Advanced Oxyfuel Combus4on Concepts for CO2 Capture

Transcription

1 Advanced Oxyfuel Combus4on Concepts for CO2 Capture Richard L. Axelbaum Department of Energy, Environmental and Chemical Engineering

2 Typical Power Plant h:p://

3 First Genera4on Oxy- fuel Combus4on 1 atm pressure 4% 7% 0.5% h:p:// Capture- and- Storage.htm

4 The Basic Premise With tradi4onal approaches to oxy- combus4on, genera4ng oxygen and compressing CO 2 are taken as necessary loads and costs, and there is no benefit from them. Can we design a system that benefits from them, so that we can improve the efficiency and reduce the cost of oxy- combus4on? In other words, can we make lemonade out of lemons?

5 Pressurized Oxy- Combus4on The requirement of high pressure CO 2 for sequestra4on enables pressurized combus4on as a tool to increase efficiency and reduce costs. Benefits of Pressurized Combus4on Latent heat in flue gas recovered à Increased efficiency Latent heat recovery can be combined with integrated pollu4on removal à Lower capital and O&M Reduced volume à Lower capital and O&M Avoids air- ingress à Lower purifica4on cost Reduces oxygen requirements à Increased efficiency

6 First Thoughts on Temperature Control in Oxy- Combus4on Temperature in oxy- combus4on is typically controlled by addi4on of RFG or water (CWS or steam). But, global combus4on temperature is also a func4on of stoichiometric ra4o, λ = (O 2 ) act /(O 2 ) stoich

7 Fuel- Staged Oxy- Combus4on Mul4ple boiler modules connected in series w.r.t combus4on gas Enables near- zero flue gas recycle

8 SPOC Process Flow Diagram Dry N 2 to Cooling Tower Coal Moist N 2 Cooling Water Vent Gas Coal Milling N 2 Air ASU Cold Box Coal Feeders O2 Steam Cycle Steam Cycle Steam Cycle Steam Cycle Steam Cycle CO 2 Boost Compressor CO 2 Pipeline Compressor BFW Air Steam Cycle Main Air Compressor O 2 Compressor Particulate Filter CO 2 Purification Unit Direct Contact Cooler Sulfur Scrubber CO 2 to Pipeline ph Control Steam Cycle BFW BFW BFW BFW BFW BFW Bottom Ash Bottom Ash Bottom Ash Bottom Ash Fly Ash Cooling Tower

9 Latent Heat Recovery Cooling Water (CW) Dried Flue Gas DCC wash column Pressure (bar) Exit Temp (C) Wet Flue Gas CW + Condensate

10 SOx, NOx, Hg Removal at High P Following similar approach to Air Products: NO is oxidized to NO 2 at high pressure (>15 bar) which oxidizes SO 2 to H 2 SO 4 and NO to HNO 3 [SO 2 ]/[NOx] ra4o must approach unity for complete removal. For typical systems it is much higher so process is not effec4ve. Hg will also be removed, reacts with the nitric acid that is formed. Auto- Refrigerated for Removal of Inerts Ar, N 2, O 2

11 Process Modeling Results for Staged Pressurized Oxy- Combus4on Net Efficiency: SPOC process increases the efficiency up to 6 percentage points over conven4onal oxy- combus4on. a b c Efficiency higher than Current US Average. a DOE/NETL #2010/1411 & EIA; b DOE/NETL #2010/1405; c DOE/NETL #2012/1557

12 Economic Performance Summary NETL Baseline Case 11 (no CCS) NETL Case 12 w/ post combust. capture SPOC Case A SPOC Case B Coal Illinois #6 Illinois #6 PRB PRB Steam Conditions Supercritical Supercritical Supercritical A-USC Heat Rate (Btu/kWhr) First Year COE ($/MWhr) % increase in COE 8,686 12,002 9,555 8, % 25% 27% 2011 cost basis CO2 purity meets specifica4ons for enhanced oil recover (EOR) COE does not include revenue from sale of CO2, or costs for geologic storage.

13 Boiler Temperature Distribu4on Products T r mixing Q_rad T Q_rad x r

14 Reduced Recycle Experiments at 1 atm Advanced Coal & Energy Research Facility (ACERF) Results Radiative Heat Flux [kw/m2] Air Firing 40% O2 air Distance from Quarl Exit [m] 40% O2

15 Effects of Pressure on Heat Flux For typical coal loading and constant temperature distribution Radia4ve Trapping Absorbed Incident radiation Scattered Emitted Distance [m]

16 Radia4ve Trapping in SPOC Emiss. T 4 4 ka* dx Qwall T * E O 2 Op4cally thick medium Fuel O 2 Incoming radiation CO 2 H 2 O Coal/Char/Ash Outgoing radiation 16

17 Wall Heat Flux Under SPOC Condi4ons First Stage Temperature (K) Absorp. coeff. (1/m)

18 High- Pressure Test Furnace

19 Summarizing Key Features of SPOC Process Increased efficiency by capturing latent heat Minimal parasi4c loads Increased radia4ve heat transfer Ideal for integrated NO x and SO x removal Low Cost of Electricity for CCUS

20 Acknowledgements Wash U: B. Kumfer, A. Gopan, F. Xia, B. Dhungel, M. Holtmeyer & Z. Yang EPRI: J. Phillips, D. Thimsen Ameren: Rick Smith, George Mues, Tom Callahan Burns & McDonnell: Jim Jurzcak, Janel Junkersfeld, Dean Huff, Gary Mouton Funding: U.S. Department of Energy: Award # DE- FE Advanced Conversion Technologies Task Force, Wyoming Consor4um for Clean Coal U4liza4on, Washington University in St. Louis Sponsors: Arch Coal, Peabody Energy, Ameren U.S. Government Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

21 Backup slides

22 Air-fired plant Atm.-oxy (conservative) Atm.-oxy (optimized) Press.-oxy ISOTHERM Press.-oxy SPOC Gross Electric Output (MW e ) Aux. Load (MW e ) Net Plant Efficiency (% LHV )