Spray pyrolysis reactors

Spray pyrolysis reactors involve decomposing a heavy petroleum fraction with air under conditions of partial combustion. This method is used to produce carbon black (which is used in rubber and in products such as inks and other pigments). 

Films at NASA GRC were deposited using homemade spray or aerosol-assisted chemical vapor deposition (AACVD) reactors to exploit the lower deposition temperature enabled by the simpler decomposition chemistry for the SSPs.6 9 AACVD is a simple and inexpensive process that offers the advantage of a uniform, large-area deposition, just like metal organic CVD (MOCVD), while also offering the low-temperature solution reservoir typical of spray pyrolysis methods. 

Recently it was experimentally proven that the highest yield of nanoparticles of different substances, including semiconductor and magnetic ones, is obtained in low pressure spray pyrolysis of special multicomponent solutions [1], During this pyrolysis micron size droplets of the multicomponent aqueous solution evaporate in a low pressure aerosol reactor. Additionally these droplets often have solid precursors of nanometer size, so we can consider every droplet as a colloidal solution. 

The aim of our work is to present simulation results to give a clear physical picture of interference of complex processes in the evaporating droplet during the low pressure spray pyrolysis. For different conditions the drop of temperature of an evaporating droplet is displayed in Fig. 1. The volatile components are water and ammonia. Total pressure in the aerosol reactor is 60 Torr. The initial droplet temperature is 300 K and its initial radius is about 2 pm. For the gas flow... 

In the first chapter of this book, an overview of CVD techniques has been given, and more detailed descriptions can be found in several textbooks [9, 10]. Many different CVD reactors have been used for the deposition of conducting films, i.e., thermal, UV-enhanced CVD (UVCVD), laser-assisted CVD (LACVD), plasma-enhanced CVD (PECVD) and metal-organic CVD (MOCVD). In addition, two techniques were included, which are not typically part of CVD, chemical transport and spray pyrolysis. 

A series of catalysts for the low temperature WGS reaction has been prepared by flame spray pyrolysis. The catalysts consist of a traditional Cu/Zn0/Al203 sample, a ceria promoted Cu/Zn0/Al203 catalyst and a series of ceria and/or zirconia supported Cu or Pt catalysts. Flame spray pyrolysis results in high surface area catalysts with good dispersion. The WGS activity of the catalyst samples has been measured in a plug-flow reactor in the temperature range 180-315 °C. ... 

Decreasing operation temperature of solid oxide fuel cells (SOFCs) and electrocatalytic reactors down to 800-1100 K requires developments of novel materials for electrodes and catalytic layers, applied onto the surface of solid electrolyte or mixed conducting membranes, with a high performance at reduced temperatures. Highly-dispersed active oxide powders can be prepared and deposited using various techniques, such as spray pyrolysis, sol-gel method, co-precipitation, electron beam deposition etc. However, most of these methods are relatively expensive or based on the use of complex equipment. This makes it necessary to search for alternative synthesis and porous-layer processing routes, enabling to decrease the costs of electrochemical cells. Recently, one synthesis technique based on the use... 

I. W. Lenggoro, I. W. T. T. Hata, F. Iskandar, M. M. Lunden, and K. Okuyama An experimental and modeling investigation of particle production by spray pyrolysis using a laminar flow aerosol reactor. Journal of Material Research, 15(3), 133-143 (2000). 

As explained in Sect. 38.2, to produce particles using a conventional spray pyrolysis (CSP) process, the precursor is first atomized into a reactor where the aerosol droplets undergo evaporation and solute condensation drying and thermolysis of the precipitate particles at higher temperature forms micro- or meso-porous particles, and, finally, sintering of these porous particles forms dense particles. However, sub-micrometer to micrometer-sized particles traditionally are formed using the CSP process based on the one-droplet-to-one-particle (ODOP) principle due to the difficulty of generating very fine droplets (below 1 pm) [1-3]. 

Figme 3.58 shows a schematic diagram of a representative flame assisted spray pyrolysis (FASP) reactor, which has been used to synthesize oxide nanoparticles... 

Li, M. and Guo, L. (2011) Spray Pyrolysis in Membranes for Membrane Reactors Preparation, Optimization and Selection in Basile, A. and Gallucci, F. Membranes for Membrane Reactors Preparation, Optimization and Selection, Wiley. 

The generic apparatus used in a vapor precursor process is very similar to that used in spray pyrolysis, except that the precursor material is introduced to the reactor as a vapor (see Figure 2.1, 2. la). If the precursor is a liquid, carrier gas is typically bubbled through it. If the precursor is a solid, then the carrier gas is often passed through a heated, packed bed of the material. The vapor-laden carrier gas then flows to a furnace reactor, where thermal decomposition of the precursor occurs and particle formation results. Product powder is collected or measured at the reactor outlet. Flame processes also fall into the vapor precursor/thermal decomposition category of gas-phase powder synthesis. The only difference is that the thermal energy is provided by combustion as opposed to an external source. 

In the flame spray pyrolysis method [54], the metal precursor (titanium tetrai-sopropoxide) was diluted with a mixture of xylene and acetonitrile [54] or N2 [55] and fed into a reactor, simultaneously with O2 and methane (fuel), producing titania particles. 

Fig. 2 Updated flash pyrolysis pilot plant for biomass (PDU-Scalc) (1 hopper, 2 vibration conveyor, 3 screw feeder. 4 fluidised bed reactor, 5 cyclone system. 6 monopump. 7 quench liquid reservoir, 8 heat exchanger, 9 spray tower, 10 electrostatic precipitators, 11 heat exchanger, 12 flare, 13 compressor, 14 gas preheater 1. 15 gas preheater 2, 16 overflow pipe, 17 char collection vessel).

Huber et al. performed the catalytic fast pyrolysis of pine wood with spray-dried ZSM-5 in a bubbling fluidized-bed reactor with co-feeding of different alcohols, viz. methanol,... 

As described in the previous section. Brown et al. obtained an aromatic yield of 1% in the catalytic fast pyrolysis of milled wood lignin with ZSM-5 at 600°C, which was considerable lower than the yields obtained from cellulose and hemicellulose [286]. Also, the coke yield from lignin (59%) was much higher. Huber et al. used the lignin residue obtained after H SO hydrolysis of maple wood as a substrate for pyrolysis in a fluidized-bed reactor with spray-dried ZSM-5 at 600°C [298]. Next to lignin, this substrate also contains humic residue, a compound also composed of phenolic entities. An aromatic and olefin yield of only 2% and 1% was obtained, compared to respective yields of 15% and 7% from pure maple wood. The coke yield from the solid residue (69%) was also much higher than the coke yield from maple wood (32%). 

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