Parametric Study on the CO2 Capture Efficiency of The Carbonate Looping Process in a 10 kW Dual Fluidized Bed

Increased installation of renewable electricity generators requires different technologies to compensate for the associated fast and high load gradients. In this work, sorption enhanced gasification (SEG) in a dual fluidized bed gasification system is considered as a promising and flexible technology for the tailored syngas production for use in chemical manufacturing or electricity generation. To study different operational strategies, as defined by gasification temperature or fuel input, a simulation model is developed. This model considers the hydrodynamics in a bubbling fluidized bed gasifier and the kinetics of gasification reactions and CO2 capture. The CO2 capture rate is defined by the number of carbonation/calcination cycles and the make-up of fresh limestone. A parametric study of the make-up flow rate (0.2, 6.6, and 15 kg/h) reveals its strong influence on the syngas composition, especially at low gasification temperatures (600–650 °C). Our results show good agreement with the experimental data of a 200 kW pilot plant, as demonstrated by deviations of syngas composition (5–34%), lower heating value (LHV) (5–7%), and M module (23–32%). Studying the fuel feeding rate (22–40 kg/h), an operational range with a good mixing of solids in the fluidized bed is identified. The achieved results are summarized in a reactor performance diagram, which gives the syngas power depending on the gasification temperature and the fuel feeding rate.

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CO2 capture with CaO in a 200 kWth dual fluidized bed pilot plant

Energy Procedia ◽

10.1016/j.egypro.2011.01.073 ◽

2011 ◽

Vol 4 ◽

pp. 441-448 ◽

Cited By ~ 46

Author(s):

C. Hawthorne ◽

H. Dieter ◽

A. Bidwe ◽

A. Schuster ◽

G. Scheffknecht ◽

...

Keyword(s):

Fluidized Bed ◽

Co2 Capture ◽

Pilot Plant ◽

Dual Fluidized Bed

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Analysis and Comparison of Reactivity and CO2 Capture Capacity of Fresh Calcium-Based Sorbents and Samples From a Lab-Scale Dual Fluidized Bed Calcium Looping Facility

Volume 3: Controls, Diagnostics and Instrumentation; Cycle Innovations; Marine ◽

10.1115/gt2010-22192 ◽

2010 ◽

Author(s):

Senthoorselvan Sivalingam ◽

Stephan Gleis ◽

Hartmut Spliethoff ◽

Craig Hawthorne ◽

Alexander Charitos ◽

...

Keyword(s):

Fluidized Bed ◽

Co2 Capture ◽

Test Facility ◽

Experimental Conditions ◽

Fast Heating ◽

Fresh Sample ◽

Calcium Looping ◽

Process Modification ◽

Dual Fluidized Bed ◽

Capture Capacity

Naturally occurring limestone and samples from a lab scale dual fluidized bed (DFB) calcium looping (CaL) test facility were analysed in a thermo gravimetric analyser (TGA). The reactivity of the samples evaluated at typical carbonation conditions prevailed in the carbonator was compared with raw samples. Carbonations were carried out at 600, 650 &700°C and 5, 10 &15 vol-% CO2 atmosphere using a custom designed sample holder that provided ideal conditions for solid gas contact in a TGA. The rate of carbonation and carbonation capacity of the samples were compared with respect to the following three categories: number of calcination-carbonation cycles, carbonation temperature and CO2 concentration. Notable differences in total conversion (XCaO) and the rates of conversions were observed between the raw and DFB samples in all three cases. It is suspected the much lower activity of the DFB sample is attributed to the differences in experimental conditions: ie., partial carbonation of the DFB particles, fast heating rate in the calciner and thus a rapid calcination reaction, and particle attrition in the CFB calciner riser. These harsh conditions lead sintering and thus a loss of surface area and reactivity. Sintered DFB samples showed low (nearly 1/3 of the raw samples) but stable conversions with increasing number of cycles. The sorbent taken from the DFB facility did not decrease with respect to carbonation rate or maximum conversion over 4 cycles whereas the fresh limestone changed significantly over 4 cycles. Hydration was used as an attempt to regenerate the lost capture capacity of partially carbonated DFB sample. Hydration of the sintered DFB sample was successful in increasing the maximum capture capacity in the fast reaction regime to values almost as high as that of a fresh sample in its first carbonation cycle. Although more investigation is required to investigate the effect of hydration on the CaO particle morphology, a process modification to enhance the CO2 capture efficiency of the carbonator via particle hydration was proposed.

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Analysis and Comparison of Reactivity and CO2 Capture Capacity of Fresh Calcium-Based Sorbents and Samples From a Lab-Scale Dual Fluidized Bed Calcium Looping Facility

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4002683 ◽

2011 ◽

Vol 133 (7) ◽

Cited By ~ 1

Author(s):

Senthoorselvan Sivalingam ◽

Stephan Gleis ◽

Hartmut Spliethoff ◽

Craig Hawthorne ◽

Alexander Charitos ◽

...

Keyword(s):

Fluidized Bed ◽

Co2 Capture ◽

Test Facility ◽

Experimental Conditions ◽

Fast Heating ◽

Fresh Sample ◽

Calcium Looping ◽

Process Modification ◽

Dual Fluidized Bed ◽

Capture Capacity

Naturally occurring limestone and samples from a lab-scale dual fluidized bed (DFB) calcium looping test facility were analyzed in a thermogravimetric analyzer. The reactivity of the samples evaluated at typical carbonation conditions prevailed in the carbonator was compared with raw samples. The rate of carbonation and carbonation capacity of the samples were compared with respect to the following three categories: number of calcination-carbonation cycles, carbonation temperature, and CO2 concentration. It is suspected that the much lower activity of the DFB sample is attributed to the differences in experimental conditions, i.e., partial carbonation of the DFB particles, fast heating rate in the calciner and thus a rapid calcination reaction, and particle attrition in the circulating fluidized bed calciner riser. These harsh conditions lead to sintering and thus a loss of surface area and reactivity. Sintered DFB samples showed low (nearly one-third of the raw samples) but stable conversions with increasing number of cycles. Hydration was used as an attempt to regenerate the lost capture capacity of partially carbonated and sintered DFB sample. Hydration of the DFB sample was successful in increasing the maximum capture capacity in the fast reaction regime to values almost as high as that of a fresh sample in its first carbonation cycle. Although more investigation is required to investigate the effect of hydration on the CaO particle morphology, a process modification to enhance the CO2 capture efficiency of the carbonator via particle hydration was proposed.

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