Engineering Conferences International ECI Digital Archives Fluidization XV Proceedings 5-24-2016 Numerical simulation of hydrogen production by chemical looping reforming in a dual interconnected fluidized bed reactor Piero Bareschino Dipartimento di Ingegneria, Università degli Studi del Sannio, Italy, piero.bareschino@unisannio.it Roberto Solimene Istituto di Ricerche sulla Combustione, Consiglio Nazionale delle Ricerche, Italy Giuseppe Diglio Dipartimento di Ingegneria, Università degli Studi del Sannio, Italy Erasmo Mancusi Dipartimento di Ingegneria, Università degli Studi del Sannio, Italy Francesco Pepe Dipartimento di Ingegneria, Università degli Studi del Sannio, Italy See next page for additional authors Follow this and additional works at: http://dc.engconfintl.org/fluidization_xv Part of the Chemical Engineering Commons Recommended Citation Piero Bareschino, Roberto Solimene, Giuseppe Diglio, Erasmo Mancusi, Francesco Pepe, and Piero Salatino, "Numerical simulation of hydrogen production by chemical looping reforming in a dual interconnected fluidized bed reactor" in "Fluidization XV", Jamal Chaouki, Ecole Polytechnique de Montreal, Canada Franco Berruti, Wewstern University, Canada Xiaotao Bi, UBC, Canada Ray Cocco, PSRI Inc. USA Eds, ECI Symposium Series, (2016). http://dc.engconfintl.org/fluidization_xv/97 This Abstract and Presentation is brought to you for free and open access by the Proceedings at ECI Digital Archives. It has been accepted for inclusion in Fluidization XV by an authorized administrator of ECI Digital Archives. For more information, please contact franco@bepress.com.
Authors Piero Bareschino, Roberto Solimene, Giuseppe Diglio, Erasmo Mancusi, Francesco Pepe, and Piero Salatino This abstract and presentation is available at ECI Digital Archives: http://dc.engconfintl.org/fluidization_xv/97
Università degli Studi del Sannio Dipartimento di Ingegneria Università degli Studi di Napoli Federico II Dipartimento di Ingegneria Chimica, dei Materiali e della Produzione Industriale Numerical Simulation of Hydrogen Production by Chemical Looping Reforming in a Dual Interconnected Fluidized Bed Reactor Giuseppe Diglio, Piero Bareschino, Erasmo Mancusi, Francesco Pepe Università degli Studi del Sannio, DING Benevento (Italy) Roberto Solimene Consiglio Nazionale delle Ricerche, IRC Napoli (Italy) Piero Salatino Università degli Studi di Napoli Federico II, DICMaPI- Napoli (Italy) FluidizationXV May 22-27, 2016
H 2 as fuel can contribute to reduce CO 2 emissions Currently H 2 is produced mainly by SMR - Highly energy demand - Need of post-processing for CO 2 separation CLR can overcome these issues Numerical simulation - Which type of reactor configuration? - Which type of oxygen carrier?
Literature Most of numerical simulations of CLR in DIFB are focused only on kinetic scheme What you need? An appropriate hydrodynamic model of the whole system in order to point out stable operating conditions. Aim of the work To develop a simple mathematical tool coupling a CLR reactive scheme and a simple hydrodynamic model of a DIFB system.
1 2 3 4 5 FR split in two zones: dense zone below diluted zone/freeboard (FB) Dense zone is modelled as a CSTR, while FB is modelled as a PFR AR is modelled as CSTR (dense regime) or PFR (diluted regime) Conversion is uniform throughout solid particles In the FB only homogeneous WGS was taken into account
DEPLETED AIR CH 4 +CO+CO 2 +H 2 O+H 2 +N 2 CH 4 +2NiO 2Ni+2H 2 H 2 +NiO Ni+H 2 O m *+, = m -.- + m 01 + m " + m 2/04 m -.- = A -.- g ' P -.- m 01 = 1 ε 8 ' ρ : ' A 1: ' L < I <> + 1 ε 8 ' ρ : ' A 1? ' I 1? + 1 ε " ' ρ : ' A "? ' h "? m " = A " g ' P " m 2/04 = 1 ε A ' ρ : ' A A ' L A + 1 ε 4 ' ρ : ' A 2 ' H ' η L 4 H + L 4 ' η H L 4 CO+NiO Ni+CO 2 CH 4 +NiO Ni+2H CH 4 +H 2 O 3H CH 4 +CO 2 2H 2 +2CO CO+H 2 O H 2 CH 4 +N" Ni-C+2H 2 C+H 2 O H C+CO 2 2CO CH 4 +H 2 O+N 2 dm 2/04 dt dm " dt = W " W < = W 01 W " 2Ni+O 2 2NiO AIR dm 01 dt = W - W 0<
DEPLETED AIR Bubbling Fluidized Bed (BFB) hp: elutriation is negligible Mass flow rate CH 4 +CO+CO 2 +H 2 O+H 2 +N 2 W - = H 0 h 2,- < h - W < h 2,- h - CH 4 +2NiO 2Ni+2H 2 H 2 +NiO Ni+H 2 O CO+NiO Ni+CO 2 CH 4 +NiO Ni+2H CH 4 +H 2 O 3H CH 4 +CO 2 2H 2 +2CO CO+H 2 O H 2 CH 4 +N" Ni-C+2H 2 C+H 2 O H C+CO 2 2CO Pressure drop P -.- = ρ : ' 1 ε 2 ' g ' h 2,- CH 4 +H 2 O+N 2 2Ni+O 2 2NiO AIR
DEPLETED AIR Loop Seal Loop Seal works in complete fluidization condition between Supply Chamber (SC) and Recycle Chamber (RC). CH 4 +CO+CO 2 +H 2 O+H 2 +N 2 CH 4 +2NiO 2Ni+2H 2 H 2 +NiO Ni+H 2 O CO+NiO Ni+CO 2 CH 4 +NiO Ni+2H CH 4 +H 2 O 3H CH 4 +CO 2 2H 2 +2CO CO+H 2 O H 2 CH 4 +N" Ni-C+2H 2 C+H 2 O H C+CO 2 2CO CH 4 +H 2 O+N 2 Mass flow rate W 01 = W < Aeration gas flow rate Q 01 = Q 1? + Q "? Gas leakage between SC and RC W " ' ε 8Q U 0< U 8Q A 1? ' ρ : ' 1 ε 8Q 2Ni+O 2 2NiO AIR
DEPLETED AIR CH 4 +CO+CO 2 +H 2 O+H 2 +N 2 CH 4 +2NiO 2Ni+2H 2 H 2 +NiO Ni+H 2 O CO+NiO Ni+CO 2 CH 4 +NiO Ni+2H CH 4 +H 2 O 3H CH 4 +CO 2 2H 2 +2CO CO+H 2 O H 2 CH 4 +N" Ni-C+2H 2 C+H 2 O H C+CO 2 2CO CH 4 +H 2 O+N 2 2Ni+O 2 2NiO AIR Riser hp: 1) transition between dense and dilute phase takes place when mass flow rate approaches the value corresponding to its saturation carrying capacity; 2) the variation of voidage along the riser and with the mass flux have been neglected. Mass flow rate G < = H G S = β ' ρ : ' 1 ε 8Q ' U " G < G S G U = U 1 h " ' m " A " G < < G S Pressure drop P " = ρ : ' 1 ε 2 ' g ' h 2 + g ' W " A " ' U 1 ' h " h 2
DEPLETED AIR Cyclone hp: Collection efficiency was assumed to be 1. Pressure drop P?V? = ρ Q ' K? ' U? CH 4 +CO+CO 2 +H 2 O+H 2 +N 2 CH 4 +2NiO 2Ni+2H 2 H 2 +NiO Ni+H 2 O CO+NiO Ni+CO 2 CH 4 +NiO Ni+2H CH 4 +H 2 O 3H CH 4 +CO 2 2H 2 +2CO CO+H 2 O H 2 CH 4 +N" Ni-C+2H 2 C+H 2 O H C+CO 2 2CO CH 4 +H 2 O+N 2 2Ni+O 2 2NiO AIR
DEPLETED AIR Downcomer/L-Valve CH 4 +CO+CO 2 +H 2 O+H 2 +N 2 CH 4 +2NiO 2Ni+2H 2 H 2 +NiO Ni+H 2 O CO+NiO Ni+CO 2 CH 4 +NiO Ni+2H CH 4 +H 2 O 3H CH 4 +CO 2 2H 2 +2CO CO+H 2 O H 2 CH 4 +N" Ni-C+2H 2 C+H 2 O H C+CO 2 2CO Pressure drop P 2XS H L Y = K 4 ' u Q[ u <[ P 04 L A = K A ' u Q\ u <\ P 04 = 0.0649 ' ρ : a.bbc ' L A D 04 a.efg ' d : a.hif Aeration gas flow rate Q 04 = Q A + Q 4 W 1 A " a.jfk CH 4 +H 2 O+N 2 2Ni+O 2 2NiO AIR
ΔH 0, kj/mol R1) 2Ni + O h 2NiO -479 R6) CH g + H h O q* 3H h + CO R2)CH g + 2NiO 2Ni + 2H h + CO h 161 R3) H h + NiO Ni + H h O -2 R4)CO + NiO Ni + CO h -43 R5)CH g + NiO Ni + 2H h + CO 203 Oxygen Carrier: 15 wt.% Ni/γ-Al 2 O 3 Efficiency of air pre-heater: 90% CH 4 :H 2 O is 3:1 FR is isothermal AR is adiabatic R7) CH g + CO h q* 2H h + 2CO 206 247 R8) CO + H h O q* H h + CO h -41 R9)CH g + Ni q* Ni C + 2H h 74 R10) C + H h O q* H h + CO R11) )C + CO h q* 2CO 131 172 C. Duesoet al., Chem. Eng. J. 188 (2012) 142-154 I. Iliuta et al., AIChE J. 56 4 (2010) 1063 1079 F. Bustamante et al., AIChE J. 50 (2004) 1028 1041 F. Bustamante et al., AIChE J. 51 (2005) 1440 1454
Mass Balances Dense regime/phase Q u,*+ ' C v,*+ Q u,wxy ' C v,u + m <>,u ' * r * ' α v =0 W u,*+ ' C <>,*+ W u,wxy ' C <>,u + M <> ' m <>,u ' * r * ' α v =0 Diluted regime/free Board 1 A u dn v,u = r dh * ' α v u * Parameters Operating conditions Properties of bed materials T [ ] 300 3 fuel K ρ p [ kg m ] 2540 5 P[ Pa] 10 dp [ m] 2.55 10 m [ kg] 11.6 ε mf [ ] 0.445 U ε D[ ] 0.445 U [ ] 2.7 ε B[ ] 0.445 Q [ m s ] 5.5 10 εv [ ] 0.423 U m s U ε [ ] 0.488 inv 1 B [ m s ] 0.5 1 R m s 3 1 5 LV 1 LS [ ] 2 mf H GEOMETRICAL CHARACTERISTICS Riser L-valve DR[ m] 0.102 DLV[ m] 0.04 hr[ m] 5.6 LH[ m] 0.4 BFB LE [ m] 0.4 DB [ m] 0.12 Cyclone hb[ m] 2 KC[ ] 78 Downcomer Loop-Seal D m A m L [ m] 3.6 h [ m] 0.2 2 D [ ] 0.04 sc [ ] 0.0025 V rc 4 Energy balances W u,*+ ' <> 1 M <> ' C <>,*+ ' h <>,*+ W u,wxy ' <> 1 M <> ' C <>,u ' h <>,u + Q u,*+ ' v C v,*+ ' h v,*+ Q u,wxy ' v C v,u ' h v,u + "* * H "* ' n v,u =0
Fuel Reactor: effect of height of the BFB weir h - m -.- and G < so τ -.- and O 2 WGS reaction rate decreases with T
Fuel Reactor: effect of solid circulation rate G < NiO: CH 4 so η?a and η A H h + NiO Ni + H h O
Air Reactor: effect of inlet air pre-heat exchanger Without pre-heat exchanger the temperature of inlet air is too low to drive Ni oxidation reaction
A simple tool to evaluate the performance of a CLR process carried out in a DIFB was developed. The model is able to predict both main hydrodynamic variables and CLR performances. Higher H 2 production can be achieved reducing the amount of oxygen available in the FR decreasing solid circulation rate. If no air pre-heating is used, the temperature of air at the inlet of AR is too low to drive Ni oxidation reaction.