Tubular Flame Combustion for Nanoparticle Production - Industrial

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Tubular Flame Combustion for Nanoparticle Production Tomoyuki Hirano, Jun Kikkawa, Febrigia Ghana Rinaldi, Kenshi Kitawaki, Daisuke Shimokuri, Eishi Tanabe, and Takashi Ogi Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.9b00620 • Publication Date (Web): 15 Apr 2019 Downloaded from http://pubs.acs.org on April 15, 2019

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Industrial & Engineering Chemistry Research

Tubular Flame Combustion for Nanoparticle Production Tomoyuki Hirano1, Jun Kikkawa1, Febrigia Ghana Rinaldi1, Kenshi Kitawaki2, Daisuke Shimokuri2, Eishi Tanabe3 and Takashi Ogi1* 1Department

of Chemical Engineering, Graduate School of Engineering, Hiroshima University,

1-4-1 Kagamiyama, Higashi Hiroshima, Hiroshima 739-8527, Japan. 2

Department of Mechanical Science and Engineering, Graduate School of Engineering,

Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima, Hiroshima 739-8527, Japan. 3Hiroshima

Prefectural Institute of Industrial Science and Technology, 3-10-31 Kagamiyama,

Higashi Hiroshima, Hiroshima 739-0046, Japan

*Corresponding Author: Takashi Ogi, [email protected]

ACS Paragon Plus Environment

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ABSTRACT Requirements for nanoparticle processing based on energy and cost-effective technologies have increased in recent years. Flame synthesis is widely used on an industrial scale and is superior to gas phase one-step processes for producing nanoparticles; however, further improvements are required from the viewpoint of energy efficiency. In this work, we present a new aerodynamically stable nanoparticle processing method with extremely low energy losses, based on the use of a tubular flame. The developed tubular flame apparatus is inexpensive and simple to set up, allowing for a uniform and high temperature field with a high energy efficiency. Consequently, highly crystalline and uniform WO3 nanoparticles were successfully synthesized with a high production rate. The simple and energy-effective process proposed in this paper has potential for application to various types of functional nanoparticle production.

KEYWORDS Tubular flame, Flame synthesis, Aerosol, Nanoparticle, Tungsten oxide, Energy effective process


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1. INTRODUCTION Nanomaterials with controlled structures, sizes, and morphologies are widely used as functional materials in many fields.

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Energy efficient and environmentally friendly processes

are required for nanoparticle synthesis within a sustainable society. Routes for manufacturing nanoparticles can be classified into top-down and bottom-up processes. In general, bottom-up processes are used to efficiently produce uniform and homogeneous nanoparticles. Among various bottom-up processes, aerosol processes involve syntheses where the main reactions occur in the gas phase

1,2.

Such processes are often applied

on an industrial scale. Flame (assisted) spray pyrolysis [F(A)SP] is a widely used aerosol process for producing single- and multi-component nanoparticles with high purity in a single step5,6 based on various types of flame systems, such as a Bunsen flame,7,8 co-flow diffusion flame,9-16 spray flame,17,18 and flat flame.19,20 Although the flame types commonly used for F(A)SP are available with inexpensive and simple set ups, the energy efficiency of combustion should also be considered. Owing to the structure of these flames, energy is lost from the system, for example, in the form of radiation. It is also difficult to fully understand the particle formation mechanisms in flames owing to the inhomogeneous temperature distribution and impracticability of obtaining an adiabatic flame temperature. Tubular flame has been extensively studied from a fundamental viewpoint over the past three decades.21-23 The structure of this flame gives a symmetrical homogeneous temperature distribution and the conductive heat loss from the flame is negligible. Thus, it is possible to efficiently use its combustion energy, which is intrinsic to the flame, for material production. Furthermore, the flame consists of a low-density inner burnt gas region and a high-density outer unburned gas region (see Figure S1 in the Supporting Information). Therefore, according to the


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Rayleigh stability criterion,24 the flame is aerodynamically stable when it is formed in a rotating vortex flow. Because the shape of a tubular flame is geometrically well controlled, it can be incorporated in-line with various processes. Figure 1 shows a comparison between Bunsen and tubular flames. In a Bunsen flame, the temperature rises near the flame front where the combustion reactions occur, but then decreases upward along the axial direction owing to energy losses. In addition, the temperature inside the flame, through which particles and precursor pass, is low because unburned gas is present. Whereas in the tubular flame, the unburned cold gas covers the outer periphery of the hot burned gas. Hence, the burner wall is maintained at low temperature and undamaged, thus enabling long term operation. This is important for practical applications. Furthermore, owing to its high thermal insulation properties, a high temperature region is maintained homogeneously inside the tubular flame through which the particles and precursor pass through. The flat profile itself affects to the burned gas temperature. The flat profile indicates that heat loss to the downstream region can be neglected and that almost adiabatic condition can be achieved in the burned gas region. In other words, we have the possibility to use combustion energy effectively without any heat losses. As described above, a tubular flame has excellent heat insulating properties, a convenient shape for application to various process, unique combustion characteristics, and is attractive from the viewpoint of engineering and practical applications. However, there have been no reports on the synthesis of particle materials by tubular flame methods. We investigated the preparation of tungsten oxide (WO3) particles using a tubular flame for the first time and developed a new process for nanoparticle production. In the case of WO3, the flat profile of temperature is indeed important because its oxidation state is very sensitive to temperature. So far, WO3 particles have been prepared by FSP,25,26 FASP,12 and spray pyrolysis


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Figure 1. Bunsen flame (left) and tubular flame (right). methods.27,28 Righettoni et al. reported a method to synthesize pure and Si-doped WO3 nanoparticles films onto Al2O3 substrates using a FSP reactor in combination with a watercooled substrate holder. Osi et al. reported a synthesis process of Pt-loaded submicrometer-sized WO3 particles by FASP method with methane/oxygen combustion. Although adiabatic flame temperature of this combustion system could attain around 3000 K, nanometer-sized particles could not be produced. It indicates large heat losses behind the flame.15 Hence, the tubular flame combustion has a potential to enable nanoparticle production with high yield and higher energy efficiency. The as-prepared powders were characterized by X-ray diffraction and scanning electron microscope (SEM) and transmission electron microscope (TEM) imaging to evaluate their sizes, morphologies, and crystal structures.

2. EXPERIMENTAL PROCEDURES The experimental setup used to synthesize particles, based on a tubular flame, is shown in Figure 2 (a). The setup consisted of three sections, namely, a spray generator, tubular flame


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burner, and particle collector (bag filter). The spray generator section consisted of an ultrasonic spray nebulizer equipped with a 1.75-MHz resonator (NE-U17, Omron Healthcare Co., Ltd., Tokyo, Japan). The droplets were transported into a tubular flame burner by a stream of argon (Ar) gas, and the flow rate (QC) was varied from 0.1 to 0.5 m3/h. Methane (CH4) was used as the fuel gas (0.1 m3/h). Compressed air was fed into the tubular flame burner using a compressor. Temperature profiles were observed using a silica-coated Pt/Pt-13% Rh thermocouple with a wire diameter of 0.2 mm. A solution of ammonium tungstate pentahydrate [ATP, (NH4)10(W12O41)⸱5H2O; purity 88–90%; Kanto Chemical Co., Inc., Tokyo, Japan] in ultrapure water with a concentration of 10 mmol/L was used as the main precursor. Tubular flame can be established when the fuel and oxidizer (or their mixture) is tangentially injected into a cylindrical tube. There is one key parameter called "swirl number", which is the characteristic of swirl intensity.21,29 The swirl number of the burner is desired to be over 0.6 to form a strong swirl flow in the burner. Figure 2 (b) shows a tubular flame burner used in this research. The burner, made of duralumin, consisted of two tangential inlet slits and a downstream quartz tube (100 mm). A combustible mixture of gases (CH4/Air) was fed tangentially from the inlet slit into the burner. The precursor droplets were fed into the inner hot gas region of the tubular flame from the bottom by Ar. Detailed information on the tubular flame burner setup (e.g., quartz tube dimensions, mounting details, etc.) is provided in Figure S2 in Supporting Information. The SEM ( S-5200, Hitachi, Tokyo, Japan; operated at 20 kV) and TEM (JEM-3000F, JEOL Ltd., Tokyo, Japan; operated at 297 kV) were used to observe the sizes, morphologies, and crystal structures of the as-synthesized particles. The crystal structures of the prepared particles


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were also investigated using an X-ray diffractometer (XRD; D2 PHASER, 40 kV and 30 mA, Bruker Corp., USA).

Figure 2. Experimental set-up (a) and tubular flame burner (b).

3. RESULTS AND DISCUSSION There are many parameters in tubular flame combustion that affect the properties of the synthesized particles, for example, the gas flow rates for both the carrier and premixed gases, types of fuel and oxidizer, ratio of fuel/oxidizer, and the diameter of the tubular flame. Here we synthesized WO3 particles at various carrier gas (Ar) flow rates as a first step towards tubular flame synthesis.


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3.1 Effect of carrier gas flow rate on morphology and crystallinity of WO3 particles Figure 3 shows XRD patterns of the as-synthesized particles formed at various carrier gas flow rates (QC = 0.05–0.5 m3/h) with a fixed premix gas flow rate. The XRD patterns suggested that the prepared particles had two types of WO3 crystal structures: monoclinic (COD no. 01072-0677) and hexagonal (COD no. 01-075-2187). The monoclinic structure was formed when QC at 0.05–0.3 m3/h, whereas particles with both monoclinic and hexagonal structures were formed when QC at 0.4 and 0.5 m3/h. The presence of hexagonal structures indicates that the supplied energy was insufficient to produce stable and pure monoclinic structures. We attribute this result to the low synthesis temperature and short residence time, which resulted because as QC was increased, the maximum synthesis temperature decreased (see temperature distribution of tubular flame in Figure S3 of Supporting Information) and the residence time also decreased. To investigate the morphology of the tubular flame-synthesized particles, we conducted SEM observations of WO3 particles synthesized at QC = 0.05–0.5 m3/h, and the results are shown in Figure 4. At QC = 0.5 m3/h, the obtained particles were mainly of sub-micrometer size, over 400 nm with a few nanoparticles less than 50 nm. At QC = 0.15–0.4 m3/h, the proportion of submicrometer-sized particles decreased, and nanoparticles with sizes less than 50 nm started to form. At QC = 0.05–0.1 m3/h, the submicrometer-sized particles disappeared completely and only nanoparticles were obtained. These results show that sufficient energy was supplied to completely segregate submicrometer-sized particles at low carrier gas flow rates.


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Figure 3. XRD patterns of WO3 particles prepared via the tubular flame method at different carrier gas flow rates.


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Figure 4. SEM images of WO3 particles prepared in tubular flame at different carrier gas flow rates.


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The morphology of WO3 nanoparticles synthesized at QC = 0.1 m3/h was observed further through TEM observations, as depicted in Figure 5 (TEM images at other flow rates are shown in Figure S4 in Supporting Information). In a low magnification image (Figure 5a), nanoparticles with a relatively high dispersion were observed and no submicrometer-sized particles were observed. As shown in Figure 5b, necking of the nanoparticles was observed and the primary particle sizes were in the range of 5–20 nm. The corresponding HR-TEM image (Figure 5c) confirmed that the prepared nanoparticles had a uniform orientation with a lattice spacing at 0.34 nm. This result is consistent with the d spacing of the (002) planes of the monoclinic WO3 crystal structure.

Figure 5. TEM images of WO3 nanoparticles prepared at QC = 0.1 m3/h.

3.2 Formation mechanisms of WO3 nanoparticles by the tubular flame method We propose mechanisms for the WO3 nanoparticle formation in the tubular flame, as illustrated in Figure 6. According to previous studies on the synthesis of WO3 particles in the gas phase,15,16 droplets containing ATP were sprayed into the tubular flame and underwent reactions to form, in sequence: ATP particles → intermediate WO3 particles → WO3 particles after the


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solvent evaporation. The morphology and crystal phase of the particles changed depending on the QC. 27,30 At a high QC (0.5 m3/h), after the nebulized droplets containing the ATP precursor were introduced into the flame zone, solvent evaporation and thermal decomposition occurred instantaneously, and submicrometer-sized WO3 particles formed. As QC decreased (0.4 to 0.15 m3/h), the particle residence time inside the flame increased, indicating a longer exposure of energy for the submicrometer-sized particles, which subsequently partially vaporized resulting in the formation of WO3 nuclei. These nuclei grew to form nanoparticles through a crystal growth process as they moved inside the glass flame reactor. As a result, submicrometer-sized WO3 particles were produced together with nanoparticles. At QC = 0.4–0.5 m3/h, the obtained particles had a hexagonal WO3 crystal structure, which is a metastable phase, indicating that insufficient energy was supplied. When QC was further decreased (0.05–0.1 m3/h), the submicrometer-sized WO3 particles completely vaporized. Consequently, the submicrometer-sized particles disappeared and WO3 nanoparticles were produced. 31,32


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Figure 6. Schematic illustration showing mechanisms for formation of WO3 particles in tubular flame at different carrier gas flow rates.

The radial temperatures at a point 50 mm from the bottom of the burner for each QC are listed in Table 1. Detailed information on temperature distribution is available in Figure S3 (see Supporting Information). To minimize the insertion effect, a thin 200 μm silica-coated R-type thermocouple was used for the measurement. Corrections for thermometric errors owing to radiation were applied to the results. The emissivity value was obtained by applying 0.2233 for the coated platinum thermocouple value, and the physical property values of the combustion gas were obtained by applying the estimation formula given by the gas molecular kinetics.34 For the combustion gas velocity, the average axial velocity obtained from the premixed gas flow rate and the burner cross section was used. The temperature at a point where the precursor passed through


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the tubular flame (r = 0, 1, 2, 3 mm) tended to decrease as QC increased. This is simply because when QC is high, the amount of gas flowing into the tubular flame increased such that the supplied energy was consumed heating the Ar gas and the precursor droplets. As the temperature in the system decreased, vaporization of submicrometer-sized particles was incomplete, resulting in the formation of both submicrometer- and nanometer-sized particles. Furthermore, for the swirl-type tubular flame used in this research, the carrier gas that was fed from the bottom of the burner swirled along with the surrounding fluid (combustion gas) entering from the sides of the burner. Thus, the hot surrounding fluid without particles mixed rigorously with the cold carrier gas containing the particles, which increased the heat transfer area between these two fluids.35 In addition, the swirl intensity was high under the operation conditions used in this study. Therefore, not only the heat transfer, but rather the mixing itself was also improved owing to the high turbulence in the tangential direction.35 When QC was low, the residence time and the heat transfer area increased as the carrier gases mixed, and the proportion of combustion gas increased. Thus, a large amount of energy was supplied to the particles, resulting in complete vaporization of the submicrometer-sized particles.

Table 1. Temperature in tubular flame at different carrier gas flow rate (Z = 50 mm). Qc [m3/h] Tr = 0 [℃] Tr = 1 [℃] Tr = 2 [℃] Tr = 3 [℃] 0.1

1276

1314

1335

1339

0.2

1251

1299

1348

1360

0.25

1178

1214

1264

1355

0.4

1032

1057

1065

1076

0.5

878

924

947

963


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3.3 Comparison between tubular flame-made WO3 and premixed Bunsen flame-made WO3 To compare the particles synthesized via a tubular flame and premixed conventional burner, WO3 particles were also synthesized with a premixed Bunsen burner (see Figure S5 in the Supporting Information) under the same conditions as the flame burner setup, i.e., a CH4 flow rate at 0.1 m3/h, air flow rate of 0.95 m3/h, and carrier gas flow rate of 0.1 m3/h. The XRD patterns of both particles indicated monoclinic phase (see Figure S6 in the Supporting Information). Figure 7 shows SEM images of the Bunsen flame-made WO3 particles and tubular flame-made WO3 particles. As shown in Figure 7a, the particles range from micrometer- to nanometer size. Because there was no mixing of gases and considerable heat loss from the system, insufficient energy was supplied to the WO3 particles. Particle size distribution of these particles is shown in Figure 7c. It shows that Bunsen flame produced WO3 particles in a bimodal size distribution. Whereas, tubular flame-made WO3 particles have a narrow particle size distribution (dav = 25.1 nm, σg = 1.21). Table 2 summarizes the methane, air, and carrier gas flow rate settings and the corresponding production yields, average particle sizes (dav), geometric standard deviations (σg), and crystal structures. The successful production of fine and monodispersed WO3 nanoparticles indicates that the tubular flame combustion is a promising approach as an energy efficient nanoparticle production. Moreover, several techniques, such as pilot flame, bluff body, opposing jet, and recess walls are commonly used to stabilize flames,35-38 including the Bunsen burner method. However, in the case of a tubular flame burner, it is possible for a large amount of gas to combust without using these stabilizing techniques owing to the inherent stability of the flame. This is a considerable advantage of tubular flame reactors for practical applications in cost and energy effective production of nanoparticles.


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Figure 7. SEM images of WO3 particles prepared with the use of (a) Bunsen flame, (b) tubular flame and (c) particle size distribution of WO3 particles prepared in tubular and Bunsen flames.


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Table 2. Production yields, average particle sizes (dav), geometric standard deviations (σg), and crystal structure of the particles prepared in tubular- and Bunsen flame reactors. Gas flow rate [m3/h]

Tubular flamemade Bunsen flamemade

Prod. yields [%]

dav [nm]

σg [-]

Crystal structure

Size distribution

25.1

1.21

monoclinic

Monodisperse

55.6

1.39 monoclinic

Bimodal

2926.5

1.91

CH4

Air

Carrier (Ar)

0.1

0.95

0.1

12.14

0.1

0.95

0.1

6.22

nanometer sized micrometer sized

On the basis of these temperature measurements and previous research,21 we found that the combustion field of the tubular flame separated into two regions, an outer unburned gas region with a low temperature and an inner burnt gas region with a high temperature. Because of the nearly symmetrical temperature distribution, which was close to flame extinction limit, there was minimal or no heat loss outside the flame. Therefore, the hot gas region inside the flame offers ideal adiabatic conditions for the flame, which makes lean combustion possible even for large injection velocities. The homogeneous and high-temperature combustion field of the tubular flame as a reaction field, enables synthesis of highly crystalline and homogeneous particles, which cannot be obtained with the use of a Bunsen flame, co-flow diffusion flame, spray flame, or flat flame. In this research, as the first step in our research on nanoparticle synthesis with a tubular flame rector, we successfully demonstrated the potential of the system for WO3 nanoparticle synthesis. Furthermore, we established control over the particle morphology by changing the carrier gas flow rate. We expect that other unique particles might be synthesized in the homogeneous, high-temperature tubular flame combustion field, with the use of a larger burner with higher gas flow rates, to achieve a long, high, and homogeneous temperature field. Therefore, tubular flame systems show promise as a new heat source for flame synthesis of materials with high energy efficiency.


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4. CONCLUSION A tubular flame was used to synthesize WO3 nanoparticles at various carrier gas flow rates as the first step in our research toward development of novel nanoparticle processing. The size of the tubular flame-made WO3 particles increased in proportion to the carrier gas flow rate. Because the conductive heat losses from the tubular flame were negligible and the flame was aerodynamically stable, our new approach to synthesizing nanoparticle shows great promise for practical application to nanoparticle production based on new energy-efficient flame method.

Supporting Information Structure of a tubular flame for nanoparticle production; Structure of a tubular flame burner; Temperature distribution of tubular flame; TEM images of tubular flame-made WO3 particles; Structure of a Bunsen flame; XRD patterns of Bunsen and tubular flame-made WO3 particles. The Supporting Information is available free of charge on the ACS Publications website.

AUTHOR INFORMATION Corresponding Author *E-mail for T. O.: [email protected] ORCID Tomoyuki Hirano: 0000-0003-3622-0606 Takashi Ogi: 0000-0003-3982-857X


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Notes The authors declare no competing fanatical interest.

ACKNOWLEDGMENTS This work was supported by JSPS KAKENHI Grant Number 26709061 and 16K13642. This work was partly supported by the Center for Functional Nano Oxide at Hiroshima University. The authors thank Dr. Eishi Tanabe of Hiroshima Prefectural Institute of Industrial Science and Technology and Dr. Makoto Maeda of the Natural Science Center for Basic Research and Development (N-BARD) at Hiroshima University for TEM observations and discussion. We thank Andrew Jackson, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript.

REFERENCES (1) Okuyama, K.; Wuled Lenggoro, I. Preparation of nanoparticles via spray route. Chem. Eng. Sci. 2003, 58, 537-547. (2) Pratsinis, S. E. Flame aerosol synthesis of ceramic powders. Prog. Energy Combust. Sci. 1998, 24, 197-219. (3) Ogi, T.; Nandiyanto, A. B. D.; Okuyama, K. Nanostructuring strategies in functional fineparticle synthesis towards resource and energy saving applications. Adv. Powder Technol. 2014, 25, 3-17. (4) Ogi, T.; Zulhijah, R.; Iwaki, T.; Okuyama, K. Recent Progress in Nanoparticle Dispersion Using Bead Mill. KONA Powder and Particle Journal 2017, 34, 3-23. (5) Teoh, W. Y.; Amal, R.; Madler, L. Flame spray pyrolysis: An enabling technology for nanoparticles design and fabrication. Nanoscale 2010, 2, 1324-1347.


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(6) Koirala, R.; Pratsinis, S. E.; Baiker, A. Synthesis of catalytic materials in flames: opportunities and challenges. Chem. Soc. Rev. 2016, 45, 3053-3068. (7) McMillin, B. K.; Biswas, P.; Zachariah, M. R. In situ characterization of vapor phase growth of iron oxide-silica nanocomposites: Part I. 2-D planar laser-induced fluorescence and Mie imaging. J. Mater. Res. 1996, 11, 1552-1561. (8) Guo, B.; Yim, H.; Khasanov, A.; Stevens, J. Formation of magnetic FexOy/silica core-shell particles in a one-step flame aerosol process. Aerosol Sci. Technol. 2010, 44, 281-291. (9) Pratsinis, S. E.; Zhu, W. H.; Vemury, S. The role of gas mixing in flame synthesis of titania powders. Powder Technol. 1996, 86, 87-93. (10) Johannessen, T.; Pratsinis, S. E.; Livbjerg, H. Computational analysis of coagulation and coalescence in the flame synthesis of titania particles. Powder Technol. 2001, 118, 242-250. (11) Purwanto, A.; Wang, W.-N.; Ogi, T.; Lenggoro, I. W.; Tanabe, E.; Okuyama, K. High luminance YAG:Ce nanoparticles fabricated from urea added aqueous precursor by flame process. J. Alloys Compd. 2008, 463, 350-357. (12) Hidayat, D.; Purwanto, A.; Wang, W.-N.; Okuyama, K. Preparation of size-controlled tungsten oxide nanoparticles and evaluation of their adsorption performance. Mater. Res. Bull. 2010, 45, 165-173. (13) Widiyandari, H.; Purwanto, A.; Balgis, R.; Ogi, T.; Okuyama, K. CuO/WO3 and Pt/WO3 nanocatalysts for efficient pollutant degradation using visible light irradiation. Chem. Eng. J. 2012, 180, 323-329. (14) Arutanti, O.; Nandiyanto, A. B. D.; Ogi, T.; Iskandar, F.; Kim, T. O.; Okuyama, K. Synthesis of composite WO3/TiO2 nanoparticles by flame-assisted spray pyrolysis and their photocatalytic activity. J. Alloys Compd. 2014, 591, 121-126. (15) Arutanti, O.; Arif, A. F.; Balgis, R.; Ogi, T.; Okuyama, K.; Iskandar, F. Tailored synthesis of macroporous Pt/WO3 photocatalyst with nanoaggregates via flame assisted spray pyrolysis. AlChE J. 2016, 62, 3864-3873. (16) Hirano, T.; Nakakura, S.; Rinaldi, F. G.; Tanabe, E.; Wang, W.-N.; Ogi, T. Synthesis of highly crystalline hexagonal cesium tungsten bronze nanoparticles by flame-assisted spray pyrolysis. Adv. Powder Technol. 2018, 29, 2512-2520. (17) Mueller, R.; Mädler, L.; Pratsinis, S. E. Nanoparticle synthesis at high production rates by flame spray pyrolysis. Chem. Eng. Sci. 2003, 58, 1969-1976. (18) Fujiwara, K.; Pratsinis, S. E. Atomically dispersed Pd on nanostructured TiO2 for NO removal by solar light. AlChE J. 2017, 63, 139-146. (19) Ehrman, S. H.; Friedlander, S. K.; Zachariah, M. R. Characteristics of SiO2/TiO2 nanocomposite particles formed in a premixed flat flame. J. Aerosol Sci 1998, 29, 687-706.


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(20) Bakrania, S. D.; Miller, T. A.; Perez, C.; Wooldridge, M. S. Combustion of multiphase reactants for the synthesis of nanocomposite materials. Combust. Flame 2007, 148, 76-87. (21) Ishizuka, S. On the behavior of premixed flames in a rotating flow field: Establishment of tubular flames. Symposium (International) on Combustion 1985, 20, 287-294. (22) Ishizuka, S. Characteristics of tubular flames. Prog. Energy Combust. Sci. 1993, 19, 187226. (23) Ishizuka, S.; Dunn-Rankin, D. Tubular combustion; Momentum Press, 2013. (24) Rayleigh, L. On the dynamics of revolving fluids, proceedings of the royal society of london. Series a 93 1916, 148-154. (25) Righettoni, M.; Tricoli, A.; Pratsinis, S. E. Si:WO3 Sensors for highly selective detection of acetone for easy diagnosis of diabetes by breath analysis. Anal. Chem. 2010, 82, 3581-3587. (26) Hammond, C.; Straus, J.; Righettoni, M.; Pratsinis, S. E.; Hermans, I. Nanoparticulate Tungsten Oxide for Catalytic Epoxidations. ACS Catalysis 2013, 3, 321-327. (27) Arutanti, O.; Ogi, T.; Nandiyanto, A. B. D.; Iskandar, F.; Okuyama, K. Controllable crystallite and particle sizes of WO3 particles prepared by a spray-pyrolysis method and their photocatalytic activity. AlChE J. 2014, 60, 41-49. (28) Nandiyanto, A. B. D.; Arutanti, O.; Ogi, T.; Iskandar, F.; Kim, T. O.; Okuyama, K. Synthesis of spherical macroporous WO3 particles and their high photocatalytic performance. Chem. Eng. Sci. 2013, 101, 523-532. (29) Syred, N.; Beér, J. M. Combustion in swirling flows: A review. Combust. Flame 1974, 23, 143-201. (30) Nakakura, S.; Arif, A. F.; Rinaldi, F. G.; Hirano, T.; Tanabe, E.; Balgis, R.; Ogi, T. Direct synthesis of highly crystalline single-phase hexagonal tungsten oxide nanorods by spray pyrolysis. Adv. Powder Technol. 2019, 30, 6-12. (31) Widiyastuti, W.; Hidayat, D.; Purwanto, A.; Iskandar, F.; Okuyama, K. Particle dynamics simulation of nanoparticle formation in a flame reactor using a polydispersed submicron-sized solid precursor. Chem. Eng. J. 2010, 158, 362-367. (32) Widiyastuti, W.; Purwanto, A.; Wang, W.-N.; Iskandar, F.; Setyawan, H.; Okuyama, K. Nanoparticle formation through solid-fed flame synthesis: Experiment and modeling. AlChE J. 2009, 55, 885-895. (33) Kaskan, W. In The dependence of flame temperature on mass burning velocity, Symposium (International) on Combustion, Elsevier: 1957; pp 134-143. (34) Bird, R. B.; Stewart, W. E.; Lightfoot, E. N. Transport phenomena. 2nd. New York 2002.


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(35) Shimokuri, D.; Ishizuka, S. Flame stabilization with a tubular flame. Proceedings of the Combustion Institute 2005, 30, 399-406. (36) Karlovitz, B.; Denniston Jr, D.; Knapschaefer, D.; Wells, F. Studies on Turbulent flames: A. Flame Propagation Across velocity gradients B. turbulence Measurement in flames, Symposium (international) on combustion, 1953, 4, 613-620. (37) Williams, G.; Hottel, H.; Scurlock, A. Flame stabilization and propagation in high velocity gas streams, Symposium on Combustion and Flame, and Explosion Phenomena, 1948, 3, 21-40. (38) Lewis, B.; Von Elbe, G. Combustion, flames and explosions of gases; Elsevier, 2012.


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Tubular Flame Combustion for Nanoparticle Production - Industrial

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