Bio-oil

Bio-oil upgrading over Ga modified zeolites in a bubbling fluidized bed reactor... 

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. 

Table 2. Water content and higher heating value of bio-oil...

The time taken for biotechnological developments in oil refining has been, so far, very long. However, it should be noted that the MB and GE advances have only been recent and the magnitude of involvement and efforts by the oil industry itself has not been substantial. Assuming a more proactive involvement of the oil industry, the incorporation of modern tools and the building of the much needed multidisciplinary team, the developmental time should decrease. Nevertheless, any current development has to be oriented to address the issues that will come up in stated future scenarios, such as the integrated bio-oil-refineries of the future. 

Hybrid catalysts consisting of a zeolite (ZSM-5 or Beta) and bentonite as a binder were prepared and characterized by XRD, pyridine FTIR and nitrogen adsorption. The hybrid catalysts exhibited similar properties as the combined starting materials. Catalytic pyrolysis over pure ZSM-5 and Beta as well as hybrid catalysts has been successfully carried out in a dual-fluidized bed reactor. De-oxygenation of the produced bio-oil over the different zeolitic materials was increased compared to non-catalytic pyrolysis over quartz sand. 

Pyrolysis is the decomposition of organic material due to the influence of heat. By performing controlled pyrolysis the woody biomass can be converted into high value added products, namely bio oil, formed in addition to char and gases. 

The highly oxygenated bio oil can be de-oxygenated, and thereby upgraded, over acidic zeolite catalysts through the formation of mainly water at low temperatures and C02 and CO at higher temperatures [1-3], Successful catalytic pyrolysis of woody biomass over Beta zeolites has been performed in a fluidized bed reactor in [4]. A drawback in the use of pure zeolitic materials has been the mechanical strength of the pelletized zeolite particles in the fluidized bed. 

The produced bio oil was analyzed by GC-MS and Karl Fischer titration. The surface area of the spent catalyst was also measured. Regeneration of the spent catalyst was performed at 450°C for 2h in a muffle oven in the presence of air. The regenerated catalysts were characterized in a similar fashion as the fresh ones. 

Pyrolysis of pine wood biomass was conducted at 400°C followed by catalytic deoxygenation at 450°C. The yield of the different product phases was gravimetrically determined. The gas yield was calculated by the difference. The water content of the bio oil was measured by Karl Fischer titration. The yield of the different product phases is given in Table 3, calculated from the pyrolyzed biomass. The non-catalytic experiment was carried out in the same way as the catalytic ones with the exception that the upper catalyst bed was empty. 

The chemical composition of the produced oil was analyzed by GC-MS. The samples were prepared by diluting the bio oil in methanol in a way that the fraction of organic oil was the same in each GC-vial. The products found in the oil were grouped as aldehydes, acids, alcohols, ketones, phenols, polyaromatics and others. The most interesting groups are shown in Table 4 and Table 5, arranged according to their retention time (RT). The procedure for the GC-MS analysis has been previously reported by the authors [4],... 

The chemical composition of the bio oil was changed depending on the catalyst used. The more acidic ZSM-5 catalysts produced more polyaromatics and less aldehydes than the less acidic Beta catalysts. Interestingly, levoglucosan was only found in the non-catalytic and in the pure ZSM-5 zeolite oil. 

Table 4 Polyaromatics [area-%] found in the bio oil produced over different catalysts...

Fast pyrolysis is a high temperature, fast heating process in which vapor is produced, that is, subsequently condensed as a dark brownish liquid, bio-oil, with some coproduction from char and permanent gases. High yields of pyrolysis vapors/bio-oil can be achieved... 

The BioTherm process of the company Dynamotive (Vancouver, Canada). The process is based on a stationary FB and the largest plant processes about 100 t/day of biomass. This unit is situated in Ontario (Canada) and its feedstock is woody waste. In this application, the obtained bio-oil is converted into electricity using an Orenda gas turbine (2.5 MWe). 

The Biolig process of the research center Karlsruhe FZK, Germany. Here, flash pyrolysis, with emphasis on straw as feedstock, is tested to produce a bio-oil-char slurry. The pyrolysis reactor compares to the ER reactor (Lurgi-Ruhrgas) by which sand as heat carrier is mixed and transported together with biomass in a double (twin) screw feeder. A novel unit is constructed with a biomass processing capacity of 12 t/day. 

Typical bio-oil production prices are still relatively high Peacocke et al 04 mention values of 13.2-14.6/GJ for FB and rotating cone technology, respectively, based on the assumptions of biomass costs of 50/t dry and feeding rates of 10 dry t/h. 

Currently, there is renewed interest in this process. At Twente University (The Netherlands), research is performed toward the use of bio-oil from (flash) pyrolysis as the reducing agent for the oxidized iron.149 Therefore, a CO-containing gas stream and a relatively pure H2 stream is generated separately from the biomass-derived bio-oil. 

Henrich, E. Raffelt, K. Stahl, R. Weirich, F., Clean syngas from bio-oil/char-slurries. In Science in Thermal and Chemical Biomass Conversion, Bridgwater, A. V. Boocock, D. G. B., Eds., CPL press, Victoria, 2004, pp. 1565-1579. 

Pyrolysis produces a liquid product called bio-oil, which is the basis of several processes for the development of fuels, chemicals, and materials. The reaction is endothermic ... 

The oil can be formed in 66 wt% yields. Catalytic steam reforming of bio-oil at 750 to 850°C over a nickel-based catalyst is a two-step process that includes the shift reaction ... 

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