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In this work is presented a repeatability study applied to a cookstove based on wood pellets gasification (19.03 MJ/kg). The analysis is carried out under a modified water boiling test (WBT 4.2.3). The repeatability of the gasification-based cookstove was assessed by means of two methodologies, such as the variation coefficient (CV, %) and the analysis of variance (ANOVA). The answer variables evaluated under repeatability were the efficiency (η, %), power (P, kW), fuel consumption (FC, g/min), fuel specific consumption (SFC, g/L), energy specific consumption (SFEC, kJ/L), and energy specific consumption per unit time (SFCT, kJ/L-min). By the CV analysis, the global average CV was 4.69% ± 0.87%. Therefore, as CV ≤ 5%, it is concluded that the gasification based cookstove is statistically repeatable. Concerning the ANOVA, the P-values of the variables studied were higher than 0.05 (P>0.05), thereby, it is stated that the improved cookstove is repeatable with a confidence level of 95%. Consequently, it is highlighted that the average thermal efficiency reached by the cookstove is ~29% ± 2.25%, with a confidence level of 95%. This thermal efficiency value is comparable with other biomass cookstoves based on gasification reported in the literature with values between 16 and 38%. The methodology and the results of this work constitute a theoretical foundation for assessing future developments of biomass cookstoves since the results reliability found in the prototypes tested at the laboratory level can be quantified and analyzed. [ABSTRACT FROM AUTHOR]

Biochar is the product from the decomposition of biomass, whose physicochemical characteristics are associated with its origin and the combustion method used. Among these properties, the surface area, the formation of macro and micropores, and the presence of functional groups are highlighted. Due to these characteristics, biochar becomes an alternative material with a high adsorption capacity for toxic compounds contained in polluted wastewater. This work provides information on the biochar generation mechanisms and how they interfere with its physicochemical characteristics. Likewise, the parameters involved in the pollutant removal processes are described, and the treatments under which the biochar can be subjected for its adsorption capacity to be improved are mentioned. Finally, the possible uses or the suitable final disposition that the biochar must have in order to contribute to the circular economy strategy are indicated. [ABSTRACT FROM AUTHOR]