The use of oxygen-enriched air, instead of ambient air, can significantly improve the energy efficiency of combustion processes and reduce the cost of CO 2 capture from flue gases throughout manufacturing industries. This study examines the overall energy savings and economic benefits that can be obtained using oxygen-enriched combustion based on novel membranes and processes to produce oxygen-enriched air. Membrane processes using low-pressure air as a countercurrent sweep in the permeate were used to minimize the energy cost of producing oxygen-enriched air. High-performance thin film composite membranes based on a series of perfluoropolymers and bench-scale spiral-wound modules were prepared, and showed oxygen permeance as high as 1200 gpu (1 gpu = 10 −6 cm 3 (STP)/cm 2 •s•cmHg) combined with O 2 /N 2 selectivity of 3.0. The membrane-based oxygen-enriched combustion processes show good energy savings (defined as the fuel savings less the energy consumption of producing oxygen-enriched air) and economic benefits (defined as the value of fuel saved less the operating cost of producing oxygen-enriched air), especially at flue gas temperatures higher than 1090 °C (or 2000 °F). For example, at a flue gas temperature of 1649 °C (or 3000 °F), membrane-based oxygen-enriched combustion shows a net energy savings of 35% and a net economic benefit of 29%, compared to the combustion process with air. The effect of oxygen-enriched air on NO x emissions in a natural gas furnace was also experimentally investigated.

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Advances in tank melter, refractory, controls, and heat source technology have paralleled progress in glass chemistry, quality, and production scale for decades. These same advances have also led to a revival of the 75-year-old concept of bottom heating for glass melting. To create high-intensity heat transfer and rapid melt homogenization, bottom heating, or submerged combustion melting, uses forced convection and direct contact heat transfer. The work of European, American, and Ukranian scientists has demonstrated that bottom heating offers energy savings, emissions reductions, and cost savings relative to conventional melting. Recent work by the Gas Technology Institute of the United States, in partnership with a consortium of glass companies, has advanced the bottom heating technology for a number of glass products to the brink of commercialization. With ongoing work a practical, rapid refining process could be developed to enable bottom melting as an alternative melting approach for a broad range of commercial glasses.