This Small Business Innovation Research Phase I project proposes to develop a highly permeable inorganic membrane for olefin/paraffin separation. Zeolite membranes have a number of advantages over polymer membranes and other inorganic membranes, including greater chemical and mechanical stability, higher selectivity and permeance, and longer operation life. The project aims to develop, demonstrate and commercialize a robust, cost-effective, high permeability and selectivity, excellent hydrothermal and chemical stable olefin/paraffin membrane separation technology. The molecular sieving and facilitated transport properties of the novel modified zeolite membrane will be used more efficiently to separate olefin/paraffin mixtures from the down-streams of steam cracker. This technology is an attractive alternative to replace current high energy intensive cryo-distillation process.
The broad impact/commercial potential of this project will be realized by enabling a substantial saving in energy expenditure in olefin/paraffin separations in the petrochemical industry with significant capital cost savings compared to current energy intensive separation processes. With yearly production in the US exceeding 25 million tons for ethylene and 16 million tons for propylene, respectively, ethylene and propylene are the most commonly produced light olefins. It is estimated that over 120 trillion Btu of energy per year is consumed by the current distillation processes for the separation of ethylene/ethane and propylene/propane mixtures in the United States. Even small improvements in these separations could results in significant energy and cost savings. On the other hand, increasing worldwide concerns about the environment protection, and energy security has been demanding the production of commodity chemicals such as ethylene and propylene in an efficient and economical way. Membrane separation technology has been considered as the critical technology that must be developed in order to realize this goal. Therefore, there is strong commercial market pull for developing a cost-effective olefin/paraffin separation technology as a significantly more energy efficient alternative to current practice.
With yearly production in the US exceeding 25 million tons for ethylene and 16 million tons for propylene, respectively, ethylene and propylene are the most commonly produced light olefins. It is estimated that over 120 trillion Btu of energy per year is consumed by the current distillation processes for the separation of ethylene/ethane and propylene/propane mixtures in the United States. Even small improvements in these separations could results in significant energy and cost savings. On the other hand, increasing worldwide concerns about the environment protection and energy security has been demanding the production of commodity chemicals such as ethylene and propylene in an efficient and economical way as the major objective of future development. Membrane separation technology has been considered as the critical technology that must be developed in order to realize this goal. Membrane separation for olefin/paraffin mixtures offers an appealing energy-efficient alternative to the cryo-distillation process. Membranes could combine high selectivity with high permeability. It has been estimated that the membrane application in the C2 and C3 separation alone could save at least 8% (1.5 GJ/ton ethylene) process energy. However, membrane separation is still believed to be a challenge in separating olefin/paraffin mixtures. Although substantial effort has been dedicated in developing a high flux, high selectivity olefin separation membrane, the state-of-the-art membrane cannot meet the stringent requirements of real life olefin/paraffin separation. Therefore, there is strong commercial market pull for developing a cost-effective olefin/paraffin separation technology. The project aims to develop, demonstrate and commercialize a robust, cost-effective, high permeability and selectivity, excellent hydrothermal and chemical stable olefin/paraffin membrane separation technology. In this program, a novel composite membrane has been successfully developed and evaluated. The membrane has shown very high permeance (1.6×10-8 mol/m2.s.Pa), very high propylene/propane selectivity (> 300) and superior stability, far better than those reported in the literature. Hence, the feasibility of the proposed membrane for olefin separation has been successfully proven.
