Applications of the constrained Gibbs energy method in modelling thermal biomass conversion.

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GTT-Technologies' 7th Annual Users' Meeting, Herzogenrath, Germany, July

1 VTT TECHNICAL RESEARCH CENTRE OF FINLAND LTD Applications of the constrained Gibbs energy method in modelling thermal biomass conversion GTT-Technologies' 7th Annual Users' Meeting, Herzogenrath, Germany, July -3, 205 Petteri Kangas and Pertti Koukkari VTT Technical Research Centre of Finland

2 In 203: CFE for in the kraft recovery boiler modelling presented in GTT Annual Users meeting 2

3 Methodology

4 Methodology Constrained Free Energy (CFE) method CFE is an extension to Gibbs free energy method where additional immaterial constraints are incorporated to chemical system Chemical system can be constrained by extent of reaction, electrochemical potential, surface area or volume The distinct benefit of this method lies in the calculation of constrained chemical reactions, enthalpic effects and state properties simultaneously and interdependently ChemSheet is applied as modelling tool, as it allows extending chemical system with virtual constraints Kangas, P 205, Dissertation, Åbo Akademi University 4

5 5 Chemical system is constrained by defining immaterial constraints based on the extent of reactions Non-stoichiometric chemical system is solved by minimising the Gibbs energy with Lagrange method of undetermined multipliers Additional immaterial components and constituents are implemented into system for applying chemical kinetics Methodology Constrained Free Energy (CFE) method Y L X K L K L K K Y L L L,,,,,,,, K k L l K k l k kl l k k b n n G L 0 L l kl l k n k k n n L 0 l k K k kl l b n L l n x C x (T) f x x dt r t x x 0 xr xf x r r r b a b j k r ) / ( exp RT E B AT k (constant value) (temperature dependent model) (global and elementary kinetic reactions)

6 NO emissions

7 Modelling NO emissions with CFE Aim: Evaluate how reaction kinetic models could be implemented into CFE methodology Model thermal and fuel NO emissions CFE method Constrained thermodynamic equilibrium with major kinetic reactions implemented [2,3] ChemSheet [5] applied as modelling tool Reference and validation Pure kinetic model of combustion and NO formation ÅA mechanism 37 kinetic reactions applied ChemKin applied as modelling tool 7

8 (i) NO emissions - Dry air Extended stoichiometric matrix for CFE Table - Extended stoichiometric matrix; Total 60 gaseous species and 2 immaterial constraints; r : N 2 + O NO + N; r 2 : N + O 2 NO + O Phase Constituent O N N* NO* Gas O O 2 2 N N 2 2 NO NO 2 2 Constraints r : N 2 + O NO + N r 2 : N + O 2 NO + O - 8

(i) NO emissions - Dry air Synthetic air: 2 v-% of O 2 and 79 v-% of N 2 No moisture Heating air (no combustion here) Temperature range: 200-2200 C Pressure bar Zeldovich mechanism applied 2 reaction

9 (i) NO emissions - Dry air Synthetic air: 2 v-% of O 2 and 79 v-% of N 2 No moisture Heating air (no combustion here) Temperature range: C Pressure bar Zeldovich mechanism applied 2 reaction limiting NO formation r : N 2 + O NO + N r 2 : N + O 2 NO + O Local equilibrium considered otherwise (eg amount of radical O) => CFE model agrees with kinetic model when dry air is considered Figure 6 NO formation in dry air 9

10 (ii) NO emissions - Combustion of CO Extending stoichiometric matrix Table 3 Extended stoichiometric matrix; Total 60 gaseous species and 3 immaterial constraints; r : N 2 + O NO + N; r 2 : CO + O 2 CO 2 + O; r 3 : CO + O + M CO 2 + M Phase Constituent O C N Ar NO* O* CO* Gas CO CO 2 2 O N 2 N 2 2 NO Ar Constraints r : N 2 + O NO + N r 2 : CO + O 2 CO 2 + O - r 3 : CO + O + M CO 2 + M - - 0

(ii) NO emissions - Combustion of CO; Dry air Combustion of carbon monoxide Excess air: λ = 2 Dry air: 2 v-% of O 2 and 79 v-% of N 2 Two additional constraints for CO + O: r 2 : CO + O 2 CO 2 + O r

11 (ii) NO emissions - Combustion of CO; Dry air Combustion of carbon monoxide Excess air: λ = 2 Dry air: 2 v-% of O 2 and 79 v-% of N 2 Two additional constraints for CO + O: r 2 : CO + O 2 CO 2 + O r 3 : CO + O + M CO 2 + M Simplified Zeldovich mechanism for N: r : N 2 + O NO + N NO formation during combustion (CFE) agrees with reference model (pure kinetics) when dry air is considered Figure 3 NO formation; CO combustion; 500 C; Dry air; Figure 4 NO formation; CO combustion; 500 C; Dry air;

12 (iii) NO emissions - Combustion of CO; Wet air Rapid combustion if moisture present Super-equilibrium of O-, H-, and OH-radicals formed Additional elementary reactions needed (O-, H- and OH- radicals) Additional constraints implemented to calculation and stoichiometric matrix is extended again Table 4 Elementary reactions for CO, wet air Constituent Reaction CO CO+OH CO 2 +H CO+O+M CO 2 +M H CO+OH CO 2 +H O+OH H+O 2 OH CO+OH CO 2 +H O+OH H+O 2 OH+OH O+O O O+OH H+O 2 CO+O+M CO 2 +M OH+OH O+O 2

13 (iii) NO emissions - Combustion of CO; wet air Extending stoichiometric matrix Table 5 Extended stoichiometric matrix; Total 60 gaseous species and 5 immaterial constraints; Phase Constituent O H C N Ar CO* NO* O* H* OH* Gas CO CO O 2 O H O NO Ar Constraints r : ΣΔr CO r 2 : ΣΔr NO r 3 : ΣΔr O r 4 : ΣΔr H r 5 : ΣΔr OH 3

(iii) NO emissions - Combustion of CO; Quasi steady-state assumption Two

Oscillation, when Δr 2 Δr 3 n O Quasi steady-state Figure 6 NO formation;

d[o]/dt=0=> k 3 [CO][O][M]=k 2 [CO][O 2 ] [O]=k 2 /k 3 *[O 2 ]/[M]

14 (iii) NO emissions - Combustion of CO; Quasi steady-state assumption Two competing reactions (O-radical) r 2 : CO+O 2 CO 2 +O r 3 : CO+O+M CO 2 +M Oscillation, when Δr 2 Δr 3 n O Quasi steady-state Figure 6 NO formation; Euler-method One possible solution is quasi steady-state assumption d[o]/dt=0=> k 3 [CO][O][M]=k 2 [CO][O 2 ] [O]=k 2 /k 3 *[O 2 ]/[M] Improves stability Fails close to O(eq) Figure 8 NO formation; Steady-state assumption 4

15 (iv) NO emissions - Combustion of CH 4 Larger amount of reactions are involved for CH 4 combustion and related Several hydrocarbons involved for NO X formation Need for extending stoichiometric matric further Several competing reactions could cause numerical problems during simulation; stiff chemical system Global kinetic model applied instead of models based on the elementary kinetic reactions Table 6 Applied global kinetic model Reaction R N+NO N 2 +O R2 CH 4 +½O 2 CO+2 R3 CH 4 + O CO+3 R4 +½O 2 O R5 O +½O 2 R6 CO+ O CO 2 + R7 NH 3 +O 2 NO+ O+½ R8 NH 3 +NO N 2 + O+½ 5

16 (iv) NO emissions - Combustion of CH 4 Table 6 Extended stoichiometric matrix; Total 60 gaseous species and 5 immaterial constraints; Phase Constituent O H C N Ar CH 4 * CO* NH 3 * NO* * Gas CO CO O 2 O CH 4 4 NH 3 3 NO Ar Constraints r : ΣΔr CH4 r 2 : ΣΔr CO r 3 : ΣΔr NH3 r 4 : ΣΔr NO r 5 : ΣΔr H2 6

17 (iv) NO emissions - Combustion of CH 4 Separate models for: oxidation of methane oxidation of carbon monoxide oxidation of ammonia CFE method is applicable for modelling fuel NO emissions if global kinetic models are used => However timing is slightly off as model does not consider radical build-up 7

18 Gasification

Gasification - Background During biomass gasification light hydrocarbons (eg : CH 4,, H 4,, C 3 H 8, C 6 ), ammonia, tars and char are formed among syngas This affects on the composition of major

19 Gasification - Background During biomass gasification light hydrocarbons (eg : CH 4,, H 4,, C 3 H 8, C 6 ), ammonia, tars and char are formed among syngas This affects on the composition of major species in syngas (CO, CO 2,, O) Assuming thermodynamic equilibrium the superequilibrium of hydrocarbons, ammonia, tar and char is not taken into account Phenomena based and semi-empirical models have been developed for describing the superequilibrium Phenomena based models become tedious with several parameters Current semi-empirical models provide only ad-hoc solution Aim: evaluate the use of experimental models with CFE and to study different model structures Figure Example of gasification process [] Figure 2 Example of multi-step semi-empirical model 9

20 Gasification - Cases with different sets of constraints EQ: Thermodynamic equilibrium is used as base case No additional constraints are defined Super-EQ: super-equilibrium where carbon conversion, tar and ammonia formation are defined is studied In addition the amount of carbon in volatile hydrocarbons (CH 4,, H 4,, C 3 H 8 and C 6 ) is fixed Super-EQ2 where previous case is extended by introducing additional constraint for the amount of hydrogen in volatile hydrocarbons Super-EQ3 replaces the hydrogen constraint by introducing a constraint for CH 4 Super-EQ4 defines the amount of carbon bound to unsaturated hydrocarbons hydrocarbons ( and H 4 ) and benzene (C 6 ) Super-EQ5 introduces a fully constrained system where the amount of every hydrocarbon constituent is defined by empirical models However the water-gas shift reaction is not constrained, but local equilibrium is assumed 20

Gasification Extended stoichiometric matrix Components: C-O-H-N-S Phases: gas (4

virtual components 2 virtual constituents Extended model is used to predict the

combinations of immaterial constraints are evaluated from thermodynamic equilibrium

21 Gasification Extended stoichiometric matrix Components: C-O-H-N-S Phases: gas (4 constituents), biomass (4), water, char and ash Extending matrix with CFE method: 2 virtual components 2 virtual constituents Extended model is used to predict the super-equilibrium of char, tar, ammonia, and light hydrocarbons in syngas Different combinations of immaterial constraints are evaluated from thermodynamic equilibrium to fully constrained system Figure 6 Extending chemical system with additional immaterial constraints 2

22 Gasification - EQ - stoichiometric matrix Table Extended stoichiometric matrix C-O-H-N-Si system Phases Constituents Cases C O H N Si 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 Gas phase CO 0,,2,3,4,5 0,,2,3,4,5 2 CO 2 0,,2,3,4,5 2 N 2 0,,2,3,4,5 2 O 0,,2,3,4,5 2 CH 4 0,,2,3,4,5 4 0,,2,3,4,5 2 2 H 4 0,,2,3,4, ,,2,3,4,5 2 6 C 3 H 8 0,,2,3,4,5 3 8 C 6 0,,2,3,4,5 6 6 C 0 H 8 0,,2,3,4,5 0 8 NH 3 0,,2,3,4,5 3 O 2 0,,2,3,4,5 2 Biomass C 0,,2,3,4,5 O 0,,2,3,4,5 H 0,,2,3,4,5 N 0,,2,3,4,5 Water O 0,,2,3,4,5 2 Char C 0,,2,3,4,5 Ash SiO 2 0,,2,3,4,5 2 No additional virtual constraints 22

23 Gasification Super-EQ - Extended stoichiometric matrix Table 2 Extended stoichiometric matrix C-O-H-N-Si system Phases Constituents Cases C O H N Si Char* HC_C* Tar* Amm* 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5,2,3,4,5,2,3,4,2,3,4,5 0,,2,3,4,5 Gas phase CO 0,,2,3,4,5 0,,2,3,4,5 2 CO 2 0,,2,3,4,5 2 N 2 0,,2,3,4,5 2 O 0,,2,3,4,5 2 CH 4 0,,2,3,4,5 4 0,,2,3,4, H 4 0,,2,3,4, ,,2,3,4, C 3 H 8 0,,2,3,4, C 6 0,,2,3,4, C 0 H 8 0,,2,3,4, NH 3 0,,2,3,4,5 3 O 2 0,,2,3,4,5 2 Biomass C 0,,2,3,4,5 O 0,,2,3,4,5 H 0,,2,3,4,5 N 0,,2,3,4,5 Water O 0,,2,3,4,5 2 Char C 0,,2,3,4,5 Ash SiO 2 0,,2,3,4,5 2 Constraints R_Char,2,3,4,5 R_HC_C,2,3,4 R_Tar,2,3,4,5 R_Amm,2,3,4,5 Constraints for char, tar, ammonia, and carbon in hydrocarbons 23

24 Gasification Super-EQ2 - Extended stoichiometric matrix Table 3 Extended stoichiometric matrix C-O-H-N-Si system Phases Constituents Cases C O H N Si Char* HC_C* HC_H* Tar* Amm* 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5,2,3,4,5,2,3,4 2,2,3,4,5 0,,2,3,4,5 Gas phase CO 0,,2,3,4,5 0,,2,3,4,5 2 CO 2 0,,2,3,4,5 2 N 2 0,,2,3,4,5 2 O 0,,2,3,4,5 2 CH 4 0,,2,3,4, ,,2,3,4, H 4 0,,2,3,4, ,,2,3,4, C 3 H 8 0,,2,3,4, C 6 0,,2,3,4, C 0 H 8 0,,2,3,4, NH 3 0,,2,3,4,5 3 O 2 0,,2,3,4,5 2 Biomass C 0,,2,3,4,5 O 0,,2,3,4,5 H 0,,2,3,4,5 N 0,,2,3,4,5 Water O 0,,2,3,4,5 2 Char C 0,,2,3,4,5 Ash SiO 2 0,,2,3,4,5 2 Constraints R_Char,2,3,4,5 R_HC_C,2,3,4 R_HC_ R_Tar,2,3,4,5 R_Amm,2,3,4,5 Constraints for char, tar, ammonia, carbon in hydrocarbons and hydrogen in hydrocarbons 24

25 Gasification Super-EQ3 - Extended stoichiometric matrix Table 4 Extended stoichiometric matrix C-O-H-N-Si system Phases Constituents Cases C O H N Si Char* HC_C* Tar* Amm* CH 4 * 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5,2,3,4,5,2,3,4,2,3,4,5 0,,2,3,4,5 3,5 Gas phase CO 0,,2,3,4,5 0,,2,3,4,5 2 CO 2 0,,2,3,4,5 2 N 2 0,,2,3,4,5 2 O 0,,2,3,4,5 2 CH 4 0,,2,3,4,5 4 0,,2,3,4, H 4 0,,2,3,4, ,,2,3,4, C 3 H 8 0,,2,3,4, C 6 0,,2,3,4, C 0 H 8 0,,2,3,4, NH 3 0,,2,3,4,5 3 O 2 0,,2,3,4,5 2 Biomass C 0,,2,3,4,5 O 0,,2,3,4,5 H 0,,2,3,4,5 N 0,,2,3,4,5 Water O 0,,2,3,4,5 2 Char C 0,,2,3,4,5 Ash SiO 2 0,,2,3,4,5 2 Constraints R_Char,2,3,4,5 R_HC_C,2,3,4 R_Tar,2,3,4,5 R_Amm,2,3,4,5 R_CH 4 3,5 Constraints for char, tar, ammonia, carbon in hydrocarbons and CH 4 25

26 Gasification Super-EQ4 - Extended stoichiometric matrix Table 5 Extended stoichiometric matrix C-O-H-N-Si system Phases Constituents Cases C O H N Si Char* HC_C* Tar* Amm* UN_C* 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5,2,3,4,5,2,3,4,2,3,4,5 0,,2,3,4,5 4 Gas phase CO 0,,2,3,4,5 0,,2,3,4,5 2 CO 2 0,,2,3,4,5 2 N 2 0,,2,3,4,5 2 O 0,,2,3,4,5 2 CH 4 0,,2,3,4,5 4 0,,2,3,4, H 4 0,,2,3,4, ,,2,3,4, C 3 H 8 0,,2,3,4, C 6 0,,2,3,4, C 0 H 8 0,,2,3,4, NH 3 0,,2,3,4,5 3 O 2 0,,2,3,4,5 2 Biomass C 0,,2,3,4,5 O 0,,2,3,4,5 H 0,,2,3,4,5 N 0,,2,3,4,5 Water O 0,,2,3,4,5 2 Char C 0,,2,3,4,5 Ash SiO 2 0,,2,3,4,5 2 Constraints R_Char,2,3,4,5 R_HC_C,2,3,4 R_Tar,2,3,4,5 R_Amm,2,3,4,5 R_UN_C 4 Constraints for char, tar, ammonia, carbon in hydrocarbons and carbon in unsaturated hydrocarbons + aromatics 26

27 Gasification Super-EQ5 - Extended stoichiometric matrix Table 6 Extended stoichiometric matrix C-O-H-N-Si system Phases Constituents Cases C O H N Si Char* Tar* Amm* CH 4 * * H 4 * * C 3 H 8 * C 6 * 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5,2,3,4,5,2,3,4,5 0,,2,3,4,5 3, Gas phase CO 0,,2,3,4,5 0,,2,3,4,5 2 CO 2 0,,2,3,4,5 2 N 2 0,,2,3,4,5 2 O 0,,2,3,4,5 2 CH 4 0,,2,3,4,5 4 0,,2,3,4,5 2 2 H 4 0,,2,3,4, ,,2,3,4,5 2 6 C 3 H 8 0,,2,3,4,5 3 8 C 6 0,,2,3,4,5 6 6 C 0 H 8 0,,2,3,4, NH 3 0,,2,3,4,5 3 O 2 0,,2,3,4,5 2 Biomass C 0,,2,3,4,5 O 0,,2,3,4,5 H 0,,2,3,4,5 N 0,,2,3,4,5 Water O 0,,2,3,4,5 2 Char C 0,,2,3,4,5 Ash SiO 2 0,,2,3,4,5 2 Constraints R_Char,2,3,4,5 R_Tar,2,3,4,5 R_Amm,2,3,4,5 R_CH 4 3,5 R_ 5 R_ H 4 5 R_ 5 R_C 3 H 8 5 R_C 6 5 Constraints for char, tar, ammonia, CH 4,, H 4,, C 3 H 8 and C 6 27

28 Gasification Full extended stoichiometric matrix Table 7 Extended stoichiometric matrix C-O-H-N-Si system Phases Constituents Cases C O H N Si Char* HC_C* HC_H* Tar* Amm* CH 4 * * H 4 * * C 3 H 8 * C 6 * UN_C* 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5 0,,2,3,4,5,2,3,4,5,2,3,4 2,2,3,4,5 0,,2,3,4,5 3, Gas phase CO 0,,2,3,4,5 H 0,,2,3,4,5 2 2 CO 0,,2,3,4,5 2 2 N 0,,2,3,4,5 2 2 O 0,,2,3,4,5 2 CH 0,,2,3,4, H 0,,2,3,4, H 0,,2,3,4, H 0,,2,3,4, C 3 H 0,,2,3,4, C 6 H 0,,2,3,4, C 0 H 0,,2,3,4, NH 0,,2,3,4,5 3 3 O 0,,2,3,4,5 2 2 Biomass C 0,,2,3,4,5 O 0,,2,3,4,5 H 0,,2,3,4,5 N 0,,2,3,4,5 Water O 0,,2,3,4,5 2 Char C 0,,2,3,4,5 Ash SiO 0,,2,3,4,5 2 2 Constraints R_Char,2,3,4,5 R_HC_C,2,3,4 R_HC_ R_Tar,2,3,4,5 R_Amm,2,3,4,5 R_CH 3,5 4 R_ H 5 2 R_ H 5 4 R_ H 5 6 R_C 3 H 5 8 R_8 6 H 5 6 R_UN_C 4

29 Gasification Applied constraints Temperature dependent constraints: carbon in char carbon in hydrocarbons hydrogen in hydrocarbons carbon in unsaturated and aromatics carbon in CH 4,, H 4,, C 3 H 8 Constant values: carbon in tar nitrogen in ammonia Table 8 Applied constraints for SuperEQ SuperEQ5 cases Experimental model is taken from literature Constraint Unit Expression Case C in char [mol/kg carbon in dry biomass ] *T,2,3,4,5 C in tar [mol/kg dry biomass ] 30,2,3,4,5 N in ammonia [mol/kg dry biomass ] 0042,2,3,4,5 C in hydrocarbons [mol/kg dry biomass ] *T,2,3 H in hydrocarbons [mol/kg dry biomass ] *T 2 C in unsaturated and aromatic [mol/kg dry biomass ] *T 4 CH 4 [mol/kg dry biomass ] *T 3,5 [mol/kg dry biomass ] *T 5 H 4 [mol/kg dry biomass ] *T 5 [mol/kg dry biomass ] *T 5 C 3 H 8 [mol/kg dry biomass ] *T 5 C 6 [mol/kg dry biomass ] carbon in C 6 Models based on empirical data 29

30 Gasification Validation Five different gasification setups modelled (A-E) Six different model construction evaluated (Cases EQ, Super- EQ-Super-EQ5) Table 9 Validation data Nitrogen removed Data from [] A B C D E C in dry biomass [w-%] H in dry biomass [w-%] N in dry biomass [w-%] O in dry biomass [w-%] Ash in dry biomass [w-%] Fuel moisture [%] Gasifier temp [C] Pressure [MPa] Oxygen-to-fuel ratio [kg/kg dry fuel] Steam-to-fuel ratio [kg/kg dry fuel] CO [v-%] CO 2 [v-%] [v-%] CH 4 [v-%] O [v-%]

31 Gasification Validation: Measured vs modelled syngas components (CO, O, CO 2, and CH 4 ) Ref: Kangas, P, et al, 204 Fuel 29, doi:006/jfuel

32 Gasification - Validation of CFE model with other gasifiers Ref: Kangas, P, et al, 204 Fuel 29, doi:006/jfuel

33 In Delft: Biomass gasification in supercritical water I 2-phase model II single SC fluid phase 0 w-% wood, 34 Mpa, 409 C 29 min 06 M-glucose, 28 Mpa, 600 C 50 sec Yakaboylu,O et al, Fuel Processing Technology, 38, (205),

34 Conclusions

35 Conclusions this study CFE is successfully applied for modelling biomass gasification and NO emissions Experimental model, global kinetic models and reactions based elementary kinetic reactions can be implemented as constraints in CFE calculation Requires less parameters than a mechanistic kinetic approach Best result are achieved when moderate amount of reactions are limiting the system Kangas, P 205, Dissertation, Åbo Akademi University 35

Conclusions - Other uses of kinetic constraints In chemical and

efficiency (up to 40 % savings in energy and/or CO 2 release) In

biofuel In pulp and papermaking processes for control of chemical

36 Conclusions - Other uses of kinetic constraints In chemical and metallurgical reactors for improved control of autogenic energy efficiency (up to 40 % savings in energy and/or CO 2 release) In rotary drums and other furnaces for replacement of fossil fuels with biofuel In pulp and papermaking processes for control of chemical dosage and process ph In developing new chemistry concepts for in-situ reactions 36

Conclusions CFE provides a rigorous method to include work-related and dynamic factors to min(g) Serves for quantitative calculation of both partial equilibria and

provide data of reaction rate controlled local chemical equilibrium systems Has gained increasing interest with its wide applicability in both materials and process

37 Conclusions CFE provides a rigorous method to include work-related and dynamic factors to min(g) Serves for quantitative calculation of both partial equilibria and para-equilibrium systems in chemistry and materials science Can be used for approximate local equilibria in complex reaction systems With accurate reaction kinetics, will provide data of reaction rate controlled local chemical equilibrium systems Has gained increasing interest with its wide applicability in both materials and process research* Overviews published in: wwwvttfi/inf/pdf/technology/204/t60pdf wwwvttfi/inf/pdf/science/205/s92pdf * 37

Three-dimensional modelling of steam-oxygen gasification in a circulating fluidized bed

Lappeenranta University of Technology From the SelectedWorks of Kari Myöhänen June, 2012 Three-dimensional modelling of steam-oxygen gasification in a circulating fluidized bed Kari Myöhänen, Lappeenranta