1

Course on Carbon dioxide to Chemicals and Fuels

PRESENTATION - SIX27TH February 2014

On Line Course of NCCR(Total Number of Projections for this Lecture is 32)

FOCUS

This Lecture mainly deals with reforming of carbon dioxide with

methane for synthesis gas

COVERAGE

THERMODYNAMICSTEMPERATURE RANGE

CATALYST SYSTEMSROLE OF THE COMPONENTS

OTHER RELEVANT REACTIONSREACTORS

Reproduced from Hongyan Ma presentation

Halmann, Martin M. (1993). "Carbon Dioxide Reforming". Chemical fixation of carbon dioxide: methods for recycling CO2 into useful products. CRC Press. ISBN 978-0-8493-4428-2

Carbon dioxide reforming (dry reforming) is for producing synthesis gas by the reaction of CO2 with hydrocarbons especially methane. Synthesis gas is conventionally produced via the steam reforming of naphtha. This has relevance to the concern on the greenhouse gases to global warming. It is a method of replacing steam as reactant with carbon dioxide.The methane carbon dioxide reforming reaction is:CO2 + CH4 → 2H2 + 2COHalmann, Martin M. (1993). Carbon di oxide reforming. Chemical fixation of carbon dioxide: methods for recycling CO2 into useful products. CRC Press. ISBN 978-0-8493-4428-2

DRY REFORMING OF CARBON DIOXIDE

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009)

Catalyst Technology for carbon dioxide reforming with methane to synthesis gas

Carbon dioxide Reforming Scheme

• O=C=O Methane

Catalyst(?)

SYN GAS (CO /H2)

TRANSPORT SECTOR AUTOMOBILES,DIESEL ENGINES

AEROPLANES

STORAGE Gas stations

Storage in gas Pressure vessels

RELEVANT REACTIONS• (1)CH4+ CO2↔ 2CO + 2H2 ΔH0

298=247 ΔG0=61770-67.3T

• (2)CH4+H2O ↔ CO + 3H2 =206;

• (3)CH4↔ C + 2H2 75; 2190-26.5T

• (4)2CO↔CO2+ C -171; 39810+40.9T

• (5)CO2+ H2 ↔ CPO + H2O 41; -8545+7.84T

• (6)CO + H2↔ C + H2O -131

• The first figure refer to the ΔH0298 in kJ/mol

• The second figure refer to ΔG0

• Reaction T (K)• DRM 913• Methane cracking (3) 830• Boudouard Reaction (4) 973• RWGS (5) 1093• Limiting temperatures for different reactions DRM

Catalyst component Proposed mechanism

Metal active site (M(as)) CH4 + 2M(as)↔CH3-M(as)+ H-M(as)

CH3-M(as)+ M(as)↔CH2-M(as) + H-M(as)

CH2-M(as) + M(as)↔CH-M(as)+H-M(as)

CH-M(as) + M(as)↔C-M(as) + H-M(as)

2h-M(as)↔ H2(g) +2M+(as)

Catalyst component and corresponding proposed mechanism

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009)

Catalyst component Proposed Mechanism

Support ( Acidic support)

Support ( BASIC SUPPORT)

CO(g)↔CO2(metal)

CO2(metal)↔CO(metal) + O(metals)

CO(metal)↔CO(g)

CO2(g) ↔ CO2(support)

CO2(support) + O2-(support) ↔CO3(support)

2-

2H(metal)↔ 2H(support)

CO3(support)2- +2H(support)↔HCO3

-(s)

+ OH-

(s)

CO(support)↔CO(g)

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009)

Catalyst component Proposed Mechanism

Promoter

CO(g)↔CO(support)+ O(promoter)

O(promoter) + C(metal) ↔CO(g)

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009

Catalyst Temp. (K)

Conversion % Remarks

NiO/CaO/CoO-MgO/MgO 873-1123 80-100(CH4) High selectivity Ru/SiO2/MgO/TiO2 973-1073 28-35 deactivation Co/SiO2/MgO-SiO2 873 41-46(CH4) Better than Ni Ir/Al2O3 873 18-50 preparation

Different types of catalysts used for the DRM reaction

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009

Characterization of DRM reaction catalysts

Catalyst type Techniques Aspects Monometallic supported catalysts Ni/CeO2,Pt/Al2O3,Ni/SiO2,Ru/SiO2,Ir/Al2O3

XRD,TPR,XPS,EPR,TPO,TPH Metal dispersion, reducibility, coke

Bimetallic supported catalysts Ni-Co, Ni-Rh

XRD,XRF,XPS,TG,DTA, chemisorption

Composition, phase, coke, metal dispersion

Metal oxide supported catalysts CoO-MgO/CeO2

TPO, XRD,XPS Resistance to C, phases

Promoted supported catalysts on alumina Ni-K,Ni-Sn,Ni-Ca,Ni-Mn

TG,TPH,TPR,XRD,TEM,TPO Carbon, active sites, reduction behaviour

Perovskite catalysts, LaNiOx, LaNiMgOx, LaNiCoOx, LaSrNiOx,LaCeNiOx

XRD,TPR,TPO,TEM,SEM Calcination temp, structure, phases, reversibility, sintering

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009)

Catalyst Technology for carbon dioxide reforming with methane to synthesis gas

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009)

Catalyst Technology for carbon dioxide reforming with methane to synthesis gas

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009)

Catalyst Technology for carbon dioxide reforming with methane to synthesis gas

Mun-Sing Fan et al., ChemCatChem, 1,192 (2009)

Catalyst Technology for carbon dioxide reforming with methane to synthesis gas

CO2 reforming on Ni/Cu catalyst

• Factors like addition of copper to supported Ni system surface geometry, electronic structure, the extent of CH2 species, and hydrogen spill over contribute to Ni-Cu/support catalyst in CO2 reforming.

1. 1 wt% Cu8 wt% Ni/siO2 stability >7600C2. active site is stabilized by Cu3. Carbon formation same as Ni and Ni/Cu4. Cu-Ni species inhibit the C formation5. Cu addition promotes CH4 cracking and inactive Coke does

not accumulate on Cu/Ni catalyst• H-W Chen et al., Catalysis Today 97,173 (2004)

• TD favours carbon formation• Noble metals and Ni alleviate this problem

Summary of Catalytic Reforming of CO2/CH4

CatalystCO2/CH4

conversion (%)

Temp (K)

Ni/NaY 1:1 84.0 873Ni/Al2O3 1:1 36.3 873Ni/SiO2 1:1 14.9 873Pd/NaY 1:1 29.2 873Pt/NaY 1:1 156.3 873KNiCa/Al2O3 1:1 17 923KNiCa/SiO2 1:1 21 923KNiCa/ZSI 1:1 78 923Rh/TiO2 1:1 88.2 893Rh/SiO2 1:1 5.1 893Rh/Al2O3 1:1 85.1 893Ni/Al2O3 1:1 80−90 1050Pd/Al2O3 1:1 70−75 1050Ru/Al2O3 1:1 60−70 1050Rh/Al2O3 1:1 85−90 1050Ir/Al2O3 1:1 85−90 1050

Wang et al, Energy & Fuels, 10,896 (1996)

Catalyst Conversion % Temperature, K Ni/NaY/Al2O3/SiO2/ 15-85 873 Pd/NaY/Al2O3/MgO 29, 70-75,84 873,1050,963 Pt/NaY/MgO 156,85 873,963 Rh/TiO2/SiO2/Al2O3 88,5,85 893 Ni/Al2O3/MgO-Al2O3/CaO-Al2O3/CaO-TiO2Al2O3 75,,100,86,88,100 1050,1213 Ru/Al2O3/Eu2O3/MgO 60,75,90, 1050,923,963 Ir/Eu2O3/Al2O3/ 88,85 1000,1050

Table Catalytic reforming of CO2/CH4 with 1:1 mixture on various catalysts collected from literature

Co,MgO/C 1:1 65−75 923Ni/CaO-MgO 1:1 80 1123Rh/Al2O3 1:1 85 1073Ru/Al2O3 1:1 83 1073Ru/Eu2O3 1:1 75 923Ir/Eu2O3 1:1 88 1000Ru/MgO 1:1 90 963Rh/MgO 1:1 88 963Pt/MgO 1:1 85 963Pd/MgO 1:1 84 963Ni/Al2O3 2.38:1 100 1213Ni/MgO−Al2O3 2.38:1 86 1211Ni/CaO−Al2O3 2.01:1 88 1211Ni/CaO−TiO2−Al2O3 2.01:1 100 1223

Summary of Catalytic Reforming of CO2/CH4

Wang et al, Energy & Fuels, 10,896 (1996)

metal activity metal loading (wt %) temp (K)

1.  Al2O3    Rh > Pd > Ru > Pt > Ir 1 823 Rh>Pd>Pt>Ru 0.5−1 823−973Ir > Rh > Pd > Ru 1 1050 Ni>Co >>Fe 9 773−973Ni>Co>> Fe 10 1023Ru > Rh 0.5 873Ru > Ru 0.5 923−10732.  SiO2    Ru > Rh > Ni > Pt > Pd 1 973Ni > Ru > Rh >Pt > Pd >> Co 0.5 8933.  MgO    Rh > Ru > Ir > Pt > Pd 0.5 1073Ru > Rh > Ni > Pd > Pt 1 973 Ru> Rh ~Ni > Ir > Pt > Pd 1 823Ru > Rh > Pt > Pd 1 9134.  Eu2O3    Ru > Ir 1−5 873−9735.  NaY    Ni > Pd > Pt 2 873

Catalytic Activities of Metals on Various Supports

Wang et al, Energy & Fuels, 10,896 (1996)

Effect of Support on Catalyst Activity

activity ordertemp (K) metal loading (wt %)

Ru    Al2O3 > TiO2 > SiO2 893 0.5TiO2 > Al2O3 > SiO2 893 0.5Pd    TiO2 > Al2O3 > NaY > SiO2 > MgO > Na-ZSM-5 773 5TiO2 > Al2O3 > SiO2 > MgO 773 1Rh    

 YSZ > Al2O3 >TiO2 >SiO2>> MgO 923 0.5

Al2O3 > SiO2 > TiO2 > MgO 773 1Ni    Al2O3 > SiO2 800−1000 40Al2O3 > SiO2 873 10NaY > Al2O3 > SiO2 873 2SiO2 > ZrO2 > La2O3 > MgO > TiO2 823 4

Wang et al, Energy & Fuels, 10,896 (1996)

Synthesis gas over Ni/ZrO2-SiO2

• Helium treatment –generate distribution of active Ni sites

• Heterogeneity of Ni sites on hydrogen treatment

• CO treatment carbon covered metallic sites deactivation

Dapeng Liu, Yifan Wang, Daming Shi, Xinli Jia, Xin Wang, Armando Borgna, Raymond Lau and Yanhui Yang, Internationl Journal of Hydrogen energy,37,10135 (2012)

CO2 reforming on Co-Pd/Al2O3

• Co containing promoted by noble metal (Pd) with respect to activity, selectivity, resistance to carbon formation Co-Pd/Al2O3 depend on composition and process conditions. Oxygenates are produced.

Sh.S.Itkulova et al., Bull Korean chem.soc., 26,2017 (2005)

Stable CO2 reforming over modified Ni/Al2O3

• Ni/Al2O3 promotedby C,Cu,Zr,Mn,Mo,Ti,Ag and Sn

• Cu,Co,Zr improved Mn reduces carbon formation

Jae-Sung Choi, Kwang-ik Moon, Young Gul Kim, Jae Sung Lee, Cheol-Hyun Kim, and David L.Trim, catalysis Letters, 52,43 (1998)

Table 2. Catalyst component and corresponding proposed mechanism.

Catalyst component Proposed mechanismMetal active site (M(as)) CH4+2 M(as) CH3-M(as)+H-M(as) ⇌

CH3-M(as)+M(as) CH2-M(as)+H-M(as) ⇌ CH2-M(as)+M(as) CH-M(as)+H-M(as) ⇌

CH-M(as)+M(as) C-M(as)+H-M(as) ⇌ 2 H-M(as) H2(g)+2 M(as)⇌Support Acidic support: CO2(g) CO2(metal) ⇌ CO2(metal) CO(metal)+O(metal) ⇌ CO(metal) CO(g)⇌ Basic support: CO2(g) CO2(support) ⇌ CO2(support)+O 2-

(support) CO⇌ 32-

(support) 2 H(metal) 2 H(support)⇌ CO3

2-(support) +2 H(support) HCO⇌ 3

- (support) + OH-(support)

CO(support) CO(g)⇌Promoter CO2(g) O(promoter)+CO(support) ⇌ O(promoter)+C(metal) CO(g)⇌

Mun-Sing Fan et al., ChemCatChem.,1,192 (2009)

Processes occurring in the catalytic membrane reactor during the combined POM/DRM reaction

In this work, we have performed first principle calculations to study the adsorption of hydrogen on combined TM-decorated B-doped graphene surface. We found that transition metals Ni, Pd and Co show the great advantage of both hydrogen adsorption and H spillover method in the hydrogen storage process. Our results show that all the calculated activation barriers are sufficiently low for the H diffusion along the Ni-Pd and Pd-Co paths, indicating that a fast H diffusion on the substrate can be achieved under ambient conditions. Moreover, the calculated desorption energies of the hydrogen molecules on these TM decorated B-doped surface are close to the energies required to obtain reversible storage at room temperature and hence the proposed TM decorated boron doped graphene surface will be a good candidate to enhance the reversible hydrogen storage capacity.

Different isotope dependences on reaction kinetics have been observed during RBM of pure Mg powder and Mg–Ti powder mixtures. For pure Mg, gas absorption depends on the isotope nature and the rls is assigned to H(D)-diffusion in MgH2 phase. In contrast, in presence of Ti, the diffusion lengths in MgH2 phase are strongly shortened due to the abrasive properties of TiH(D)2. Thus, gas absorption turns to be isotope independent and the rls is assigned to the milling efficiency.

Analysis of hydrogen and deuterium kinetic curves under isothermal conditions (548 K) has highlighted outstandingly fast reaction rates for the nanocomposite. Absorption is diffusion controlled whereas desorption depends on the Mg/MgH2 interface displacement.

Finally, we have shown by means of HP-DSC the superior cycling stability of 0.7MgH2–0.3TiH2 nanocomposite over 100 cycles. Though, the crystallite growth associated to cycling at moderate temperatures (<650 K) induces modifications in the absorption mechanism, which changes on cycling from extended MgH2 nucleation at Mg/TiH2 interfaces to H-diffusion across the MgH2 layer. Nevertheless, the composite material exhibits excellent kinetics and cycling properties as compared to pure Mg.