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A study of the pyrolysis and gasification of biomass residues such as oil palm shells and fibers,
coffee shells, sugarcane bagasse and beech wood is presented. All of them are abundant
agroindustrial biomass residues in Latin American countries.
The characterization of the raw materials and products includes proximate analysis (water, ash and
volatile matter contents) and ultimate analysis. Pyrolysis and gasification experiments are carried out
in a thermobalance and in a pilot scale rotary kiln reactor. Both facilities are equipped with evolved
gas analysis.
Pyrolysis experiments were carried out using nitrogen as carrier gas by heating up to a temperature
of 950 °C. Gasification is performed using water vapour as reaction agent in a concentration of 70 %
H2O in nitrogen. The gasification temperature is set to 850 °C.
All wastes show similar behavior during pyrolysis in the thermobalance with the main mass loss at
temperatures below 550 °C. The solid fraction varied from 18 % for sugarcane bagasse to 27 % for
oil palm shells and the gas fraction from 18 % for oil palm shells to 22 % for sugarcane bagasse.
The main evolved gases are CO2 (9 – 12%), CO (3.5 – 7.5 %) and CH4 (1.6 – 3 %). H2 was also
found but in a very small fraction (0.5 – 0.7 %) (all fractions are referred to the initial dry mass). The
heating value of the pyrolysis products from the experiments in the thermobalance of the different
wastes presented small variations with a mean value of 6.5 MJ kg-1 for the evolved gas, 20 MJ kg-1
for the tar and 19 MJ kg-1 for the solid residual.
The presence of secondary reactions in the rotary kiln affects considerably the amount of gas and
tar in the products. The higher heating value of the evolved gases varies between 17 and19 MJ kg-1.
The obtained results allow a possible further technological use of these materials as a cheap
renewable energy source in countries where these materials can be found.

In the present work, premixed flames from the combustion of producer gas have been analyzed.
Two different compositions have been tested, corresponding to air and steam gasification processes
(the latter leading to a better quality gas due to its higher CO and H2 concentration and its lower N2
content). The main objectives of the work have been the determination of the flame stability region
(placed between the flashback and the blowoff limits) for each producer gas composition, as well as
the study of the OH and CH radicals. The combustion experimental tests have been carried out by
using an atmospheric burner and a chemiluminescence camera.
The results obtained show that producer gas coming from biomass entrained-flow steam gasification
seems to be more adequate to be used in combustion systems, since it provides a larger flame
stability region, and its blowoff limit for a given relative producer gas/air ratio is higher (which enable
to obtained more power). From the study of CH and OH radicals, it can be deduced that it is possible
to reduce the nitrogen oxides emissions up to 18.6 and 15.2 % with producer gas from steam
gasification and air gasification respectively by using lean mixtures (while keeping the flame
stability).

In recent years many researchers show a high interest in co-digestion, simultaneous anaerobic
decomposition of a homogenous mixture of at least two biodegradable waste. Anaerobic codigestion
is reported to offer several benefits over digestion of separate materials, such as increased
cost-efficiency, increased biodegradation of the treated materials, as well as increased biogas
production. Most often sewage sludge is digested alone while co-digestion with other substrates
could be beneficial.
In this study, the feasibility of co-digestion sewage sludge and grease trap waste (GTW) from meatprocessing
plant was investigated in lab-scale reactor experiment. The research was made on the
sewage sludge coming from municipal wastewater treatment plant and grease trap waste coming
from meat industry company. Anaerobic co-digestion was studied in semi-continuous experiment at
37oC. Feeding of reactors was performed once a day with hydraulic retention time (HRT) of 10 days.
The grease trap waste accounted for 2, 4, 6, 8 and 10 % of the mixture on the volatile solids basis.
The mixtures were analyzed for the following parameters: total solids, volatile solids, pH, volatile
fatty acids and long chain fatty acids (LCFAs). The control of digestion process was made every day
on the basis of the measurement of the biogas production. What is more, there was determined the
volatile solid removal as well the biogas yield in order to assess the efficiency of co-digestion
process.
It was found that co-digestion of sewage sludge and grease trap waste improved both biogas
production and methane content. Grease trap waste addition of 10% of feed VS increased the
biogas production by 16 % as well as methane concentration (72 % of biogas) compared to the
period when reactor was feed only with sewage sludge. Moreover, the addition of GTW to the
anaerobic digestion of sewage sludge increased organic matter removal.
Although, the significant variations in LCFAs reduction, the biogas production and methane yield
increased with higher addition of GTW.
The results of the present laboratory study revealed that the use of GTW as a co-substrate is
considered to be interesting option for sewage sludge digestion due to increased methane
production. However, the feed should be planned carefully with stepwise increase to the desired
feed ratio in order to acclimatize the bacteria and to prevent reactor overloading.

Analysis and simulation of the behaviour of gas turbines for power generation using different nonconventional
fuels obtained from different renewable sources are presented. Three biomass-tobiofuel
processes are considered: anaerobic digestion of biomass (biogas), biomass gasification
(synthesis gas) and alcoholic fermentation of biomass and dehydration (bioethanol), each of them
with two different biomass substrates (energy crops and municipal solid waste) as input.
The gas turbine behaviour in a Brayton cycle is simulated both in an isolated operation and in
combined cycle. The differences in gas turbine performance when fired with the considered biofuels
compared to natural gas are studied from different points of view related with the current complex
energetic context: energetic and exergetic efficiency of the simple/combined cycle and CO2
emissions. Two different tools have been used for the simulations, each one with a different
approach: while PATITUG (own software) analyses the behaviour of a generic gas turbine allowing a
total variability of parameters, GT-PRO (commercial software) is more rigid, albeit more precise in
the prediction of real gas turbine behaviour. Different potentially interesting configurations and its
thermodynamic parameters have been simulated in order to obtain the optimal range for all of them
and its variation for each fuel.