STUDIES ON NUCLEAR HYDROGEN PRODUCTION BY STEAM COAL GASIFICATION IN ARGENTINA

Transcription

1 Technical Meeting to Examine the Role of Nuclear Hydrogen Production in the Context of Hydrogen Economy STUDIES ON NUCLEAR HYDROGEN PRODUCTION BY STEAM COAL GASIFICATION IN ARGENTINA G.G. Fouga, D. Nassini, H.E. Nassini, A.E. Bohé July, 17 th - 19 st 2017 Vienna - Austria

2 Nuclear Hydrogen Production 02/22 Hydrogen Production Using Nuclear Energy. IAEA Nuclear Energy Series. No. NP-T-4.2 Nuclear Energy for Hydrogen Production. Reihe Energietechnik / Energy Technology; Band / Volume 58. ISSN I. Khamis. Non- Electric Applications of Nuclear Energy. DFC-CAB-CNEA - Argentina Heterogeneous reactions. Solid-Gas Solid Fuels Gasification. Halogenation.

3 Argentinean Nuclear Power Plants 03/22 Atucha 1 Nameplate capacity: 357 MW Reactor type: PHWR-Siemens Status: operational. Atucha 2 Nameplate capacity: 745 MW Reactor type: PHWR-Siemens Status: operational. Embalse Nameplate capacity: 648 MW Reactor type: PHWR-CANDU Status: renovating. Life extension program.

4 CAREM Nuclear Reactor 04/22 IAEA SMR Booklet 2014 CAREM Nuclear Reactor Characteristic (Videos) CAREM Nuclear Reactor Under Construction (Videos)

5 Gasification 05/22 Gasification refers to a thermo-chemical process that converts solid carbonaceous fuels into either fuel gas (usually containing CH 4 and some N 2 ) or syngas (containing mainly H 2 and CO). C(s) + H 2 O(g) H 2 (g) + CO(g) CO(g) + H 2 O(g) H 2 (g) + CO 2 (g) C(s) + CO 2 (g) 2CO(g) C(s) + 2H 2 (g) CH 4 (g) G 0 r = T (KJ/mol) G 0 r = T (KJ/mol) G 0 r = T (KJ/mol) G 0 r = T (KJ/mol) Gasification involves the possibility of co-generation of electricity, chemicals and fuels in the same energy facility. nco + (2 n) H 2 CnH 2n + nh 2O nco + (2 n) H C H OH + ( n 1) H O 2 n 2n+ 1 2 nco + (2n + 1) H 2 CnH 2n+ 2 + nh 2O Alkenes Alcohols Paraffins

6 Gasification 06/22 Gasification also involves the possibility of using a wide range of feed stocks including low-cost fuels like: petroleum coke, biomass and also municipal waste. Argentinean Natural Solid Fuels Evaluated Sub-bituminous coal: Rio Turbio Ortho-Asphaltite: F4 Meta-Asphaltite: EM Asphaltites are complex mixtures containing compounds ranging from nonpolar aliphatic and naphthenic hydrocarbons to highly polar aromatic molecules.

7 Two Steps Gasification Process 07/22 Solid Fuel Gasification Syngas Fluidized Bed Reactor Pyrolysis Step 1 Volatile Matter Gasification Syngas Step 2A Char Gasification Syngas Step 2B Ratelimiting step

8 Two Steps Gasification Process 08/22 Step 1: Pyrolysis Step 2A: Volatile Matter Gasification Pyrolysis Reactor Volatile components of solid fuels are rapidly released Volatile Matter + H 2 O(g) Tars Pyrolysis gas H 2 O(g) Light hydrocarbons H 2 (g) + CO(g) Solid Fuel Coal Asphaltites petroleum coke Biomass, etc. Heat Provided by Nuclear Reactor N 2 (g) At T between 300 and 500 ºC CH 4 + H 2 O 3H 2 + CO CH 4 + 2H 2 O 4H 2 + CO 2 C n H m + nh 2 O (n+m/2)h 2 + nco C n H m + 2nH 2 O (2n+m/2)H 2 + nco 2 Char Composed of fixed carbon and mineral matter

9 Two Steps Gasification Process 09/22 Step 2B: Char Gasification Gasifier Reactor Syngas H 2 (g) + CO(g) C(s) + H 2 O(g) H 2 (g) + CO(g) Char Ratelimiting step Composed of fixed carbon and mineral matter Ash Composed of mineral matter To V, Ni and U Recovery Gasifying agent (Steam) Provided by Nuclear Reactor RT: SiO 2 and Fe 2 O 3. EM: SiO 2 ; Fe 2 O 3 ; CaSO 4 ; Ca 3 V 2 O 8 and CaSiO 3 F4: NaV 6 O 15 and SiO 2.

10 Natural Solid Fuels Deposits in Argentina 10/22 Natural Solid Fuels H 2 O + Volatile Material Pirólisis Fixed Carbon + + Char Ash Determinati on HT in air. (105 C) HT in Ar. (950 C) % of Char % of Ash HT in air. (950 C) ASTM standard ASTM D ASTM D ASTM D Determination Coal (Río Turbio) EM (Meta) Asphaltites F4 (Ortho) Moisture (wt%) Volatile Matter (wt%) Fixed carbon (wt%) Ash (wt%) Density (g cm 3 ) C T N T S T Calorific Power kj/kg Asphaltites Coal Peat

11 Experimental Program 11/22 Objective: characterize the behaviour of Argentine solid carbonaceous fuels under typical pyrolysis and gasification conditions, to identify the most suitable operational parameters in nuclear-assisted two-stage gasifiers. Scope: Theoretical and experimental studies designed to get the necessary information about the fundamental mechanisms and kinetic parameters of pyrolysis and gasification reactions for hydrogen production, on laboratory scale.

12 Experimental Setup for Pyrolysis 12/22 Particle-free fall Pyrolysis Silica glass tubular reactor Preheated Ar/N 2 Char with high BET area Char more reactive Drop tube reactor Powder Fluidizing system for coal particle feeding

13 Experimental Setup for Pyrolysis 13/22 Fixed bed reactor after pyrolysis Effects of pyrolysis conditions as temperature, heating rate and holding time on: Microstructure and gasification reactivity of chars. Kinetic regime of the gasification reaction. Yield and composition of the evolved tar and pyrolysis gas. Fixed bed reactor

14 Fixed Bed Reactor for Solid Fuels Gasification With Steam 14/22 The gasification with steam needs a complex experimental setup: it consist of a steam generator, a gasification reactor and a water condenser; coupled in series with a GC and a FTIR.

15 Analysis setup for gaseous components. 15/22 Infrared Spectrometer Perkin Elmer, Model: Spectrum 400 Gas Chromatograph CG/MS Perkin Elmer. Model Clarus 600/680 TCD: H 2 ; METANIZER-FID: CO, CO 2 Gasification reaction kinetics Characterised CO(g) concentration Peak areas Gas cell αα tt = nn CCCC tt nn CCCC tt ff In chromatograms registered every 5 minutes n CO (t) is the number of CO(g) moles formed from the beginning until time t. n CO (t f ) is the number of total moles formed during the whole reaction.

16 Steam Gasification in Fixed Bed Reactor 17/22 70 CO 2 4.0x x10 3 CO 2 CO H 2 Signal (mv) CO (inner column) CO (outer column) Signal (mvx10 3 ) 3.0x x x x x x Time (min) 10 0 CH 4 H Time (min) CO(g)-CO 2 (g) Molar relationship C(s) + H 2 O(g) H 2 (g) + CO(g) CO(g) + H 2 O(g) H 2 (g) + CO 2 (g) H 2 Production: EM RT F CO CO 2 F4 = H 2 moles/c moles RT = 0.74 H 2 moles/c moles EM = H 2 moles/c moles

17 Steam Gasification in Fixed Bed Reactor 16/22 Temporal evolution of reaction degree (α) CHAR Determination EM RT F4 BET area (m 2 g-1 ) C content (wt %) Ash in Char Reaction kinetics Affected by Rank Ash Composition Reactivity Rank Rate (EM) > Rate (RT) > Rate F4 As the rank the reactivity These results show that Argentinean solid carbonaceous fuels tested are susceptible to be gasified since their reactivity's are comparable with those of low-rank coals used in large-scale gasifiers.

18 Batch Fluidized Bed Reactor for Solid Fuels Gasification With Steam 18/22 Solid feeding system [H 2 ] [CO] [CO 2 ] [CH 4 ] Thermal conductivity detector Maihak S710/THERMOR Non-dispersive infrared (NDIR) Maihak S710/UNOR Gas feeding system [O 2 ] Wate r dosing + steam generator system. Paramagnetic analyzer Siemens OXYMAT 5E Continuous gas analyzers

19 Char Gasification With Steam in a Batch FBR at 950 C 19/ H 2 EM Asphaltite 6.0 F4 Asphaltite H 2 H Río Turbio Coal Molar Flows (mol/s) CO CO 2 ( ) CO CO CO CO Time (min) Determination Time (min) CHAR EM F4 5 RT 13 BET area (m 2 g-1 ) C content (wt %) Ash in Char Time (min) H2 CO CO2

20 Fluidized bed reactor for solid fuel gasification 20/22 Parameter φ Int Bed mass Height of the bed Height of the bed (mfc) R mf P fr FBR 25,8 mm 40 g 5 cm 8 cm 30 l/min No detected

21 Concluding Remarks 21/22 Solid fuels gasification assisted by nuclear energy is a promissory process for hydrogen production. For this purpose, a theoretical and experimental program on laboratory scale is underway with the objective of characterizing the behaviour of selected feed materials under typical pyrolysis and gasification conditions. The research program included the development of specially-designed experimental setups for gasification using steam as gasifying agents. These studies allow to get relevant information about the reaction mechanisms and kinetic parameters of the pyrolysis and the gasification reactions, in order to be used in large-scale gasifier design.

22 22/22 Thank you for your attention!!! Bariloche - Argentina