Pulse combustion spray drying system

Pulse Combustion Spray Drying Systems http //www.pulsedry.com/... 

Figure 14.7 Pulse combustion spray-drying system. (From Ozer et al., 1993.)...

FIGURE 23.6 A vertical pulse combustion spray drying installation and its pulse combustor developed by Pulse Combustion Systems, the United States, (a) Schematic of the PC spray dryer (1, air 2, unidirectional air valve 3, eombustion chamber 4, fuel 5, pilot 6, tailpipe 7, atomizer 8, quench air 9, liquid 10, drying chamber), (b) Photo of pulse combustor used in the PC spray dryer. 

As noted above, pulse combustion spray-drying experiments are difficult to perform because of the high gas temperature in the chamber, the high noise level, and the short drying time. In order to avoid removing samples from the chamber, Zbicinski et al. (2002) applied a particle dynamic analysis (PDA) technique to determine the water evaporation level as a function of the distance to the atomizer in a horizontal valved PCD system. The laser-based PDA system counts the number of droplets in a cross-section of the dryer, which in turn makes it possible to estimate the flux of the discrete phase in the chamber. 

Figure 23.9 shows three types of commercial pulse combustion spray dryers offered by the Pulsecom Dryer System, Japan. The pulse combustor used gaseous fuels such as coal gas and natural gas, and the drying capacity of the PC dryers varied from 25 to 4000 kg water/h. The energy consumption to evaporate unit water was about 800 kcal/kg water. The product temperature was 50°C-70°C due to short residence time, and the outlet temperature of the exhaust temperature was about 90°C-120°C. For the PC dryer with an evaporation of 4000 kg water/h, it has a dimension of 13 m length x 10 m width x 17 m height and an electric consumption of 75-110 kw - h. 

FIGURE 23.9 Types of commercial pulse combustion spray dryers offered by Pulsecom Dryer System, Japan, (a) The pulse combustion spray dryer with a cylindrical drying chamber, (b) The pulse combustion spray dryer with a cylindrical drying chamber and air recycle pipe, (c) The pulse combustion spray dryer with a big volume drying chamber. 

Pulse combustion drying combines high economic of direct fire heating system with high intensity of drying of disperse material. Typical power consumption is 3,000-3,500 kJ/kg H2O evaporated (4,500 to -11,500 for spray dryer and 3,200-6,500 for drum dryer) [53,54]. The main advantages of pulse combustion drying are as follows ... 

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