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We investigated the effects of carbonation and regeneration temperature on the C[O.sub.2] capture characteristics using SorbKX35, a potassium-based solid sorbent in a bubbling fluidized-bed reactor. A dry sorbent, SorbKX35 consists of [K.sub.2]C[O.sub.3] for absorption and supporters for mechanical strength. We also measured the physical properties of the sorbent, such as pore size, pore volume, and surface area after carbonation or regeneration, to confirm the extent of the reaction. With [H.sub.2]0 vapor pretreatment, nearly complete C[O.sub.2] removal was initially achieved and maintained for about 10 min within a temperature range of 333.15-363.15 K with 2 s gas residence time. At lower temperature, C[O.sub.2] capture was more effective during 1 h of carbonation. From the results of temperature programmed desorption and gas adsorption method (BET), we found that the regeneration of carbonated SorbKX35 was not complete at 473.15 K. The results obtained in this study can be used as basic data for designing and operating a large-scale C[O.sub.2] capture process with two fluidized-bed reactors. DOI: 10.1061/(ASCE)0733-9372(2009)135:6(473) CE Database subject headings: Fluidized beds; Reactors; Carbonation; Temperature effects; Bubbles.

Experiments of C[O.sub.2] capture and sorbent regeneration characteristics of limestone, dolomite, and CaO/[Ca.sub.12][Al.sub.14][O.sub.33] at high temperature were investigated in a thermogravimetric analyzer (TGA) and a fluidized bed reactor. The effect of reactivity decay of limestone, dolomite, and CaO/[Ca.sub.12][Al.sub.14][O.sub.33] sorbents on C[O.sub.2] capture and sorbent regeneration processes was studied. The experimental results indicated that the operation time of high efficient C[O.sub.2] capture stage declined continuously with increasing of the cyclic number due to the loss of the sorbent activity, and the final C[O.sub.2] capture efficiency would remain nearly constant, due to the sorbent already reaching the final residual capture capacity. After the C[O.sub.2] capture step, the Ca-based sorbents need to be regenerated to be used for a subsequent cycle, and the multiple calcination processes of Ca-based sorbent under different calcination conditions are studied and discussed. Reactivity loss of limestone, dolomite and CaO/[Ca.sub.12][Al.sub.14][O.sub.33] sorbents from a fluidized bed reactor at both mild and severe calcination conditions was compared with the TGA data. At mild calcination conditions, TGA results of sorbent reactivity loss were similar to the experimental results of fluidized bed reactor for three sorbents at 850[degrees]C calcination temperature, and this indicated that TGA experimental results can be used as a reference to predict sorbent reactivity loss behavior in fluidized bed reactor. At severe calcination condition, sorbent reactivity loss behavior for limestone and dolomite from TGA compare well with the result from a fluidized bed reactor. DOI: 10.1061/(ASCE)EE.1943-7870.0000066 CE Database subject headings: Carbonation; Reactors; Gas; Fluidized beds.

A novel liquid-impregnated clay sorbent [R. V. Siriwardane, U.S. Patent No. 6,908,497 B1 (2003)] was developed for carbon dioxide (C[O.sub.2]) removal in the temperature range of ambient to 60[degrees]C for both fixed-bed and fluidized-bed reactor applications. The sorbent is regenerable at 80-100[degrees]C. A 20-cycle test conducted in an atmospheric reactor with simulated flue gas with moisture demonstrated that the sorbent retains its C[O.sub.2] sorption capacity with C[O.sub.2] removal efficiency of about 99% during the cyclic tests. The sorbents suitable for fluidized-bed reactor operations showed required delta C[O.sub.2] capacity requirements for sorption of C[O.sub.2] at 40[degrees]C and regeneration at 100[degrees]C. The parameters such as rate of sorption, heat of sorption, minimum fluidization velocities, and attrition resistance data that are necessary for the design of a reactor suitable for capture and regeneration were also determined for the sorbent. A 20-cycle test conducted in the presence of flue-gas pollutant sulfur dioxide--S[O.sub.2] (20 parts per million)--indicated that the sorbent performance was not affected by the presence of S[O.sub.2]. DOI: 10.1061/(ASCE)EE.1943-7870.0000003 CE Database subject headings: Carbon dioxide; Combustion; Gas; Fluidized beds; Clays.

Sintering during calcination/carbonation may introduce substantial economic penalties for a C[O.sub.2] looping cycle using limestone/dolomite-derived sorbents. Here, cyclic carbonation and calcination reactions were investigated for C[O.sub.2] capture under fluidized bed combustion (FBC) conditions. The cyclic carbonation characteristics of CaC[O.sub.3]-derived sorbents were compared at various calcination temperatures (700-925[degrees]C) and different gas stream compositions: pure [N.sub.2] and a realistic calciner environment where high concentrations of C[O.sub.2] > 80-90% (and the presence of S[O.sub.2]) are expected. The conditions during carbonation employed here were 700[degrees]C and 15% C[O.sub.2] in [N.sub.2] and 0.18% or 0.50% S[O.sub.2] in selected tests, i.e., typically expected for a carbonator. Up to 20 calcination/carbonation cycles were conducted using a thermogravimetric analyzer (TGA) apparatus. Three Canadian limestones were tested: Kelly Rock, Havelock, and Cadomin, using a prescreened particle size range of 400-650 [micro]m. In addition, calcined Kelly Rock and Cadomin samples were hydrated by steam and examined. Sorbent reactivity was reduced whenever S[O.sub.2] was introduced to either the calcining or carbonation streams. The multicyclic capture capacity of CaO for C[O.sub.2] was substantially reduced at high concentrations of CO2 during the sorbent regeneration process and carbonation conversion of the Kelly Rock sample obtained after 20 cycles was only 10.5%. Hydrated sorbents performed better for C[O.sub.2] capture, but also showed significant deterioration following calcination in high C[O.sub.2] gas streams. This indicates that high C[O.sub.2] and S[O.sub.2] levels in the gas stream lead to lower CaO conversion because of enhanced sintering and irreversible formation of CaS[O.sub.4]. Such effects can be reduced by separating sulfation and carbonation and by introducing steam to avoid extremely high C[O.sub.2] atmospheres, albeit at a higher cost and/or increased engineering complexity. DOI: 10.1061/(ASCE)EE.1943-7870.0000079 CE Database subject headings: Fluidized beds; Calcination; Combustion; Gas; Limestone.

Coal resource is abundant in China, while the reserves of natural gas and petroleum are limited. Due to the rapid increase in the number of automobiles, a competitive way to produce liquid fuels from coal is urgently needed in China. A so-called 'coal topping process' is under development at the Institute of Process Engineering, Chinese Academy of Sciences, from which liquid products can be obtained by flash pyrolysis in an integrated circulating fluidized bed system. In order to achieve a high yield of liquid products from high volatile coal, controlling the residence time of coal particles and produced gas may be of importance for minimizing the degree of the secondary reactions; i.e., polymerization and cracking of the liquid products. Experiments of the flash pyrolysis of coal have been conducted in an entrained bed reactor: which is especially designed to study the influence of the coal particle residence time on the product distribution. The results show that the gaseous, liquid, and solid product distribution, the gas compositions as well as the liquid compositions depend strongly on the gas and particle residence time. [DOI: 10.1115/1.2719208] Keywords: lignite, flash pyrolysis, residence time, fluidized bed

Byline: Massimiliano Barletta, Annamaria Gisario, Luca Lusvarghi Fluidised Bed Coating (FBC) is a viable and low-cost technique to apply, at ambient temperature, thin adherent ceramic coatings onto metal and non metal substrates. Al2O3 films, by virtue of its special thermo-mechanical, chemical, electrical and optical properties, belong to a class of ceramic coatings of particular interest in several manufacturing processes. In this respect, the present paper reviews selected applications in manufacturing of Al2O3 coated aluminium substrates. In particular, the use of fluidised bed deposited thin Al2O3 films has been reported as surface overlay coatings to improve the fatigue behaviour of aluminium components, as absorption and thermal barrier coatings in sheet laser forming and, finally, as anti-wear protective coatings.