2. Experimental
2.1. Materials
The biomasses studied were wheat spent grains (WSG) and rape
seed meal (RSM), where the WSG was obtained from a pilot scale
brewer at University of Nottingham and RSM was obtained from
a local bio-diesel producer. The residues were oven-dried at
80 C for 3 days to remove moisture and subsequently ground below
500 lm using a rotor miller. A commercial bituminous coal,
namely Gregory was used for comparison with particles size below
2 mm.
2.2. Method
The pyrolysis experiments using RSM were carried out in the
temperature range 460–520 C. The pyrolysis of WSG was only carried
out at 520 C. All the pyrolysis experiments were carried out
under nitrogen atmosphere using a bench-scale fluidised bed reactor
shown in Fig. 1. About 5 g of sample was used and the bio-oil
was condensed using dry ice. The bio-oils generated were recovered
and water contained in the oils was removed using a rotavapor
at mild temperatures to avoid condensation reaction in the
bio-oil. The residue was recovered with hexane that was later removed
using room temperature evaporation. The bio-oils were further
treated using the Thermo-t setup shown in Fig. 2. About 1 g of
dry RSM and WSG bio-oils were heated to temperature 400 C
(WSG) and 410 C (RSM) for 30 min at 35 bar using a sand bath.
The WSG was also run with 5wt.% of distilled water added. After
each run the reactor was quenched in a bucket of cold water. The
bio-crude and bio-coke (BC) products were collected by washing
the reactor with toluene and separated used a reflux-filtration unit.
2.3. Analysis
The weight losses experiments were carried out using a Perkin
Elmer Pyris1 thermo-gravimetric analyzer using about 10 mg of
sample. Nitrogen was used to study loss of volatiles and air was
used to evaluate the combustion behaviour of pure bio-cokes, the
coal and their blends. The maximum temperature was set at
900 C and the heating rate at 15 C/min. The ultimate analyses
were performed using a Flash EA 1112 Series elemental analyzer.
The Scanning Electron Microscopy used was an Oxford Inca 200
EDS on an FEI Quanta 600 (Tungsten filament). The Bomb
Calorimeter used was an IKA 5000 Series bomb calorimeter. For
some bio-cokes their yields were to low to actually measure and
were calculated with the following equation: HHV =
0.3491C + 1.1783H + 0.1005S 0.1034O 0.0151 N 0.0211A
(MJ/kg) [29]. This correlation presents an absolute error of 1.5%. The
FTIR analyses were carried out using a Thermo Nicolet 380.