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Oxygen Selective Metal Organic Framework Adsorbents for High Efficiency Air Separation
Phone: (303) 940-2349
Phone: (303) 940-2300
While cryogenic ASU is the technology of choice to supply oxygen to large plants, it requires very expensive and complex hardware that prevents cost-effective scale down for small installations. At small scale, pressure swing adsorption (PSA) is widely used. However, the conventional small-scale PSA process delivers a somewhat more expensive product, mainly due to the inefficiencies involved in the adsorption of the major component (nitrogen) from high pressure air and its subsequent discharge at ambient pressure (the work input during compression is lost). Sandia National Laboratory (SNL) researchers have recently identified novel open-pore metal-organic-frameworks (MOFs) which have a high uptake and selectivity for oxygen. TDA Research Inc. (TDA) is scaling up the production of these MOF materials, designing an efficient air separation process utilizing the new sorbent, and carrying out detailed engineering design and process simulations, to improve the system and determine its costs. In Phase I, we developed procedures to pelletize these oxygen selective MOFs using low energy densification techniques and identified modifiers to further increase their oxygen selectivity against nitrogen. We demonstrated the stable operation of the new material through many cycles under representative conditions in bench-scale tests, and then designed a process and a cycle sequence that achieves high product yield and purity. In Phase II, we have designed and fabricated a prototype system capable of producing 10 kg/day oxygen to carry out proof-of-concept evaluations for the full unit. We have completed the scale-up of the MOF production so that we can carry out tests with the prototype unit. We will next conduct tests with our prototype unit and based on these results we will evaluate the techno-economic viability of the new air separation technology. TDA has recently identified an improved MOF formulation that provides a significantly higher selectivity for O2 than the SNL identified MOFs and could significantly reduce the cost of oxygen produced, increasing the commercial viability of the oxygen selective air separation process. The new MOF replaces the scandium used in the SNL MOF with transition metals, which reduces the cost of the MOF by an order of magnitude. In the Phase IIA, TDA proposes to scale-up this new MOF for the oxygen selective air separation process and test it in our 10 kg/day prototype unit to complete proof-of-concept demonstrations in a multi-bed system, demonstrating high O2 purity, O2 flow, O2 recovery and reduced energy consumption. Oxygen is a strategic chemical, with a $3.8 billion market value in the U.S. It supports many industrial processes and chemical syntheses. The new technology has the potential to provide a lower cost oxygen product.
* Information listed above is at the time of submission. *