A brief introduction about CO2 reforming of methane

Hongyan Ma2013.05.10

• Decreasing in coal and oil reserves• A large number of consumption of natural gas• Rich reserves in shale gas and coaled methane• And the support of policies

• Research about the application of methane

1.Background

Kazuhiro Takanabe, Journal of the Japan Petroleum Institute, 2012,55(1), 1-12

• Transform natural gas and CO2 into valuable syngas • Give syngas with a lower ratio of H2/CO of

approximately 1:1 • Make full use of carbon dioxide in low-grade natural

gas resource

advantages

Mun-sing F. Ahmad Z.A.,ChemCatChem.,2009,1,192-208

2.Reaction condition

T=550 ℃

T=640 ℃

T=700 ℃

T=820 ℃

Influence the ratio of H2/CO

Main reaction

Carbon deposition

other reaction(RWGS)

• The reaction proceeds at temperatures in excess of 913 K (640 ).℃

• At temperatures in excess of 1093K(820 ), the ℃RWGS and Boudouard reactions will not take place.

• Formation of carbon most likely takes place within the temperature range 830 K–973, from both the Boudouard reaction and methane decomposition.

Mun-sing F. Ahmad Z.A.,ChemCatChem.,2009,1,192-208

Conclusion about conditions

• The temperature is important for distribution of products. Finally chose the range of 700-850 ℃.

Y. Sun. T. Ritchie,Journal of Natural Gas Chemistry ,2011,20,568–576Y.H. Li, Y.Q.Wang, International journal of hydrogen energy,2008,33,2507-2514

• Pressure : the main reaction is not favorable in higher pressure, so chose ambient pressure in experiment in the laboratory .

• CH4/CO2: Although the excess CO2 is helpful for the conversion of CH4 and resistance for carbon deposition, a lots of energy will need to recycle the CO2. So now chose the stoichiometric ratio, namely 1:1.

单击图标添加图片

3.The reaction process

metal active surface(M) prompter (P)

acidic support basic support(S)

Mun-sing F. Ahmad Z.A.,ChemCatChem.,2009,1,192-208Anatta W.B.,S.H.Song.Catal Surv Asia,2012,16,183-197

4.The main challenges

• Poisoning• Carbon deposition• Sintering• Solid-state transformation• Metal oxidation

Deactivation

Pio F., Luca L.,Catalysis Today,1999,52,165-181Anatta W.B.,S.H.Song.Catal Surv Asia,2012,16,183-197

Carbon deposition and sintering

• Effective method• (1) metal: size,morphology,structure The critical size of Ni particles to inhibit coke deposition was suggested to be about 10nm. The surface defects can facilitate carbon formation, like steps and kinks.

Beatriz Fidalgo,Chin.J.Catal.,2011,32,207–216Kazuhiro Takanabe, Journal of the Japan Petroleum Institute, 2012,55(1), 1-12

• (2)promoter: enhance the adsorption of CO2 ,enhance the surface reaction, or decrease the rate and degree of methane activation and dissociation• (3)support: well-defined structure like ABO3 or spinels,and form strong interaction with active metal.• (4) others: form solid solutions or alloy with Ni , Co, Fe, Mg，Mn metal

.

Chang-jun Liu,ChemCatChem,2011, 3, 529 – 541

4, the practical method

• Form some fine particles in reducing strong Ni-x bond, like Ni-Mg alloy and NiAl2O4.

• Form strong interaction in reduction to fixed metal practicles, like Pt-Zr+ in Pt/ZrO2

• Disperse active site (1)using S or B to cover part of site. (2) special structure like spinel (3)some inactive species cover some of site formed in reduction. Like VOx in V2O5 and TiOx in TiO2, MnOx in MnO2. (4) add some promoter to disperse sites• Control the size with special structure-encapsulation

Y. H.Hu, E.Ruckenstein ,Adv. Catal. 2004,48,297 – 345

Thank you