Energy valorisation of crude glycerol and corn straw by means of slow co-pyrolysis: Production and characterisation of gas, char and bio-oil

In recent years the amount of crude glycerol, by product of the biodiesel production process, has been increasing as a result of the high demand of biodiesel. Developing new processes for crude glycerol revalorization could make the biodiesel production process more profitable. An alternative use of crude glycerol by means of a co-pyrolysis with corn straw is studied at the following ratios [1:0], [3:1], [1:1], [1:3] and [0:1] in the present work aimed to energy recovery. Initially, thermal analysis (TG and DTG profiles) was performed to identify possible interactions and they were found throughout all the devolatilization process at different degrees. Then, a series of slow pyrolysis tests were run in a laboratory size reactor. Yields of pyrolysis fractions: char, bio-oil and gas were measured. And the products were analysed and characterised. The pyrolysis of crude glycerol produced rich gas and bio-oil. The gas had a L. H. V of 46 MJ/m(3) but low yield (23 wt.%). Mixing the crude glycerol with corn straw the gas yield could be increased and still having good heating value, for instance the blend [1:1] presented a LHV:29 MJ/m(3) and 39 wt.% of yield. The resulting gas was rich in light hydrocarbons and had a good H-2 concentration. The blending ratios also affected the bio-oil and char production. The selection of blending ratios is a function of the desired fraction to be maximised. (C) 2013 Elsevier Ltd. All rights reserved.