Sandrina Pereira

Bio: Sandrina Pereira is an academic researcher from Instituto Superior Técnico. The author has contributed to research in topics: Energy supply & Bioenergy. The author has an hindex of 6, co-authored 7 publications receiving 127 citations.

Techno-economic analysis of a trigeneration system based on biomass gasification

Abstract: Biomass is one of the renewable energy sources (RES) with highest potential to contribute to the world's energy needs and can thereby play a key role in the path towards smart energy systems. Smart energy systems aim to integrate all energy sectors to increase the penetration of RES in the energy supply. Biomass gasification is a key technology to fulfil the goal of sustainable RES systems. Its main product (syngas) can be used as fuel, in various conversion technologies, to produce different products, including electricity, heat, cooling, biofuels and chemicals, which makes this technology an important tool for the energy system flexibility. Initially, the present manuscript reviews the relevant studies on the use of biomass gasification in trigeneration and polygeneration systems. Subsequently, it presents a case study that assesses the potential of the use of biomass gasification in an existing Portuguese trigeneration natural gas-fired plant located in Lisboa. The literature review revealed that most of the studies analysed are based on modelling data and not on experimental and/or pilot installations data. These studies show the environmental and energy added value of this type of system but stress the system's complexity and high investment costs. As for the case study, all scenarios considered show a negative net present value; nevertheless, the decrease of the biomass cost or the increase of the natural gas cost can turn financially feasible some scenarios.

Review of Pulverized Combustion of Non-Woody Residues

Abstract: The intense use of wood-derived fuels in (co)firing processes results in an enormous pressure on the forest. In order to alleviate this pressure and to proceed with the CO2 emissions reduction process, it is necessary to increase the use of non-woody residues, in particular herbaceous materials and agricultural residues. (Co)firing using such residues can cause a number of problems due to the presence of alkali metals, chlorine, and other ash-related impacts as well as corrosion of metallic surfaces and particulate matter emissions. This may limit the variety of biomass residues that can actually be used in (co)firing processes. This review aims to summarize recent developments in the combustion of pulverized non-woody residues and includes experimental and numerical studies of single particle combustion and combustion in small- and large-scale furnaces. The review provides an overview of the properties of non-woody residues, describes the existing research facilities to study the subject, and summarizes ...

Kinetics of Poplar Short Rotation Coppice Obtained from Thermogravimetric and Drop Tube Furnace Experiments

Abstract: This article concentrates on the kinetics of poplar short rotation coppice obtained from thermogravimetric and drop tube furnace (DTF) experiments. Three poplar samples were studied, specifically, clone AF8 from two different plantations, one located in Italy (AF8-I) and another located in Portugal (AF8-P), and clone AF2 from a plantation located in Portugal. Initially, the combustion behavior of the three clones was evaluated by thermogravimetry. For the devolatilization zone, the thermogravimetric experiments yielded apparent activation energies of 109.7, 117.7, and 118.6 kJ mol–1 for clones AF8-I, AF8-P, and AF2, respectively. For the char oxidation stage, the apparent activation energies were 267.4, 252.0, and 264.3 kJ mol–1 for clones AF8-I, AF8-P, and AF2, respectively. Subsequently, the combustion behavior of the clone AF8-I was examined in a DTF. The data reported includes gas temperature and particle burnout measured along the DTF for five wall temperatures (900, 950, 1000, 1050, and 1100 °C). Th...

Short rotation coppice for bioenergy: From biomass characterization to establishment – A review

Abstract: The co-firing of biomass with coal in power plants is an important way to reduce greenhouse gas (GHG) emissions and energy dependency and to ensure security of energy supply. The development of energy cultivations, namely the implementation of wood short rotation coppice (SRC) cultivations can represent an energy and environmental sustainable solution to provide biomass to the power plants and can foster the economic development of the regions where these cultivations will be implemented. A full knowledge of the combustion behaviour of the biomass is needed to optimize the co-firing process of biomass with coal. In this sense, it is important to critically review the relevant studies on the kinetics of the combustion and/or pyrolysis of woody biomass from SRC cultivations. Moreover, it is also important to critically assess the economic and technical feasibility of the implementation of wood SRC cultivations to produce bioenergy. These represent the two main objectives of this manuscript. The review revealed that data from two main experimental techniques are used to estimate the kinetic parameters of biomass combustion and pyrolysis – thermogravimetric analysis and drop tube furnaces. It can be also concluded that different methods can be used to estimate the kinetic parameters from these experimental data, namely model-fitting and model-free methods. Additionally, the review showed that the kinetic parameters depend on the biomass characteristics, on the experimental technique and on the method applied. In regard to wood SRC cultivations for bioenergy, it is concluded that they have a positive net energy, contribute to the reduction of GHG emissions, but its financial viability depends on subsidies or grants.

Climate change 2014 - Mitigation of climate change

Abstract: The talk with present the key results of the IPCC Working Group III 5th assessment report. Concluding four years of intense scientific collaboration by hundreds of authors from around the world, the report responds to the request of the world's governments for a comprehensive, objective and policy neutral assessment of the current scientific knowledge on mitigating climate change. The report has been extensively reviewed by experts and governments to ensure quality and comprehensiveness.

Catalytic thermochemical conversion of biomass for biofuel production: A comprehensive review

Abstract: The increasing demand for energy and diminishing sources of fossil fuels have called for the discovery of new energy sources. The effective energy conversion process of biomass is able to fulfill energy needs. Among the advanced biomass conversion technologies, thermochemical processes hold considerable potential approaches and needed for optimization. Thus, this study presents a comprehensive review of the research and development on the effects of catalysts on the thermochemical conversion of biomass to determine the progress of catalytic thermochemical conversion processes. The effects of catalysts on torrefaction, pyrolysis, hydrothermal liquefaction, and gasification are highlighted. Aspects related to reaction conditions, reactor types, and products are discussed comprehensively with the reaction mechanisms involved in the catalytic effects. Hydrogenation and hydrodeoxygenation can occur in the presence of zeolite catalysts during fast pyrolysis while producing highly aromatic bio-oil. A heterogeneous catalyst in liquefaction increases the hydrocarbon content and decreases viscosity, acid value, and oxygenated compounds in the bio-oil. Thus, expanding and enhancing knowledge about catalyst utilization in the thermochemical conversion technologies of biomass will play an important role in the generation of renewable and carbon-neutral fuels.