Fine particle capture in biomass boilers with recirculating gas cyclones: Theory and practice

Salcedo, Romualdo; Chibante, Vânia; Fonseca, Ana; Cândido, G.

doi:10.1016/j.powtec.2006.10.027

Cited by 14 publications

(18 citation statements)

References 13 publications

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“…However experimental results at pilot and industrial scales with RS VHE cyclones, with internal diameters ranging from 0.46 to 0.70 m, with recirculator diameters up to 1.3 m, showed much higher particle removal efficiencies as compared to smaller diameter multicyclone systems, viz. above 90% against 40-60% for biomass boiler applications [14,17,18].…”

Section: Resultsmentioning

confidence: 99%

“…The recirculation of the gas and particles is assured by a small ASME ventury (0.002 m throat diameter). The recirculation fraction was about 14% [17]. The Stairmand HE cyclone of 0.02 m internal diameter was modified by decreasing the vortex tube diameter by 60%, in order to increase its collection efficiency for the slaked lime test dust from 57% [12] to over 90%.…”

Section: Methodsmentioning

confidence: 99%

“…Partial recirculation of the gas and solids is promoted by some means, such as by a venturi for laboratory-scale or by a blower or ejector for industrial-scale and high temperature applications. These recirculating cyclones were already tested both at laboratory, pilot and industrial scales, achieving, under some circumstances, particle removal efficiencies comparable to those of a jet-pulse bag filter [14,[16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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Dry scrubbing of acid gases in recirculating cyclones

Chibante

Fonseca

Salcedo

2007

Journal of Hazardous Materials

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This paper describes a laboratory-scale study on the use of recirculating cyclones as reaction chambers for dry scrubbing of gaseous HCl with solid slaked lime particles. This gas cleaning system combines a numerically optimized reverse flow gas cyclone (RS VHE geometry) with a straight-through cyclone concentrator, which simultaneously increases the capture of the solid particles and promotes their partial recirculation. A laboratory-scale study was undertaken to test this technology and to compare its performance to a modified Stairmand HE reverse flow cyclone without recirculation. The experimental conditions were: reaction temperature ≈326 K, gas flow rate ≈2.9 × 10 −4 N m 3 s −1 and relative humidity of the gas ≈8.5%. The experimental variables tested were the solids load (1.0-9.2 × 10 −7 kg s −1 ) and HCl concentration (0.4-2.8 × 10 −2 mol m −3 ) in the inlet gas.The experimentally obtained particulate removal efficiencies with the recirculating cyclones (≈98%) were higher than those obtained with the Stairmand HE cyclone (≈93%), with the additional advantage of having significantly lower pressure drop. As for the acid removal efficiencies (≈10-96%), no significant differences were found between the two systems tested under the same experimental conditions.The possibility of using optimized recirculating cyclones for gas cleaning in a dry scrubbing process is very promising, since this is a low cost technology, highly efficient both for the removal of acid gases and for the capture of solid particles, which has the advantage of not requiring a post-reaction de-duster.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dry scrubbing of acid gases in recirculating cyclones

Chibante

Fonseca

Salcedo

2007

Journal of Hazardous Materials

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“…The Hurricane cyclone has shown consistently good results when applied to very different dusts both at pilot and industrial scales [1,9,29,32,33]. Many experimental results showed abnormal high collection for very fine particles (<1-2 μm), a characteristic that none of the classical models for gas cyclones, such as Mothes and Löffler [19], was able to predict.…”

Section: Agglomeration/clustering In Cyclonesmentioning

confidence: 99%

“…Three experiments were performed at different inlet concentrations with this specific sample, consisting of ashes from a wood-waste bio-mass boiler obtained from a mechanical ReCyclone® [32],placeddown-stream from a low pressure drop cyclone acting as a primary deduster. The particle size distribution at the inlet of the optimized Hurricane_MK cyclone given in Fig.…”

Section: Case 2 -Sample Bmentioning

confidence: 99%

Cyclone optimization including particle clustering

Alves¹,

Paiva²,

Salcedo

2015

Powder Technology

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In this work, a new family of geometries of reverse-flow cyclones was obtained through numerical optimization, using a stochastic random search global optimizer coupled with the PACyc model. The objective was to optimize the geometry of a reverse-flow cyclone taking into account inter-particle agglomeration (clustering), since this phenomenon usually occurs to some degree in industrial cyclone operation, increasing the collection of fine particles.Experimental results for three kinds of particles and particle size distributions are shown using a pilot-scale unit. An industrial implementation of the new optimized cyclone is described and the results concerning the performance of the system are shown and compared with predictions from the PACyc model.The results show a highly improved global efficiency when compared to that of a cyclone geometry obtained by a similar optimization methodology while neglecting the agglomeration/clustering effect. This opens the possibility of using reverse-flow cyclones to capture very fine particles, complying with strict emission limits, such as those from biomass boiler exhausts.

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