1. Institute of Paper Science and Technology
In Situ Causticization for Black Liquor Gasification: Feasibility, Development, Economics, and Mill Integration
Principal Investigator: Scott Sinquefield, IPST
Collaborators: Ingrid Nohlgren and Jeff Empie, IPST
Daniel Centempo, Jacobs Engineering Group
Consultant: Honghi Tran, University of Toronto
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2. Institute of Paper Science and Technology
Project data
Sponsor: U.S. Department of Energy
(Agenda 2020)
Level of Funding: $ 600,000
(DOE: 480,000 and IPST: 120,000)
Period of Perfomance: Sept 2002-Aug 2005
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3. Institute of Paper Science and Technology
Background
One of the gaps identified on the Peachtree Summit (May 2001) was the increased causticization load for both high and low temperature gasification compared to conventional technology
Alternative causticization processes, such as in situ causticization, would be possible gap filling technologies
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4. In situ causticization
Addition of a chemical agent to the black liquor, which reacts directly in the gasifier with the sodium to form a salt and thus allow the carbon to be released as CO2
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5. In situ causticization
Autocausticization
causticization with a soluble mixed oxide, eg BO2
Autocausticization means ”self-causticization”, i.e. The pulping alkali causticizes itself during the combustion or gasifiction
Direct causticization
causticization with an insoluble metal oxide, eg TiO2
The causticization agent is added and subsequently removed, and added again...
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6. Institute of Paper Science and Technology
Overall objective
Testing and evaluation of three in-situ causticization processes at realistic gasifier conditions for feasibility of partial and complete in situ causticization during black liquor gasification.
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7. The three in situ causticization processes
Direct causticization using titanates
Direct causticization using manganates
Autocausticization using borates
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8. Direct causticization using titanates
Main reactions:
In gasifier:
7 Na2CO (Na2O3TiO2) (s)  3 (4Na2O  5TiO2) (s) + 7 CO2 (g)
In leaching unit:
3 (4Na2O  5TiO2)(s) + 7 H2O  14 NaOH (aq)+5 (Na2O3TiO2) (s)
The kinetics has been shown to be fast enough to occur within a HTBLG system ( C, pyrolysis and CO2 gasification)
A number of studies have shown that titanates will causticize sodium carbonate under conditions relevant to LTBLG
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9. Direct causticization using manganates
Main reactions:
In gasifier:
Na2CO3 + Mn3O4  2 NaMnO2 + MnO + CO2
In leaching unit:
2 NaMnO2+ MnO + H2O  2NaOH(aq) + Mn3O4
Previous work has shown that addition of Na2S led to oxidization to Na2SO4, however no metallic sulfide (MnS) was found Na2S + 4 Mn3O4  Na2SO4 + 12MnO
 Only study at LTBLG
Will H2S released during LTBLG react to form MnS?
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10. Autocausticization using borates
Main reactions:
In gasifier:
NaBO2 + Na2CO3  Na3BO3 + CO2
Hydrolysis:
Na3BO3 + H2O  2NaOH(aq) + NaBO2 (aq)
Earlier work focused on recovery boiler operation
Borates are alkaline soluble  dead load  partial autocausticization
Potentials for LTBLG or HTBLG?
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11. Institute of Paper Science and Technology
Objectives
Determine if any of the in situ processes studied can achieve a high yield of causticization or an acceptable degree of partial causticization for each BLG technology (HTBLG/LTBLG)
Evaluate each of the successful causticization technologies during repeated recycling of the causticizating agent
Identify viable methods of purging dregs
Resolve the technical barriers to commercialization and mill integration
Perform a complete techno-economical evaluation of the processes selected.
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12. How we plan to accomplish the work
Phase 1: Experimental testing at realistic BLG conditions of the in situ causticization technologies
High temperature borate and titanate cases will be evaluated using the pressurized, entrained-flow reactor at IPST
Low temperature experiments with borate, titanate and manganate will be carried out at IPST using a semi-batch fixed bed reactor
In all cases, the goal is to gasify the liquor/agent mixtures under conditions representative of the industrial gasifiers
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13. Institute of Paper Science and Technology
Phase 1 - Tasks
Thermodynamic modelling using FactSage (titanate, manganate and borate)
HTBLG of borate doped liquor and titanate doped liquor respectively under oxygen blown, and water vapor, pressurized conditions (950˚C, 5 and 15 bar)
Evaluation under LTBLG conditions using water vapor
Titanates: (600˚C & 800˚C, 1 bar)
Manganates: (600˚C, 1 bar)
verify that the causticization and gasification reactions proceed in parallel and that H2S gas does not react with Mn3O4 during gasification
Borates: (600˚C, 1 bar)
Hydrolyze the solid products and characterize the insolubles (manganates)
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14. How we plan to accomplish the work
Phase 2: The processes that pass phase 1 will be developed for potential ways of purge dregs.
Tasks:
Characterization of the dregs from successful processes
Identify and evaluate feasible ways of purging dregs, examples:
selective dissolution
filtration
liquid cyclones
addition of agglomerating agents.
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15. How we plan to accomplish the work
Phase 3: The processes that pass phase would undergo an economic evaluation including a plan for mill/gasifier integration
Tasks:
Assess the economics of all processes that pass phase 2
Mill integration requirements for causticization processes for both high and low temperature BLG, and for both partial and complete in situ causticization
This will be done by Jacobs Engineering Group with the support of all collaborators as needed
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16. Institute of Paper Science and Technology
Facilities at IPST
Laminar Entrained Flow Reactor (LEFR)
Pressurized Entrained Flow Reactor (PEFR)
Fixed bed reactors
Analytical:
2 FT-IR’s, GC, Duo-Titrator, NO/NO2
(Mass Spec coming soon)
Chemical Analysis group on site (SEM, XRD, MS, ICP, etc.)
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17. Institute of Paper Science and Technology
LEFR C
1 bar
black liquor solids flow : g/min
Primary gas flow rate: l/min
Secondary gas flow rate: l/min
Reaction gases: N2, O2, H2O (v), CO2, H2, CO, CH4, SO2, H2S.....
Steam flow rate: g/min
Residence times up to 3 sec with movable quenching collector
On-line FT-IR and NOx analysers
Filter for fume collection
3 micron cyclone for char collection
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18. Institute of Paper Science and Technology
PEFR C
2-80 bar
black liquor solids flow : g/min
Primary gas flow rate: l/min
Secondary gas flow rate: l/min
Reaction gases: N2, O2, H2O (v), CO2, H2, CO, CH4, SO2, H2S.....
Steam flow rate: g/min
Residence times up to 8 sec with movable quenching collector
On-line FT-IR and NOx analysers
Filter for fume collection
2 micron cyclone for char collection
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19. Institute of Paper Science and Technology
Fixed bed reactor
Sample boat in a ceramic tube in a tube furnace
Feed gas composition chosen to approximate the product gas composition from an industrial gasifier
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20. IPST Gasification program (Elective Research Consortia)
Member companies allocate their dues toward the consortiums of greatest interest
9 companies make up the gasification consortium
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21. IPST Gasification program (Elective Research Consortia)
Personnel
Dr. Scott Sinquefield (program leader)
Prof. Ingrid Nohlgren
Prof. Jeff Empie
Dr. Chris Verrill
Dr. Xiaoqun Wu (Post-Doc)
Xiaoyan Zeng (Post-Master)
Alan Ball (Sr.Technician)
Jennifer Mattews (MS student)
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22. IPST Gasification program (Elective Research Consortia)
Subprograms:
Stability and Regenerability of Catalysts for Destruction of Tars Formed during Black Liquor and Biomass Gasification (3-year DOE funded, GIT Prof. Pradeep Agrawal, ending Feb, 2003)
Black Liquor Gasification with Borate Autocausticization (funded by US Borax and IPST ERC)
An External Benefits Study of Black Liquor Gasification (3-year Sloan Foundation, GIT Prof. Michael Farmer, started July 2002)
In Situ Causticization for Black Liquor Gasification: Feasibility, Development, Economics, and Mill Integration (3-year DOE-funded, Jacobs Engineering, starting Sept 2002)
Black Liquor Gasification Kinetics (On-going research. Funding levels TBD)
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23. IPST Gasification program (Elective Research Consortia)
DOE Proposals (April 2002 solicitation):
Development and Optimization of Catalysts for the Destruction of Tars Formed in Black Liquor/Biomass Gasification
(GIT – Pradeep Agrawal (prime))
An Experimental Investigation of the Chemical Processes in High-Temperature Pressurized Gasification of Black Liquor
(IPST(prime), Chalmers – Hans Theliander, Jim Frederick, Kristiina Iisa, GIT – Pradeep Agrawal)
Integrated Sulfur Recovery and Causticization for Black Liquor Gasification
(U of Maine, A. Van Heiningen (prime), U of Utah - K. Whitty, Weyerhaeuser - C. Brown and IPST)
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24. Collaboration potentials?
The pressurized gasifier (PEFR) at IPST is a unique and versatile facility for gathering kinetic data for creation/validation of kinetic models of pyrolysis, gasification, and combustion
IPST is an integrated pulp and paper research facility; an ideal site for modified pulping studies and BLG mill integration research
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