Lessons Learned in Material Selection and Reliability of Shell and Tube Heat Exchangers in Direct Seawater Cooled LNG Plants

摘要

The majority of LNG liquefaction trains in service today utilize direct seawater cooling for large shell and tube heat exchangers, including the refrigerant condenser, sub-cooler and compressor coolers. While direct seawater cooling is typically more efficient then the alternatives such as indirect seawater, or air cooling; there are increased challenges to overcome in terms of reliability, and maintainability of heat exchangers. An analysis of the lessons learned over the past 30 years reveals that the use of titanium in place of copper alloys can dramatically improve heat exchanger reliability and reduce plant life cycle cost. New heat exchanger designs utilizing anti-vibration baffle supports and low fin tubing have further improved the reliability, performance and cost-effectiveness of titanium shell and tube heat exchangers used in Liquid Natural Gas (LNG) plant service.