Methanation of CO 2. the power to gas approach. Chair Applied Physics, Cottbus, Germany Brandenburgische Technische Universität Cottbus (BTU)

Transcription

1 Methanation of CO 2 the power to gas approach Klaus Müller, Johannes Israel, Fabian Rachow, Michael Fleige, Matthias Städter, Dieter Schmeißer Chair Applied Physics, Cottbus, Germany Brandenburgische Technische Universität Cottbus (BTU)

2 The Power to Gas approach

3 Energy ln conversion The Sabatier Reaction CO H 2 => CH H 2 O DH 0 = kj/mol, exothermic at 25 C Conversion X exp E Activation RT Arrhenius-plot of the Conversion Activation Energy, lowered by catalyst 55 dy/dx=-70,36 Educt 20 RuO 2 /Al 2 O 3 -catalyst Flow: 50ml/min Product 7 Reaction coordinate: for example, distance or binding angle 0,18 0,20 0,22 0,24 0,26 0/RT For a NiO/SiO 2 catalyst, an activation energy of 56.0 kj/mol is extracted For a RuO 2 /Al 2 O 3 catalyst, an activation energy of 70.4 kj/mol is calculated

4 Reaction of CO 2, even with H 2 is slow at low temperatures: We need an enhancement of the reaction rate: We need a catalyst! Catalysts: enhancment of reaction rate without structural/chemical changes without change of thermodynamic equilibrium Ref: Hans Niemantsverdriet, University of Technology, Eindhoven Enables lower energy effort for reactions Reactions in industrial scale (for example Haber-Bosch-method) selective production without byproducts the workhorse of chemical industry very important for CO 2 - utilisation

5 Experimental setup schematic Thermocouple 1 Reactor 0.8x10cm Thermocouple 2 Product gas Educt gas T= const Reaction Line 1: MFC-2a sccm min -1 N 2 MFC-2b 10- sccm min -1 N 2 MFC-2c 0-10 sccm min -1 N 2 Reaction Line 2: MFC-1a sccm min -1 H 2 MFC-1b sccm min -1 CO 2 MFC-1c sccm min -1 N 2 Micro channel reactor Reactor tube Financial Support: BMBF: GeoEN ~2 kg /d

6 Performance (%) (%) Catalysts for Methanation of CO 2 RuO/Al 2 O 3 NiO/SiO Ausbeute CH RuO/Al 4 2 O 3 Selektivität Temperatur ( C) Umsatz CO 2 Conversion X CO n CO, in 2 2 n n CO, in 2 CO, out 2 80 Yield Y CH n n 4 CH, out 4 CO, in Selectivity S CH n CH, out 4 4 n CO2, in n CO, out NiO/SiO 2 conversion CO2 Yield CH4 Selectivity Temperatur ( C)

7 CO 2 -Umsatz (%) Performance (%) (%) Reaktor ( C) Stability RuO/Al 2 O 3 Catalyst 370 NiO/SiO 2 Catalyst ,0 0,8 0,6 0,4 0,2 Umsatz CO 2 Ausbeute CH 4 Selektivität Reaktortemperatur ( C) Zeit (h) Ru/Al 2 O 3 50ml/min Temperatur 350 C 0, Zeit (h) Umsatz CO 2 Ausbeute CH 4 Selektivität Temperatur 350 C Zeit (h) NiO/SiO 2 50ml/min

8 Performance in % Technical Oxyfuel CO 2 NiO/SiO 2 catalyst Sabatier reaction with technical oxyfuel CO 2 from pilot plant Schwarze Pumpe Conversion CO 2 Yield CH 4 Selectivity Time / h Error of measurement ~ +5% Composition of Oxyfuel CO 2 CO 2 >99.7% N 2, Ar, O 2 <0.3% H 2 O < 50 ppm SO 2 < 2.5 ppm SO 3 < 0.5 ppm CO < 10 ppm NO < 5.0 ppm NO 2 < 15 ppm Reference: Vattenfall Europe, Pilot Plant Schwarze Pumpe In technical oxyfuel CO 2 (from pilot plant Schwarze Pumpe, Vattenfall) the conversion remains stable and is not influenced by contamination, Synthetic mixtures with more SO 2 (12.5ppm) and NO 2 (25ppm) show also no differences in performance.

9 The direct CO 2 methanation of flue gas from conventional power plants typical compositions CO 2 N 2 O 2 H 2 O SO 2 NO x H 2 S CH 4 Flue gas 14% 75% 5% 4% <90ppm <120ppm - - Oxyfuel >99% <0,3% >0,3% <50ppm <2,5ppm <15ppm - - Biogas 25-50% 0-10% 0-1% 0-6% % 50-75% A mixture of five parts N 2 and one part CO 2 reflects a synthetic flue gas composition. Four parts H 2 are necessary as additive for the methanation: Synthetic gas mixture N 2 : CO 2 :H 2 = 5:1:4 but without oxygen and minor SO 2 and NO 2 contaminations. Financial Support BMWi/03ET7002A

10 Performance % Performance % Methanation in synthetic flue gas Reference gas mixture with N 2 : CO 2 :H 2 = 5:1:4 NiO/SiO 2 catalyst 80 long term stability in a reference gas mixture S CH4,CO 2 X CO2 Y CH4,CO 2 components and ratio: 5N 2 : 4H 2 : 1CO 2 T furnace =350 C p reactor =1,2bar space vel.=1.200h process time (h) Umsatz CO 2 Ausbeute CH 4 Selektivität O 2 Gehalt im Rauchgas O 2 -Gehalt im Rauchgas [vol-%] A highly selective conversion of CO 2 with a CH 4 yield > 80% was measured also for flue gas. The catalyst performance is stable investigated time frame of 2 days Influence of oxygen is due to oxygen hydrogen reaction.

11 Demonstration plant Upscaling to 1.) 20g Catalyst 2) 5-10kg Catalyst Demonstration plant for estimation of energy balance and costs for industrial application Technical data Catalyst: Nickel on Silica/Alumina wt% 66 Reactor volume: 30 dm 3 Amount of catalyst: up to 2 kg Temperature: 350 C Pressure: 10 bar maximal gas flow: 1200 Nm 3 /Day -> 500 kg CO 2 /Day CH 4 Yield: 200 Nm 3 /Day Financial support: EFRE/ )

12 Demonstrator Setup of reactor Tube reactor Cooling trap Quadrupole massspectrometer H 2 CO 2 UHV Vacuum chamber Preheater Financial support: EFRE/ ) Mass Flow Controler Thermoelements for temperature control inside reactor

13 CO2 Verbrauch in kg/tag. Laboratory scale vs Demonstrator 1,0 0,8 0,6 0,4 yield conversion selectivity 0,2 0, time [min]. Laboratory scale Demonstrator Entwicklungstrend conversion > 85% yield > 85 % selektivity = % Financial support: EFRE/ ) ,01 0,05 7,1 Jun. 11 Dez. 11 Jun. 12 Dez. 12 Jun. 13 Dez. 13 Labor Technikum Conversion > 80% yield > 80 % selektivity = 90 %

14 Possible Cooperations Catalyst Development for Mass Production Reactor design for the Sabatier reaction in technical scale Production of Methanol from CO 2 : Catalyst development, Scale up into technical value