Selection and Development of. Natural Gas Power Systems:

Transcription

1 Gas-FACTS project: Gas - Future Advanced Capture Technology Systems WP 2.1: Gas-Specific Solvents 2 nd Post Combustion Capture Conference Session 3: 2 nd & 3 rd Generation Capture Technologies Selection and Development of Specific Solvents for CO 2 Capture from Natural Gas Power Systems: monophasic & biphasic Jiafei Zhang, Paul Fennell, Martin Trusler Bergen, 18 th Sept. 2013

2 Outline Introduction PCC for gas-fired power plants Overview of Gas-FACTS Project Results and discussion Solvents selection Measurement parameters Density, Viscosity Heat capacity (C p ) Vapour-Liquid Equilibrium (VLE) Net CO 2 capacity Degradation Surface tension, Contact angle Process development Summary Absorption Desorption Image Source: Siemens 2

3 PCC for Gas-fired power plants Natural gas becomes the new coal for power generation burns much cleaner than coal but... Lower CO 2 partial pressure Reduce α -CO2 Seeking specific solvents to reduce: solvent flow column size CapEx & OpEx to achieve: ~90% of CO 2 removal CO 2 Emissions (kg/mwh) Higher O 2 concentration Degradable solvents can not be considered Solvents resisting oxidation Exhaust Gas Recycle (EGR) to increase the CO 2 concentration Two baseline cases Without EGR: ~4% CO 2, ~12% O 2 With EGR: 6-8% CO 2, 8-10% O 2 After Combustion: CO 2 H 2 O O 2 N 2 Ar w/o w/ CCS Coal-fired Coal-fired ~100 Gas-fired ~40 Gas-fired

4 Project overview Work packages EPSRC Reference: EP/J020788/1 2.1 Gas-Specific Solvents 2.2 Flexible Capture Systems 2.3 Advanced Testing Consortium Members: 4

5 Solvents selection Advanced solvents Monoethanlamine (MEA) as benchmark primary amine 2-Amino-2-methyl-1-propanol 2 methyl (AMP) sterically hindered Dimethylaminoethanol (DMAE) tertiary Diethylaminoethanol (DEAE) tertiary Piperazine (PZ) as activator diamine Piperazinyl ethylamine (PZEA) triamine HO HO NH 2 NH 2 Blended amines recommended Formulations DMAE+PZ Rapid reaction DEAE+PZ kinetics AMP+PZ Low energy consumption High net CO 2 loadings Chemically stable HN 5 NH

6 Solvents selection Thermomorphic biphasic solvents (TBS) Hydrophobic Hydrophilic Using lipophilic amines as activating components Examples Hexylamine (I) HA N H Dipropylamine (II) DPA N,N-Dimethylbutylamine (III) DMBtA Liquid-liquid phase separation N NH 2 N Before During After regeneration regeneration regeneration ~40 o C o C Screened lipophilic amines Alkylamines linear, branched, cyclic Aromatic amines - derivatives of benzylamine Cyclic amines derivatives of piperidine 6

7 Measurement parameters Density Feed flow C +/ g/cm³ Viscosity Column packings BPR C Bath m Peltier Deviation < 1.5% Device T 1 Heat capacity Energy consumption P T C, bar (Sensible heat) < 0.5% (low T), < 1.5% (high T) Surface tension / Contact angle Packing wettability C < 1% VLE / net CO 2 capacity Column size C, kpa Pump VLE rig + GC 7

8 Density Measurement Various amine solutions: single & blended with CO 2 loadings Anton-Paar model DMA 5000 M densimeter 8

9 Viscosity - advanced amine solvents 30wt% MEA and other amine solutions: Influence of α fitted by Weiland s (1998) correlation 4.8 cp at 35 o C solution T a wam b T c wam d X CO e w f T g 2 Am exp 2 T H T 2O 1 w Am 0.78 cp at 80 o C U-Tube capillary viscometer 9

10 Viscosity biphasic amine solvents NH 2 N HO NH NH 10

11 Heat capacity Flow calorimeter C p Q net m T Influence: T C p α C p (/g) Peltier Device α C p (/ml) P Bath BPR m Pump T 1 T 2 11

12 Heat capacity Solvents: DMAE + PZ AMP + PZ PZEA etc. 12

13 VLE Advanced amine solvents 30% DMAE (+, ) 25% DMAE + 5% PZ (, ) Biphasic amine solvents 4M pmca (blended solvent) Compared to 30% MEA (eq. 5M) in-house data from D. Tong P CO2 (mbar) MEA MEA, 40 o C MEA, 120 o C 60 pmca DMX-1, 40 o C 50 pmca, 40 o C pmca, 90 o C Loading (mol -CO2 /kg -sol. ) 13

14 Net CO 2 capacity Higher than benchmarks o C for alkanolamine o Cfor lipophilic amine 14

15 Degradtion N Analysis Heat stable salts (HSS): titration Volatile components: GC-MS Main reactions Demethylation / Methylation Ketonisation & Oximation for MCA HN N 6 5 w/o Fe(II/III) w/ Fe(II/III) HSS / % TBS 1 0 AMP Blend DMCA MEA MCA 15

16 Surface tension & Contact angle +CO 2 loading Increase ST Increase CA θ Some plastic materials such as PE-HD: also wettable to lipophilic amines α 16

17 PFD for TBS Process flow diagram for TBS with phase splitting and stripping 17

18 Summary Viscosity Lean solvents: PZEA > AMP DEAE > DMAE > MEA > TBS > H 2 O Rich solvents: TBS > AMP > DMAE > MEA CO 2 loading: Heat capacity Solvents: α η H 2 O > DMAE > AMP PZEA > MEA > TBS CO 2 loading: α C p (/g) or C p (/ml) Loading capacity & chemical stability Higher α than conventional solvents at low p Lower degradation than MEA Further studies Explore & formulate new solvents Optimise solvent recipe & modelling Advanced Testing at UKCCSRC s PACT Facilities 8 m absorber up to 1 ton/day of CO 2 18

19 Acknowledgement The gas-specific solvents were studied in the Imperial College London and financial supported by the EPSRC. Consortium Members: The biphasic solvent system was studied in the Technical University of Dortmund and supported by the Shell Global Solutions Int. B.V. Advisors: Prof. Dr. David W. Agar Dr. Frank Geuzebroek Ir. Mark Senden Dr. Robert Moene Dr. Xiaohui Zhang 19

20 Thank you for your attention! Selection and Development of Specific Solvents for CO 2 Capture from Natural Gas Power Systems: monophasic & biphasic Jiafei Zhang Department of Chemical Engineering Imperial College London, UK Tel: +44 (0) jiafei.zhang@imperial.ac.uk The Queen's Tower in the South Kensington Campus 20