Sorbent attrition in a carbonation/calcination pilot plant for capturing CO2 from flue gases

Abstract

There is increasing interest in CO 2 looping cycles that involve the repeated calcination and carbonation of the sorbent as a way to capture CO 2 from flue gases during the carbonation step and the generation of a pure stream of CO 2 in the oxyfired calcination step. In particular, attrition of the material in these interconnected fluidized bed reactors is a problem of general concern. Attrition of limestone derived materials has been studied in fluidized-bed systems by numerous authors. In this work, we have investigated the attrition of two limestones used in a system of two interconnected circulating fluidized bed reactors operating in continuous mode as carbonation and calciner reactors. We observed a rapid initial attrition of both limestones during the calcination step which was then followed by a highly stable period (up to 140 h of added circulation for one of the limestones) during which particle size changes were negligible. This is consistent with previous observations of attrition in other systems that employ these materials. However, a comparison of the attrition model constants with the data reported in the literature showed the two limestones to be particularly fragile during the initial calcination and the first few hours of circulation. Thus, a careful choice of limestone based on its attrition properties must be taken into account in designing future carbonate looping systems.

Additive effects of steam addition and HBr doping for CaO-based sorbents for CO 2 capture

“…The carrying capacity here is considered as the uptake of CO2 per mole of the original sorbent; therefore, any attrition of particles that results in losses of material from the bed will reduce the observed carrying capacity from the actual fractional conversion of the particles in the bed. Attrition has been shown to vary across different limestones and treatment methods and to be problematic in FBRs of a similar scale as the one used for this paper (Blamey et al, 2010b, Fennell et al, 2007b as well as on a pilot scale (González et al, 2010). Table 3 shows the mass loss data for all the limestones, after 13 cycles, doped and undoped, with or without steam present.…”

Microlith-based Structured Sorbent for Carbon Dioxide, Humidity, and Trace Contaminant Control in Manned Space Habitats

“…Furthermore, using the new insulating mesh materials (with less open area vs. the one used in the subscale development effort) and the new washcoat formulation, the overall volumetric sorbent loadings on the insulating meshes were increased by ~13-20%. The results give potential benefits to the overall adsorber performance (e.g., longer adsorption time, less exposure to thermal cycles, lower overall power consumption, and size benefits) due to the higher sorbent density and thus a higher expected volumetric sorption capacity (i.e., g of CO 2 or H 2 O uptake per cm 3 of adsorber unit). During the sorbent coil assembly, up to eight thermocouples were placed between the "jelly roll" coil layers for temperature readout during the actual adsorption and regeneration process.…”

“…Furthermore, these sorbent materials can be readily regenerated via either thermal swing adsorption (TSA) or pressure swing adsorption (PSA), and therefore, they are suitable for a continuous control of CO 2 and trace contaminant levels during long duration spacecraft missions. These regenerable adsorber systems do not have to be replaced during mission duration, and can be smaller and lighter than the disposable adsorber beds.…”

“…Currently, packed beds of sorbent pellets are mostly used in the adsorption systems; however, recent studies have shown that these materials can be easily fluidized and/or eroded, due to both thermal cycling and mechanical vibration, and can generate fine particulates that bypass the downstream mesh filters. 1,2 This results in particulates buildup in downstream pumps, blowers, and other components, and has been problematic in some aerospace applications. Furthermore, these packed beds of pellets create a large pressure drop across the adsorption system resulting in high parasitic losses.…”

Compact, Lightweight Adsorber and Sabatier Reactor for CO2 Capture and Reduction for Consumable and Propellant Production

“…Currently, packed beds of sorbent pellets are mostly used in the adsorption systems; however, recent studies have shown that these materials can be easily fluidized and/or eroded, due to both thermal cycling and mechanical vibration, and can generate fine particulates that bypass the downstream mesh filters. [9][10][11] This results in particulates buildup in downstream pumps, blowers, and other components, and has been problematic in some aerospace applications. Furthermore, these packed beds of pellets create a large pressure drop across the adsorption system resulting in high parasitic losses.…”