DUAL ENHANCED TUBES FOR LARGE SHELL AND TUBE HEAT EXCHANGERS FOR LNG - A MATURE TECHNOLOGY

摘要

Extruded low-finned and dual enhanced tubes are an established heat transfer enhancement technology used since decades in multiple industries such as the heating, automotive, air-conditioning and refrigeration industries as well as the power and hydrocarbon industries. Over the last 15 years, Technip and Wieland have collaborated to qualify dual enhanced tubes with the aim of becoming a hydrocarbon processing industry standard especially for large shell-and-tube heat exchangers for grassroots LNG and ethylene plants. From 1996 onward, a joint academia-industry R&D program supported by the EU established the necessary thermal design information for enhanced horizontal shellside nucleate boiling operations for light hydrocarbons, primarily propane. Further work packages concentrated on enhanced tubeside heat transfer and pressure drop performance in single-phase as well as two-phase / condensation forming a solid basis for compact and efficient enhanced heat exchanger designs. Industrial references have been established starting in 2000 for thermosiphon, kettle reboiler and chilling services in polypropylene, ethylene and LNG plants - first in debottlenecking and finally in grassroots applications. The key advantages are: Higher overall heat transfer coefficient, compared to conventional technologies Improved process efficiency based on very low temperature approaches, compared to conventional technologies The presentation reviews the whole development and qualification process, the implementation of the dual enhanced tubes first in debottlenecking then in grassroot applications. Field test data confirm the industrial suitability of this technology from start- up with stable performance over the years in line with the design expectations. Furthermore, dedicated preservation guidelines for the whole supply chain from tube fabrication to start-up confirm proper operation.