Reactor, free-fall

Slow Pyrolysis, Therombalance Rapid Pyrolysis, Free Fall Reactor ... 

Li, S., Xu, S., Liu, S., Yang, C., Lu, Q. 2004. Fast pyrolysis of biomass in free-fall reactor for hydrogen-rich gas. Fuel Proc Technol 85 1201-1211. 

Qader, et al., (4) reported work on hydrogenation in a dilute phase free fall reactor at temperatures in the order of 515°C, pressures of 2000 psi and with a heavy dose of catalyst, 15% stannous chloride by weight of coal. Up to 75% conversion was reported with a product distribution of 43% oil, 32% gas and 25% char. The residence time of the coal feed particles was estimated to be in the order of seconds, however, no measurement was made and aromatics were reported after further hydrorefining in a second stage hydrogenation. 

Waste Plastic Pyrolysis in Free-Fall Reactors... 

Free-fall reactors (FFR) are a good choice for rapid or flash pyrolysis. They have been widely harnessed to pyrolyze coal and, more recently, biological mass. A pioneering group at Ankara University was the first to attempt pyrolysis of waste plastics in a FFR. Then-results are very promising indeed compared with other alternatives in the literature. 

A FREE-FALL REACTOR SYSTEM FOR FLASH PYROLYSIS... 

Figure 23.1 depicts the current version of the free-fall reactor developed and used in... 

Polystyrene was flash pyrolyzed in a free-fall reactor nnder vacnnm [49, 50] giving yields at the level of flnidized-bed figures [33, 51]. Also investigated [49] was flash vacnnm pyrolysis of LDPE whose results are now presented here in this manuscript with an additional experiment nsing the same system. 

RESULTS FROM ATEKLAB FREE-FALL REACTOR... 

The free-fall reactor operating under vacuum has the added advantage over both the sweeping fixed bed and fluidized-bed reactor types that it does not dilute the gaseous products with an inert. 

It is interesting to compare flash vacuum pyrolysis of LDPE and PS in a free-fall reactor. Temperature rise causes the solid residues to fall and the liquid and gas yields to increase. The LDPE figures exceed the corresponding PS values in the case of the solid residue and gas yield by about 50 and 10% respectively. In contrast, the liquid yield of LDPE is about one-fifth of PS. These findings are in harmony with the activation energies 270-331 kJ/mol for LDPE and 126-151 kJ/mol for PS [34]. 

In this study [25], waste polystyrene was flash pyrolyzed in a free-fall reactor under vacuum with the aim to assess the effects of both the operating temperature and the feed particle size on the kinds and relative distributions of products. 

Figure 23.7 The temperature effects on product phase yields of PS. (Reproduced from Journal of Analytical and Applied Pyrolysis, 60 (2), A. Karaduman, Flash pyrolysis of polystyrene wastes in a free-fall reactor under vacuum, 179-186(2001), with permission from Elsevier)...

This study showed that polystyrene pyrolysis in a free-fall reactor under vacuum is a promising technique to obtain important liquid chemicals such as benzene, toluene, and naphthalene besides styrene monomer and valuable gaseous output. The liquid yield... 

R.Zanzi, K.Sjostrdm and E. Bjombom, Rapid high-temperature pyrolysis of biomass in a free-fall reactor. Fuel, 75(5), 545-550 (1996). 

W. -C. Xu, K. Matsuoka, H. Akiho, M. Kumagai and A. Tomita, High pressure hydropyrolysis of coals using a continuous free-fall reactor. Fuel, 82, 677-685 (2003). 

H. Er ahan and A. Y. Bilgesu, Products from flash pyrolysis of Turkish lignite in a free-fall reactor under vacuum. Fuel Sci. Techn. Int, 12, 1475 (1994). 

A Karaduman, M. (( . Kogak and A. Y. Bilgesu, Flash vacuum pyrolysis of low density polyethylene in a free-fall reactor, Polymer-Plastics Technology and Engineering, 42(2), 181-191 (2003). 

Figure 2. Free-fall reactor and fluid bed gasifier system Conclusions...

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