The Role of Zeolite Structure and Acidity in Catalytic Deoxygenation of Biomass Pyrolysis Vapors

Abstract

Catalytic upgrading of paddy husk was performed over 10-MR zeolites (MCM-22, ITQ-2 and ZSM-5) in a drop type fixed-bed reactor. This work investigated the role of structure and acidity of zeolites on pyrolysis-oil yield and degree of deoxygenation. Catalytic pyrolysis experiments were carried out at the catalyst/biomass ratio (0.05 -0.5) at temperature of 450 °C. The oil yield decreased by using catalyst and this decrease oil yield is attributed to catalytic cracking of bio-oil vapor on the catalyst. The route for deoxygenation of pyrolysis vapors was identified to be dehydration, decarboxylation and decarboxylation. ITQ-2 showed high degree of deoxygenation as compare to MCM-22 which is due to more accessible external active sites of ITQ-2.The organics yield in pyrolysis oil was highest with ZSM-5 in comparison with other zeolites.

Co-pyrolysis of Rice Husk with Underutilized Biomass Species: A Sustainable Route for Production of Precursors for Fuels and Valuable Chemicals

“…Studies on pyrolysis of RH to bio-oil have been carried out by many researchers [13][14][15][16][17][18][19][20][21][22][23][24]. Bio-oil yields between 25 and 38 wt% rich in acid and ketones are mostly recorded during the pyrolysis of RH at around 600°C [15,16,19,[21][22][23][24]. Catalytic pyrolysis is also being used towards improving the oil quality from RH, and a considerable degree of deoxygenation is achieved at the detriment of oil yield [23][24][25].…”

“…High biooil yield up to 75 % can be obtained under a careful control of process parameters [10][11][12]. Studies on pyrolysis of RH to bio-oil have been carried out by many researchers [13][14][15][16][17][18][19][20][21][22][23][24]. Bio-oil yields between 25 and 38 wt% rich in acid and ketones are mostly recorded during the pyrolysis of RH at around 600°C [15,16,19,[21][22][23][24].…”

“…Catalytic pyrolysis is also being used towards improving the oil quality from RH, and a considerable degree of deoxygenation is achieved at the detriment of oil yield [23][24][25]. This process is normally conducted through in-bed mixing, having biomass and catalyst in the same reactor or the use of multiple reactors with materials in separate compartment [22][23][24][25][26]. In the former, utilization of all pyrolysis products for energy production may not be possible.…”

“…Bio-oil yields between 25 and 38 wt% rich in acid and ketones are mostly recorded during the pyrolysis of RH at around 600°C [15,16,19,[21][22][23][24]. Catalytic pyrolysis is also being used towards improving the oil quality from RH, and a considerable degree of deoxygenation is achieved at the detriment of oil yield [23][24][25]. This process is normally conducted through in-bed mixing, having biomass and catalyst in the same reactor or the use of multiple reactors with materials in separate compartment [22][23][24][25][26].…”

Catalytic and Thermal Cracking of Bio-Oil from Oil-Palm Empty Fruit Bunches, in Batch Reactor

“…This result was in accordance with the result obtained by Trisunaryanti et al [14], that loading of Co, Ni, and Pd metals onto mordenite could increase the number of both Brønsted and Lewis acid sites. According to Naqvi et al [15], increasing acidity of catalysts can facilitate converting biomass into an organic compound with lower molecular weight. An almost similar situation occurred in this research, whereby the use of Ni/NZA catalyst during CBO cracking into fuel brought out more numerously the fragmented and lower molecular weight organic compounds in the product, thereby contributing greatly to the increased fuel yield, compared to the cracking without catalyst (Table 2).…”