation to predict plant performance even under off-design conditions.  By using the rigorous rating model, one can predict the performance of plate-fin exchangers and ultimately better predict and optimize the performance of the plant, allowing for a more robust and cost effective design.