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Chemical & Process Engineering Novel Material for the Separation of Mixtures of Carbon Dioxide and Nitrogen Mohamed A. M. Elsayed Supervisors : Prof. P. J. Hall & Dr. M. J. Heslop
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Chemical & Process Engineering Introduction POROUS CARBON Naturally occurring carbonaceous material Physical or chemical activation Polymer precursor Fewer minerals impurities & controlled pore structure Pyrolysis Sol-gel process
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Chemical & Process Engineering Sol-Gel Technologies and their Products
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Chemical & Process Engineering OBJECTIVES First stage 1- further developing and modifying resorcinol formaldehyde sol-gel synthesis procedure to make high surface area carbon xerogels with a controlled pore structure. 2- Studying factor affecting on the texture properties and characteristics of the produced material. 4 - Using different techniques for characterization and analysis (BET, TPD, FTIR, TGA, XRD, SEM, etc…) Second stage 3- Further chemical impregnation to produce nitrogen-enriched carbon xerogels 1-Investigation of full binary isotherms for CO 2 and N 2 from composition and flow-rate transient times in chromatographic columns 2- Studying factor affecting on the selectivity of CO 2 and N 2 2- Studying factor affecting on the selectivity of CO 2 and N 2.
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Chemical & Process Engineering Experimental Resin synthesisRF-xerogelsCarbon xerogels Active carbon xerogels Carbon characterization N 2 adsorption-desorption techniques Drying Pyrolysis Co 2 gasification
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Chemical & Process Engineering Result and discussion Resin analysis Ultimate and Proximate analyses using Elemental and Thermogravimetric analyzer respectively Ultimate and Proximate analyses using Elemental and Thermogravimetric analyzer respectively Nomenclature Ultimate (wt% dry-ash-free basis )Proximate (wt% ) CHNOMoistureVolatileFixed carbon Ash RF-MEA RF-DEA RF-MDEA RF-NH 4 HCO 3 RF-K 2 CO 3 RF-Na 2 CO 3 62.98 64.73 64.67 64.47 63.04 72.90 5.45 5.24 5.63 4.86 5.12 6.00 0.42 0.35 0.31 0.32 0.00 31.15 29.68 29.40 30.37 31.84 21.10 4.664 3.397 2.479 2.447 2.292 3.530 61.796 52.308 63.733 57.133 50.438 49.675 33.293 43.060 34.007 39.705 45.173 46.155 000000000000 R/F= 0.5 and R/C = 300 by mole PH=6 and R/W = 0.25 g/cm 3
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Chemical & Process Engineering Thermogravimetric analysis of a dried resorcinol- formaldehyde gel
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Chemical & Process Engineering FTIR spectra for the synthesis resins with different type of catalytic species -OH -CH 2 - aromatic amides & amines lactamenitrile
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Chemical & Process Engineering Carbon xerogels characterization by BET. Effect of changing catalyst species and the catalyst ratios. (a) R/C= 300 by mole with different type of catalytic species (b) MEA was used as a catalyst with different R/C ratio
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Chemical & Process Engineering Characteristic pore properties of RF carbon xerogels Nomenclature R/CS BET a (m 2 /g) V t b ( cm 3 /g) V mic c (cm 3 /g) V mes d (cm 3 /g) D p e (nm) Volume fraction % % micro% meso RF-Na 2 CO 3 RF-K 2 CO3 RF-NH 4 HCO3 RF-MEA RF-DEA RF-MDEA RF-MEA 300 50 100 200 300 672 436 496 488 444 485 652 600 546 484 1.258 0.337 0.232 0.238 0.208 0.229 1.127 0.563 0.446 0.229 0.304 0.200 0.229 0.226 0.205 0.224 0.295 0.251 0.224 0.954 0.137 0.003 0.012 0.003 0.005 0.832 0.268 0.195 0.005 7.476 3.089 1.870 1.952 1.876 1.893 6.914 3.452 3.265 1.899 24.2 59.3 98.7 94.9 98.5 97.8 26.2 52.4 56.3 97.8 75.8 40.7 1.30 5.10 1.50 2.20 73.8 47.6 43.7 2.20 a Specific surface area determined from the BET equation. b Total pore volume. c Micropore volume determine by Horvath-Kawazoe equation. d Mesopore volume. e Mean pore diameter.
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Chemical & Process Engineering Pore size distribution of the RF carbon xerogels (a) R/C= 300 by mole with different type of catalytic species (b) MEA was used as a catalyst with different R/C ratio R/F=0.5 by mole and R/W=0.25 g/cm 3
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Chemical & Process Engineering Effect of R/W on porous structure of carbon xerogels. R/F=0.5, R/C= 100, PH=6 and MEA as a catalyst (a) BET surface area and surface area of micropores (b) Total and micropores volume
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Chemical & Process Engineering Effect of pH on the on porous structure of carbon xerogels R/F=0.5 R/C=100 by mole, R/W=0.25 g/cm 3 and MEA as a catalyst. (a) BET surface area and surface area of micropores (b) Total and micropores volume
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Chemical & Process Engineering Effect of degree of Burn-off. R/F=0.5 R/C=100 by mole, R/W=0.25 g/cm 3 and MEA as a catalyst. Variation of the BET surface area, pore volume and micropore volume with the burn off level of carbon xerogels gasified in CO 2 at 900°C
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Chemical & Process Engineering Structural characterization with scanning electron microscopyanalysis. Structural characterization with scanning electron microscopy analysis. SEM images of cross-section of (a) and (b) samples synthesized under condition pH=6, R/C=300 and R/W=0.25 before and after pyrolysis respectively (c) and (d) carbon xerogels synthesized under condition pH=6, R/C=100 and R/W=0.25 with 0 % and 37% burn-off respectively. (All the samples were prepared using MEA as catalyst) (a) (b) ( c )(d)
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Chemical & Process Engineering Conclusion Microporous carbons with high porosity and surface area can be prepared from Resorcinol-Formaldehyde resins The samples evolve from micro-mesoporous solid (RF-Na 2 CO 3 : combination of types I and IV isotherms) with 24.2% micropore to an exclusively microporous material (RF-NH 4 HCO 3 : type I isotherm) with 98.7% micropore. It is possible to tailor the morphology of these materials by varying the initial pH of the precursor’s solution in a narrow range FTIR study shows that samples prepared by MEA, DEA, MDEA and NH 4 HCO 3 contain nitrogenated functional groups High surface area (> 2890 m 2 /g) can be obtained at high burn off levels (>75%). These porous materials with these functional groups are being expected as suitable candidates for acidic gas capture like CO 2 and SO 2, which will be studied in the next stage.
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Chemical & Process Engineering Thank-You&Questions
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