Elias A. Christoforou

A review of olive mill solid wastes to energy utilization techniques.

In recent years, the utilization of olive industry by-products for energy purposes has gained significant research interest and many studies have been conducted focused on the exploitation of olive mill solid waste (OMSW) derived from the discontinuous or continuous processing of olive fruits. In this review study, the primary characteristics of OMSW and the techniques used to define their thermal performance are described. The theoretical background of the main waste-to-energy conversion pathways of solid olive mill wastes, as well as the basic pre-treatment techniques for upgrading solid fuels, are presented. The study aims to present the main findings and major conclusions of previously published works undertaken in the last two decades focused on the characterization of olive mill solid wastes and the utilization of different types of solid olive mill residues for energy purposes. The study also aims to highlight the research challenges in this field.

A review of quantification practices for plant-derived biomass potential.

The quantification of biomass potential is a useful task that may deem necessary under various circumstances. This study aims to identify the practices that have been followed in the recent past for the quantification of the plant-derived biomass potential. The employed methodology was based on an extensive literature review of recent studies in the field of biomass quantification. The review was classified in two fields: agriculture and crop residues potential, and forest residual potential. Within this study, the best quantification practices were collected and categorized and the main principles of plant-derived biomass quantification models were identified. Databases of typical properties of various types of biomass were established and a matrix of options for calculating biomass potential, depending on incoming data was delivered.

Multicriteria analysis for the selection of the most appropriate energy crops: the case of Cyprus

Energy crops are considered key actors in meeting the international and European carbon reduction targets, increasing the national energy security through renewable energy production, mitigating climate change impacts, and promoting sustainability. Multicriteria analysis is a suitable decision-making tool for the energy sector, where the final decisions have to consider for a range of aspects, and can be utilised as well for deciding on appropriate energy crops. In this paper, a popular multicriteria method, PROMETHEE, is employed for the identification of the most optimal energy crops for their exploitation in Cyprus. The criteria and the weights of each are defined, and accordingly five different scenarios are developed and examined. The obtained results indicated that the promotion of second-generation energy crops is more ideal in terms of the set objectives, as well as more sustainable than the exploitation of any first-generation energy crop.

Monte Carlo parametric modeling for predicting biomass calorific value

Due to the nonlinear relationship between the calorific value and the elemental concentration of biomass, methods such as linear regression, widely used in the literature to model this relationship, produce models that fail to provide well-grounded results. In this study, a novel approach, based on Monte Carlo parametric modeling, for calculating the calorific value of biomass from measurements provided by elemental analysis, is presented. Olive husk, a biomass source widely used in the Mediterranean basin, was the subject under investigation. A comprehensive analysis of the thermal properties of olive husk was conducted. The elemental analysis, as well as the calorific value, the moisture content the sampling and the preparation of the examined biomass were performed using the appropriate CEN standards and procedures. Based on the Monte Carlo parametric modeling, the parameters of an exponential model linking the elemental analysis and the calorific value of olive husk were estimated. This study is anticipated to provide further insight to the discussion on models for predicting the calorific value of biomass, by introducing a novel mathematical approach.

Techno-Economic Study and Environmental Assessment of Food Waste Based Biorefinery

Sustainability consists of three major components, namely economic, ecological and social impacts. The most important driver for food waste based biorefinery is whether the proposed design is profitable. The development of highly efficient and cost-effective biorefineries is a prerequisite for such a bio-based economy. There are many factors that influence the overall costs and returns of the food waste based biorefinery process, and affect the overall economic performance as well. In this chapter, the economic and environmental impacts of food waste based biorefinery is evaluated by using Techno-economic Study and Life Cycle Assessment (LCA) in terms of non-renewable energy use (NREU) and greenhouse gases (GHG) emission. Special focus on the economics of Green Chemistry, and the current status of LCA studies on succinic acid and thermochemical processes for biomass conversion to biofuels are covered.

Life cycle sustainability assessment of biofuels

Abstract Sustainable bioenergy production can be considered a key issue in the global effort for the mitigation of greenhouse gas (GHG) emissions and effects of climate change. A holistic investigation of the supply chain and the production routes of biofuels is required in order to accomplish sustainable processes. This analysis should consider technical, economic, and environmental issues regarding the production of raw biomass, the applied conversion technologies, as well as end-product distribution and use. While the technical and economic aspects can be quantified by means of well-established physics and finance techniques, the quantification of the environmental impact has always been a complex task. The numerous environmental aspects, as well as the different methodologies of their analysis, have resulted, in previous years, in a scientific Babel Tower. Life-Cycle Assessment (LCA), a technique introduced in the 1960s and established since the 1990s, presents a comprehensive methodology for the quantification of the environmental impact of processes, including biofuel production, as well as being as a reliable decision-making tool.