Effect of Fuel Gas Composition in Chemical-Looping Combustion with Ni-Based Oxygen Carriers. 1. Fate of Sulfur

Garcı́a-Labiano, F.; Diego, Luis F. de; Gayán, Pilar; Adánez, Juan; Dueso, Cristina

doi:10.1021/ie801332z

Cited by 99 publications

(63 citation statements)

References 22 publications

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“…Moreover, the catalytic activity of metallic Ni made of them suitable materials for H 2 production when reforming processes are involved. An additional advantage of the joint use of these Ni-based materials and bioethanol is the absence of deactivation processes by sulphur that normally happens when fossil fuels are used [26]. Germany GmbH) as support [27].…”

Section: Methodsmentioning

confidence: 99%

Syngas/H2 production from bioethanol in a continuous chemical-looping reforming prototype

Garcı́a-Labiano

García-Díez

Diego

et al. 2015

Fuel Processing Technology

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Abstract:Chemical-looping reforming (CLR) allows H 2 production without CO 2 emissions into the atmosphere. The use of a renewable fuel, bioethanol, in an auto-thermal CLR process has the advantage to produce H 2 with negative CO 2 emissions. This work presents the experimental results obtained in a continuously operating CLR unit (1 kW th ) using ethanol as fuel. Two NiO-based oxygen carriers were used during more than 50 hours of operation. The influence of variables such as temperature, water-to-fuel 2 and oxygen-to-fuel molar ratios was analysed. Full conversion of ethanol was accomplished and carbon formation was easily avoided. A syngas composed by ≈61 vol.% H 2 , ≈32 vol.% CO, ≈5 vol.% CO 2 and ≈2 vol.% CH 4 was reached at auto-thermal conditions for both materials. Gas composition was closed to the given by the thermodynamic equilibrium. These results demonstrate the technical viability of H 2 /syngas production by using bioethanol in an auto-thermal CLR process.

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Section: Methodsmentioning

confidence: 99%

Syngas/H2 production from bioethanol in a continuous chemical-looping reforming prototype

Garcı́a-Labiano

García-Díez

Diego

et al. 2015

Fuel Processing Technology

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“…Among the main results it must be mentioned the scale-up of the CLC process up to 120 kW th on a unit built at Vienna University of Technology (TUWIEN) [42]; the scale-up of the carrier production by using spray-drying [43] and impregnation [44] methods; the successfully long-term operation during more than 1000 hours at CHALMERS using Ni-based particles manufactured by spray-drying of commercial raw materials [43]; and the testing of the effect of gas impurities such as H 2 S and light hydrocarbons over the nickel oxide particles at ICB-CSIC [44][45][46].…”

Section: Process Overview Of Chemical Looping Cycles For Co 2 Capturementioning

confidence: 99%

“…Reactivity deactivation by the presence of H 2 S in the fuel gas has been observed [45,226]. Using an impregnated Ni-based oxygen-carrier in a 500 W th unit, nickel sulphide was always formed when H 2 S was present in the fuel gas [45].…”

Section: Ni-based Oxygen-carriersmentioning

confidence: 99%

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Progress in Chemical-Looping Combustion and Reforming technologies

Adánez

Abad

Garcı́a-Labiano

et al. 2012

Progress in Energy and Combustion Science

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1,958

1,614

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This work is a comprehensive review of the Chemical-Looping Combustion (CLC) and Chemical-Looping Reforming (CLR) processes reporting the main advances in these technologies up to 2010. These processes are based on the transfer of the oxygen from air to the fuel by means of a solid oxygen-carrier avoiding direct contact between fuel and air for different final purposes. CLC has arisen during last years as a very promising combustion technology for power plants and industrial applications with inherent CO 2 capture which avoids the energetic penalty present in other competing technologies.CLR uses the chemical looping cycles for H 2 production with additional advantages if CO 2 capture is also considered.The review compiles the main milestones reached during last years in the development of these technologies regarding the use of gaseous or solid fuels, the oxygen-carrier development, the continuous operation experience, and modelling at several scales. Up to 2010, more than 700 different materials based on Ni, Cu, Fe, Mn, Co, as well as other mixed oxides and low cost materials, have been compiled. Especial emphasis has been done in those oxygen-carriers tested under continuous operation in Chemical-Looping 2 prototypes. The total time of operational experience (≈ 3500 h) in different CLC units in the size range 0.3-120 kW th , has allowed to demonstrate the technology and to gain in maturity. To help in the design, optimization, and scale-up of the CLC process, modelling work is also reviewed. Different levels of modelling have been accomplished, including fundamentals of the gas-solid reactions in the oxygen-carriers, modelling of the air-and fuel-reactors, and integration of the CLC systems in the power plant. Considering the great advances reached up to date in a very short period of time, it can be said that CLC and CLR are very promising technologies within the framework of the CO 2 capture options.

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“…NiO18-Al oxygen carrier had been previously used successfully in CLC with different fuels [45][46] even in the presence of impurities, such as sulphur [47] and light hydrocarbons [48]. Both NiO18-Al and NiO21-Al particles were also tested in CLR experiments in a continuous plant [49] and at pressurized conditions in a batch reactor [50].…”

Section: Introductionmentioning

confidence: 99%

Reduction and oxidation kinetics of nickel-based oxygen-carriers for chemical-looping combustion and chemical-looping reforming

Dueso

Ortiz

Abad

et al. 2012

Chemical Engineering Journal

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168

114

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The kinetics of reduction with CH 4 , H 2 and CO and oxidation with O 2 of two NiO-based oxygen carriers prepared by impregnation, NiO18-Al and NiO21-Al, for chemicallooping combustion (CLC) and chemical-looping reforming (CLR) was investigated in this work. The experimental tests were carried out in a thermogravimetric analyzer using different reacting gas concentrations (5-20 vol. % for CH 4 , 5-50 vol. % for H 2 and CO and 5-21 vol. % for O 2 ) and temperatures (1073-1223 K). The reduction stage using both materials proceeded in two steps: a first period of high reactivity attributed to the presence of free NiO and then a low reactivity period that corresponded to NiAl 2 O 4 reduction. Therefore, the kinetic parameters for NiO and NiAl 2 O 4 reduction were determined separately for each oxygen carrier and each reacting gas. An empirical linear model was developed to describe NiO reduction. The solid conversion was a function of the fuel concentration and NiO content in the solid. The effect of temperature was low (E a ~ 5 kJ mol -1 ) although a chemical reaction rate controlled by diffusional processes was dismissed. The shrinking core model for spherical grain 2 geometry was used to obtain the kinetic parameters of the NiAl 2 O 4 reduction working with both NiO-based oxygen carriers. Chemical reaction control was assumed for NiO18-Al whereas diffusion through product layer was also considered when NiO21-Al was used as oxygen carrier. 82-472 kJ mol -1 activation energies were obtained with NiO18-Al particles. The activation energies were 237 and 373 kJ mol -1 for the kinetic constant and 200-281 kJ mol -1 for the diffusion coefficient, respectively, in the case of NiO21-Al oxygen carrier. Reduction reaction of NiO21-Al with CO was extremely slow and the kinetic parameters were obtained for comparison purposes with chemical control of the reaction rate. In this case, the reaction order was 1 and the activation energy 89 kJ mol -1 . The combined model for consecutive reduction of NiO and NiAl 2 O 4 in the NiO18-Al particles with the kinetic parameters obtained in this work predicted adequately the experimental results. The oxidation step of both oxygen carriers was fast and complete until reaching the initial condition. An empiric linear model, which assumes a linear relation between time and conversion, was developed to determine the kinetics of Ni oxidation. The reaction order of oxidation was about 0.8 for NiO18-Al and NiO21-Al and the activation energies were low, 22 kJ mol -1 in both cases. 

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Effect of Fuel Gas Composition in Chemical-Looping Combustion with Ni-Based Oxygen Carriers. 1. Fate of Sulfur

Cited by 99 publications

References 22 publications

Syngas/H2 production from bioethanol in a continuous chemical-looping reforming prototype

Syngas/H2 production from bioethanol in a continuous chemical-looping reforming prototype

Progress in Chemical-Looping Combustion and Reforming technologies

Reduction and oxidation kinetics of nickel-based oxygen-carriers for chemical-looping combustion and chemical-looping reforming

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