Return to DOE Report Table of Contents

Return to SiC-Based Hydrogen Selective Membranes for Water-Gas-Shift Reaction Table of Contents

SiC-Based Hydrogen Selective Membranes for Water-Gas-Shift Reaction:
Final Technical Report from September 16, 1999 to December 31, 2003

Paul K. T. Liu

Media and Process Technology Inc.

In the pdf format this document has 72 pages and is 4.16MB

Table of Contents

1 EXECUTIVE SUMMARY 1
2 INTRODUCTION 3
  2.1 Project Objectives 3
2.2 Macro- and Meso-Porous SiC Membranes as Substrates for SiC-H2 Selective Membranes 4
2.3 Porous SiC Membranes via Prepyrolysis of Pre-Ceramic Polymers 4
2.4 H2 Selective SiC Membranes via Chemical Vapor Deposition/Infiltration (CVD/I) 5
2.5 Microporous SiC Membranes via Sol-Gel Approach 5
2.6 Product Development and Process Simulation for WGS 6

3

 EXPERIMENTAL PROCEDURE 6
  3.1 Macroporous SiC Membranes as Substrates for SiC-H2 Selective Membranes 6
3.2 H2 Selective SiC Membranes via Chemical Vapor Deposition/Infiltration (CVD/I) 6
3.3 H2 Selective SiC Membranes via Pyrolysis of Pre-ceramic Polymers 7
3.4 Microporous Membranes via Sol Gel Approach 7
3.5 Thermal and Hydrothermal Stability Test 8

4

 RESULTS AND DISCUSSION 9
  4.1 SiC Macro- and Meso-porous Membranes as Substrates 9
4.2 H2 Selective SiC Membranes via Chemical Vapor Deposition/Infiltration (CVD/I) 9
4.3 H2 Selective SiC Membranes via Pyrolysis of Pre -ceramic Polymers 11
4.4 Microporous Membrane via Sol-Gel Approach 12
4.5 Product Development and Process Simulation for WGS 15

5

 CONCLUSION 16
BIBLIOGRAPHY 61
LIST OF ACRONYMS AND ABBREVIATIONS 63
Publications as a result of current research under this project 64
 
LIST OF TABLES AND FIGURES  
Table 1 Helium and Nitrogen Permeances of Mesoporous SiC Membranes Prepared via Calcination of Polycarbosilane 19
Table 2 Permeance of SiC membranes after CVD/I at 750ºC and after calcination at 1,000ºC 20
Table 3 Permeance vs. temperature for SiC H2-selective membranes prepared with CVD/I technique at 700ºC 21
     
Figure 1 The cumulative particle and pore sizes distribution of substrate made from 1º (P1) average particle size powder 22
Figure 2 The permeability and separation factor of macroporous substrate (P1) 22
Figure 3 SEM photomicrograph of top surface of SiC macroporous substrate (P1) 23
Figure 4 Pore size distribution (based on BET measurement) of SiC film prepared from calcination fo polycarbosilane 23
Figure 5 XRD pattern of SiC substrate prepared from calcination of polycarbosilane 24
Figure 6 SEM photomicrograph (of top surface) of SiC microporous substrate prepared from calcination of polycarbosilane 24
Figure 7 XRD pattern ($-SiC) of unsupported SiC thin film prepared with sol-gel technique 25
Figure 8 Pore size distribution (based upon N2 adsorption) of SiC thin film prepared via sol-gel technique 25
Figure 9 Surface topograph of microporous SiC membrane prepared via sol-gel technique 26
Figure 10 Gas permeance (single component) and separation factor vs. transmembrane pressure drop of microporous SiC membrane supported on SiC macroporous substrate 27
Figure 11 XRD pattern of SiC powder prepared from pre-ceramic polymer (AHPCS) calcined at 1,000ºC to 1,600ºC 28
Figure 12 Calculated crystal size of the SiC powder prepared from pre-ceramic polymer (AHPCS) calcined at 1,000 to 1,600ºC 29
Figure 13 Effect of the number of coating on the permeance and separation factor (at room temperature) of SiC H2 selective membranes prepared from pre-ceramic polymer (AHPCS) coated on SiC macroporous substrate 30
Figure 14 Pore size distribution (microporous range) of SiC powder prepared via pyrolysis (1st, 2nd, and 3rd) of pre-ceramic powder 31-32
Figure 15 Pore size distribution (meso- and micro-porous range) of SiC powder prepared from pyrolysis of pre-ceramic polymer (AHPCS) 33
Figure 16 permeance of N2 and He as a function of temperature obtained from SiC membrane prepared with pre-ceramic polymer (AHPCS) coated on SiC macroporous substrate 34
Figure 17 Separation factor (He/N2) as a function of temperature obtained from SiC H2 selective membrane prepared with a pre-ceramic polymer (AHPCS) coated on SiC porous substrate 35
Figure 18 XRD analysis of unsupported SiC films prepared via CVD/I at 750ºC and calcined at 1,000 (bottom), 1,200 (middle), and 1,400ºC (top) 36
Figure 19a SEM photomicrograph of M&P's alumina microporous substrate (ca. 100D ) with SiC thin film deposition via CVD/I 37
Figure 19b Higher magnification of Figure 19a 37
Figure 20 SEM photomicrograph of the SiC membrane after oxidation at 400ºC in air for two hours 38
Figure 21 Permeance and selectivity vs. temperature for one of the SiC membranes (TPS-006B) 39
Figure 22 Permeance of SiC membrane at 450ºC and 30% steam (membrane after post-treated to remove excess carbon) 40
Figure 23a XRD pattern of SiC powder (prepared from Sol6) before the hydrothermal stability test at 350ºC and 50% steam (ambient pressure base) 41
Figure 23b XRD pattern of SiC powder (prepared from Sol6) after the hydrothermal stability test at 350ºC and 50% steam (ambient pressure) 41
Figure 24 Pore size distribution of SiC powder (prepared from Sol6) before and after hydrothermal stability test at 350ºC and 50% steam (ambient pressure) 41
Figure 25a Hydrothermal stability test of silicon carbon membrane (TPS-021) at 750ºC and 50% steam (atmospheric pressure) 42
Figure 25b Helium and nitrogen permeance of SiO2 membrane stability test at 600ºC and 20% steam (for comparison) 42
Figure 26 Effect of thermal cycling on SiC membrane (TPS-006B) supported in Al2O3 membrane: assessment of thermal mismatch between SiC and Al2O3 43
Figure 27 The TEM picture of the organo-silica sol type IPAST with particle size 8-11 nm, provided by Nissan Chemical Industries, Ltd. 44
Figure 28 The XRD pattern of a SiC powder treated with HF, air, and steam 45
Figure 29 The pore size distribution of the SiC powders after various treatment 46
Figure 30 The dV/dlogD of the SiC substrate utilized in the preparation of the sol-gel membrane 47
Figure 31 The argon permeance of the membrane as a function of the pressure gradient and the number of coatings 48
Figure 32 The separation factor of the membrane as a function of the pressure gradient and the number of coatings 49
Figure 33 The XRD patterns of the SiC membrane and the unsupported film (powder) prepared by the same techniques 50
Figure 34 Argon permeance of the SiC membrane in the presence of steam 51
Figure 35 A SEM picture of the cross section of the SiC membrane prepared by sol-gel technique 52
Figure 36 The XPS spectrum of the SiC powder sample 53
Figure 37 Performance of M&P Hydrogen Selective Membrane (U-130) and its Storage Stability (presented in terms of H2 Permeance) 54
Figure 38 Performance of M&P Hydrogen Selective Membrane and its Long Term Storage Stability (U-130): in terms of Nitrogen Permeance 55
Figure 39 Hydrothermal Stability Test of M&P Hydrogen Selective Membrane (200±5C with 3±-0.5bar steam) 56
Figure 40 Hydrogen purity plotted as a function of hydrogen recovery for a full-scale M&P hydrogen selective membrane at 150°C and 100 psig 57
Figure 41 CO Conversion in Packed bed vs. Membrane Reactor 58
Figure 42 CO Conversion through WGS: Effect of Steam/CO Ratio 59
Figure 43 Effect of Steam/CO ratio for Hydrogen Recovery in Membrane reactor (same condition as above) 60
Figure 44 CO Concentration in H2 Recovered from Membrane Reactor (same condition as above) 60