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Poly(ether ether ketone) (PEEK) hollow fiber membrane modules were scaled up from 2 in. diameter and 16 in. long to 4 in. diameter and 58 in. long (a factor of 90 increase in membrane area) for CO2 capture from flue gases using a membrane contactor process, which combines advantageous features of both absorption and membrane processes. Field tests of a 4-in.-diameter module with activated methyldiethanolamine (aMDEA) solvent demonstrated greater than 90% CO2 removal. The mass transfer coefficient in the absorption step was 1.2 (s)−1, which is over an order of magnitude greater than that of conventional column contactors. The membrane module was further scaled up from 4 in. to 8 in. diameter (a factor of 3 increase in membrane area). Single-gas permeation measurements indicated that 8-in. modules have an intrinsic CO2 permeance as high as 2150–2670 GPU. One 8-in.-diameter module was tested in membrane contactor mode for CO2 capture using a simulated flue gas. Carbon dioxide removal rate of 91.3% was achieved with a mass transfer coefficient of 1.5 (s)−1. Parametric tests indicated CO2 flux and capture rate increased with increasing feed pressure, solvent flow velocity and solvent temperature. PEEK hollow fiber membrane contactor is effective in capturing CO2 from low CO2-concentration feeds, showing its high potential for coal or natural gas flue gas CO2 capture.

SAPO-34 membranes were synthesized by several routes towards N2/CH4 separation. Membrane synthesis parameters including water content in the gel, crystallization time, support pore size, and aluminum source were investigated. High performance N2-selective membranes were obtained on 100-nm-pore alumina tubes by using Al(i-C3H7O)3 as aluminum source with a crystallization time of 6 h. These membranes separated N2 from CH4 with N2 permeance as high as 500 GPU with separation selectivity of 8 at 24 °C for a 50/50 N2/CH4 mixture. Nitrogen and CH4 adsorption isotherms were measured on SAPO-34 crystals. The N2 and CH4 heats of adsorption were 11 and 15 kJ/mol, respectively, which lead to a preferential adsorption of CH4 over N2 in the N2/CH4 mixture. Despite this, the SAPO-34 membranes were selective for N2 over CH4 in the mixture because N2 diffuses much faster than CH4 and differences in diffusivity played a more critical role than the competitive adsorption. Preliminary economic evaluation indicates that the required N2/CH4 selectivity would be 15 in order to maintain a CH4 loss below 10%. For small nitrogen-contaminated gas wells, our current SAPO-34 membranes have potential to compete with the benchmark technology cryogenic distillation for N2 rejection.

The feasibility of utilizing a super-hydrophobic polyether ether ketone (PEEK) hollow fiber membrane contactor in combination with chemical solvents to separate and capture CO 2 from simulated flue gases was investigated. Greater than 90% CO 2 capture with greater than 95% CO 2 purity has been achieved in one stage with both activated methyldiethanolamine (aMDEA) and activated K 2 CO 3 solvents. The measured volumetric mass transfer coefficient was as high as 1.7 s −1 , which is more than 20 times greater than the mass transfer coefficient of a packed column. Preliminary tests indicated that the CO 2 capture performance was not affected by flue gas contaminants, including O 2 , NO 2 , and SO 2 , with aMDEA solvent. The PEEK membrane module showed good mechanical properties and stable permeation properties at process design conditions for duration of the test (120 h). The process economics were evaluated assuming direct substitution of the conventional absorber by the membrane contactor, while using a conventional packed column in the regeneration step. Relative to the cost estimation with no CO 2 capture, the evaluation indicates a 56% increase in the levelized cost of electricity (LCOE) for the PEEK membrane contactor technology, which is 29% lower than DOE’s benchmark amine absorption technology (85% increase in LCOE).

With financial assistance from the US Department of Energy and the Illinois Clean Coal Institute, Gas Technology Institute (GTI) has been working with the University of California, Berkeley, for further development of their UCSRP-HP (University of California Sulfur Recovery Process-High Pressure) technology. The key focus of the UCSRP-HP technology is integrated multi-contaminant removal of hydrogen sulfide (H2S), carbonyl sulfide (COS), ammonia (NH3), chlorides and heavy metals present in coal-derived syngas. The process has two major components: 1) removal of various trace components with a solvent (e.g., diethylene glycol or water) using a high-pressure scrubbing unit and 2) removal of H2S as sulfur via reaction with SO2 (in the presence of a solvent mixed a small quantity of a homogeneous catalyst) at 120?C to 150?C and at any syngas pressure. During this research, data critical to developing and evaluating UCSRP-HP technology for multi-contaminant removal from syngas derived from Illinois #6 coal were obtained. In this paper, we have presented key economic evaluations of the UCSRP-HP process, including potential integrations with other technology options for CO2 and hydrogen separations, for a nominal Illinois #6-coal-based 550-MWe Integrated Coal Gasification Combined Cycle (IGCC) facility with CO2 capture and sequestration. GTI is exploring various options to demonstrate this technology in a pilot plant using actual syngas from a coal gasifier.

A novel concept of utilizing nanoporous coatings as effective nanovalves on microporous adsorbents was developed for high capacity natural gas storage at low storage pressure. The work reported here for the first time presents the concept of nanovalved adsorbents capable of sealing high pressure CH4 inside the adsorbents and storing it at low pressure. Traditional natural gas storage tanks are thick and heavy, which makes them expensive to manufacture and highly energy-consuming to carry around. Our design uses unique adsorbent pellets with nanoscale pores surrounded by a coating that functions as a valve to help manage the pressure of the gas and facilitate more efficient storage and transportation. We expect this new concept will result in a lighter, more affordable product with increased storage capacity. The nanovalved adsorbent concept demonstrated here can be potentially extended for the storage of other important gas molecules targeted for diverse relevant functional applications.

This report summarizes scientific/technical progress made for bench-scale membrane contactor technology for post-combustion CO2 capture from DOE Contract No. DE-FE-0004787. Budget Period 1 (BP1) membrane absorber, Budget Period 2 (BP2) membrane desorber and Budget Period 3 (BP3) integrated system and field testing studies have been completed successfully and met or exceeded the technical targets (≥ 90% CO2 removal and CO2 purity of 97% in one membrane stage). Significant breakthroughs are summarized below: BP1 research: The feasibility of utilizing the poly (ether ether ketone), PEEK, based hollow fiber contractor (HFC) in combination with chemical solvents to separate and capture at least 90% of the CO2 from simulated flue gases has been successfully established. Excellent progress has been made as we have achieved the BP1 goal: ≥ 1,000 membrane intrinsic CO2 permeance, ≥ 90% CO2 removal in one stage, ≤ 2 psi gas side pressure drop, and ≥ 1 (sec)-1 mass transfer coefficient. Initial test results also show that the CO2 capture performance, using activated Methyl Diethanol Amine (aMDEA) solvent, was not affected by flue gas contaminants O2 (~3%), NO2 (66 ppmv), and SO2 (145 ppmv). BP2 research: The feasibility of utilizing the PEEK HFC for CO2-loaded solvent regeneration has been successfullymore » established High CO2 stripping flux, one order of magnitude higher than CO2 absorption flux, have been achieved. Refined economic evaluation based on BP1 membrane absorber and BP2 membrane desorber laboratory test data indicate that the CO2 capture costs are 36% lower than DOE’s benchmark amine absorption technology. BP3 research: A bench-scale system utilizing a membrane absorber and desorber was integrated into a continuous CO2 capture process using contactors containing 10 to 20 ft2 of membrane area. The integrated process operation was stable through a 100-hour laboratory test, utilizing a simulated flue gas stream. Greater than 90% CO2 capture combined with 97% CO2 product purity was achieved throughout the test. Membrane contactor modules have been scaled from bench scale 2-inch diameter by 12-inch long (20 ft2 membrane surface area) modules to 4-inch diameter by 60-inch long pilot scale modules (165 ft2 membrane surface area). Pilot scale modules were tested in an integrated absorption/regeneration system for CO2 capture field tests at a coal-fired power plant (Midwest Generation’s Will County Station located in Romeoville, IL). Absorption and regeneration contactors were constructed utilizing high performance super-hydrophobic, nano-porous PEEK membranes with CO2 gas permeance of 2,000 GPU and a 1,000 GPU, respectively. Field tests using aMDEA solvent achieved greater than 90% CO2 removal in a single stage. The absorption mass transfer coefficient was 1.2 (sec)-1, exceeding the initial target of 1.0 (sec)-1. This mass transfer coefficient is over one order of magnitude greater than that of conventional gas/liquid contacting equipment. The economic evaluation based on field tests data indicates that the CO2 capture cost associated with membrane contactor technology is $54.69 (Yr 2011$)/tonne of CO2 captured when using aMDEA as a solvent. It is projected that the DOE’s 2025 cost goal of $40 (Yr 2011$)/tonne of CO2 captured can be met by decreasing membrane module cost and by utilizing advanced CO2 capture solvents. In the second stage of the field test, an advanced solvent, Hitachi’s H3-1 was utilized. The use of H3-1 solvent increased mass transfer coefficient by 17% as compared to aMDEA solvent. The high mass transfer coefficient of H3-1 solvent combined with much more favorable solvent regeneration requirements, indicate that the projected savings achievable with membrane contactor process can be further improved. H3-1 solvent will be used in the next pilot-scale development phase. The integrated absorption/regeneration process design and high performance membrane contactors developed in the current bench-scale program will be used as the base technology for future pilot-scale development.« less

Gas Technology Institute (GTI) is conducting this research program whose objective is to develop gas/liquid membranes for natural gas upgrading to assist DOE in achieving their goal of developing novel methods of upgrading low quality natural gas to meet pipeline specifications. Kvaerner Process Systems (KPS) and W. L. Gore & Associates (GORE) gas/liquid membrane contactors are based on expanded polytetrafluoroethylene (ePTFE) membranes acting as the contacting barrier between the contaminated gas stream and the absorbing liquid. These resilient membranes provide much greater surface area for transfer than other tower internals, with packing densities five to ten times greater, resulting in equipment 50-70% smaller and lower weight for the same treating service. The scope of the research program is to (1) build and install a laboratory- and a field-scale gas/liquid membrane absorber; (2) operate the units with a low quality natural gas feed stream for sufficient time to verify the simulation model of the contactors and to project membrane life in this severe service; and (3) conducted an economic evaluation, based on the data, to quantify the impact of the technology. Chevron, one of the major producers of natural gas, has offered to host the test at a gas treating plant. KPS will use their position as a recognized leader in the construction of commercial amine plants for building the unit along with GORE providing the membranes. GTI will provide operator and data collection support during lab- and field-testing to assure proper analytical procedures are used. Kvaerner and GTI will perform the final economic evaluation. GTI will provide project management and be responsible for reporting and interactions with DOE on this project. Efforts this quarter have concentrated on field site selection. ChevronTexaco has nominated their Headlee Gas Plant in Odessa, TX for a commercial-scale dehydration test. Design and cost estimation for this new site are underway. A HazOp review was conducted. Potting and module materials testing continued. Preliminary design of the bench-scale equipment continues. A status meeting was held in Morgantown, WV with the DOE Project Manager.

Les resultats experimentaux montrent qu'une concentration elevee d'hydrogene est absorbee sur les catalyseurs. L'addition de soufre et d'un element stabilisant augmente l'adsorption d'hydrogene et l'activite du sulfure de molybdene pur. Les catalyseurs de ce type ne sont pas empoisonne par les compose soufres et ne presentent pas de probleme de depots carbones