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800 850 900 950 1000 1050 0 2000 4000 6000 8000 10000 12000 Gas Temperature [K] Time [s] Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 5 Cycle 6 FR feed T [K] Switching from FR to AR Switching from AR to AR: End of first cycle of SE-CLSR 0 2 4 6 8 10 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 Carbon [mole % Ctotal] Fractional conversion of Oxygen Carrier Time [min] 840 880 920 960 1000 1040 1080 0 20 40 60 80 100 0 300 600 900 1200 1500 Gas temperature [K] Mole % of Product gases [%] Time [s] CH4 CO H2 CO2 T Novel Materials and Reforming Process Route for the Production of Ready- Separated CO 2 /N 2 /H 2 from Natural Gas Feedstocks Principal investigator: Valerie Dupont Co-Investigators: Tariq Mahmud, Steve J Milne Key researchers: Zaheer Syed Abbas, Zainab ISG Adiya, Robert Bloom Project funded by the UKCCSRC as part of its Call 2 for Research Proposals, in partnership with the University of Leeds and Twigg Scientific & Technical Ltd, SAFFIL, MELChemicals Project Contact: Valerie Dupont, [email protected], +44 (0)113 343 2503 Project Dates: September 2014 – August 2016 www.ukccsrc.ac.uk The UKCCSRC is supported by the EPSRC as part of the Research Councils UK Energy Programme, with additional funding from DECC Project overview Large reserves of shale gas and unconventional gases worldwide will ensure that hydrogen remains produced mainly via the catalytic steam reforming process (C-SR) for the next few decades. In conventional C-SR, the most energy intensive step is the production of syngas (CO+H 2 ) in the primary reformer which relies on fired heaters in large scale furnaces. SR plants need to be enormous in order to be economical due to syngas production stage and H2 purification steps. Aims of the project Reduce energy and materials demand for the conversion of natural gases to high purity H 2 , CO 2 and N 2 using chemical looping steam reforming with ‘sorption enhanced’ in situ calcium gased CO 2 capture (SE-CLSR), thus making the Key findings/outcomes Part 2: SE-CLSR and CL-SR in packed bed, dynamic (non equilibrium) operation: Research highlights H 2 Yield, H 2 Purity, and Energetic Analysis of SE-CLSR compared to C-SR using shale gas feedstock Part I: at chemical equilibrium Next steps • Publish work (3 papers in final editing stages, about to be submitted, two more in progress). • Complete the current research programme and then move on to look at Co and Co-Ni materials, powder CeO 2 /ZrO 3 supports.. • Extend bench scale process to integrate upstream source of feedstock and downstream utilisation of H 2 /N 2 /CO 2 products. • Move on to pilot plant implementation for mobile processes. conversion process economical at scales easily integrated strategic industries and distributed sources of gas feedstocks. Table 1 Energy demand (∆H total) of producing 1 mol of H 2 at steam reforming temperature 607 °C, S:C=3, Ca:C=1, NiO:C=1.9. Case A: without sorbent regeneration step, B: with regeneration, and C: with sorbent regeneration & ideal heat recuperation. (∆H>0 heat input required, ∆H<0 generates heat). Process Conditions. ∆H total (kJ/mol H 2 ) C-SR (no CaO, no NiO) 137 SE-CLSR with CaO, A SE-CLSR with CaO, B SE-CLSR with CaO, C -84 20 -43 Table 2 Maximum equilibrium outputs comparing C-SR and SE-CLSR at 1 bar, S:C=3, Ca:C=1, and NiO:C=1.9 Conditions H 2 yield (wt. % of available fuel) H 2 purity (%) C-SR 41.0 wt% @ 797 °C 76.0% @ 737 °C SE-CLSR with CaO sorbent 49.1 wt% @ 527 °C 99.7 @ 497 °C SE-CLSR with Ca(OH) 2 sorbent 49.2 wt% @ 507 °C 99.7 @ 487 °C Figure 2 Effect of Pressure and Temperature on H 2 yield for the SE-CLSR and C-SR processes at equilibrium. Figure 1 Motivation for the project Figure 3 Validation of chemical looping Steam Reforming (CL-SR) of methane, kinetics and species profiles in reactor correctly predicted. 800 °C, 1bar and 10% CH 4 in Ar as reducing gas. Dots: experimental results (Iliuta et al, 2010), lines: our model. Figure 4 Dynamic model of SE-CLSR of methane, shows stability of temperature profile upon multiples cycles (a). Blow up of 2nd cycle (b). Inlet T= 677 °C, 30 bar, S:C =3, CaO:C =1, NiO/C =0.5 alternating with air feed. SE-CLSR CL-SR (a) (b) y = -14659x - 1.3872 R² = 0.9546 -3.9 -3.7 -3.5 -3.3 -3.1 -2.9 1.00E-04 1.20E-04 1.40E-04 ln k, Avrami-Erofeyev model 1/RT Oxidation in Air, 3D nucleation and nuclei growth Reduction in H2, 2D nucleation and nuclei growth 18 wt% NiO impr. SAFFIL CG support Figure 5 SEM images of CG SAFFIL fibre impregnated with 18 wt% NiO. BET area of support 150 m 2 /g, 3 nm pore diameter, 0.2 cc/g pore volume Figure 7 Model and kinetic parameters of rate of oxidation and reduction of 18 wt% NiO/CG-SAFFIL chemical looping catalyst. k red = 0.223 s -1 k oxi =A exp(-E/RT), A= 0.250 s -1 , E=121.9 kJ mol -1 , nucleation and nuclei growth model. Part 3: Novel CLSR materials Figure 6 EDX image of CG SAFFIL fibre impregnated with 18 wt% NiO. Spacial distribution of Ni, Al, O and Si. 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.0 0.2 0.4 0.6 0.8 Gas composition [mole fraction] Time [min] CH4 CH4 CO CO H2 H2 H2O H2O CO2 CO2 (a) (b)
