Armando Caldeira-Pires

Economic and Energy Performance of Brazilian Bagasse-Derived Ethanol:A Macro Perspective

The increase of global biofuel production is supported mainly by energetic policies adopted by important energy markets that aim to promote the production and use of biofuels, including the promising cellulosic-derived biofuels. Brazil is facing a challenge to attain sustainability in ethanol sector and to maintain its position as a major supplier of ethanol to world market in this new era of sustainable biofuel policies. In this paper we carried out a structural path analysis on sugarcane-derived ethanol sector and on a hypothetical bagasse-derived ethanol sector in order to identify the input paths that most influencing their economic and environmental performance. We make an empirical application to the Brazilian economy, using existing data from ethanol sector for 2005 and estimating data for the hypothetical sector. The fuel burned in the transport sector and on-site transport tasks is identified as important element for the environmental performance of both sectors. Also, sugarcane sector is identified to have relevant role in the economic performance of ethanol sector, as enzyme production has in second generation ethanol sector. The results present in this article can provide valuable information for decision-making in both biofuels to address new initiative for effective economic and environmental policies efforts.

Statistical Modelling of Temperature and Moisture Uptake of Biochars Exposed to Selected Relative Humidity of Air

New experimental techniques, as well as modern variants on known methods, have recently been employed to investigate the fundamental reactions underlying the oxidation of biochar. The purpose of this paper was to experimentally and statistically study how the relative humidity of air, mass, and particle size of four biochars influenced the adsorption of water and the increase in temperature. A random factorial design was employed using the intuitive statistical software Xlstat. A simple linear regression model and an analysis of variance with a pairwise comparison were performed. The experimental study was carried out on the wood of Quercus pubescens, Cyclobalanopsis glauca, Trigonostemon huangmosun, and Bambusa vulgaris, and involved five relative humidity conditions (22, 43, 75, 84, and 90%), two mass samples (0.1 and 1 g), and two particle sizes (powder and piece). Two response variables including water adsorption and temperature increase were analyzed and discussed. The temperature did not increase linearly with the adsorption of water. Temperature was modeled by nine explanatory variables, while water adsorption was modeled by eight. Five variables, including factors and their interactions, were found to be common to the two models. Sample mass and relative humidity influenced the two qualitative variables, while particle size and biochar type only influenced the temperature.

Mass and energy allocation method analysis for an oil refinery characterization using multi-scale modeling

PurposeThe goal of this study is to characterize a single oil refinery using a mass and energy multi-scale allocation method for 13 different fossil fuel-based products. This method structures a rigorous modeling and data collection approach to fill the gap that exists in traditional methods of life cycle assessment (LCA).MethodsThe refinery system’s information is used to subdivide a main process at different sub-process levels and obtain multi-scale information using calculated factors for the main process system’s raw material inputs and outputs. The analysis was performed using derived sub-models from an overall technological model that individually simulate the production of each final refinery product. Based on the technological models of the individual product refineries, the same environmental indicators identified for mass and energy allocation were calculated.Results and discussionWith this approach, it was possible to build a mass and energy LCA model of a fully parameterized refinery capable to accurately describe up to 98% the analyzed system. Incoming raw materials and effluents are weighted by specific factors calculated from the total of each principal process refining amount and the percentage outputs of the intermediate products. From a bottom-up approach, a primary data questionnaire was obtained with the total raw materials and waste quantities for each of the five key processes and their auxiliary processes. Information that previously appeared at the system (global refinery) and processes (main processes) level can now be accounted for in sub-process terms, thus allowing the monitoring information and environmental performance of the product and intermediate products to be found in a multiproduct system.ConclusionsThe refining sub-process’ environmental impact with regard to specific and intermediate products within the refinery processing steps was accurately estimated. This resulted not only in improvement of the property allocation but also in the identification of critical points in the processing steps, thus enabling optimization and innovation with regard to the processing lines and the refining process and producing a more efficient environmental impact analysis with great quality. The obtained formulations can be extended to more complex refining systems and other manufacturing processes.