Viscosity of Aged Bio-oils from Fast Pyrolysis of Beech Wood and Miscanthus: Shear Rate and Temperature Dependence

Abstract

ABSTRACT:The viscosity of four aged bio-oil samples was measured experimentally at various shear rates and temperatures by using a rotational viscometer. The experimental biooils were derived from fast pyrolysis of beech wood at 450, 500 and 550 °C, andMiscanthus at 500 °C (in this work, they were named as BW1, BW2, BW3 and MXG) in a bubbling fluidised bed reactor. The viscosity of all bio-oils kept constant at various shear rates at the same temperature, which indicated that they were Newtonian fluids.The viscosity of bio-oils was strongly dependent on the temperature, and by increasing the temperature from 30 to 80 °C, the viscosity of BW1, BW2, BW3 and MXG decreased by 90.7%, 93.3%, 92.6% and 90.2%, respectively. The Arrhenius viscosity model, which have been commonly used to represent the temperature dependence of the viscosity of many fluids, did not fit the viscosity-temperature experimental data of all bio-oils very well, especially in the low and high temperature regions. For comparison, the Williams-Landel-Ferry (WLF) model was also used. The results showed that the WLF model gave a very good description of the viscosity-temperature relationship of each bio-oil with very small residuals and the BW3 bio-oil had the strongest viscosity-temperature dependence.

Intermediate pyrolysis of organic fraction of municipal solid waste and rheological study of the pyrolysis oil for potential use as bio-bitumen

“…It is a significant physical property, as it essentially determines the flow characteristics of a fluid in a certain temperature and therefore affects the handling methods applied for storage and transportation etc. [7] The viscosity is also of great interest when the pyrolysis liquid is used as a component or an alternative to the binder in construction material, such as bio-bitumen, as it will affect the blending temperature of the mixtures. The viscosity of pyrolysis oils as produced can vary significantly; it is largely dependent on the type of feedstock and processing technology that results in the content of water and light fraction in the liquid [1].…”

“…The results showed that the addition of bio-char (up to 20%) in pyrolysis oils could decrease the dynamic viscosity of the liquid in 40°C, but the liquid remained as a Newtonia n fluid. Cai et al [7] studied the rheology of four aged bio-oil samples from fast pyrolysis of miscanthus and beech wood at various shear rates and temperatures by using a rotational viscometer. All the pyrolysis oil samples maintained constant viscosity at various shear rates at the same temperature, which indicated their Newtonian characters.…”

Production of Fuel-Like Fractions by Fractional Distillation of Bio-Oil from Açaí (Euterpe oleracea Mart.) Seeds Pyrolysis

“…Pyrolysis makes possible the use of low quality lignin-cellulosic material to produce not only bio-oils, but also gaseous fuels, and a carbonaceous rich solid phase, as reported in the literature . Studies include biomass pyrolysis [23,24,26,45,56,57,62,67,68], bio-oil chemical upgrading techniques [26,45,50], bio-oil physical-chemical properties [21,25,26,28,34,35,43,57,62,63], as well as separation and/or purification processes to improve bio-oil quality [17][18][19][20][21][22][30][31][32][33][36][37][38][39][40][41][46][47][48]51,53,54,[59][60][61]65,…”

Theoretical Analysis of Double Logistic Distributed Activation Energy Model for Thermal Decomposition Kinetics of Solid Fuels

“…1,2 Depending on the processing temperature and atmosphere, these processes can be classified as pyrolysis, gasification and combustion. 3,4 Pyrolysis is the thermal decomposition in non-oxidizing environment, resulting in the production of a liquid, solid and gases, 5,6 and the yields of these products rely on the feedstock and processing conditions. 7,8 The combustion of solid fuels first undergo endothermic pyrolysis to produce combustible gases, which are subsequently combusted to supply heat required to produce further gases.…”