Principal Investigator: Scott Sinquefield, IPST

1. 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 Institute of Paper Science and Technology

2. 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 Institute of Paper Science and Technology

3. 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 Institute of Paper Science and Technology

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 Institute of Paper Science and Technology

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... Institute of Paper Science and Technology

6. 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. Institute of Paper Science and Technology

7. The three in situ causticization processes • Direct causticization using titanates • Direct causticization using manganates • Autocausticization using borates Institute of Paper Science and Technology

8. Direct causticization using titanates • Main reactions: • In gasifier: 7 Na2CO3 + 5 (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 (900-1000C, pyrolysis and CO2 gasification) • A number of studies have shown that titanates will causticize sodium carbonate under conditions relevant to LTBLG Institute of Paper Science and Technology

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? Institute of Paper Science and Technology

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? Institute of Paper Science and Technology

11. 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. Institute of Paper Science and Technology

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 Institute of Paper Science and Technology

13. 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) Institute of Paper Science and Technology

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. Institute of Paper Science and Technology

15. How we plan to accomplish the work • Phase 3: The processes that pass phase 2 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 Institute of Paper Science and Technology

16. 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.) Institute of Paper Science and Technology

17. LEFR 400-1100C 1 bar black liquor solids flow : 0.1-0.5 g/min Primary gas flow rate: 0.1-1 l/min Secondary gas flow rate: 2-40 l/min Reaction gases: N2, O2, H2O (v), CO2, H2, CO, CH4, SO2, H2S..... Steam flow rate: 0.2-6 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 Institute of Paper Science and Technology

18. PEFR • 600-1500C • 2-80 bar • black liquor solids flow : 0.1-30 g/min • Primary gas flow rate: 1 - 5 l/min • Secondary gas flow rate: 25-500 l/min • Reaction gases: N2, O2, H2O (v), CO2, H2, CO, CH4, SO2, H2S..... • Steam flow rate: 0.1-170 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 Institute of Paper Science and Technology

19. 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 Institute of Paper Science and Technology

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 Institute of Paper Science and Technology

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) Institute of Paper Science and Technology

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) Institute of Paper Science and Technology

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) Institute of Paper Science and Technology

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 Institute of Paper Science and Technology