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ITP Forest Products: Direct Causticizing for Black Liquor...
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. . INDUSTRIAL TECHNOLOGIES PROGRAM Nation competitiveness. Direct Causticizing for Black Liquor Gasifcation in a Circulating Fluidized Bed In-situ Causticizing during Gasifcation Could ). ( ) j j ( ) (1) Na 2 CO 3 2 (s) ↔ Na 2 2 (s) +CO 2 (g) (2) 7Na 2 CO 3 2 2 2 O. 2 )(s)+7CO 2 (g) (3) 3(4Na 2 2 2 aq)+5(Na 2 2 )(s) Bl li i i i i i causticization. Boosting the productivity and competitiveness of U.S. industry through improvements and environmental performance Benefts for Our Industry and Our Black liquor gasification (BLG) will improve the efficiency of pulping chemical recovery while producing syngas for manufacturing liquid fuels or for combined cycle power generation. In addition, the process can easily be incorporated into forest products biorefineries, which will produce a variety of fuels and market chemicals along with pulp, and boost the pulp and paper industry’s Applications in Our Nation’s Industry Black liquor gasification is being proposed to replace recovery boilers in kraft mills, while other mills could possibly use an adapted form of the process. All gasifiers will be capable of utilizing in-situ causticization, if demonstrated successfully. Enable the Replacement of Recovery Boilers and Eliminate the Lime Cycle Chemical recovery is essential to the kraft pulping process, which is used in more than 80% of U.S. wood pulp production. Black liquor, which is a mixture of spent organic matter from the wood and spent pulping chemicals, is recovered after pulping and then evaporated to concentrate the solids. In the recovery boiler, the organic solids are combusted to generate high-pressure steam that is used to drive many of the plant’s processes. The inorganic cooking chemicals form a molten smelt in the boiler and sulfur compounds are reduced to sulfide. Leaving the boiler, the smelt is dissolved in water and sent to the recausticizing plant to convert the sodium carbonate back to hydroxide and reform fresh liquor ready for pulping. Although pulping byproducts are reused or burned for steam generation, paper manufacturing still requires purchased energy (mostly heavy fuel oil to fire the lime kiln in the recausticizing plant However, energy independence for this industry is realistic through increased efficiency. To address these energy concerns, many efforts are underway to promote black liquor gasification BLG , which, when combined with combined cycle power generation, has the potential to increase the efficiency of the chemical recovery process to the point where electricity or green fuels could be produced. Currently, one of gasification’s ma or limitations is that it creates a significantly higher causticizing load than conventional recovery boilers. This pro ect seeks to perform the causticizing chemistry in situ during BLG by applying titanates to the liquor in a pressurized circulating fluidized bed CFB reactor. Reactions 1 and 2 take place within the gasifier, while reaction 3 takes place when the smelt is dissolved in water. +3 TiO O.3TiO + 5(Na O.3TiO )(s) ↔ 3(4Na 5TiO O.5TiO )(s) + 7H O ↔ 14 NaOH( O.3TiO ack quor gas ficat on process w th t tanate d rect
Transcript of ITP Forest Products: Direct Causticizing for Black Liquor...
. .
INDUSTRIAL TECHNOLOGIES PROGRAM
Nation
competitiveness.
Direct Causticizing for Black Liquor Gasification in a Circulating Fluidized Bed In-situ Causticizing during Gasification Could
).
( )
j
j
( )
(1) Na2CO3 2 (s) ↔ Na2 2(s) +CO2(g)
(2) 7Na2CO3 2 2 2O.
2)(s)+7CO2(g)
(3) 3(4Na2 2 2
aq)+5(Na2 2)(s)
Bl li i i i i icausticization.
Boosting the productivity and competitiveness of U.S. industry through improvements and environmental performance
Benefits for Our Industry and Our
Black liquor gasification (BLG) will improve the efficiency of pulping chemical recovery while producing syngas for manufacturing liquid fuels or for combined cycle power generation. In addition, the process can easily be incorporated into forest products biorefineries, which will produce a variety of fuels and market chemicals along with pulp, and boost the pulp and paper industry’s
Applications in Our Nation’s Industry
Black liquor gasification is being proposed to replace recovery boilers in kraft mills, while other mills could possibly use an adapted form of the process. All gasifiers will be capable of utilizing in-situ causticization, if demonstrated successfully.
Enable the Replacement of Recovery Boilers and Eliminate the Lime Cycle Chemical recovery is essential to the kraft pulping process, which is used in more than 80% of U.S. wood pulp production. Black liquor, which is a mixture of spent organic matter from the wood and spent pulping chemicals, is recovered after pulping and then evaporated to concentrate the solids. In the recovery boiler, the organic solids are combusted to generate high-pressure steam that is used to drive many of the plant’s processes. The inorganic cooking chemicals form a molten smelt in the boiler and sulfur compounds are reduced to sulfide. Leaving the boiler, the smelt is dissolved in water and sent to the recausticizing plant to convert the sodium carbonate back to hydroxide and reform fresh liquor ready for pulping. Although pulping byproducts are reused or burned for steam generation, paper manufacturing still requires purchased energy (mostly heavy fuel oil to fire the lime kiln in the recausticizing
plant However, energy independence for this industry is realistic through increased efficiency.
To address these energy concerns, many efforts are underway to promote black liquor gasification BLG , which, when combined with combined cycle power generation, has the potential to increase the efficiency of the chemical recovery process to the point where electricity or green fuels could be produced. Currently, one of gasification’s ma or limitations is that it creates a significantly higher causticizing load than conventional recovery boilers. This pro ect seeks to perform the causticizing chemistry in situ during BLG by applying titanates to the liquor in a pressurized circulating fluidized bed CFBreactor. Reactions 1 and 2 take place within the gasifier, while reaction 3 takes place when the smelt is dissolved in water.
+3 TiO O.3TiO
+ 5(Na O.3TiO )(s) ↔ 3(4Na5TiO
O.5TiO )(s) + 7H O ↔ 14 NaOH( O.3TiO
ack quor gas ficat on process w th t tanate d rect
INDUSTRIAL TECHNOLOGIES PROGRAM
Project Description Milestones
The goal of this project is to demonstrate the • Determine the split of sulfur between viability of combining black liquor gasification the solid and gas phases and identify the (BLG) with titanate direct causticizing in a limitations on the resultant pulping liquors pressurized circulating fluidized bed (CFB) (Expected completion: Summer 2007) reactor. Previous research has already determined • Verify acceptable carbon conversion and that titanate direct causticizing during BLG is causticizing rates at reasonable pressurizedfavorable in entrained flow reactors at pressures CFB conditions (Expected completion:below 5 bar. Elevated pressures of 15 bar Spring 2007)and up, however, are required to obtain the efficiency benefits of combined cycle power • Develop a process for recovering caustic generation, or the production of liquid fuels. that yields suitable pulping liquors Building on previous work, this project will (Expected completion: Fall 2007) characterize and verify the process conditions • Assess the material and energy balances necessary to achieve titanate direct causticizing of the CFB-based BLG recovery island,in pressurized CFB reactors. These experiments compared with a Tomlinson recovery boiler will be carried out at the gasification research (Expected completion: Early 2008)labs at the Institute of Paper Science and Technology at Georgia Tech. Commercialization
If this process is successfully demonstrated, it Barriers will be of interest to pulp and paper companies
• High pressures increase the partial pressure and to gasifier manufacturers, who will of carbon dioxide, which inhibits the ultimately be the builders and operators of causticizing reaction. forest products biorefineries.
• Titanate causticizing reactions must be thermodynamically favorable
• Recovered liquors must be suitable for reuse in pulping
Project Partners
An IPST member consortium on gasification and biorefinery development (Weyerhaeuser, Georgia Pacific, Longview Fiber, MeadWestvaco, Temple-Inland), Atlanta, GA
For additional information, please contact
Drew Ronneberg, Ph.D. Industrial Technologies Program Phone: (202) 586-0205 Fax: (202) 586-9234 E-mail: [email protected]
Scott Sinquefield, Ph.D. Institute of Paper Science and Technology at Georgia Tech Atlanta, GA Phone: (404) 385-0241 Fax: (404) 894-4778 E-mail: [email protected]
A Strong Energy Portfolio for a Strong America Energy efficiency and clean, renewable energy will mean a stronger economy, a cleaner environment, and greater energy independence for America. Working with a wide array of state, community, industry, and university partners, the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy invests in a diverse portfolio of energy technologies.
December 2006 CID# DE-FG36-06GO16042
For more information, visit www.eere.energy.gov/industry or call 1-877-337-3463
