Some Projected Add-On Control Options for CO

2

Reductions at a Coal-Fired Generating Unit

Kevin Johnson URS Corporation Raleigh-Durham, North Carolina NC DENR/DAQ CO 2 Workshop April 21, 2004

Presentation Overview

  CO 2 capture issues CO 2 – capture technologies’ overview Conventional amine absorption – Advanced amine absorption – – – Gas separation membranes Temperature swing adsorption Regenerable CO 2 sorbents  Development status and projected costs  Potential next steps 2

Coal-Fired CO

2

Capture Issues (1)

 Chemical absorption using amines is only technique used commercially to date to capture CO 2 from flue gas.

 Amine degradation via oxidation and reaction with SO 2 and other flue gas constituents.  Lower amine concentration results in larger equipment, higher solvent circulation rates, and increased energy requirements for CO 2 regeneration from the rich amine stream.

 Only a few small plants (<<1000 tpd CO 2 removal, or about <50-100 MW) in commercial operation.

3

Coal-Fired CO

2

Capture Issues (2)

 Conventional MEA absorption/stripping estimated to increase electricity costs by over 50%, and consume ~30% of plant’s output.*   Global Climate Change Initiative goals are 90% CO 2 capture and <10% increase in cost of energy services (net of any value-added benefits, e.g., EOR, CO 2 credit trading, etc.) DOE Carbon Sequestration R&D program goal is to achieve carbon capture/geologic sequestration at an incremental cost of $10/ton CO 2 emissions avoided.

* National Coal Council, “R&D Needs and Deployment Issues for Coal-Related GHG Management”, May 2003.

* EPRI, “Evaluation of Innovative Fossil Fuel Power Plants with CO 2 December 2000.

Removal”, 4

Advanced Amine Absorption (1)

 Proprietary oxidation inhibitors, other additives, membranes, custom solvent formulations/amines, contactor designs.

 Various commercial vendors pursuing process improvements: – Fluor – – – – Praxair Kvaerner MHI ABB Lummus Crest  Current cost range ~$30-40/ton CO 2.

 R&D development goal ~$20/ton CO 2 5

Advanced Amine Absorption (2)

 Advanced amine absorption processes hold promise for intermediate-term CO 2 capture, with incremental (i.e., not breakthrough) reductions in cost.

 Critical need for large-scale pilot plant demonstration(s) on SO 2 -/NO x -laden coal-fired flue gas.

 DOE Regional Sequestration Partnership program planning Phase II pilot validation tests in the 2007-2010 time period.

6

Gas Separation Membranes

 Gas-liquid or catalyzed liquid membrane separators/reactors.

 Potentially used in conjunction with unique physical solvents.

 Several process vendors actively involved in technology development: – – – Kvaerner Carbozyme (catalyzed enzyme) Electrocore (natural enzyme) 7

Temperature Swing Adsorption

 Use of custom-designed sorbents that adsorb CO 2 at lower temperature, and then desorb CO 2 at higher temperature.

 Zeolites, synthetic zeolites, activated carbon, etc.

 Adsorption Research, Inc./DOE.

8

Regenerable Sorbents

 Absorption step of CO 2 removal, followed by sorbent regeneration step where CO 2 is off gassed.

 Alkali- and alkaline-earth metals (e.g., K 2 CO 3 and CaO) deposited on a substrate support are focus of research experiments.

 Advantages over amine-based liquid systems include no large quantities of water involved in capture step, and additional energy savings due to lower gas/solid pressure drop.

 Research Triangle Institute/DOE.

9

Development Status and Projected Costs  Except for amine absorption technologies, all CO 2 capture technologies still at the laboratory, bench-scale development level.

  Based on lab results, several vendors (Carbozyme, ARI) “claiming” projected full scale cost performances on the order of $5-15/ton CO 2 .

These, and other, potential “breakthrough” CO 2 capture technologies warrant further investigation and research investments.

10

Potential Next Steps (1)

 NC program could proactively participate in DOE Regional Sequestration Partnership (SE).

– Characterize regional sources and sinks, environmental and monitoring/verification requirements, and life cycle impacts.

– – Pilot validation tests not until 2007-2010.

Based on current public commitments, more economic CO 2 capture technology will not be commercially available for coal plants before the end of the decade.

11

Potential Next Steps (2)

 NC could provide cost share/co-funding to CO 2 capture technology pilot field demonstration and testing.

 Attempt to address conflicting motivations of voluntary GHG program elements, GHG registry program development needs, and potential CO 2 follow-up response to CSA.

12