Research Activities on Oxyfuel Combustion at IVD, Universität Stuttgart

Transcription

1 1 st Young Researchers Forum Developments in Oxy-Combustion Technology for Power Plants with CCS Hamburg, Germany 8 th December 26 Hosted by: Institute of Energy Systems Technical University of Hamburg-Harburg PRESENTATION - 4 Research Activities on Oxyfuel Combustion at IVD, by: Patrick Mönckert IVD University of Stutgart, Germany

2 Institut für Verfahrenstechnik und Dampfkesselwesen Institute of Process Engineering and Power Plant Technology Prof. Dr. techn. G. Scheffknecht Research Activities on Oxyfuel Combustion at IVD, Dipl.-Ing. P. Mönckert, M.Sc. B. Dhungel, Dipl.-Ing. D. Reber, Dipl.-Ing. J. Maier, Prof. Dr. techn. G. Scheffknecht Developments in Oxy-Combustion Technology for Power Plants with CCS A Young Researchers Forum Hamburg University of Technology, 8 th December 26 Contents 1. IVD s Structure and Work Areas 2. Test Facilities 3. Oxyfuel Combustion at IVD 4. Results 5. Outlook 2

3 Structure and Work Areas of IVD Prof. Dr.-techn. G. Scheffknecht Director Prof. Dr.-Ing. Helmut Seifert Forschungszentrum Karlsruhe GmbH Institute of Techn. Chemistry Thermal Treatment of Waste Departments Dipl.-Ing. J. Maier Combustion Systems and Steam Boilers Prof. Dr.-Ing. G. Baumbach Air Pollution Prevention Dipl.-Ing. H. Thorwarth Fuels and Measurement Techniques Dr.-Ing. R. Berger Decentralized Energy Conversion Prof. Dr.-Ing. PD U. Schnell Combustion and Steam Boiler Simulation Dipl.-Ing. T. Weißbach Power Generation and Automatic Control 3 Test Facilities at IVD Lab Scale Atmospheric drop tube furnace Atmospheric drop tube furnace Slagging and fouling experimental rig Flameless combustion burner test rig Pilot Scale.5MW th Pulverised fuel combustion rig Atmospheric fluidised bed test rig (bubbling/circulating) Pressurised fluidised bed test rig (bubbling) Pressurised entrained flow reactor Investigation parameters: pyrolysis gasification homogeneous/ heterogeneous reaction flameless combustion ash formation and behavior slagging, fouling fuel conversion under pressurized conditions flue-gas cleaning Fuel preparation: Hammer and impact mills preparation of bituminous coal Beater mill preparation of lignite/ brown coal Several other mills for preparation of biogenic fuels, co-combustion material (SRF), etc. 4

4 Test Facilities - 2kW th coal combustion reactor Atmospheric drop tube furnace General caracteristics: Furnace: Ceramic tube Length of furnace: 2,5 mm Diameter: 2 mm 5 electrically heated zones (up to 14 C) Oxyfuel concentrations of carrier, primary and secondary gas streams separately adjustable Co-linear optical access at 1,55 mm Measurement parameters (fuel characterisation): Gas emission profiles (oil-cooled probe) Gas temperature profiles (suction pyrometer) Particle temperatures (2-color-pyrometry) Particle sampling (profile and fly-ash) Deposit sampling 5 Test Facilities -.5MW th Unit Pulverised fuel combustion facility FD fan Coal feeding Biomass SRF Configuration for Air Combustion Conditions (Co-combustion) Bypass ID fan Bottom ash APH SCR ESP stack 6

5 Modifications for Oxyfuel Combustion C gas distribution.5mw th storage tanks others 2kW th consumers 7.5MW th Unit Modifications for Oxyfuel Combustion Conditions C Mixing chamber -MFC Coal feeding RG orifice Process control RG fan Storage tanks and mixing ID fan Bottom ash APH SCR ESP stack 8

6 .5MW th Unit Modifications for Oxyfuel Combustion Conditions re-circulation ventilator injection system (MFC, injector) duct for re-cycled flue-gas Venturi orifice to furnace 9.5MW th Unit Modifications for Oxyfuel Combustion Conditions C After -injection Mixing chamber -MFC Coal feeding RG orifice Process control RG fan Storage tanks and mixing In-flame profile measurements: - gas emissions - temperatures - particle sampling - deposit sampling End of comb. Chamber After APH Before and after ESP ID fan Bottom ash APH SCR ESP stack 1

7 Oxyfuel Research Topics Investigation of Fuel characteristics (lab unit) - particle ignition temperature - gas emission behaviour under staged and un-staged conditions, impact of flue-gas re-circulation - ash quality Flame stability and basic oxyfuel burner set-up (lab and pilot unit) - variation of burner set-up - variation of oxygen injection Burnout and emission behaviour (lab and pilot unit) - gas emission profiles - gas temperature profiles - radiation intensity profiles (Chalmers UT) - fly-ash profiles Slagging, fouling and fly ash behaviour (lab and pilot unit) - fly-ash and burnout characterisation - exposure of deposition probes (Vattenfall UAB) Operational procedures (.5MW th pilot unit) - start-up/ shut-down procedures - identification of air-inleakage - switch from air to oxyfuel operation - parameter optimisation (variation of -injection, recycle rate, ) - maximisation of C concentration - reference flame definition 11 Results Fuel Characterization under Oxyfuel Conditions Gas emissions and gas temperature profiles: air vs. 27% oxyfuel (Kleinkopje bituminous coal) S, NO X in mg/mj 1 baseline gas temperature gas temp. in C 15 S, NO X in mg/mj 1 27% oxyfuel gas temperature gas temp. in C 15 distance from burner NO X S NO X S distance from burner in m distance from burner in m Un-staged combustion: NO X emission for referred to energy input equal or inferior at oxyfuel conditions compared to air conditions, S is not influenced. 12

8 Results Fuel Characterization under Oxyfuel Conditions Effect of oxyfuel staging on NO X emission rate (Lausitz lignite) staging with oxyfuel NO X in mg/mj baseline un-staged = 1.15 c(no X ) = 222 mg/mj =.95 = residence time in reduction zone in seconds % oxyfuel un-staged = 1.15 c(no X ) = 191 mg/mj = = = residence time in reduction zone in seconds NO X in mg/mj variation of residence time Staged combustion: NO X emission rate decreases significantly for decreasing stoichiometric ratio and with increasing residence time in the reducing zone NO X is given referred to N 13 Optimization of.5mw th Unit Identification of air-inleakages profile under oxyfuel and re-circulation conditions in vol.-% (dry basis) Measurement position range in % Mixing chamber RG orifice 3 2 end of comb. chamber after APH before ESP RG fan 1 after ESP End of comb. Before and Chamber after ESP After APH ID fan end of comb. chamber after APH before ESP after ESP Bottom ash APH SCR ESP stack 14

9 .5MW th Unit Modifications for Oxyfuel Combustion Conditions C Coal feeding Mixing chamber ambient air for start-up RG orifice RG fan -MFC Storage tanks and mixing Bypass ID fan Bottom ash APH SCR ESP stack 15 Operational behaviour: Switch from once-through to re-circulation mode C as carrier gas C at flame detectors CO C 9:49 h: C instead of air as carrier gas, C as cooling for flame detector 16

10 Operational behaviour: Re-circulation of flue-gas and reduction of ambient air supply (I) CO Flap for flue-gas re-circulation opened C 1:1 h: flue-gas re-circulation started 17 Operational behaviour: Re-circulation of flue-gas and reduction of ambient air supply (II) Re-circulated flue-gas volume increased step-by-step C CO Air flap closed! 1:19 h: ambient air flap closed tightly; remaining air entry through starter burner 18

11 Operational behaviour: Re-circulation of flue-gas and reduction of ambient air supply (III) CO Starter burner switched off C 1:32 h: starter burner switched off, maximisation of C concentration 19 Results Oxyfuel Combustion at.5mw th Unit 2

12 Results Oxyfuel Combustion at.5mw th Unit - Air in-leakage minimised - Transmission from once-through to oxyfuel combustion with flue-gas re-circulation successful - Flame ignition stable despite fuel dosing with pure C - Stable operation over several hours - Quick accumulation of C in flue-gas 21 Outlook and Work in the Next Months Operational - Implementation of new pre-heater for adjusting temperature of recycled flue-gas - Recycle rate variation - Definition of reference flames for various fuels at air and oxyfuel conditions - Burner optimisation (oxygen injection) Combustion Characteristics - Gas temperature and global temperature profiles ( heat flux, input for simulation) - Gas emission behaviour under recycle conditions: NO X behaviour, S and CO - Radiation intensity (CHALMERS) - Deposition sampling, material testing and corrosion probes exposure (with VUAB) - Investigation of ash quality under recycle conditions fly-ash 22