A. García-Maraver

Analysis of the relation between the cellulose, hemicellulose and lignin content and the thermal behavior of residual biomass from olive trees.

The heterogeneity of biomass makes it difficult if not impossible to make sweeping generalizations concerning thermochemical treatment systems and the optimal equipment to be used in them. Chemical differences in the structural components of the biomass (cellulose, hemicellulose, and lignin) have a direct impact on its chemical reactivity. The aim of this research was to study the influence of the organic components of the raw material from olive trees (leaves, pruning residues, and wood) in the combustion behavior of this biomass, as well as to find the component responsible for the higher ash content of olive leaves. Accordingly, the study used a thermogravimetric analyzer to monitor the different states and complex transitions that occurred in the biomass as the temperature varied. The decomposition rates of the different samples were analyzed in order to establish a link between each combustion phase and the composition of the raw materials. Two methods were used to determine the hemicellulose and cellulose contents of biomass from olive trees. Significant differences among the results obtained by the different methods were observed, as well as important variations regarding the chemical composition and consequently the thermal behavior of the raw materials tested.

Effect of water washing on the thermal behavior of rice straw

Rice straw can be used as a renewable fuel for heat and power generation. It is a viable mean of replacing fossil fuels and preventing pollution caused by open burning, especially in the areas where this residual biomass is generated. Nevertheless, the thermal conversion of rice straw can cause some operating problems such as slag formation, which negatively affects thermal conversion systems. So, the main objective of this research is studying the combustion behavior of rice straw samples collected from various regions by applying thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). In addition, the thermal behavior of ashes from rice straw was also analyzed in order to detect their melting points, and ash sintering was detected at different temperatures within the range between 550 and 1000°C. Since washing rice straw with water could reduce the content of undesirable inorganic compounds related to the ash fusibility, samples of washed rice straw were analyzed under combustion conditions to investigate its differences regarding the thermal behavior of rice straw. The results showed that rice straw washing led to a significant improvement in its thermal behavior, since it reduced the ash contents and sintering formation.

Biomass Pelletization Process

The production of energy by means of biomass has shown a clear trend towards the use of pellets due to their homogeneous size, which facilitates handling and feeding while also reducing costs associated with storage and transportation. The pellet quality depends on the properties of the feedstock and on the operative variables of the densification process. Quality parameters can be modified by adapting the process to the raw material to be pelletized. Whereas wood pellets from forestry residues already have successfully established technologies and markets, there is a need to develop the pelletization of agricultural biomass, which is periodically planted and harvested, and holds great energy potential, especially in rural areas.

An index to quantify street cleanliness: The case of Granada (Spain)

Urban surfaces receive waste deposits from natural and human sources, which create a negative visual impact and are identified as potentially significant contributors to water and air pollution. Local councils are usually responsible for the sweep of roads and footpaths to keep the environment clean and free of litter. Quality controls are useful in order to check whether the services are being executed according to the quantity, quality and performance standards that are provided. In this sense, several factors might affect the efficiency of the management of cleaning and waste collection services; however, only a few contributions are available in the literature on the various aspects associated with the level of street cleanliness. In this paper, the suitability of a Cleanliness Index has been checked, for the case of Granada (South of Spain), in order to contribute to the proper management of public expenditure, improving the quality and cost of an essential service for any municipality. Results have concluded that the city exhibits a good level of cleanliness, although the standard of cleaning varied from one area of the city to another. The Cleaning Index fits well to the general situation of the different districts of Granada and thus, it could be considered a useful tool for measuring the level of cleanliness of the streets of the city and for evaluating the organization of the cleaning service, such that an outsourced company would not be responsible for controlling all the cleaning services.

Slagging And Fouling Risks Derived From The Combustion Of Solid Biofuels

The interest in biomass combustion has grown exponentially in the last years, as it represents a means of renewable heat and energy that also promotes local development and mitigates climate change. However, the slagging and fouling risks of many potential feedstocks, given their high alkali, silica or chlorine contents, currently limit their application in combustion processes. This chapter presents various methods for monitoring biomass slagging and predicting fouling hazard. Discussion also addresses how the presence of such components may affect the formation of deposits in biomass boilers.

Factors Affecting Pellet Quality

The quality of pellets depends on two general factors: (1) the characteristics of the raw material itself, directly related to its chemical composition and (2) the operative variables of the pelletization process, which influence the physical and mechanical properties of the pellets produced. A suitable combination of these two factors is necessary to obtain a qualified energy product. The European Union has established standards, guidelines and thresholds for solid biofuels in order that they can be properly used and marketed as renewable fuels.