DIESEL ENGINE NOx REDUCTION

摘要

Compact Membrane Systems, Inc. and Innovative Membrane Systems, Inc. have collaborated in the development of high gas flux and chemically resistant membranes. Membrane module flux is sufficiently high that it can be placed under the hood of diesel engines to produce nitrogen-enriched air to reduce NOx emissions by 50%. These membrane modules offer a timely alternative to existing exhaust gas recirculation technologies. We will summarize results to date as well as present a framework for additional high productivity and moderate separation membrane applications. Much progress has occurred in the last 20 years in the use of membranes for gas separation. The major focus has been on high selectivity membranes for such applications as the production of relatively high purity nitrogen from air. This has involved using relatively high selectivity membranes (oxygen-nitrogen separation of permeance ratios of 5-7). These membranes are used to produce nominally 98% to 99.9% nitrogen-enriched air. The development of membranes for producing high purity (98% to 99.9%) nitrogen-enriched air is reinforced by the fact that the major industrial gas companies, Air Products, Praxair and Air Liquide, have acquired membrane divisions from Monsanto, Union Carbide and DuPont. These companies have utilized their commercial focus on producing high purity nitrogen from cryogenics and PSA (pressure swing absorption) to develop membrane-based systems for small-scale operations.