Bubbling fluidized bed gasifier

There are two recent projects, which plan to use this approach in eliminating tar (42, 43). Both are based on bubbling fluidized bed gasifiers (Fig. 5) and are... 

BUBBLING FLUIDIZED BED GASIFIER MODELING VVB GASIFICATION PLANT... 

The VUB pilot plant consists of a feeding system (a hopper equipped with a rotary valve and a conveyor screw), the fluidized bed reactor, preheating burner, cyclone and a control system. The bubbling fluidized bed gasifier has a capacity of 400 kg/h and consists of a bed (0.8 m diameter/0.6 m height) with an extended freeboard section (1.2 m diameter/2 m height). More technical details about the gasifier can be found in [16]. 

The two-phase flow theory is adopted in the model it consists in two phases, a dense phase and a bubble phase separated by a film through which the mass transfer occurs. Gases move upward in both bubble and dense phase with plug flow, which proves to be adequate to describe the flow in a bubbling fluidized bed gasifier [17],... 

El Asri R., De Ruyck J., and Verelst H., Wood Bubbling Fluidized Bed Gasifier Modeling Through ASPEN+ , Proceeding of Flowers 97, pp.657-668, 1997. 

Prepare 5-ton per day bubbling fluidized bed gasifier and a latent heat ballasting system. 

Bubbling fluidized-bed gasifier 17 Alcohol synthesis (metal sulfide catalyst)... 

Two of the major disadvantages of the bubbling fluidized bed gasifier are that high conversion of solids is not achieved due to back mixing issues, and the formation of oxidation spots due to the slow oxygen diffusion. 

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. 

Figure 2A is representative of pressurized bubbling bed air blown partial oxidation of biomass fuel. The sketch indicates that fines recycling might be used, with nonmechanical valves to control the reinjection of fines into the fluidized bed gasifier. The vessel will drain a low-carbon ash product. The sketch also suggests that overbed air injection might be used for fuel gas partial oxidation as a means for fuel gas tar destruction. The... 

Methane is undesirable in most synthesis gas applications. The HTW demonstration plant was also designed specifically for reactive brown coal. Therefore, carbon conversion was not a problem, and the gasifier was a bubbling fluidized-bed design. 

The Utility-Gas (U-Gas) gasifier was developed by the Chicago Gas Technology Institute since 1974 [158]. The pressurized (2-30bar) stationary bubbling fluidized bed features an internal ash agglomeration that permits a segregation of the... 

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