Simulation of methanol synthesis from syngas obtained through biomass gasification using Aspen Plus

Transcription

1 6th International Conference on Sustainable Solid Waste Management (NAXOS 2018) Simulation of methanol synthesis from syngas biomass gasification using Aspen Plus M. Puig-Gamero, J. Argudo-Santamaria, J. L. Valverde, P. Sanchez, and L. Sanchez-Silva Department of Chemical Engineering, University of Castilla-La Mancha, Spain Naxos Island, 15 th June

2 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 2

3 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 3

4 Energy demand Fossil fuels 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process Disadvantages Advantages Problems derived from their use 3. Results 3.1. Gasification simulation model Renewable Energies 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement 4

5 BIOMASS All organic material including trees, crops, algae and residues which are susceptible to be converted into energy Types of biomass 1. Introduction 2. Aspen plus modelling First-generation biomass 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process Second-generation biomass 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission Third-generation biomass 3.4.Optimal process improvement Fourth-generation biomass Pine bark 5

6 Energy conversion of biomass Thermochemical process Pyrolysis Combustion Gasification Licuefaction 1. Introduction 2. Aspen plus modelling Biochemical process Alcoholic fermentation Anaerobic digestion 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement Uses of syngas Syngas Methanation Fischer-Tropsch Methanol synthesis Intermedies (Toluene, isobutane) 6

7 Gasification can be defined as the conversion of biomass into a gaseous fuel by heating in a partial oxidation atmosphere 1. Introduction Biomass Gasifying agent (steam) Syngas (CO, H 2, CO 2, CH 4 ) 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results Reactions involved in gasification process: Water Gas: 3.1. Gasification simulation model 3.2. Methanol synthesis simulation Water gas shift: 3.3. Gas emission 3.4.Optimal process improvement Steam reforming: 3 Boudouard: 2 Tar forming:

8 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement Feedstock Syngas CO H 2 CO 2 CH 4 Traces Methanol synthesis Syngas composition: 2,1 2,4 2,5 Reactions 2 3 Low conversion Catalys: Cu/ZnO 0,130,14 8

9 Aspen Plus SPEED 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process PRICE The main objetive of this research was the simulation of three integrated process: pine gasification, syngas cleaning and metanol synthesis using Aspen Pilot plant Plus Simulation process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement Blocks Streams Design specifications, codes Pilot plant 9

10 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 10

11 Aspen Plus flowsheet process Syngas purification V-5 1. Introduction 2. Aspen plus modelling Gasification process 22 V-1 23 C-2 24 PSA2 26 PSA3 30 V PSA4 36 SPLIT V MIXER Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 1 R SEP-1 5 R-2 SEP-2 4 Q-2 10 Q-3 Q-1 R R-3 R HEATX HEATX MIXER-1 16 SEP C-1 SEP PSA1 27 V MIXER-2 33 C-3 40 SPLIT MIXER-3 45 C-4 46 Methanol synthesis V-6 COOLER-1 METSEP R Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement

12 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 12

13 1 R-1 3 Gasification process 11 R-2 MIXER-1 SEP-3 SEP R-3 R-4 Q Q Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2 SEP-1 R-5 Q-1 HEATX Methanol synthesis process 5 3. Results 3.1. Gasification simulation model 7 HEATX Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement Thermodynamic equilibrium model (reaction kinetics are unknown) 13

14 Gasification process 1. Introduction 2. Aspen plus modelling 1 R R-2 MIXER-1 SEP-3 SEP R-3 R-4 Q Q Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 2 SEP-1 Q-1 HEATX R-1 (RYIELD): R-5 Biomass pyrolysis reactor, it decomposed the biomass into its compounds and ash Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement 7 HEATX-1 R-2 (RGIBBS): It models chemical equilibrium minimizing the Gibss free energy. It was used to produce 6 8 CO 2, CO, CH 4,H 2 SandNH 3. SEP-1: Separator of the amount 9 of char necessary to achieve the gasification temperature. 14

15 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 1 R-1 2 SEP-1 Gasification process R-5 (RSTOIC): Char combustion reactor. 11 R-2 MIXER-1 SEP-3 SEP R-3 R-4 Q Heatx-1: Exchange heat between the outlet stream from R-5 and the 3 air inlet stream. Q-3 Design specifications: Q-1 1. Amount of char for combustion 2. Air flow HEATX R Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement 7 Heatx-1 HEATX

16 1 R-1 3 Gasification process 11 R-2 MIXER-1 SEP-3 SEP R-3 R-4 Q Q Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement 2 SEP-1 Q-1 R HEATX-1 Heatx-2 HEATX R-3 (RGIBBS): It simulated the gasifier. R-4 (RSTOIC): It was used to model the tar 6 8 reforming using Dolomite as a catalyst. Heatx-2: Heater to warm up the 9 gasifying agent (water steam). 16

17 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement 1 11 R-2 MIXER-1 SEP-3 SEP-2 R R-3 R-4 Q Q SEP-1 Q-1 HEATX R HEATX-1 The main blocks of 6 gasification 8 process were integrated energy through Q-1, Q-2 and Q-3. Energy requirements = 0 Gasification process 9 17

18 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 18

19 Specifications: 2,1 Syngas cleaning: Pressure 2,4 2,5 0,13 0,14 29 PSA4 34 V-5 35 PSA Introduction 2. Aspen plus modelling 22 V-1 23 C-2 24 PSA 2 V-3 31 SPLIT-2 32 V-4 37 MIXER Syngas cleaning: Pressure 2.3. Methanol synthesis process SEP-3 18 C-1 SEP PSA Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission V C-3 40 SPLIT Optimal process improvement MIXER C-4 25 MIXER- 3 Temperature and pressure of adsorbers: 35 ºC and 30 atm 19

20 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement SEP-3 17 SEP-3 separates the char 18 C-1 SEP-4 Syngas cleaning: Pressure SEP-4 separates the water condensed Water PSA 1 22 V-1 PSA1 23 C-2 24 PSA 2 CO PSA2 27 V PSA 3 MIXER-2 2 C-3 29 PSA 4 V-4 MIXER- 4 SPLIT-2 MIXER-2 V-3 mix the H 2 and 37 CO PSA1 separates the H 2 PSA2 separates the CO SPLIT-1 separates the CO to achieve the H 2 /CO ratio SPLIT SPLIT-1 V C-4 H 2 25 MIXER- 3 20

21 Syngas cleaning: Pressure V-5 PSA 3 29 PSA3 PSA4 PSA Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure SEP-3 V-1 C PSA3 separates the CO SEP-4 2 C-1 24 PSA 2 SPLIT-2 V-3 31 CO 2 32 V-4 CH 4 37 MIXER Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement PSA1 PSA4 separates the CH V C-3 40 SPLIT-1 42 MIXER C-4 25 MIXER- 3 21

22 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 22

23 45 C-4 Methanol synthesis process V-6 COOLER METSEP 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure MIXER-3 46 R-6 53 METHANOL 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement R-6 simulates the metanol synthesis 2 3 Catalyst: Cu/ZnO METSEP separates the crude methanol, gas-phase and impurities 23

24 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 24

25 Condicions: Temperature: 831ºC Pressure: 1 atm Model validation Biomass: Wood pellets 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement Compound Experimental composition * (vol.% db) Predicted composition (vol.% db) H CO CO CH ,2 *(British Columbia University) Error: 5-7 % 25

26 a) H 2 Effect of the S/B mass ratio on the syngas composition 800 ºC 900 ºC 1000 ºC b) CO 800 ºC 900 ºC 1000 ºC 1. Introduction H 2 (vol.% dry basis) CO (vol.% dry basis) Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement CO 2 (vol.% dry basis) S/B S/B mass (ratio) ratio 80 CO ºC 900 ºC ºC CH 4 60 c) d) CH 4 (vol.% dry basis) S/B S/B mass (ratio) ratio 800 ºC 900 ºC 1000 ºC S/B S/B mass (ratio) ratio S/B S/B mass (ratio) ratio 26

27 a) H 2 Effect of the S/B mass ratio on the syngas composition 800 ºC 900 ºC 1000 ºC b) 80 H 2 y CO 2 60 CO 800 ºC 900 ºC 1000 ºC 1. Introduction H 2 (vol.% dry basis) CO (vol.% dry basis) CO y CH Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement CO 2 (vol.% dry basis) Water Gas: S/B S/B mass (ratio) ratio Water gas shift: CO 2 CH ºC 900 ºC ºC Steam reforming: 60 3 c) d) CH 4 (vol.% dry basis) Boudouard: 2 Tar forming: S/B S/B mass (ratio) ratio 800 ºC 900 ºC 1000 ºC S/B S/B mass (ratio) ratio S/B S/B mass (ratio) ratio 27

28 1. Introduction 2. Aspen plus modelling e) C 6 H 6 (vol.% dry basis) C 6 H 6 Effect of the S/B mass ratio on the syngas composition 800 ºC 900 ºC 1000 ºC H 2 /CO mole ratio ºC 900 ºC 1000 ºC H 2 /CO = 2, Syngas cleaning: Pressure S/B (ratio) S/B mass ratio S/B mass ratio 0, Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation CH 3 OH 800 ºC 900 ºC 1000 ºC 3.3. Gas emission 3.4.Optimal process improvement CH 3 OH (kg/h) S/B = 0, S/B mass ratio 28

29 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 3. Results 2.3. Methanol synthesis process 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission Gas composition (vol.% dry basis) H 2 CO CO 2 CH 4 C 6 H 6 CH 3 OH Effect of gasification temperature Temperature (ºC) CH 3 OH yield (kg/h) 800 ºC 900 ºC 1000 ºC H 2, CO and CH 3 OH CO 2, CH 4 and C 6 H Optimal process improvement H 2 /CO mole ratio S/B mass ratio 29

30 Effect of gasification temperature Water Gas: Steam reforming: 3 Endothermics 1. Introduction 2. Aspen plus modelling Boudouard: 2 Water gas shift: Exothermics 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process Tar forming: Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement Temperature = 900ºC H 2, CO and CH 3 OH CO 2, CH 4 and C 6 H 6 30

31 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 31

32 Methanol synthesis: validation Stoichiometric reactor Equilibrium reactor % Error CH 3 OH (kg/h) Introduction Pressure and temperature influence on metanol production 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results ºC 240 ºC 260 ºC CH 3 OH Pressure 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement CH 3 OH production (kg/h) Working at high pressures: Operational risks High costs Human danger Pressure (atm) Industrial plants 55 atm 33

33 Pressure and temperatura influence on metanol production P= 55 atm CH 3 OH Temperature 32 kg/h 1. Introduction 2. Aspen plus modelling 9 kg/h 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation - At high temperatures, the catalyst can be damaged Gas emission 3.4.Optimal process improvement - At low temperatures can reduce the reaction rate Optimal conditions for metanol synthesis : 55 atm 220 ºC 34

34 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 34

35 Capture and gas emissions Capture: 80% CO 2 1. Introduction 2. Aspen plus modelling 95% CH Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement CO 2 produced from the combustión chamber Low NH 3 and H 2 S emission Emisión de gases (Kg/h) 36

36 obtained through 1. Introduction 2. Aspen Plus modelling 2.2. Syngas cleaning: Pressure 2.2. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4. Optimal process improvement 36

37 1. Introduction 2. Aspen plus modelling Optimal process improvement Char to combustion chamber: 40% 10%. C available CO methanol. CO CO 2 CO 2 capture 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement Combustion chamber: H 2 reacted with O 2 to produce H 2 O and decrease CO 2 formation. NH 3 and H 2 S were kept Caudal másico (Kg/h) Caudal másico (Kg/h) 38

38 Final simulation T = 900ºC S/B mass ratio = 0.9 Syngas cleaning V-5 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model Gasification process 1 R SEP-1 5 Q-3 R-2 R-5 SEP-2 MIXER R-3 R-4 Q Q-1 7 HEATX HEATX SEP C-1 SEP PSA1 22 V-1 23 C-2 24 PSA2 27 V PSA3 30 V-3 33 C-3 39 MIXER PSA4 36 V-4 SPLIT-2 MIXER SPLIT MIXER-3 38 C R-6 T = 220ºC P = 55 atm Methanol synthesis V-6 49 COOLER-1 50 METSEP Methanol synthesis simulation Gas emission 3.4.Optimal process improvement Recycle 39

39 Acknowledgement Authors acknowledge the financial support from the Spanish Ministry of Education, Culture and Sports for FPU grant (FPU15/02653). 1. Introduction 2. Aspen plus modelling 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model Spanish Ministry of Education, Culture and Sports for FPU grant Thanks you very much for your attention! 3.2. Methanol synthesis simulation 3.3. Gas emmission 3.4.Optimal process improvement 39

40 6th International Conference on Sustainable Solid Waste Management (NAXOS 2018) Simulation of methanol synthesis from syngas biomass gasification M. Puig-Gamero, J. Argudo-Santamaria, J. L. Valverde, P. Sánchez, and L. Sanchez-Silva Department of Chemical Engineering, University of Castilla-La Mancha, Spain Naxos Island, 15 th June

41 Conclusions - The gasification process was simulated using a thermodynamic equilibrium model which is based on the minimization of the Gibbs free energy of the system. A double chamber gasifier, which allows the separation of the gasification and combustion zones to obtain a high-quality gas, was considered. The influence of the steam to biomass (S/B) mass ratio and the temperature on the gas product composition and methanol production was studied. The best calculated operational condition of the process was 900ºC and a S/B mass ratio of One of the main technical barriers for the syngas production is the presence of tar coming from the gasification process. According to the simulation performed, tar production was hindered with increasing temperatures and steam flow rates. grant Dolomite was used as the catalyst in the decomposition of tar due to its low cost. - A pressure process was considered to clean the syngas and simultaneously capture the greenhouse gases. Therefore, about 80% of the CO 2 and 95% of the CH 4 were sequestered. - Once the H 2 /CO molar ratio of the clean syngas was fitted, the methanol synthesis proceeded. Although the methanol production is favoured at high pressures and low temperatures, a pressure of 55 atm was selected to avoid operational issues. Thus, 220ºC and 55 atm were selected as the optimal operation conditions for the methanol synthesis. - Finally, to improve the process yield, the methanol synthesis waste stream is recycled to the combustion chamber. With this recycle, the carbon required to burn is reduced from 40 to 10%. Thus, there is a higher amount of carbon available to be used in the gasification process

42 REACTING AND GAS ANALYSIS UNITS CHARACCTERIZATION Thermogravimetric analysis: Thermogravimetric analyzer TGA-DSC 1 (METTLER Toledo) Mass spectrometric analysis: Mass spectrometer Thermostar-GSD 320/quadrupole mass analyzer (PFEIFFER VACUUM) Mineral content determination: Inductively coupled plasma (ICP) (Liberty Sequential. Varian) Proximate analysis: Standard Procedure Volatile matter (VM): UNE-EN Ash content (AC): UNE-EN Moisture content (MC): UNE-EN Fixed Carbon* dab =100 (VM+AC+MC) *dab Ultimate analysis: CHNS/O analyzer (LECO CHNS-932) O* dab = 100-(C+H+N+S)* dab 42

43 Tar C 3 H 8, C 6 H 6, C 7 H 8, C 8 H 8, C 4 H 10, C 6 H 12 Tar craking Operating issues due to tar condensation 1. Introduction 2. Aspen plus modelling Removal Primary process: Optimization of gasifier and operating conditions Secondary process: Catalytic process. DOLOMITE 2.2. Syngas cleaning: Pressure 2.3. Methanol synthesis process 3. Results 3.1. Gasification simulation model 3.2. Methanol synthesis simulation 3.3. Gas emission 3.4.Optimal process improvement S/B= 0.6 T = 800 ºC