Mixed-gas permeation of syngas components in poly(dimethylsiloxane) and poly(1-trimethylsilyl-1-propyne) at elevated temperatures

Merkel, Timothy C.; Gupta, Raghubir; Turk, Brian; Freeman, Benny D.

doi:10.1016/s0376-7388(01)00452-5

Cited by 211 publications

(92 citation statements)

References 15 publications

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“…Because the transport of common gases (N 2 , O 2 , H 2 ) in PDMS is well understood, 2-23 this polymer will serve as a valuable baseline material to compare with novel candidate polymers to be tested later. Figure 2-15 presents the permeability coefficients of syngas components at room temperature in PDMS as a function of the gas critical temperature, T C (Merkel et al, 2001). Frequently, in a solubilityselective polymer such as PDMS, there is a strong correlation between the logarithm of gas permeability and T C Van Amerongen, 1964).…”

Section: Characterization Of a Baseline Solubility Selective Polymer:mentioning

confidence: 99%

Novel Technologies for Gaseous Contaminants Control

Turk¹,

Merkel²,

López-Ortíz³

et al. 2001

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The overall objective of this project is to develop technologies for cleaning/conditioning the syngas from an integrated gasification combined cycle (IGCC) system to meet the tolerance limits for contaminants such as H 2 S, COS, NH 3 , HCN, HCl, and alkali for fuel cell and chemical production applications. RTI's approach is to develop a modular system that (1) removes reduced sulfur species to sub-ppm levels using a hybrid process consisting of a polymer membrane and a regenerable ZnO-coated monolith or a mixed metal oxide sorbent; (2) removes hydrogen chloride vapors to sub-ppm levels using an inexpensive, high-surface area material; and (3) removes NH 3 with acidic adsorbents.RTI is working with MEDAL, Inc., and North Carolina State University (NCSU) to develop polymer membrane technology for bulk removal of H 2 S from syngas. These membranes are being engineered to remove the acid gas components (H 2 S, CO 2 , NH 3 , and H 2 O) from syngas by focusing on the "solubility selectivity" of the novel polymer compositions. The desirable components of the syngas (H 2 and CO) are maintained at high-pressure conditions as a non-permeate stream while the impurities are transported across the membrane to the low pressure side. RTI tested commercially available and novel materials from MEDAL using a high-temperature, high-pressure (HTHP) permeation apparatus. H 2 S/H 2 selectivities >30 were achieved, although there was a strong negative dependence with temperature. MEDAL believes that all the polymer compositions tested so far can be prepared as hollow fiber membrane modules using the existing manufacturing technology.For fuel cell and chemical applications, additional sulfur removal (beyond that achievable with the membranes) is required. To overcome limitations of conventional ZnO pellets, RTI is testing a monolith with a thin coating of high surface area zinc-oxide based materials. Alternatively, a regenerable sorbent developed by DOE/NETL (RVS-1) is being evaluated for this application. A multi-cycle test of 2-in. (5-cm) diameter monolith samples demonstrated that <0.5 ppm sulfur can be achieved.Removal of HCl vapors is being accomplished by low-cost materials that combine the known effectiveness of sodium carbonate as an active matrix used with enhanced surface area supports for greater reactivity and capacity at the required operating temperatures. RTI is working with SRI International on this task. Sorbents prepared using diatomaceous earth and sepiolite, impregnated with sodium carbonate achieved steady-state HCl level <100 ppb (target is 10 ppb). Research is continuing to optimize the impregnation and calcination procedures to provide an optimum pore size distribution and other properties.RTI and SRI International have established the feasibility of a process to selectively chemisorb NH 3 from syngas on high surface area molecular sieve adsorbents at high temperatures by conducting a series of temperature-programmed reactions at 225C (437F). Significant levels of NH 3 were adsorbed on highly acidic ads...

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Section: Characterization Of a Baseline Solubility Selective Polymer:mentioning

confidence: 99%

Novel Technologies for Gaseous Contaminants Control

Turk¹,

Merkel²,

López-Ortíz³

et al. 2001

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“…The test gas pressure was 30 psi and temperatures were varied from 20˚C to 70˚C. Dry mixed gas experiments have been carried out using a method previously described in the literature [1][2][3][4][5][6][7][8]. In the mixed gas procedure, permeation is determined analytically by gas chromatography.…”

Section: Appendicesmentioning

confidence: 99%

Water-Gas-Shift Membrane Reactor for High-Pressure Hydrogen Production. A comprehensive project report (FY2010 - FY2012)

Klaehn¹,

Peterson²,

Orme³

et al. 2013

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Idaho National Laboratory (INL), GE Global Research (GEGR), and Western Research Institute (WRI) have successfully produced hydrogenselective membranes for water-gas-shift (WGS) modules that enable high-pressure hydrogen product streams. Several high performance (HP) polymer membranes were investigated for their gas separation performance under simulated (mixed gas) and actual syngas conditions. To enable optimal module performance, membranes with high hydrogen (H 2 ) selectivity, permeance, and stability under WGS conditions are required. The team determined that the VTEC PI 80-051 and VTEC PI 1388 (polyimide from Richard Blaine International, Inc.) are prime candidates for the H 2 gas separations at operating temperatures (~200°C). VTEC PI 80-051 was thoroughly analyzed for its H 2 separations under syngas processing conditions using more-complex membrane configurations, such as tube modules and hollow fibers. These membrane formats have demonstrated that the selected VTEC membrane is capable of providing highly selective H 2 /CO 2 separation (α = 7-9) and H 2 /CO separation (α = 40-80) in humidified syngas streams. In addition, the VTEC polymer membranes are resilient within the syngas environment (WRI coal gasification) at 200°C for over 1000 hours. The information within this report conveys current developments of VTEC PI 80-051 as an effective H 2 gas separations membrane for high-temperature syngas streams.iii ACKNOWLEDGEMENTS

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“…After stirring for about 2 h at room temperature, the resulting homogeneous mixture was crystallized under static hydrothermal conditions at 373 K in a Teflon lined autoclave for 96 h. The molar composition of the initial gel mixture was 1.0:0.58:0.50:60 TEOS/CTAB/NaOH/H2O. The solid product was obtained by filtration, washed with deionized water, dried in vacuum oven at 353 K and calcined in air at 833 K for 10 hwith 1 K/min of heating rate to remove the CTAB.This method results the unmodified version of MCM-48 nanoparticles [25]. As shown in Figure 1, surface modification of MCM-48 particles was performed this way: Before removing CTAB, sylilation of MCM-48 with dimethylsilane was achived by immersionof MCM-48 nanoparticles into liquid dimethyldichlorosilane (DMDCS,Merck) for 72 h. Afterwards CTAB was removed by means of soxhlet extraction apparatus using 300 ml of methanol and 30 ml of aqueous HCL (10% vol).…”

Section: Experimental Synthesis and Functionalization Of Mcm-48 Nanopmentioning

confidence: 99%

Preparation, Characterization and Gas Permeation of Polyimide Mixed Matrix Membranes

Jomekian¹,

Pakizeh²,

Mansoori³

et al. 2011

J Membra Sci Technol

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Mesoporous MCM-48 silica was synthesized by templating method and the structure of particles was characterized by XRD, TEM, FTIR, TGA and N 2 adsorption techniques. The surface modification of particles in order to introducing into PSF matrix was performed by DMDCS sylilation agent. PDMS surface coating of membranes was performed to repair possible surface defects and enhance selectivities of membranes. For all gases tested (N 2 , CO 2 , CH 4 andO 2 ), the permeability increased in proportion to the weight percent of MCM-48 present in the film and calculating CO 2 /CH 4 and O 2 /N 2 selectivitiesof PDMS coated membranes showed enhancement in ideal and actual selectivities both.

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Mixed-gas permeation of syngas components in poly(dimethylsiloxane) and poly(1-trimethylsilyl-1-propyne) at elevated temperatures

Cited by 211 publications

References 15 publications

Novel Technologies for Gaseous Contaminants Control

Novel Technologies for Gaseous Contaminants Control

Water-Gas-Shift Membrane Reactor for High-Pressure Hydrogen Production. A comprehensive project report (FY2010 - FY2012)

Preparation, Characterization and Gas Permeation of Polyimide Mixed Matrix Membranes

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