In-situ Catalytic Upgrading Of Rape Straw Pyrolysis Vapors For Refined Bio-oil Over Zn-P/HZSM-5

Zn-P was used to modfied HZSM-5 and the rape straw as the bio-feeds, which was catalytic cracking into bio-oil under a fixed-bed reactor. The main research content was as follows:(1) Impregnation method was been used to prepared four kinds of Zn-P/HZSM-5, the loading mass of P was 3.5wt% to enhance the hydrothermal stability and anti-coking ability, Zn was used to enhance the catalytic selectivity properties, Zn laoding mass was 0, 1, 3, 5wt% respectively.(2) The physicochemical property of four kinds of Zn-P/HZSM-5 were represented with ICP-AES、XRD、SEM-EDS、FT-IR、Py-IR. The studies show the loding mass of Zn-P in modifed HZSM-5 was matched with the anticipation by the measure of negative feedback regulator. The crystal structure of modifed HZSM-5 stayed unchanged, and the Zn-P was uniformly distributed on the surface of modifed HZSM-5. The relative crystallinity of modifed HZSM-5 was slight declines. The surface topography was similarity and compact. Much of fine particle was found on the surface of grain and existed in amorphous state, thus the modifed HZSM-5 does not have the same shape. The position and the intensity of the characteristic ir adsorption peak were stayed unchange, which shows the crystal structure of modifed HZSM-5 stayed unchanged and matched with XRD. The loading mass of Zn had a significant influence with the acidity on the modifed HZSM-5. The content of L acidity was declined with Zn loading mass rised, while the B acidity on contrary. The L acidity had the highest content when Zn loading mass was 3wt%. A new active centre(L1616) was appeared with Zn loading. The form of Zn was existed on the surface of the modifed HZSM-5 was Zn(OH)+ by the information of Zn character and the characteristic ir adsorption peak.(3) Elemental analysis and proximate analysis of five kinds of common biomass(rape straw, rice straw, rice rice husk, deal and pine needle) were executed. The study shows the conent of volatile component was 72.84% and the water content was 6.12% of rape straw, thus rape straw has good thermal decomposition property. And the wide raw material source was the key to rape straw into bio-feeds. Rape straw was catalytic cracking into liquid product under the two sections of pyrolysis furnace. The liquid product appeared stratification, the superstratum was oil phase and substratum was aqueous phase.(4) The physicochemical property of four kinds of oil phase and aqueous phase were analyzed, and the liquid products were analyzed by GC-MS. The study shows the yield of oil phase was 9.34~9.91%, low oxygen levels(10.67wt%~16.52wt%), higher calorific value(33.8MJ·kg-1~36.76MJ·kg-1), low acidity(pH=4.39~5.85), fuel properties of oil phase had the larger ascension. The physical and chemical index(F) was the highest, and the fuel properties were the best when Zn loading mass was 3%. The yield of oil phase was 9.68%, oxygen content was 10.67wt%, higher calorific value was 36.76MJ·kg-1. The aqueous phase had higher water content(40.75wt%~42.56wt%), low calorific value(19.11MJ·kg-1~20.72 MJ·kg-1), which had bad manifestation fuel properties. The carboxylic acid was litter existed with Zn loding. The relative amount of aromatic compounds was 78.70%~91.93% and the most aromatic compounds were existed in the form of aromatic hydrocarbon, which shows enhanced the catalytic aromatization ability of HZSM-5. The relative amount of aromatic compounds and aromatic hydrocarbon were 91.93% and 74.63% respectively. While aldehyde&ketone, alcohol(phenol), ether had ittle content, which enhanced the stability of the fuel. Three components of biomass was generated into carbocation by dehydrogenation on the L acid of modified HZSM-5, further dehydration, decarbonylation, decarboxylation reactions would take place, in the end would generated into aromatic compounds.(5) Thermo-gravimetric analysis(TGA) was used to analyze the coking of catalysts:HZSM-5, P/HZSM-5 and Zn(3)-P/HZSM-5,which were used under same time, the results was shown P/HZSM-5 and Zn(3)-P/HZSM-5 reduced the produce of amorphous coke and had little influence on graphite type coke. The totally amount coke of P/HZSM-5 and Zn-P/HZSM-5 were 10.80% and 11.13%, which was below the 14.34% coke content of HZSM-5. P modification played dominant role while Zn modification had little influence in anti-coking capability of HZSM-5.