The proposed work is based on the successfully completed NSF sponsored project pertaining to membranes for carbon dioxide removal from low pressure (1 4 atm) gases. The specific objectives of this work are to fill the technological knowledge gaps needed for the successful translation of the proposed game-changing gas cleanup membrane technology to commercial development. This work will demonstrate the scale-up of the membrane, fabricate prototype membrane modules from the scale-up membrane and conduct the proof of concept (POC) on the carbon dioxide and hydrogen sulfide clean-up of low pressure gases using the membrane module.
The novel amine-containing membrane has a high removal rate for carbon dioxide and hydrogen sulfide and results in a simplified separation process, which can reduce capital costs and energy consumption. There are many potential markets for the novel membrane technology, such as hydrogen purification for fuel cell applications, and biogas purification. The mentoring and training for the graduate students participating should provide opportunities for interaction with industrial researchers and for learning how to translate fundamental research results into commercialization strategies.
Summary of Project Outcomes: We have scaled up and characterized the novel CO2-selective membrane containing new sterically hindered polyamine from a lab size of 2-inch diameter made in the batch mode to a prototype membrane size of 14 inches in width fabricated in the continuous mode (in a roll-to-roll operation) using the continuous membrane fabrication machine at OSU. We conducted work including the set-up, installation and debugging of the continuous membrane fabrication machine and carried out the study on the continuous fabrication process using this machine for scale-up of the novel membrane. The performance results of the scale-up, pilot/prototype membrane in terms of CO2 permeability (>5000 Barrers, 1 Barrer = 10-10 cm3 (STP) • cm/(cm2 • s • cm Hg)) and CO2/H2 selectivity (>300) have agreed very well with those obtained from the lab-scale. Also, the ratio of H2S to CO2 permeabilities was about 3. We also fabricated membrane modules by rolling the membrane into spiral-wound elements. Intellectual Merit: The specific objectives of this work are to fill the technological knowledge gaps needed for the successful translation of the proposed game-changing gas cleanup membrane technology to commercial development. This work is to demonstrate the scale-up of the membrane, conduct transport characterization of the scale-up membrane for the removal of carbon dioxide and hydrogen sulfide (proof of concept) from low pressure synthesis gas (autothermal reforming of gasoline), and fabricate prototype membrane elements/modules from the scale-up membrane. The proposed membrane technology is the first of the kind capable of possessing high CO2 and H2S permeabilities and selectivities vs. H2 at relatively high temperatures (>100oC) with game-changing improvements over the state-of-the-art technology. This work not only is of a great scientific interest but also may provide the game-changing membrane technology of significant technological importance. We believe that it represents a significant contribution to expanding the scientific knowledge and understanding in gas treating technology. Broader Impacts: The work has economic and environmental significances. The membrane developed provides an energy saving, environmentally friendly separation technology to purify hydrogen for fuel cell applications and to capture CO2 for restraining greenhouse gas emission. The membrane has many potential applications including: (1) the purification of synthesis gas, derived from natural gas, shale gas, petroleum, coal or biomass, to produce high-purity H2 for fuel cells and other applications, (2) CO2 capture from flue gas for its sequestration, and (3) CO2 removal from biogas, natural gas, shale gas, confined space air, and ambient air. Background: In view of the deficiencies of the state-of-the-art process, it is important to develop an effective process with both capital and energy savings. This project is aiming at research on a novel approach using a CO2-selective membrane. This novel approach combines the absorption and stripping of CO2, carried out in 2 separate steps in the commercial technology – the state-of-the-art amine scrubbing process, into a one-step membrane process as shown in Figure 1. This one-step process not only simplifies the separation process, but also eliminates the capital-intensive equipment of the commercial technology. This one-step process also overcomes the thermodynamic solubility limit of aqueous amine solution. Findings: We have scaled up and characterized the novel CO2-selective membrane containing new sterically hindered polyamine from a lab size of 2" diameter made in the batch mode to a prototype membrane size of 14" in width fabricated in the continuous mode (in a roll-to-roll operation) using the continuous membrane fabrication machine at the Ohio State University. On the scale-up of the membrane to the prototype, we successfully scaled up the membrane to a width of 14 inches and a length of about 260 ft. using this machine shown in Figures 2 and 3. This has demonstrated the proof of concept (POC) that the membrane can be scaled up to the prototype size. The transport characterization was carried out at the typical fuel cell pressure of 2 atm at about 106oC as the purification of hydrogen from synthesis gas generated from autothermal reforming of hydrocarbon is the first application that OSU and its collaborator, DJWT, would like to pursue. This temperature is within the range of about 100 – 120oC, which is encountered for most applications, e.g., H2 purification for fuel cells, CO2 removal from biogas, and carbon dioxide capture from flue gas. The performance results of the scale-up, pilot/prototype membrane in terms of CO2 permeability (>5000 Barrers) and CO2/H2 selectivity (>300) have agreed very well with those obtained from the lab-scale. Also, the ratio of H2S to CO2 permeabilities was about 3. We have used the scale-up, 14" wide membrane to make prototype elements/modules of 4" in diameter by 14" in length. Figure 4 shows 2 such modules. Each module has about 40 sq. ft of membrane. The modules will be used for pilot demonstration of CO2 and H2S removal for hydrogen purification for fuel cells.
