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Show KEY FACTORS AFFECTING THE ECONOMICS OF OXYGEN ENRICHED AIR PRODUCTION VIA MEMBRANES Arye Gollan, Myles H. Kieper AJG Technology Corporation Needham, Massachusetts, USA ABSTRACT The benefits of oxygen enriched air for improving combustion efficiency and overall productivity in industrial heating applications is well documented, however the adoption of this technology by industry has been very limited due to the high costs of delivered oxygen or on-site generation. An advanced hollow fiber membrane technique for on-site oxygen generation has been developed which holds promise of being the most cost-effective method of generating up to 40% oxygen enriched air. In this paper, the factors which affect the economics and power requirements of this membrane air separation process are discussed. These factors include intrinsic membrane properties, mode of operation, scale of operation, temperature and oxygen concentration. In addition, the general advantages of membrane systems over alternative oxygen generation schemes are discussed. COMBUSTION WITH OXYGEN ENRICHED AIR (OEA) is a documented means of energy conservation (1, 2). The energy reduction achieved when burning OEA is due to two fundamental principals of process thermodynamics and kinetics. First, higher flame temperatures are obtained due to reduced parasitic nitrogen in the combustion air. Consequently, in accordance with the well-known Carnot thermal efficiency equation, process thermodynamic efficiency is increased. Secondly, in terms of kinetics, higher temperature leads to higher process productivity through improved overall heat transfer coefficients, in part directly proportional to the flame temperature to the fourth power. As an example of the energy conservation aspects of combustion with OEA, one can consider the effect of oxygen concentration on natural gas savings for small torch applications as shown in Figure 1 (3). With 35% to 40% OEA combustion air, 40% to 50% natural gas savings can be achieved. It is noteworthy that above this OEA 179 concentration range the increase in savings with increased oxygen concentration diminishes and the value of higher OEA concentrations is rapidly reduced. In addition to these fuel savings, productivity improvements resulting from higher flame temperatures will further enhance the economics of OEA combustion. In fact, in many cases, the energy savings due to increased productivity alone will justify OEA combustion. SMALL TORCH APPlICAnONS o ...................... ~ .... .. o Figure 1. 20 40 80 100 OXYGEN IN COMBusnON AIR ("10) Natural Gas Savings versus Percent Oxygen |