Bubbling fluidized beds gasification

Bubbling fluidized bed Gasification in a BFB of sand, fluidized by air, steam and nitrogen at a temperature between 750 and 900°C... 

Autothermal fluidized-bed (FB) gasification, applying bubbling fluidized-bed (BFB) or circulating fluidized-bed (CFB) technology (steam/02 blown)... 

Narvaez, I. Orio, A. Aznar, M. P. Corella, J., Biomass gasification with air in an atmospheric bubbling fluidized bed. Industrial and Engineering Chemistry Research 1996, 35(7), 2110-2120. 

Pore-diffusion resistance Reactions involve solid particle size greater than about 1.6 mm All fast, noncatalytic gas-solid (G/S) reactions such as combustion and gasification Reactors with particle size lower than 100 pm to 0.1 mm Catalytic bubbling fluidized beds (BFB) Slurry reactors... 

The chemistry component of the model is, in most aspects, identical to the chemistry of the classical models of fluidized bed gasification. A major difference between the classical reactor models and the present fluidized bed coal gasifier computer model is that the classical models require specification of the bed hydrodynamics, such as bubble size. The present model can predict bubble size and the associated solids mixing. Again it is expected that the two types of models are complimentary. The present model can be used to define the hydrodynamics in the hot reactive environment and these hydrodynamics (e.g., bubble size) can then be used as... 

Gil, J., Corella, J., Aznar, M. P., Caballero, M. A. (1999a) Biomass Gasification in Atmospheric and Bubbling Fluidized Bed Effect of the Type of Gasifying Agent on the Product Distribution. Biomass Bioenergy, 17, 389-403. 

BUBBLING FLUIDIZED BED GASIFIER MODELING VVB GASIFICATION PLANT... 

Under most of the wood fluidized bed gasification conditions, benzene turns out to be the dominant element among tar species [23] a simplification is therefore made in the model by considering benzene and naphthalene to be the main tar compounds. A first order reaction rate from Van Den Aarsen [17] was adopted in the model. Since the bubble phase is assumed to be solid free, the char generated in the bubbles through tar... 

In the last several decades, many gasification processes have been developed using all three regimes of fluidization bubbling fluidized bed, circulating fluidized bed, and transport reactor. Each gasification process exploits the particular characteristics of a fluidization regime. 

At this point, bubbling fluidized beds and CFBs remain the most attractive to the market, and the most developed configurations for gasification. 

Kaewluan S, Pipatmanomai S (2011) Gasification of high moisture rubber woodchip with rubber waste in a bubbling fluidized bed. Fuel Process Technol 92 671-677... 

Oevermann, M., Gerber, S., and Behrendt F. (2009) Euler-lagrange/dem simulation of wood gasification in a bubbling fluidized bed reactor. Particuology, 7 (4), 307 316. 

Figure 2.3.5 Gasification technologies/routes (Atm. = atmospheric pressure Pres. = pressurized FB = fluidized bed [both bubbling and circulating] M/F Bed = moving or fixed bed EF = entrained flow).

A computer model has been developed to provide numerical simulations of fluidized bed coal gasification reactors and to yield detailed descriptions, in space and time, of the coupled chemistry, particle dynamics and gas flows within the reactor vessels. Time histories and spatial distributions of the important process variables are explicitly described by the model. With this simulation one is able to predict the formation and rise of gas bubbles, the transient and quasi-steady temperature and gas composition, and the conversion of carbon throughout the reactor. 

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