Epstein N., Grace J.R. Spouted and Spout-Fluid Beds: Fundamentals and Applications

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Gasiﬁcation, pyrolysis, and combustion 257

not surprising that variations in solids throughput are signiﬁcant, given the variations

in reactivity that arise from coal rank, and the fact that feed rates have not all been

converted to a moisture- and ash-free basis, as well as differences in such factors as feed

location and particle size. Nevertheless, the data summarized in Table 15.2 suggest that

at atmospheric pressure, with coal feed, units operate at solid feed mass ﬂuxes of about

0.1 to 0.2 kg/m

s, which can be raised to 0.3 to 0.6 kg/m

satP = 0.5 MPa, and to

0.9 kg/m

satP = 1.2–1.8 MPa. Wood charcoal

throughput appears to be higher.

Variations from normal spouting have been adopted in many cases. Either bed depths

were reduced, as in high velocity “jet-spouting,” or deep spout-ﬂuid beds were adopted

with some gas fed through the cone walls. Spouting must also occur in some commercial

ﬂuid bed units such as the high-temperature Winkler and Kellogg-Rust-Westinghouse

gasiﬁers, both of which operate with gases entering at the apex of a conical section in

vessels that have no g rid or distributor.

Direct comparisons of the effects of different reactor conﬁguration for the same

feedstocks have been reported. The capability of the spouted bed to better accommodate

agglomerating feedstocks, such as caking coals, has often been cited. Watkinson et al.

compared a spouted bed directly with a bubbling ﬂuidized bed. The performances of

the two types of reactor were very similar, although optimal conditions for each may

not have been achieved. Normal spouting versus “jet spouting” gasiﬁcation can be

compared,

9–11

although temperature and other conditions were not quite identical. For

charcoal gasiﬁcation, two variants of spouting have been compared.

With coconut

shells, a ﬂuid bed gave slightly better quality gas than a ﬂat-bottomed bed spouted via a

single central oriﬁce.

Although the spout-ﬂuid gasiﬁer appears to be the most successful type of spouted

bed for coal as scale has increased to ∼1 m in diameter, for much larger integrated

power plant processes, higher temperature entrained-bed slagging gasiﬁers appear to be

favored over dry-ash units such as the spouted bed.

For municipal solid waste, spouted

beds have been investigated

at a substantial demonstration scale of 680 kg/h.

15.5 Modeling of spouted bed gasiﬁcation

Numerous efforts have been made to model spouted bed gasiﬁcation. These range from

simple mass-balance equilibrium models, which do not consider solids or gas motion,

2,15

through streamtube models that treat only the gas phase reactions.

The pyrolysis step

is usually treated separately as an instantaneous reaction with or without an equilibrium

stage. Jet-spouting (i.e., dilute spouting) models have been developed

using simpliﬁed

kinetics. Both isothermal and nonisothermal two-region models are available that treat

the spout and the annulus as plug ﬂow sections.

Conversion of char in the gasiﬁer is

most readily handled with backmix ﬂow models and simpliﬁed kinetics for the gas–solid

reactions listed in Table 15.1.

Li et al.

recently outlined a three-dimensional kinetic

and computational ﬂuid dynamic model for a pressurized spout-ﬂuid bed and provided

veriﬁcation based on experimental studies.

258 A. Paul Watkinson and Antonio C. L. Lisboa

15.6 Spouted bed pyrolysis of coal, shale, biomass, and solid wastes

Pyrolysis is of considerable importance on its own as a process for producing liquid

products from solids such as coal, shale, heavy oil, biomass, and waste plastics. It is

also a step preceding gas–char reactions in gasiﬁcation or combustion processes. Key

features of pyrolysis not evident in the single equation of Table 15.1 are reﬂected in a

two-stage reaction, which allows for tar cracking:

Carbonaceous Solid −→ Char

+ Tar + Gas

(R1)

Tar −→ Char

+ Gas

(R2)

The main heat requirement in pyrolysis is t o raise the solids to the devolatilization

temperature, at which reactions R1 and R2 proceed with small endothermic or exother-

mic heat effects. For processes whose purpose is to produce liquids, tar destruction

reactions such as R2 should be minimized. Liquid yields go through a maximum with

increasing temperature, as high temperatures promote reaction R2. In biomass gasiﬁca-

tion, by contrast, a tar-free gas is desired, and conditions that favor reactions such as R2

should be promoted. Char is a by-product of pyrolysis. Because of its low market value,

coal char is usually either gasiﬁed or combusted in a separate unit. However, production

of biochar from biomass feedstocks is an active area of research and development.

Pyrolysis of coals and oil shales has been investigated in spouted bed systems for

liquid production, as well as for its effect on subsequent char gasiﬁcation. Results are

summarized in Table 15.3. Most lab-scale investigations have been aimed primarily at

determining tar, char, and gas yields and compositions as functions of feedstock and

spouted bed operating conditions (e.g., temperature, solid and gas feed rates, particle

size, bed materials).

Pioneering work on coal carbonization in Australia

was intended to produce a

smokeless char rather than to recover liquids. This work showed that a spouted bed

could accommodate caking (agglomerating) coals. Pyrolysis or retorting of shale to

produce oil has been pursued since the 1960s and 1970s.

34,35

Beginning in the 1980s,

Petrobras evaluated spouted bed pyrolysis for oil shale material too small to be used

as feed in its moving bed retort. Leite et al.

initially used a 0.08-m-diameter spouted

bed for retorting oil shale of 1.11 mm size. Subsequent work

was performed in a

0.3-m-diameter unit that processed 110 to 240 kg/h of oil shale as a demonstration of

the technology, using a nonideal feed containing about 45 percent of particles smaller

than 0.84 mm.

A miniature spouted bed with a continuous feed of 0.002 to 0.05 kg/h was used by

Teo and Watkinson

to prepare coal pyrolysis liquids for subsequent detailed chem-

ical characterization. On a larger scale, studies of both coal pyrolysis

and oil shale

retorting

were carried out in 0.15-m-diameter beds at 1 to 8 kg/h solid feed rate to

establish temperature, feed rate, bed composition, and particle size for maximum liquid

yields. Maximum liquid yields from coals of the order of 25 percent were observed at

bed temperatures of about 525

◦

C to 600

◦

C, depending on the rank of the coal and other

factors. For low-rank coals in particular, the liquid contains an aqueous fraction that can

Gasiﬁcation, pyrolysis, and combustion 259

Table 15.3. Spouted bed pyrolysis studies of coal, oil shale, and biomass.

∗

Feed

Reactor

type D (m) Spout gas

Feed rate

(kg/h)

Mass ﬂux

(kg/m

Max. liq.

yield % T (

◦

Bed

material

Bed. mat.

dia (mm) Ref.

coal,

lignite

S 0.03 N

<0.05 0.028 30 440−740 silica 0.43 38

coal S 0.13 N

+CO

0.6−6 0.13 20 480−650 sand 0.8−1.4 39

coal S 0.15 air-N

6−18.5 0.29 − 490−635 char 2.5 33

shale S 0.08 N

,St 36

shale S 0.13 N

+CO

1−4.5 0.097 7.4 454−555 sand/

shale

0.8−1.2 40

shale

coal

S 0.15 ﬂue

gas

1.6−3.5 0.055 11 shale

15 coal

475−650 char,

sand

shale

1.3−1.5 41

shale CS 0.17 air-pyr.

gas

9.5 0.12 510−730 shale <6.4 34

shale S 0.30 air 150 0.59 ∼4 430−600 shale 0.8−6.4 37

biomass CS 0.12 N

0.1−0.6 0.015 72 350−700 silica 0.7−1.4 42

biomass SD 0.15 N

<4 0.063 73 440−520 − 44

wood S 0.19 N

−St 1.5 0.015 14 500−700 <6.4 43

∗

Spout gas: St = steam; pyr. gas = pyrolysis gas

Reactor type: S = spouted, SD = spouted with draft tube, CS = conical spouted

inﬂate liquid yield data. For oil shales, the corresponding oil yield maxima are about

10 percent, depending on the Fischer assay of the shale. Several studies, such as that by

Jarallah and Watkinson,

have shown that the prominence of secondary reactions (R2)

increases with particle size. Therefore, smaller particles are preferred.

In a commercial process, the sensible heat needed for pyrolysis must be provided

somehow. Injection of a small amount of air, with coal

or shale,

results in lowering

of tar yield, although this permits much larger solids throughputs. Tamm and Kuehler

described a second spent shale combustion reactor, with recirculation of heat transfer

solids to the retort. Rovero and Watkinson

developed a vertical two-stage autothermal

unit with coal or shale pyrolysis in an upper spouted bed in which the heat for the pyrolysis

came from the gases exiting the lower reactor, in which combustion or gasiﬁcation of

the spent char or shale took place. Liquid yield reaching a maximum with increasing

temperature is shown in Figure 15.4.

The use of a large spouted bed “mild-gasiﬁer,” carbonizer, or pyrolyzer in the PSDF

power plant system

was included under gasiﬁcation in Table 15.2. The very high

temperature of 980

◦

C would minimize production of liquids.

Pioneering work on the conical spouted bed reactor, including its use for pyrolysis

of wood waste, cork waste, postconsumer plastics, and tire material, is covered in

Chapter 5. As an example, sawdust is fed at up to 0.6 kg/h together with 0.7- to 1.3-mm

sand, to a 0.12-m-diameter pyrolyzer. Data on effects of temperature on yields and

compositions of gas, liquid, and char are presented by Aguado et al.

Table 15.3

summarizes other spouted bed biomass and waste pyrolysis studies. Janar thanan and

Clements

operated a 0.2-m-diameter gasiﬁer, primarily in the pyrolysis mode, and at

260 A. Paul Watkinson and Antonio C. L. Lisboa

450 470 490

N.B. Oil Shale

4.47

2.68

dp = 1.27 mm

m(kg/h)

510 530 550

TEMPERATURE (°C)

OIL YIELD (%)

Figure 15.4. Oil yield from New Brunswick shale versus spouted bed pyrolyzer temperature.

low throughput. Fast pyrolysis of biomass in a spout-ﬂuidized bed reactor equipped with

a draft tube (Chapter 7) was reported by Chen et al.

Maximum liquid yield of about

72 percent occurred at about 450

◦

42,44

which is typical for wood pyrolysis. Throughput

of the draft-tube spout-ﬂuid bed seems to have been substantially higher than for the

conical spouted bed for the single case repor ted for each.

Pyrolysis of dry sewage sludge over short periods of time to determine gas yield and

composition has been mentioned previously.

The use of a plasma jet to provide heat

within a spouted bed has been investigated to provide reducing gases for a solid oxide fuel

cell

using biomass feed. No liquid production was reported in either of these studies.

15.7 Combustion of solid fuels

Combustion of solids may be carried out using a number of diverse contacting techniques,

including bubbling ﬂuidized beds, circulating ﬂuidized beds, entrained beds, and spouted

beds. Whereas coal is often burned as a powder in power plants, in developing countries

the most common way to produce steam or hot gases has been by feeding larger particles

onto a vibrating grate, which moves the particles horizontally while air rises across the

bed. The vibration avoids sintering (agglomeration) of particles, a problem always

present in moving or ﬁxed beds. The burning rate is usually limited by the resistance

to diffusion of oxygen along the particle pores, rather than by the intrinsic kinetics or

external transport resistance. Therefore, to increase the combustion rate, actions need

to be taken to reduce the internal resistance posed by the diffusion of oxygen within the

pores. As little can be done to increase the effective diffusivity of oxygen within the

pores, higher coal combustion rates can be accommodated by reducing the particle size

and selecting an adequate gas–solid contacting technique to handle it.

Gasiﬁcation, pyrolysis, and combustion 261

Each of the aforementioned gas–solid contacting techniques is suitable for a speciﬁc

particle size range. From large to small size, the choices would be: vibrating moving

bed, spouted bed, bubbling ﬂuidized bed, circulating ﬂuidized bed, and entrained bed.

Each technique must impose brisk agitation to prevent sintering, an ever-present threat

to smooth operation.

The spouted bed technique is most suited to particles in the diameter range of 1 to

20 mm. When the feedstock to be burned is within this size range, a spouted bed may

be a viable option. As in gasiﬁers, spouting can be maintained using an iner t material

of convenient size distribution, with a solid fuel stream of different size fed to the bed.

Typical size distributions for spouted bed combustors and other operational features are

discussed in the next section.

15.8 Spouted bed combustion of coal and other solids

The most common feedstock in investigations of spouted bed combustion has been

coal

46–54

of various qualities, including sub-bituminous, bituminous, coal rejects of dif-

fering ash contents, low-rank coals, lignite, highly caking coals, and anthracite. Usually

the bed includes an inert material such as sand or gravel, which dictates the hydrody-

namics of the bed. The fuel is fed either on top or with the spouting gas.

Many other materials have also been used for spouted bed combustion: sawdust

peat,

46,56

low-heating-value fuels and wastes,

46,57,58

rice husks,

59,60

and sewage

sludge.

Efﬁciencies of three different designs of spouted beds have been determined

in combustion of wood charcoal.

Oil shale has also been partially combusted in a

spouted bed

as part of the retorting process. Continuous and batch operations have

been carried out with extensive operating time, demonstrating that the spouted bed can

operate steadily at high temperature. Figure 15.5 shows a photo of batch combustion of

coal in a half-cylindrical column in which the bed material was 1.8-mm sand and the

fuel was 0.55- to 2.2-mm coal particles.

47–48

Investigations on batch and pilot scales indicate that the spouted bed technique is

mature enough to be applied at larger scales. A signiﬁcant characteristic of a spouted-

bed combustor, ﬁrst demonstrated with liquid fuels,

is to lower the effective lean

ﬂammability limit – that is, to be able to burn fuels with low heating value. Another

advantage is the ability to use bed materials, such as alumina or bauxite, that can

withstand high temperatures.

Table 15.4 summarizes some details of spouted bed solids combustion studies. In a

typical operation burning bituminous coal in a 0.30-m diameter vessel

(Figure 15.6) at

temperatures of 740

◦

C to 980

◦

C, and coal feed rates of 6 to 22 kg/h, efﬁciencies were

above 90 percent at an excess airﬂow of 15 percent to 20 percent. This investigation

compared the spouted bed with ﬂuidized and spout-ﬂuid bed operation and concluded

that “the spout-ﬂuid bed tended to give somewhat higher combustion efﬁciencies at

the lower temperatures, greater temperature uniformity and improved bed-to-immersed-

surface heat transfer than the other two modes of operation.”

262 A. Paul Watkinson and Antonio C. L. Lisboa

Table 15.4. Summary of studies on spouted and spout-ﬂuid bed combustion of solid fuels.

∗

Feed

Reactor

type Dia. (m)

Feed size

(mm)

Feed rate

(kg/h)

Inert

bed

Inert size

(mm)

Temp.

(

◦

Efﬁciency

XS air

(%) Ref.

coal S 0.077 1−3.4 0.5 sand 0.8−1 700−850 51, 52

coal S 0.15 0.4−2.4 batch sand 1−2.4 590−810 47, 48

coal SF 0.28 6.3−19 45 lstone 3−12 880 94 20 50

coal S, SF, F 0.30 0.1−56−22 grav.,

sand

1.2−2.8

0.5−2.0

740−980 <90 15−20 49

coal,

wastes

S, SF, F 0.30 1−38−23 grav 1−3 700−950 83−99 70−140 46

rice

husk

MSF 0.7 ×0.7 ∼20 sand 0.3−1 400−900 85−91 0−30 59

ag.

waste

MHS 2 ×2 1725 sand 1.6−497 58

sew.

sludge

S 0.18 1.2 ∼6 none − 99 25 61

wood

char.

S 0.15 0−5 1 sand 0.3−0.6 860 <97 <31 62

shale S 0.30 <6.4 110−240 none 430−600 <

037

∗

MHS = multiple horizontal spout, MSF = multiple spout-ﬂuid, lstone = limestone, grav. = gravel, Ref. =

reference.

(a) (b)

Figure 15.5. Coal burning in a half-column combustor under (a) stable, and (b) pulsator y

spouting.

Gasiﬁcation, pyrolysis, and combustion 263

Average bed temperature (°C)

700 750 800 850 900 950 1000

Combustion efficiency (%)

100

Fluidized bed

Spout-fluid bed

Figure 15.6. Combustion efﬁciency versus bed temperature in spout-ﬂuid and ﬂuidized bed

reactors, adapted from Lim et al.

The Battelle spout-ﬂuid combustor

bur ned 45 kg/h coal in a 0.28-m-diameter unit

equipped with a unique design of wall cooling and bayonet cooler. At a velocity of about

2 m/s, throughput was markedly higher than in the study of Lim et al.

Spout air was

25 percent to 40 percent of the total. A direct comparison was made of the spout-ﬂuid

bed and the ﬂuidized bed with limestone injection, which showed lowering of NO

and

better sulfur capture in the spout-ﬂuid bed.

The largest spouted bed combustion system found in this review,

a 7-MW combustor

of 4 m

bed area, was developed by 1980, prior to most other solids combustion research

in spouted beds. I n this design, a multiplicity of individual spouts (Chapter 17), created

by horizontally directed air jets, promoted the circulation of the 1.6- to 4-mm sand

bed material. Although not strictly a spouted bed, this combustor possessed similar

characteristics of solid circulation promoted by gas jetting. Operating characteristics

of two commercial units were discussed. Units had been sold for incineration of solid

agricultural materials, such as grain milling wastes, and industrial liquid wastes. A

bench-scale unit of 0.055 m

with a single spout had been in operation f or more than

5000 hours to test feedstocks, bed materials, and a proprietary distributor.

The 0.30-m-diameter spouted bed reactor of Lisboa and Watkinson,

mentioned

previously, employed air as the spouting gas to promote in situ combustion during

retorting of oil shales. The reactor temperature was maintained at a level sufﬁcient for

pyrolysis without air preheating. Some runs were carried out just to burn shale and a

mixture of shale and shale oil sludge. The spouted-bed pilot plant is shown in Figure 15.7.

Vuthaluru et al.

51–54

investigated several methods to reduce agglomeration during

coal burning in a spouted bed: (1) mineral additive, (2) alternative bed inert solids, and

(3) pretreatment of coal. Coal blends were also used with the same purpose; the authors

observed that “no par ticle agglomeration and bed de-ﬂuidization were evident after 15 h

of operation with the blends at 800

◦

C.”

Table 15.4 shows that most studies of spouted-bed combustion have used the classical

spouted bed geometry – a cylindrical column with a conical bottom. A large range of

internal angles, deﬁned as the angle between the central axis and the wall, have been

264 A. Paul Watkinson and Antonio C. L. Lisboa

Figure 15.7. Photograph of ﬁve-story spouted bed pilot plant for oxidative pyrolysis of oil shale.

used, from 90

◦

(ﬂat bottom) to the sharp angles of a patented

conical spouted bed

combustor (Chapter 5). The largest column diameter reported for classical spouting

seems to be 0.30 m. Larger vessels not based on the classical geometry were mentioned

by Albina,

59,60

in particular a 0.7 m × 0.7-m square cross-section vessel with four air

supply nozzles, undoubtedly a solution for scaling up, and by Baker and Wilkinson,

described earlier, with multiple spouts created by horizontally directed air jets. Other

ways to inject air, which could also be used on a larger scale, were developed by Rasul,

with the introduction of air into a cylindrical column through a circular slit and into a

square-duct column through a rectangular slit spanning the whole cross-section. Particles

can be fed either on top of the bed or pneumatically with the spouting air, as shown in

Figure 15.1a.

15.9 Concluding remarks

This chapter highlights the wide spectrum of spouted bed applications in gasiﬁcation,

pyrolysis, and combustion, in which many feedstocks have been examined under various

operating conditions. The scale of normal spouted beds or spout-ﬂuid beds also covers a

wide range, with diameters of single vessels up to about 1 m. As is evident elsewhere in

this book, challenges for spouting processes occur at large scale. As diameters approach

∼1 m and greater, spout-ﬂuid contacting appears to be more advantageous for thermal

Gasiﬁcation, pyrolysis, and combustion 265

processing. For gasiﬁcation processes, pressurized operation is advantageous, and high-

capacity units are appearing for limited reactor diameters. For combustors, particularly

for biomass and wastes, multiple spout units in square vessels operated at atmospheric

pressure have been developed.

References

1. R. Fernando. Coal Gasiﬁcation. International Energy Agency Clean Coal Centre Report

CCC/140, Oct. 2008.

2. S. K. Foong, C. J. Lim, and A. P. Watkinson. Coal gasiﬁcation in a spouted bed. Can. J. Chem.

Eng., 58 (1980), 84–91.

3. S. K. Foong, G. Cheng, and A. P. Watkinson. Spouted bed gasiﬁcation of Western Canadian

coals. Can. J. Chem. Eng., 59 (1981), 625–630.

4. A. P. Watkinson, G. Cheng, and C. B. Prakash. Comparison of coal gasiﬁcation in ﬂuidized

and spouted beds. Can. J. Chem. Eng., 61 (1983), 468–473.

5. A. P. Watkinson, G. Cheng, and C. J. Lim. Oxygen-steam gasiﬁcation of coals in a spouted

bed. Can. J. Chem. Eng., 65 (1987), 791–798.

6. A. P. Watkinson, G. Cheng, and D. P. C. Fung. Gasiﬁcation of oil sand coke. Fuel, 68 (1989),

4–10.

7. Z. Haji-Sulaiman, C. J. Lim, and A. P. Watkinson. Gas composition and temperature proﬁles

in a spouted bed coal gasiﬁer. Can. J. Chem. Eng., 64 (1986), 125–132.

8. K. Kikuchi, A. Suzuki, T. Mochizuki, S. Endo, E. Imai, and Y. Tanji. Ash-agglomerating

gasiﬁcation of coal in a spouted bed reactor. Fuel, 64 (1985), 368–372.

9. O. Uemaki and T. Tsuji. Gasiﬁcation of a sub-bituminous coal in a two-stage jet-spouted

bed reactor. In Fluidization V, ed. K. Ostergaard and A. Sorensen (New York: Engineering

Foundation, 1986), pp. 497–504.

10. T. Tsuji, T. Shibata, K. Yamaguchi, and O. Uemaki. Mathematical modeling of spouted bed

coal gasiﬁcation. In Proceedings of the International Conference on Coal Science (Tokyo:

New Energy Development Organization, 1989), pp. 457–460.

11. T. Tsuji and O. Uemaki. Coal gasiﬁcation in a jet-spouted bed. Can. J. Chem. Eng., 72 (1994),

504–510.

12. J. Gale and C. J. Bower. Development of the British Coal gasiﬁcation process for the manuf ac-

ture of low caloriﬁc value gas. Presented at Applied Energy Conference, Swansea, September

1989.

13. M. St. J. Arnold, J. J. Gale, and M. K. Laughlin. The British Coal spouted ﬂuidised bed

gasiﬁcation process. Can. J. Chem. Eng., 70 (1992), 991–997.

14. T. Sue-A-Quan, A. P. Watkinson, R. P. Gaikwad, C. J. Lim, and B. R. Ferris. Steam gasiﬁcation

in a pressurized spouted bed reactor. Fuel Proc. Technol., 27 (1991), 67–81.

15. T. Sue-A-Quan, G. Cheng, and A. P. Watkinson. Coal gasiﬁcation in a pressurized spouted

bed. Fuel, 74 (1995), 159–164.

16. Y. Hatate, Y. Uemura, S. Tanaka, Y. Tokumasu, Y. Tanaka, D. F. King, and K. Ijichi. Develop-

ment of a spouted bed-type coal gasiﬁer with cycling thermal medium particles. Soc. Chem.

Engrs, Japan, 20 (1994), 758–764.

17. R. Xiao, M. Zhang, B. Jin, and Y. Huang. High-temperature air/steam-blown gasiﬁcation of

coal in a pressurized spout-ﬂuid bed. Energy & Fuels, 20 (2006), 715–720.

266 A. Paul Watkinson and Antonio C. L. Lisboa

18. R. Xiao, M. Zhang, B. Jin, Y. Xiaong, H. Zhou, Y. Duan, Z. Zhong, X. Chen, L. Shen, and

Y Huang. Air blown partial gasiﬁcation of coal in a pilot plant pressurized spout-ﬂuid bed

reactor. Fuel, 86 (2007), 1631–1640.

19. D. L. Moore, Z. Haq, T. E. Pinkston, R. E. Rush, P. Vimalchaud, J. D. McClung, and M. T.

Quandt. Status of the advanced PFBC at the Power Systems Development Facility. Report

DOE/MC/25140–94/C0353 (1994), pp. 127–137.

20. N. Paterson, Y. Zhuo, D. R. Dugwell, and R. Kandiyoti. Investigation of ammonia formation

during gasiﬁcation in an air-blown spouted bed: reactor design and initial tests. Energy &

Fuels, 16 (2002), 127–135.

21. Y. Zhuo, N. Paterson, B. Avid, D. R. Dugwell, and R. Kandyoti. Investigation of ammonia

formation during gasiﬁcation in an air blown spouted bed: the effect of the operating conditions

on ammonia formation and the identiﬁcation of ways of minimizing its formation. Energy &

Fuels, 16 (2002), 742–751.

22. N. Paterson, Y. Zhuo, G. P. Reed, D. R. Dugwell, and R. Kandiyoti. Pyrolysis and gasiﬁcation

of sewage sludge in a spouted-bed reactor. Wa t e r & Env i r. J. , 18 (2004), 90–94.

23. S. Hanson, J. W. Patrick, and A. Walker. The effect of coal particle size on pyrolysis and

steam gasiﬁcation. Fuel, 81 (2002), 531–547.

24. C. Zak and P. B. Nutcher. Spouted ﬂuid-bed gasiﬁcation of biomass and chemical wastes-some

pilot plant results. In Energy from Biomass and Wastes X, ed. D. K. Klass (London: Elsevier

and Chicago: Institute of Gas Technology, 1987), pp. 643–653.

25. U.S. Environmental Protection Agency Report EPA/540/F-93/XXX. “Energy Technology

Bulletin – Spouted Bed Reactor,” Energy and Environmental Research Corporation (Irvine,

CA, 1993).

26. M. Thamavithya and A. Dutta. An investigation of MSW gasiﬁcation in a spout-ﬂuid bed

reactor. Fuel Proc. Technol., 89 (2008), 949–957.

27. P. A. Salam and S. C. Bhattacharya. A comparative study of charcoal gasiﬁcation in two types

of spouted bed reactors. Energy, 31 (2006), 228–243.

28. M. M. Hoque and S. C. Bhattacharya. Fuel characteristics of gasiﬁed coconut shell in a

ﬂuidized and a spouted bed reactor. Energy, 26 (2001), 101–110.

29. C. J. Lim, J. P. Lucas, M. Haji-Sulaiman, and A. P. Watkinson. A mathematical model of a

spouted bed gasiﬁer. Can. J. Chem. Eng., 69 (1991), 596–606.

30. J. P. Lucas, C. J. Lim, and A. P. Watkinson. A non-isothermal model of a spouted bed coal

gasiﬁer. Fuel, 77 (1998), 683–694.

31. B. H. Song and A. P. Watkinson. Three-stage well-mixed reactor model for a pressurized coal

gasiﬁer. Can. J. Chem. Eng., 78 (2000), 143–155.

32. Q. Li, M. Zhang, W. Zhong, X. Wang, R. Xiao, and B. Jin. Simulation of coal gasiﬁcation in

a pressurized spout-ﬂuid bed gasiﬁer. Can. J. Chem. Eng., 87 (2009), 169–176.

33. R. K. Barton, G. R. Rigby, and J. S. Ratcliffe. The use of a spouted bed for the low temperature

carbonization of coal. Mech. Chem. Eng. Trans., 4 (1968), 105–112.

34. L. P. Berti and J. H. Gary. Spouted bed oil shale retort. Colorado School of Mines Quart., 61

(1966), 553–560.

35. P. W. Tamm and C. W. Kuehler, Spouted-bed shale retorting process. U.S. Patent 4,125,453

(1978).

36. A. C. B. Leite, R. M. P. Wodtke, A. C. L. Lisboa, and F. Restini. Pyrolysis of oil shale ﬁnes in a

spouted bed reactor. XVI Congresso Latino Americano de Quimica, Rio de Janeiro, October

1984.