Suppression of natural limestones deactivation during cyclic carbonationdecarbonation

Transcription

1 Suppression of natural limestones deactivation during cyclic carbonationdecarbonation process in CCS technology Presented by: Dipl.-Ing. Marek Staf, Ph.D UNIVERSITY OF CHEMISTRY AND TECHNOLOGY PRAGUE FACULTY OF ENVIRONMENTAL TECHNOLOGY DEPARTMENT OF GAS, COKE AND AIR PROTECTION Research supported by grant from Norway; Project Nr.: NF-CZ08-OV Acronym: hitecarlo

2 Research aims Primary aim Particular aims Development of technology of high-temperature decarbonation for CO 2 removal from flue gas: 1 st step in laboratory scale 2 nd step design of fluidized bed pilot plant. targets of this study 1. Evaluation, how chemical composition and physical parameters of limestones influence sorption capacities and their stability during cyclic decarbonations/carbonations; 2. Evaluation, how chemical composition of flue gas influences the efficiency of CO 2 sorption and stability of sorption capacity; 3. Evaluation, how temperature conditions during carbonation/decarbonation influence stability of sorption capacity; 4. Assessment of limestone reactivation using water vapor. No.: 2 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

3 Post combustion CO 2 capture Estimated as the best way for retrofitting existing coal-fired power plants and heat plants Common scheme Fig. 1 Task for this project No.: 3 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

4 Carbonate looping Carbonate looping (particular method involved within post combustion processes) Fig. 2 Natural limestones: Low purchase cost Sintering, pores blockage, drop of capacity No.: 4 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

5 Overview of applied methods Basic characterisation of samples 1. XRF 2. TGA 3. Physical properties measurement 4. Evaluation of BET surface Study of sorption properties 1. Measurement of breakthrough curves of CO 2 under dynamic conditions Decarbonation with nitrogen flow through the reactor Decarbonation with CO 2 /N 2 mixture flow Tests of changes in calcination temperature, composition of gas mixture for carbonation, reactivation using water vapor etc. Introducing nitrogen flow saturated by water vapor. No.: 5 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

6 Apparatus with tubular reactor Fig. 3 Sketch of apparatus (RS 232 data acquisition not depicted) 1 needle valve, 2 gas flow meter, 3 gas flow controller, 4 bypass, 5 thermometer, 6 sample zone, 7 preheating zone, 8 furnace, 9 spiral cooler, 10 ball valve, 11 gas flow meter, 12 bypass over IR spectrometer, 13 IR analyzer, 14 gas meter, 15 gas outlet, 16 heating mantle with distillation flask, 17 mixer, 18 hygrometer, 19 humidity sensor No.: 6 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

7 Apparatus with tubular reactor Front view of the apparatus (PC and gas meter not depicted) Fig. 4 Apparatus (state after experiment); Cooling down after calcination No.: 7 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

8 Tests in quartz reactor Conditions of test with calcination in N 2 or in mixture N 2 /CO 2 Samples Temperature program Granulometry: fraction 1 2 mm Bulk density: 1,29 1,42 g/cm 3 Input amount: bulk volume 70 ml weight g Calcination: 850 or C (ramp 10 C.min -1 ) atmosphere N 2 (flow 2 dm 3.min -1 ) or N 2 + O 2 12 % + CO 2 12 % Carbonation: 650 C (isotherm) atmosphere N 2 + CO 2 14 % or N 2 + O 2 12 % + CO 2 12 % Measurement conditions CO 2 : Temperature: Gas volume: Gas humidity: IR analyzer thermocouple Ni-CrNi wet drum gas meter hygrometer No.: 8 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

9 Breakthrough curves Calcination C in N 2, carbonation 650 C in N % CO 2 Note: sample name HVIZD = abbreviation of the quarry Fig. 5 6 cycles carbonation-decarbonation No.: 9 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

10 Breakthrough curves Calcination C in N 2, carbonation 650 C in N % CO 2 Note: sample name BRANZ = abbreviation of the quarry Composition: CaCO 3 98,22 % wt. MgCO 3 0,93 % wt. Theor. capacity: 43,67 g/100g Fig. 6 Changes of capacity during 6 cycles carbonation-decarbonation No.: 10 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

11 Results impact of atmosphere Tests without water vapor regeneration Calcination Example Impact of different calcination atmosphere: if calcined in the atmosphere with CO 2 shift of the beginning of CO 2 emission by C higher if calcined in the atmosphere with CO 2 decrease of released and captured CO 2 in first 4 8 cycles 6 cycles of sample CERT capacities in g / 100 g Cycle Calcination in N 2 Calcination in N 2 +CO 2 Released Captured Released Captured 1 44,7 37,1 39,6 24,7 2 37,7 28,8 24,5 18,5 3 25,2 24,3 18,2 17,1 4 20,8 20,2 14,5 12,6 5 17,4 17,7 14,3 12,1 6 15,5 15,6 12,5 10,9 No.: 11 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

12 Results impact of atmosphere Comparison of different atmospheres used for calcination Fig. 7 ( N2 = pure N 2, CO2 = mixture N 2 + O 2 12 % + CO 2 12 %) No.: 12 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

13 Results other factors Normal drop of capacity Capacity in 1st cycle 6 37 g CO 2 / 100 g; Significant decrease within first 5 cycles; Capacity after 20 cyklech 3,5 12,5 g CO 2 / 100 g; Technical transferring capacity Good limestone = high CaCO 3 content, low MgCO 3 content; Longterm stable capacity up to 11 kg CO 2 / 100 kg; Influence of calcination temperature Within C acceleration of capacity decre ase by 2 3 cycles; Effect of water re-activation Injecting of vapor-saturated nitrogen after each calcination; Improvement of capacity by 4 6 g CO 2 / 100 g; Problem Cooling down the limestone before application of vapor regeneration Ca(OH) 2 dehydration at 512 C. No.: 13 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

14 Thank you! Research supported by grant from Norway; Project Nr.: NF-CZ08-OV Acronym: hitecarlo Dipl.-Ing. Marek Staf, Ph.D. University of Chemistry and Technology, Prague, Department of Gas, Coke and Air Protection

15 Additional information about experiments Research supported by grant from Norway; Project Nr.: NF-CZ08-OV Acronym: hitecarlo Dipl.-Ing. Marek Staf, Ph.D. University of Chemistry and Technology, Prague, Department of Gas, Coke and Air Protection

16 Pre-combustion Other variants for CO 2 capture Fig. 8 Oxycombustion Fig. 9 No.: 16 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

17 Sample base Quantity 11 different limestones Characteristics Name Apparent density (g.cm -3 ) BET surface (m 2.g -1 ) Chemical composition ; (% wt.) Theor. capacity (% wt.) CaCO 3 MgCO 3 Fe 2 O 3 Al 2 O 3 SiO 2 BRANZ 2,8 0,26 98,2 0,9 0,2 0,2 0,3 43,7 CERT 2,8 0,11 98,9 0,8 0,0 0,0 0,2 43,9 ENVI 2,5 14,53 74,4 1,7 1,3 6,1 14,9 33,6 HASIT 2,8 0,12 82,6 12,5 0,4 0,8 3,1 42,9 HOLY 2,7 1,04 84,2 3,6 0,3 1,0 10,3 38,9 HVIZD 2,6 3,27 69,3 3,6 1,4 3,9 20,3 32,4 LIBO 2,8 0,39 96,5 1,2 0,0 0,4 1,1 43,0 MORINA 2,8 1,39 91,5 4,4 0,4 1,2 2,1 42,5 SPICKA 2,8 3,24 78,3 3,3 1,8 5,0 10,3 36,2 TETIN 2,8 0,45 96,6 1,6 0,2 0,5 0,9 43,3 VITO 2,7 0,34 98,0 0,6 0,1 0,4 0,7 43,4 No.: 17 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

18 Data processing Expression of results Sorption capacities evaluated for each cycle and expressed in grammes of CO 2 captured by 100 g of initial sample (limestone before first calcination). The same value was expressed for weight of CO 2 released during each calcination. The values were used for construction of line-segment graph useful for mutual comparison of sorption capacities decrease during cycles. Kinetics of carbonation phase was calculated by construction of straight line, being parallel with increasing branch of the breakthrough curve Sorption capacities were discussed in context of BET surface, pore sizes distribution, elemental analysis and sample crystallinity (according to XRD). No.: 18 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

19 Water vapor regeneration Order of steps Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Standard calcination up to temperature 850 or C; Cooling down the reactor under pure nitrogen to 200 C; Introduction of nitrogen with flow 0,5 l/min into boiling water; Nitrogen saturated with H 2 O, condensate removed in mixer; Pipe between mixer and reactor is heated to 110 C; Saturation of nitrogen checked using hygrometer; Exothermal hydration demonstrated by temperature increase; Regeneration finished when temperature of the sample is stabilized at the internal temperature of the furnace (110 C); Pure nitrogen introduced into the reactor + apparatus heated up to standard temperature of carbonation. No.: 19 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

20 Breakthrough curves Calcination C in N 2, carbonation 650 C in N % CO 2 Fig. 10 Comparison of changes in capacities of 7 selected samples No.: 20 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

21 Breakthrough curves Calcination C in N 2, carbonation 650 C in N % CO 2 Fig. 11 CO 2 release during calcination under different atmospheres No.: 21 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

22 Water vapor regeneration Fig N 2 inlet, 2 hygrometer, 3, 4, 5 vapor generator, 6 reactor in oven, 7, 8 gas outlet Detail of regeneration part of the experimental apparatus No.: 22 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.

23 Fluidised bed reactor Fig. 13 Fluidised bed reactor uder construction No.: 23 University of Chemistry and Technology, Prague Dipl.-Ing. Marek Staf, Ph.D.