Project No: FE0009484
Performer: Alstom Power Inc


Contacts

Richard Dennis
Technology Manager (Acting)
Advanced Combustion Systems
National Energy Technology Laboratory
3610 Collins Ferry Road
P.O. Box 880
Morgantown, WV 26507-0880
304-285-4515
richard.dennis@netl.doe.gov

Briggs White
Federal Project Manager
National Energy Technology Laboratory
3610 Collins Ferry Road
P.O. Box 880
Morgantown, WV 26507-0880
304-285-5437
briggs.white@netl.doe.gov

Herbert Andrus
Principal Investigator
Alstom Power
200 Great Pond Drive
Windsor, CT 06095-1566
860-285-4770
herbert.e.andrus@power.alstom.com

Duration
Award Date:  10/01/2012
Project Date:  09/30/2016

Cost
DOE Share: $8,891,848.00
Performer Share: $2,222,962.00
Total Award Value: $11,114,810.00

Performer website: Alstom Power Inc - http://www.poweralstom.com

Advanced Energy Systems - Advanced Combustion Systems

Alstom's Chemical Looping Combustion Technology with CO2 Capture for New and Retrofit Coal-Fired Power

Project Description

Alstom Power, through prior U.S. DOE funding, has been developing a limestone-based chemical looping combustion technology. The selected project will continue this work by enabling the full analysis of the process through an engineering system and economic study along with the development of a screening tool for process improvements. Additional analyses include an evaluation of pressurizing the limestone chemical looping combustion process.

Alstom’s LCL-C process implementation

Alstom’s LCL-C process implementation.


Program Background and Project Benefits

Advanced combustion power generation from fossil fuels involves combustion in a high-oxygen (O2) concentration environment rather than air. This type of system eliminates introduction of most, if not all, of the nitrogen (N2) found in air into the combustion process, generating flue gas composed of CO2, water (H2O), trace contaminants from the fuel, and other gas constituents that infiltrated the combustion system. The high concentration of CO2 (≈60 percent) and absence of nitrogen in the flue gas simplify separation of CO2 from the flue gas for storage or beneficial use. Thus, oxygen-fired combustion is an alternative approach to post-combustion capture for Carbon Capture and Storage (CCS) for coal-fired systems. However, the appeal of oxygen-fired combustion is tempered by a number of challenges, namely capital cost, energy consumption, and operational challenges associated with supplying O2 to the combustion system, air infiltration into the combustion system that dilutes the flue gas with N2, and excess O2 contained in the concentrated CO2 stream. These factors mean oxygen-fired combustion systems are not cost-effective at their current level of development. Advanced combustion system performance can be improved either by lowering the cost of oxygen supplied to the system or by increasing the overall system efficiency. The Advanced Combustion Systems Program targets both of these possible improvements through sponsored cost-shared research into two key technologies: (1) Oxy-combustion, and (2) Chemical Looping Combustion (CLC).

In chemical looping systems, oxygen is introduced to the system via oxidation-reduction cycling of an oxygen carrier. The oxygen carrier is usually a solid, metal-based compound. It may be in the form of a single metal oxide, such as an oxide of copper, nickel, or iron, or a metal oxide supported on a high-surface-area substrate (e.g., alumina or silica) that does not take part in the reactions. For a typical CLC process, combustion is split into separate oxidation and reduction reactions that take place in multiple reactors. The metal oxide supplies oxygen for combustion in the fuel reactor, operated at elevated temperature, and is reduced by the fuel. The reaction in the fuel reactor can be exothermic or endo¬thermic, depending on the fuel and the oxygen carrier. The combustion product from the fuel reactor is a highly concentrated CO2 and H2O stream that can be purified, compressed, and sent to storage or for beneficial use. The reduced metal carrier is then sent to the air reactor, which also operates at elevated temperatures, where it is regenerated to its oxidized state. The air reactor produces hot flue gas, which is used to create steam that drives a turbine, generating power.

 

Current CLC R&D efforts are focused on development and refinement of oxygen carriers with sufficient oxygen capacity that can withstand the harsh environment associated with CLC operation, development of effective and sustainable solids circulation and separation techniques, reactor design to support fuel and oxygen carrier choices, effective heat recovery and integration, and overall system design and optimization.

Alstom is continuing development of a limestone chemical looping combustion (LCL-C™) system. The LCL-C™ power production system has the potential to use smaller, less-expensive, more efficient reactors than conventional systems with carbon capture, producing a nearly pure CO2 stream without the need for an oxygen-production plant. These factors have the ability to drive down the cost of electricity and the cost of CO2 capture relative to conventional coal-fired power plants with CCS. This project will focus on addressing technology gaps identified for the 1-MWe prototype system, with emphasis on solids handling and carrier capacity. Successful prototype testing of this CLC system including validation of projected full-scale cost and performance will provide a basis for design, development, and testing of a larger pilot-scale prototype, furthering progress toward full-scale demonstration.

This project is a continuation of an ongoing effort that has been performed by Alstom under "Alstom's Chemical Looping Combustion Prototype for CO2 Capture from Existing Pulverized Coal Fired Power Plants" (Contract No.: DE-NT0005286.) A Fact Sheet for the original project provides more detailed discussion of the work.


Project Scope and Technology Readiness Level

The Phase II objectives are to address the technical gaps identified during Phase I operation of the 3-MWth chemical looping prototype facility and conduct updated techno-economic analyses for a commercial-scale 550-MW coal power plant based on the chemical looping technology. The technology is a promising option for generating power from coal while achieving greater than 90 percent carbon capture and increasing the cost of electricity by no more than 35 percent compared to a new supercritical pulverized coal plant.

The Technology Readiness Level (TRL) assessment identifies the current state of readiness of the key technologies being developed under the DOE’s Clean Coal Research Program.  In FY 12, this project was assessed a TRL of 5.

The TRL assessment process and its results including definition and description of the levels may be found in the "2012 Technology Readiness Assessment-Analysis of Active Research Portfolio".


Accomplishments

The project was selected for continuation into Phase II. The final Phase I Technology Engineering Design and Economic Analysis Report has been completed and submitted to DOE. The performance of four Limestone Chemical Looping Combustion (LCL-C™) systems includes overall plant, environmental, and thermal performance plus detailed mass and energy balances for the key process streams and a summary of the key LCL-C™ components and subsystems. Economic evaluations were completed for the plant configurations. The report also provides a summary of the Aspen Plus and Thermoflow models developed for simulation of this case.

Alstom conducted a series of engineering studies, which included methods of pressurizing coal feed to a pressurized reactor, sensitivity of plant efficiency to reducer operating pressure, methods of operating two reactors with different pressures under steady state and load change conditions, modifying or including equipment for process improvements that include solids separation, increasing carbon conversion and the purity of gas leaving the reducer, and finally, methods for condensing and scrubbing moisture from the gas stream. Bench-scale thermogravimetric analysis tests were performed to determine process performance under pressurized conditions with and without the use of LCL-C™ reaction promotion methods.