HAPPIPOLTTOKONSEPTIT - OXYCONCEPTS

Transcription

1 HAPPIPOLTTOKONSEPTIT - OXYCONCEPTS IV Liekkipäivä , Tampere Toni Pikkarainen & Antti Tourunen

2 Project content & partners OXYCONCEPTS PHEOMENA burning ash formation materials (corrosion, erosion) OXYGEN PRODUCTION cryogenics membranes solid adsorption COMBUSTION PROCESS CFB PC CLC grate CO 2 STORAGE transports disposal follow-up CO 2 SEPARATION compression and liquation solid adsorption liquid adsorption CONCEPTS simulation optimization demonstration plan competitiveness RESEARCH INSTITUTES VTT Technical Research Centre of Finland (54%), coordinator Lappeenranta University of Technology (17%) Helsinki University of Technology (11%) Tampere University of Technology (18%) PARTICIPANTS Fortum PVO Foster Wheeler Metso Power VAPO Jyväskylä Energy TEKES VTT TUT TOTAL 1.36 M Project in Tekes ClimBus-programme, duration 06/ /2008 2

3 Goals & results Main goals: to evaluate technically and economically different oxygen production techniques, combustion and CO 2 capture processes, and the integration of these to overall concepts to create technical readiness for demonstration of oxygen combustion by using state-of-the-art knowledge, experiments, modeling and simulation to create demonstration plan for oxygen combustion for an existing power plant(s) in Finland to evaluate oxygen enriched combustion for power boosting of a power plant Main results evaluation of oxygen combustion business potential for implementation in existing and new power plants improvement of competitiveness of Finnish companies in energy sector by developing CO 2 -free power production technologies 3

4 Tasks 1. Oxygen production and enrichment study of commercial and developing techniques, their costs and potential 2. Applications of oxygen combustion a. PC and CFB boilers applications for retrofit plants (O 2 content 21-28%) b. PC and CFB boilers applications for green field plants (O 2 content 28-60%) c. Oxygen enrichment for power boosting of power plant (replacing the use small peak load oil/gas burning plants) 3. Chemical Looping Combustion (CLC) survey for state-of-the-art, creating of modeling tool and estimation of competitiveness 4. CO 2 capture and storage study of technical and economical aspects and potential new solutions 5. Concept development optimization of the whole oxygen combustion concept, demonstration plan for selected existing power plant(s) and competitiveness of the concept compared to other CO 2 mitigation techniques 6. Phenomena research experiments and model development of burning and emissions applied to oxygen combustion conditions 4

5 Oxygen combustion Using of oxygen instead of air to avoid nitrogen diluting the flue gas makes the capture of CO 2 favourable Air Coal Air separation O 2 Boiler N 2 Partial CO 2 circulation Flue gas cleaning CO 2 /H 2 O Part of the flue gas (mainly CO 2 and H 2 O) needs to circulated back to the boiler to control the flame temperature Condensation Purification Compression CO 2 CO 2 is separated from the flue gas by compression and cooling Vent gas Steam turbine G H 2 O Transport Storage Ship or pipeline trasport to storage site in supercritical form (p= bar, high density & low viscosity) Temperature [ C] Air combustion Examples of differences between air/oxyfuel combustion of bituminous coal Adibatic combustion temperature Flue gas recirculation rate Flue gas recirculation [%] Feed gas composition Flue gas composition Air comb. Oxyfuel comb. Air comb. Oxyfuel comb. O 2 [%-wet] N 2 [%-wet] CO 2 [%-wet] H 2 O [%] SO 2 [ppm-wet] Normalized flow [wet gas] ~ Feed gas O2 content [%, wet] 5

6 Chemical looping combustion (CLC) Oxidation Reduction Images of the oxygen carrier composed of 40% Mn3O4 on 60% Mg-ZrO2 Air (to storage) Chemical looping combustion is a process where a direct contact between fuel and combustion air is avoided. This is accomplished by an oxygen carrier, i.e. a metal oxide, by which the oxygen is transferred from the combustion air to the fuel in the oxidation reactor. Oxygen carrier is then conveyed into the reduction reactor, where it is reduced by gaseous fuel e.g. methane. Flue gas formed is rich in CO 2 and H 2 O, when CO 2 could be separated by means of compression and cooling. 6

7 Task 1 - Oxygen production Energy consumption [kwh e /tn O 2 ] Fuel power [MW th ] Cryogenic distillation Pressure swing adsorption 500 Ion transfer membranes Theoretical minimum Cost [ /tn O 2 ] Maintenance 3 % Labour 17 % Power 27 % Capital 53 % Capacity [tn O 2 /day] Capacity [tn O 2 /day] Cryogenic distillation is currently the only commercial large scale, high purity oxygen production method Membrane technics are attractive because of their low specific energy consumption and compact size, but these are still in development stage 7

8 Task 2 - Applications of oxygen combustion A set of CFB-pilot tests with bituminous coal was carried out at normal air combustion and oxygen combustion conditions All process values was kept as equal as possible Air combustion (without limestone) Air combustion Air combustion (without limestone) Air combustion Oxygen combustion Fuel power kw Limestone-Ca to fuel-s ratio mol/mol Feed gas O2 % wet Primary gas share % Bed temperature ºC Flue gas O2 % dry Flue gas recirculation To stack Bag filter FTIR sampling port Gas analysator Sampling port Gas cooling Observation port Deposit probe port Secondary cyclone Relative value [%] Oxygen combustion (O2=28%) Sampling port Sampling port Sampling port Fuel containers 1 and 2 Additive container Zone 4 Primary Sampling port cyclone FTIR sampling port Zone 3 Sampling port Zone 2 Zone 1 Secondary gas O2, CO2, N2 25 M 0 CO NO N2O SO2 HCl Sulphur capture All the emissions were lower at oxygen combustion mode PC control and data logging system 8 Primary gas heating Sampling port Air

9 Task 2 - Applications of oxygen combustion Development of stationary 3D CFB-model for oxygen combustion and application of the model in reactor process studies and optimisation Case-study based on Lagisza CFB (460 MW e, SC OTU): 1) Air combustion (reference) 2) Oxygen combustion 1: Reduced furnace HTEX-area (O 2 = 23.9 % wet) 3) Oxygen combustion 2: Original HTEX-area (O 2 = 23.9 % wet) 4) Oxygen combustion 3: Original HTEX-area and reduced flue gas recirculation (O 2 = 29.6 % wet) AIR OXY 1 OXY 2 OXY 3 Effect on combustion process and heat fluxes was small, thus CFB oxygen combustion is feasible as retrofit (with existing boiler construction) 9

10 Task 2 - Applications of oxygen combustion PARTICLE FLOW MODEL A reacting particle (fuel or limestone) encounters zones with different temperatures and different gas concentrations while travelling inside the furnace. The particle history affects the reactions (e.g. buildup of sulfate layer). Transient particle models are developed to calculate the reactions, mass and heat transfer for a particle in a changing environment. In the 3D process model, the particle tracks are solved in Lagrangian frame using a random walk model. Example of process values experienced by a particle during one particle track. Illustrative image showing mean particle track (red) and stochastic tracks (black) in 3D oxygen concentration field. For actual model, thousands of tracks are calculated and fluctuations are larger. 10

11 Task 2 - Applications of oxygen combustion Prosim process simulation of oxygen enriched combustion cases and reference air combustion case: case 1: normal 100% load air combustion = 267 MW st case 2: 2.5 % oxygen enrichment to sec./tert. air = +15 MW case 3: 5.0 % oxygen enrichment to sec./tert. air = +30 MW Additional power was recovered by new district heating heat exchanger installed as last heat exchanger Economical evaluation of oxygen enrichment was done, when the addional heat replaces the use of small (oil fired) heating stations As a result, break-even point for oxygen enrichment was calculated as /ton O 2 produced basis (price includes in addition to cost of oxygen production, costs of district heating installation and other required modifications) M / Year Fuel costs Tax for fossils Subsidy for bio CO2 charge ~0.9 M savings ~1.7 M savings Case 1 (normal) Case 2 (+15 MW) Case 3 (+30 MW) Savings in operating costs (without O 2 -production): case 2: about 0.9 M /year case 3: about 1.7 M /year compared to reference case 1. Break-even points for oxygen enrichment: case 2: about 57.3 /ton O 2 case 3: about 49.5 /ton O 2 Power boosting by oxygen enrichment could be in a certain circumstances competitive concept 11

12 Task 3 - Chemical looping combustion Modeling tool development based on literature and 0D mass & heat balance calculation first estimation of CLC combustor design Laboratory scale oxygen carrier experimentals to support modeling "novel" Ni-based carrier materials are produced oxidising/reducing tests in termobalance at different conditions Sample holder Ø16mm Expansion valve Filter Steam condenser Microbalance Winch system He-flushing Sample lock Reactor Thermocouple/ Pyrometer data acquisition data acquisition PRESSURISABLE THERMOBALANCE Pressure range 1-90 bar Temperature max = 1000 C CO 2 H 2 Steam generator air/o 2 /N 2 CO Water pump 12

13 Task 5 - Concept development Suitability of different simulation programs - Prosim, Balas, IPSEpro and partly Aspen) - for oxygen combustion concept development was estimated by "simulation-matrix" based on Meri-Pori -case (565 MW e PC-boiler) All the programs were found to be capable for simulations with their own strengths/weakness: Prosim and IPSEpro were better in power plant process simulations Balas and Aspen were better in chemical process simulations (e.g. ASU and CO 2 purification/separation) Simulation models has been created based on two utility scale power plant chosen as concept development/optimisation subject - Lagisza CFB 460 MW e and Meri-Pori PC 565MW e - and parameters studied are for example: Purity of oxygen produced (by ASU) effect on (eletricity production) efficiency, Burning gas oxygen concentration (O 2 + FGRC) effect on efficiency (see figure), Separation degree of CO 2 effect on efficiency, and Pressure level of CO 2 separation (primary compression) effect on separation efficiency, product gas purity and specific energy consumption Electrical efficiency as a function of O2-concentation into the burner (Burning power 1275 MW, design case) 35 Electrical Efficiency [%] O2-concentration into burner [%] 13

14 Task 6 - Phenomena research Drop tube reactor tests for studying and comparing burning at air and oxygen combustion conditions Pyrolysis and char combustion tests for different fuels and particle size fractions in gas atmosphere containing O 2 + N 2, N 2 + H 2 O, CO 2 + N 2 and CO 2 + O 2 + H 2 O with different mixing ratios and temperatures submodels of combustion and emission formation will be developed for CFD modeling of furnace Volatile Matter USA Coal Volatile Matter % Coal µm Coal µm Temperature C 14

15 Thank you for your attention! Addional information: Toni Pikkarainen, Antti Tourunen, 15