Metallic membranes for N2 separation & postcombustion CO2 capture improvement

Transcription

1 Engineering Conferences International ECI Digital Archives CO2 Summit II: Technologies and Opportunities Proceedings Spring Metallic membranes for N2 separation & postcombustion CO2 capture improvement Simona Liguori Stanford University, Kyoungjin Lee Stanford University Jennifer Wilcox Stanford University Follow this and additional works at: Part of the Environmental Engineering Commons Recommended Citation Simona Liguori, Kyoungjin Lee, and Jennifer Wilcox, "Metallic membranes for N2 separation & post-combustion CO2 capture improvement" in "CO2 Summit II: Technologies and Opportunities", Holly Krutka, Tri-State Generation & Transmission Association Inc. Frank Zhu, UOP/Honeywell Eds, ECI Symposium Series, (2016). This Abstract and Presentation is brought to you for free and open access by the Proceedings at ECI Digital Archives. It has been accepted for inclusion in CO2 Summit II: Technologies and Opportunities by an authorized administrator of ECI Digital Archives. For more information, please contact

2 METALLIC MEMBRANES FOR N 2 SEPARATION & POST- COMBUSTION CO 2 CAPTURE IMPROVEMENT Simona LIGUORI, Kyoungjin LEE, Jennifer WILCOX CEC Lab., Stanford University CO 2 Summit II: Technologies and Opportuni9es April 10-14, 2016 Santa Ana Pueblo, New Mexico, USA

3 Outline I. IntroducWon II. III. IV. MoWvaWons Gas separawon by membrane i. N 2 separawon Conclusion and Future Works

4 CO 2 Emissions IntroducWon [1] [2] 5.0 CO 2 emissions (PgC) Developed countries 2.5 Developing countries Year CO 2 emissions are growing Atmospheric CO 2 concentrawon is correlated with global average temp. Fossil fuel combuswon for electricity generawon and transportawon is the major contribuwon to the current CO 2 emissions [1] Peters, Glen P, et. al.. "Rapid Growth in Co2 Emissions a]er the Global Financial Crisis." Nature Climate Change 2, no. 1 (2012): 2-4. [2] Ref U.S. Greenhouse Gas Inventory Report, Chapter 2

5 Membrane use MoWvaWon Hydrogen powered Fuel Cell vehicles only emit water. CO 2 + H 2 (CO, H 2 O, CH 4, traces) H 2 uwlizawon (PEM fuel cell) CO 2 + N 2 (O 2, H 2 O, traces) Wilcox et al., Journal of Physical Chemistry, 2014, 118,

6 Inorganic Metallic Membranes Niobium, Vanadium, Tantalum Gas SeparaWon Palladium and its alloy N 2 Membrane AdsorpWon CatalyWc DissociaWon N 2 N N N N Bulk Diffusion N N 2 Solu9on/diffusion mechanism 1. adsorpwon 2. dissociawon 3. the chemisorbed molecule dissociates into atomic form H or N 4. diffusion 5. recombinawon 6. desorpwon

7 PermeaWon Mechanism Permea9ng Flux through dense membranes is governed by: Permeability of the membrane, Pe Thickness of the membrane, δ Difference in parwal pressure across the membranes, (p n i,retentate pn i,permeate ) Where i = N 2 or H 2 J i = Pe δ (p n i retentate LimiWng step determined by exponent: n = 0.5, bulk permeawon limited diffusion n = 1.0, surface reacwon limited diffusion n p i permeate ) Gas SeparaWon (Ideal selectivity) α i/he, CO2 = Permeance i Permeance He, CO2

8 Set- up for N2 PermeaWon Tests N2 - SeparaWon Vent Retentate Feed or Sweep gas (Ar, N2, He, CO2) Membrane module in the furnace Permeate Mass Spectrometer Sweep gas Feed Back pressure Metallic Foil Membranes: - Niobium - Vanadium - Tantalum High temperature Furnace Permea9on Test Opera9ng Condi9ons: - Temperature: 400 C - Permeate pressure: 1 bar - Sweep gas: Ar (50 ml/min) - Retentate pressure: 3 6 bar Gasket Diffuser Gasket Membrane PSS Support Inside the Membrane Module Gases Used: - N2 - CO2 - He CO2 Summit II: Technologies and Opportuni9es, Apr 10 14, 2016, Santa Ana Pueblo, New Mexico

9 Nb Foil (40 µm) - N 2 permeawon tests 1.6E'05% J i = Pe δ (p n n i retentate p i permeate ) N 2 #Permea3ng#Flux#(mol/s!m 2 )# 1.4E'05% 1.2E'05% 1.0E'05% 8.0E'06% 6.0E'06% 4.0E'06% 2.0E'06% 0.0E+00% R²#=# # R²#=# # R²#=# # R²#=# # R²#=# # J permeating(co2,he) = 0 n=0.5# n=0.6# n=0.7# n=0.8# n=0.9# n=1# R²#=#0.9807# 0% 1% 2% 3% 4% 5% 6% p n N2@Retentate#@#p n N2@Permeate## N 2 - SeparaWon Similar to a Pd- based membrane for H 2 separawon, N 2 molecules preferenwally permeate through metallic membrane by the soluwon- diffusion mechanism

10 V Foil (40 µm) - N 2 permeawon tests N 2 - SeparaWon 1.2E'05% 1.0E'05% R²#=# # R²#=# # R²#=# # R²#=# # R²#=# # R²#=# # N 2 #Permea6ng#Flux#(mol/s!m 2 )# 8.0E'06% 6.0E'06% 4.0E'06% 2.0E'06% J permeating(co2,he) = 0 n=0.5# n=0.6# n=0.7# n=0.8# n=0.9# n=1# 0.0E+00% 0% 1% 2% 3% 4% 5% 6% p n N2CRetentate#C#p n N2CPermeate##

11 Ta Foil (40 µm) - N 2 permeawon tests N 2 - SeparaWon 1.6E'05% 1.4E'05% R²#=# # R²#=# # R²#=# # R²#=# # R²#=# # R²#=# # N 2 #Permea5ng#Flux#(mol/s!m 2 )# 1.2E'05% 1.0E'05% 8.0E'06% 6.0E'06% 4.0E'06% 2.0E'06% J permeating(co2,he) = 0 n=0.5# n=0.6# n=0.7# n=0.8# n=0.9# n=1# 0.0E+00% 0% 1% 2% 3% 4% 5% 6% p n N2BRetentate #B#pn N2BPermeate ##

12 High N 2 SelecWvity, Very Low Flux N 2 - SeparaWon 400 C N 2 Permea9ng Flow rate [L/m 2 /day] Δp [bar] Nb Ta V Metallic membranes (V, Nb, Ta) are enwrely selecwve for N 2 over He and CO 2 (α = ) Fluxes are low Metallic thin films, an order of magnitude thinner than foils, may lead to significantly higher fluxes

13 Surface CharacterizaWon by SEM and EDX Nb Membrane before test 5 µm O 10 µm 20 µm 5 µm Nb EDX of Metal Oxida9on Ta V 20 µm Membrane aper test V O V N2 - SeparaWon V 5 µm Ta O Ta CO2 Summit II: Technologies and Opportuni9es, Apr 10 14, 2016, Santa Ana Pueblo, New Mexico

14 Thin V membrane Work in Progress N2 - SeparaWon Vanadium target: 99.95% purity q Spuwering condiwons Base pressure: 1E- 6 Torr Ar pressure and mass flow: 5E- 3 Torr, 30 mlpm DC power: 75W q q Ceramic support furnished by OSU 600 nm of V on the ceramic support (2 membranes) Permea9on measurement V#1 (600 nm) V#2 (600 nm) Temperature [ C] RT, 400 RT, 100, 200, 300, 400 p [bar] 3, 4, 5 3, 4, 5 CO 132 Summit II: Technologies and Opportuni9es, Apr 10 14, 2016, Santa Ana Pueblo, New Mexico

15 Thin V#1 membrane Main Results N2 - SeparaWon As deposited Mirror- like finish Membrane cracked a]er 400 C, Ar exposure 2 µm 500 nm 500 nm CO2 Summit II: Technologies and Opportuni9es, Apr 10 14, 2016, Santa Ana Pueblo, New Mexico

16 Thin V#2 membrane Main Results N 2 - SeparaWon As deposited Mirror- like finish V#1 - A]er 400 C Under gasket V#2 - A]er slow heat up to 400 C Same color changes regardless Hea9ng profile of exposure Wme (surface oxide) Ramp rate of 2 C/min for all temperature changes Direct heat up: RT to 400 C (6h dwell, broken) à RT Slow heat up: RT à 100 C (12h dwell) à 200 C (18h dwell) à 300 C (19h dwell) à 400 C (10h dwell) à RT (Not broken) Permea9on measurement à No significant selecwvity observed for N 2 /Ar (Knudsen rawo) No selecwvity found probably due to the dominant Knudsen flux

17 Gas SeparaWon: Metallic Membranes for N 2 SeparaWon q Metallic Membrane for N 2 separawon has been inveswgated V, Nb, Ta, Fe show infinite ideal selecwvity à only N 2 can permeate through the membranes N 2 permeawon flux through the membrane is extremely low and affected by oxidawon of the surface Membrane performance are improved by increasing pressure, temperature q q Prepare defect- free inorganic membrane able to work for long periods Fabricate composite alloy membranes for enhancing N 2 permeawon flux and reducing oxidawon effect.

18 Thank you for your attention!