The preparation of high-grade bio-oils through the controlled, low temperature microwave activation of wheat straw

The Overview of Thermal Decomposition of Cellulose in Lignocellulosic Biomass

“…Compared to the on-line pyrolysis study of cellulose, the off-line pyrolysis of cellulose is mostly carried out under the relatively high temperature (above 400 o C) or high heating rate (more than or around 1000 o C/s) [12,32,36,40,[44][45][46][47][48] and sometimes under low temperature heating (below 400 o C) [49,50], concerning the following issues: 1) the distributions of the gas, liquid and solid products; 2) the formation of the specific compounds and the pyrolytic chemical pathways. How these two issues may be influenced by the pyrolytic reactors and the variables like temperature, residence time, heating rate, pressure, particle size, catalytic salts and crystallinity is extensively examined in the literature, in order to promote the product specificity, maximize the yield and improve the understanding of the pyrolytic mechanism.…”

“…Clark has made a remarkable contribution on the microwave pyrolysis of biomass under low temperature (less than 350 o C) [49,50,73]. Milestone ROTO SYNTH Rotative Solid Phase Microwave Reactor is used for microwave pyrolysis of wheat straw [49].…”

“…The condensable fraction produced during the process was collected through a vacuum unit. The yield of solid, liquid and gas products is estimated to be 29%, 57% and 14% by weight of feedstock at 180 o C. Compared to that of conventional pyrolysis under relevantly high temperature [77], the oxygen content of the bio-oil obtained from lowtemperature microwave pyrolysis is significantly reduced facilitating the following upgrading processes [49]. The microwave pyrolysis of cellulose was carried out at the temperature between 100 o C and 300 o C in a CEM Discovery laboratory microwave, regarding the yield of char and its formation mechanism.…”

Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain

“…Application of the microwave on wheat straws was first reported as a method to increase subsequent enzymatic hydrolysis rates in a bioethanol production approach 346 or to improve the solubilisation of straws for subsequent methane generation. 347 Thermochemical conversions, including hydrogen, 348 bio-gas 349 and bio-oils, 350 were also extensively studied under microwave assistance. A MW-assisted process is also reported to ensure the selective production of furfural and 5-hydroxymethylfurfural from C-5 and C-6 containing carbohydrates.…”

Production of Pyrolyzed Oil from Crude Glycerol using a Microwave Heating Technique

“…A microwave pyrolysis method has been successfully used to pyrolyze a variety of feedstock including waste engine oil (Lam et al, 2010;Lam et al, 2016), wheat straw (Budarin et al, 2009), scrap tires (Appleton et al, 2005;Undri et al, 2013), oil palm biomass waste (Salema & Ani, 2011) and waste plastic (Russell et al, 2012). Valliyappan et al (2008) performed a study on the pyrolysis of glycerol for the production of hydrogen or syngas by using a conventional heating method.…”