Bubbling fluidized beds pyrolysis

Catalytic upgrading of bio-oil was carried out over Ga modified ZSM-5 for the pyrolysis of sawdust in a bubbling fluidized bed reactor. Effect of gas velocity (Uo/U ,f) on the yield of pyrolysis products was investigated. The maximum yield of oil products was found to be about 60% at the Uo/Umf of 4.0. The yield of gas was increased as catalyst added. HZSM-5 shows the larger gas yield than Ga/HZSM-5. When bio-oil was upgraded with HZSM-5 or Ga/HZSM-5, the amount of aromatics in product increased. Product yields over Ga/HZSM-5 shows higher amount of aromatic components such as benzene, toluene, xylene (BTX) than HZSM-5. 

In spite of the major effort in this field in the last 30 years, the development at industrial scale of post-consumer plastic pyrolysis has considerable uncertainties concerning the selection of the more suitable technology. The more developed technology in the literature is the bubbling fluidized bed reactor [1-5] where the fused plastic coats the inert particles (sand). Nevertheless, the operation at large scale in this reactor presents problems of defluidization, due to particle agglomeration provoked by fusion of particles coated with plastic [4]. 

Raw biomass and all the pretreated samples except those receiving the water wash (for reasons explained in the Results and Discussions section) were thermally processed in the fast pyrolysis pilot plant at RTI, Ltd. This bubbling, fluidized bed reactor operates between 360 C and 490 C with gas residence times on the order of 2 s. Details on this system can be found in Reference 14. Operating conditions for pyrolysis of the switchgrass and comstover samples are detailed in Tables II and III, respectively. 

Detailed analysis of literature data showed that products of high quality and economic advantage may be obtained under dynamic conditions using bubbling fluidized bed reactor for burning or pyrolysis of RRHs [11, 17, 73, 77-89]. The fluidized bed technology is selected as preferable for the production of amorphous silica from rice husks. 

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,... 

The reactor is the core and is generally the most researched part of the pyrolysis technology. Extensive literature is available for catalytic pyrolysis that has been carried out at both bench/laboratory scale (ie, bubbling and circulating fluidized beds, auger reactors, and conical spouted bed reactors) and analytical scale reactors (ie, analytical pyrolysis or py-GC/MS either tubular quartz micro reactor or packed bed reactor). Specific reactor designs are not discussed in this work. Catalytic fast pyrolysis can be split into two different operation modes defined by the location of the catalyst in the process in situ and ex situ (Tan et al., 2013) (Fig. 14.2). 

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