CO 2 Catch-up Project. Dr. Kay Damen 7th Dutch CCS Symposium

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1 CO 2 Catch-up Project. Dr. Kay Damen 7th Dutch CCS Symposium

2 Content Project goal and rationale Timeline Parties involved Pilot plant design Pilot plant operation Results water-gas shift section Results CO 2 absorption section Conclusions Scientific output

3 Goal Demonstrate pre-combustion CO 2 capture at the pilot plant in Buggenum in order to verify the technology performance and to generate knowledge in the form of validated models and operational experience that can be applied to optimise the design and operation of the full-scale CO 2 capture unit at the Magnum IGCC. 3

4 Why a pilot plant? Water-gas shift and CO 2 -H 2 separation have been proven in the chemical industry, but: Different configuration due to the different purpose (maximum H 2 production, energy consumption not key driver!) These units primarily treat syngas produced from natural gas or oil residues (CO concentration, trace elements). Little experience with coal-fired IGCC with Selexol and sweet shift Units in chemical industry are typically operated as base-load plants Pre-combustion capture components Selexol plant Coffeyville (source: UOP) WGS shift unit Curitiba (source: Encap)

5 Project timeline Q1 Start test campaign I Q4 Start test campaign II Q4 Start test campaign III Hand over of report to Agenschaap NL Closure of R&D program 2011 Summer shutdown IGCC Summer shutdown IGCC End of pilot plant operation 2014 Hand over of report to internal customers Test campaign I (Random packing, trial period, no analyzers available) Plant modifications (additional measurements, water injection absorption system) Test campaign II (Random packing, main plant performance tests) Plant modifications (packing, liquid distributor) Test campaign III (Structured packing, repetition of several parametric tests )

6 Key parties involved Vattenfall Research and Development: project management Nuon Power Buggenum: operation of pilot plant ECN: WGS catalysis research Delft University of Technology: process modelling Haldor Topsoe: water gas shift catalyst Clariant: solvent Raschig: packing 6

7 Simplified PFD pilot plant Waste water Make- up Water Reaction Water Gas Quench

8 Pilot plant features Main inputs Syngas Demi-water Main outputs CO 2 H 2 rich syngas 1224 kg/h 644 kg/h 1386 kg/h 435 kg/h CO 2 capture efficiency 80-85% CO 2 composition 97 mol% CO 2 H 2 rich syngas composition 83 mol% H 2 Water-gas shift section Sweet (iron-chromium catalyst) Absorption section Physical (mixture of dimethyl ether polyethylene glycols)

9 Pilot plant operational statistics Total operating time: 5886 Hours Total syngas consumption: 6235 Ton Total CO 2 production: 4478 Ton Total electricity consumption: 9184 MWh Number of starts: 39 - Number of trips/shut downs: 16 - Number of test runs: 61 - Number of Lost Time Incidents in the lifetime of the project: 0 -

10 Mass balance Balance region Mass flow in [kg/h] Mass flow out [kg/h] Relative difference [%] Overall Syngas conditioning CO shift and condensate recovery CO 2 Absorption Water balance

11 Results water-gas shift section Operational experience Materials and corrosion CO conversion efficiency Catalyst stability, selectivity and carbiding 370 mm 320 mm 400 mm 320 mm 400 mm 320 mm 492 mm 370 mm 355 mm TL-TL 6190 mm 3500 mm TL-TL 6220 mm 3500 mm TL-TL 6220 mm 3500 mm 200 mm 200 mm 200 mm 385 mm 440 mm 440 mm

12 Highlights operational lessons learned Start-up issues WGS - heat loss between R2 and R3 - condensation during pre-heating with N 2 Temperature excursions in R1 upon trip Temperature excursions during catalyst oxidation after shutdown

13 Materials and corrosion Material WGS reactors: 2.25Cr-1Mo Mechanisms: high temperature H 2 attack Measurements: corrosion probes, wall thickness Wall thickness measurements gave no uniform and clear picture. Endoscopic inspection was performed, no signs of corrosion observed.

14 CO conversion efficiency Reactor 1 Reactor 2 Reactor 3 in out in out in out T C H 2 %wet N 2 %wet CO %wet CO 2 %wet Ar %wet H 2 O %wet S/CO= mol.mol Flow= kmol.h Xco % 93.2% 80.8% 40.7% Xco, Ri % 34.9% 52.7% 5.1% Xco % 34.9% 87.6% 92.7%

15 Catalyst stability and selectivity FeCr catalyst pellet deactivation due to sintering (temperature and steam content), poisoning and carbiding. The reactor 1 and 2 catalyst activity decreases at a much slower rate than expected by the catalyst vendor Reactor 3 catalyst has a much lower activity than anticipated. Repeated chemical analysis hinted towards over reduction (steam condensation start-up?) Catalyst selectivity:

16 Catalyst carbiding No signs of carbiding upon reduction of steam/co ratio in reactor 2: Step-wise increase of CH 4 concentration (but stabile after each set point). Catalyst activity before and after low steam/co similar Absence of C2+C3 hydrocarbons in the reactor 2 effluent Uncompromised reactor 2 pellet strength measured after the entire campaign 600 measured CH4 content [ppmwet] CH 4 inlet CH 4 outlet reactor 2 steam/co ratio [mol/mol]

17 Potential for energy saving Results pilot plant measurements have been used in optimisation study in Aspen for the full-scale CO 2 capture plant (thesis Carsten Trapp).

18 Results CO 2 absorption section Operational experience Materials and corrosion CO 2 absorption efficiency and parametric tests Modelling and packing comparison

19 Materials and corrosion Materials CO 2 absorption section: SS 316 and CS Mechanisms: wet CO 2 corrosion The corrosion rate for carbon steel parts is low as long as the wall is covered with DEPEG. Carbon steel with 3 mm corrosion allowance can be selected. Care should be taken for a good conservation during shutdown (top absorber). Deposits at the compressor parts downstream the intercooler

20 Highlights operational lessons learned Stable unit, only minor control modifications implemented. Start-up procedure syngas compressor and CO 2 absorption section was changed in order to: - Prevent DEPEG entrainment during start-up - Pressurise the flash vessels in order to circulate the solvent Solvent analysis after test programme shows no signs of degradation/low accumulation of impurities (no degradation of CO 2 absorption in time) Lean/rich loading measurements problematic

21 CO 2 absorption efficiency and parametric tests (1) CO2 absorption efficiency [-] using H2 Rich gas using 3rd Flash vessel Absorber pressure [bara]

22 CO 2 absorption efficiency and parametric tests (2)

23 Packing comparison Tested packings: Raschig Super-Ring 0.6 and Raschig Super-Pak 250Y The random packing has better absorption efficiency than the structured packing TC-II TC-IIIl CO2 capture efficiency [-] Shifted syngas flow rate [kg/h]

24 Hydrodynamics The purpose is to test high L/G operating conditions with solvent flow rate up to 240 m³/m 2 /h (hydraulic limits and absorption efficiency) for Raschig Super-Ring 0.6 (left) and Raschig Super-Pak 250Y (right) flooding of the liquid distributor? 100 Flooding lower section floods and entrainment of the liquid solvent into the upper section? 55 No sign of flooding, linear correlation indicates that plant is still far from loading region y = 0,0038e 0,3787x 50 Pressure drop (log) [mbar] 10 y = 1,8671e 0,1151x y = 0,0021e 0,4046x y = 0,9378e 0,1448x Pressure drop [mbar] ,0 16,5 17,0 17,5 18,0 18,5 19,0 19,5 20,0 20,5 21,0 21,5 22,0 22,5 23,0 23,5 24,0 24,5 25,0 25,5 26,0 26,5 Solvent flow rate [kg/s] ELH10CP001 ELH10CP Solvent flow rate [kg/s] ELH10CP001 ELH10CP002

25 Process modelling Rate-based model in Aspen Plus V7.3 using PC-SAFT EoS (fitted using experimental data from Clariant). The trends in CO 2 absorption efficiencies with the change of the process variables (mass flows, concentrations, temperatures, pressures) are predicted correctly by the model. The CO 2 absorption efficiency is predicted with a standard deviation of and is slightly underestimated (in reference state) which results in a safe prediction for up-scaling CO2 absorption efficiency RSP Calculated Experimental Reference state TR-CIII-011 SP1 TR-CIII-011 SP2 TR-CIII-011 SP3 TR-CIII-012 SP1 TR-CIII-012 SP2 TR-CIII-012 SP3 Diagonale

26 Mass transfer coefficients Fitting of C L and C V of the Billet & Schultes mass transfer coefficient correlation The optimized values for RSR 0.6 are C L = and C V = The optimized values for RSP 250 are C L = and C V = As the resistance against the mass transfer is concentrated in the liquid phase, RSR 0.6 seems to be a more suitable packing for the physical absorption of CO 2 for the specific hydraulic conditions tested in the pilot plant. However, the fitted values for C L and C V are significantly lower than the default values in Aspen and used by Raschig. - Occurrence of foaming? - Gas back-mixing as the gas velocity is very low and liquid can entrain the gas? CO2 molar fraction [-] CL=0.2193; CV= CL=1.38; CV=0.40 experimental data Axial position in column [m]

27 Conclusions Pilot plant has been operated without major problems, with the exception of the sampling conditioning and analyzers. Overall pilot plant performance is according expectations, but the performance of individual components (catalyst activity, RSP versus RSR) is deviating from design/expectations. There is potential for energy saving by further reduction of steam/co ratios WGS catalyst. Steady-state and dynamic pilot plant models have been validated successfully and can be used for up-scaling.

28 Scientific output Performance and modelling of the pre-combustion capture pilot plant at the Buggenum IGCC (Public report). 3 PhD projects - Carsten Trapp: Advances in model-based design of flexible and prompt energy systems - Abrar Hakeem: Water-gas shift catalyst development for energy efficient applications - Marina Stavrou: Simultaneous Solvent and Process Optimization for CO 2 pre-combustion Capture with the method of Continuous Molecular Targeting (CoMT) - Computer Aided Molecular Design (CAMD) Several scientific publications and conference proceedings -Damen et al. Developments in the pre-combustion CO 2 capture pilot plant at the Buggenum IGCC -Van Dijk et al. Water-gas shift optimization for pre-combustion CO 2 capture within an IGCC as a result of the Vattenfall CO 2 Catch-up project