Project No: FE0009761
Performer: Babcock & Wilcox Power Generation Group


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

Steven Richardson
Federal Project Manager
National Energy Technology Laboratory
3610 Collins Ferry Road
P.O. Box 880
Morgantown, WV 26507-0880
304-285-4185
steven.richardson@netl.doe.gov

Luis Velazquez-Vargas
Principal Investigator
Babcock & Wilcox Power Generation Group
20 South Van Buren Avenue
Barberton, OH 44203-0351
330-860-6203
lvargas@babcock.com

Duration
Award Date:  10/01/2012
Project Date:  11/30/2015

Cost
DOE Share: $3,244,605.00
Performer Share: $1,259,151.00
Total Award Value: $4,503,756.00

Performer website: Babcock & Wilcox Power Generation Group - http://www.babcock.com

Advanced Energy Systems - Advanced Combustion Systems

Commercialization of the Iron Base Coal Direct Chemical Looping Process for Power Production with in situ Carbon Dioxide Capture

Project Description

The project goal is to develop a 550 MW commercial-scale economic case study of Babcock and Wilcox (B&W) and The Ohio State University’s coal direct chemical looping (CDCL) process for CO2 capture and separation that can be used for retrofit, repowering, and/or Greenfield installations. Project objectives are to validate the CDCL process application for power generation through engineering system and economic analysis and an experimental, bench scale system suitable for addressing the identified technology gaps.

CDLC Process Concept (click to enlarge)


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 endothermic, 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.

Babcock & Wilcox is continuing development of Ohio State University’s coal-direct chemical looping process (CDCL), an iron-based CLC system. The CDCL reactor design leverages high oxygen carrier conversion rates and improved solids separation, reducing equipment size, complexity, and cost relative to conventional systems, and 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 supercritical coal-fired power plants with CCS. This project will focus on solids handling and carrier capacity through bench-scale testing, modeling, and simulation. Testing will support refinement of the projected full-scale cost and performance analysis, as well as providing a basis for design of a small pilot-scale prototype

This project is a continuation of an ongoing effort that has been performed by Ohio State University under "Coal Direct Chemical Looping Retrofit for Pulverized Coal-Fired Power Plants with In-Situ CO2 Capture" (Contract No.: DE-NT0005289) A Fact Sheet for the original project provides more detailed discussion of the work.
 


Project Scope and Technology Readiness Level

The scope for the project during Phase II includes 1) reducing technology gaps identified during Phase I of the project by conducting laboratory testing and analysis to support the development of robust oxygen-carrier particles for CDCL, and evaluating the critical pilot plant performance and design parameters; 2) designing, constructing, and testing a small CDCL bench-scale reducer reactor to demonstrate critical aspects of the CDCL process; and 3) updating the design and cost performance of the pilot and commercial 550-MWe CDCL 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 4.

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. B&W completed the CDCL preliminary commercial design and drawing for Phase I, performed char gasification experiments, and performed a techno-economic analysis. The cost for the 550-MWe CDCL plant, developed at the Total Plant Cost level, which includes equipment, materials, indirect labor costs, engineering, and contingencies, is approximately $2,508 per net kilowatt. The cost of electricity without transmission and substation (T&S) is $102.672/MWh. Char gasification kinetics were studied using a thermogravimetic analyzer. The tests studied the effect of temperature, char particle size, and presence of oxygen carriers on the rate of char gasification under carbon dioxide conditions. Results of these studies showed that—for char particle sizes larger than 500µm—the effect of particle size on the char residence time was almost insignificant and the overall residence time was much less in the presence of oxygen carriers and at elevated temperatures.