As the demand for natural gas in the United States continues to grow, there is a renewed interest in the import of LNG as an energy source. Imported LNG is stored, pressurized, and vaporized before it is injected into the national pipeline grid. The LNG vaporizer, which regasifies the LNG from liquid to gaseous form, is one of the main components at an LNG import terminal. Various LNG vaporizer technologies have been developed and utilized. Most of the existing LNG terminals in the US use Submerged Combustion Vaporizer (SCV) technology as a baseload regasifier. The SCV's have high thermal efficiency, easy of start-up, and are capable of long term operation.

However, the conventional SCV generates air emissions due to fuel combustion, which then produces nitrogen oxides (NOx), carbon monoxide (CO), and other toxins. The concern to minimize the environmental impact of the energy industry has been dramatically increased. This trend affects the emissions from the LNG regasification process and requires more tight air emissions control. This paper discusses advanced designs of SCV that have been newly developed to reduce NOx and CO emissions in the exhaust gases from the SCV. Conventional SCV designs, including the process and major factors impacting emissions, are also presented in this paper.