Estimation of Landfill Gas and Its Renewable Energy Potential from the Polesgo Controlled Landfill Using First-Order Decay (FOD) Models

Methane generation in landfills and its inadequate management represent the major avoidable source of anthropogenic methane today. This paper models methane production and the potential resources expected (electrical energy production and potential carbon credits from avoided CH4 emissions) from its proper management in a municipal solid waste landfill located in Ouagadougou, Burkina Faso. The modeling was carried out using two first-order decay (FOD) models (LandGEM V3.02 and SWANA) using parameters evaluated on the basis of the characteristics of the waste admitted to the landfill and weather data for the site. At the same time, production data have been collected since 2016 in order to compare them with the model results. The results obtained from these models were compared to experimental one. For the simulation of methane production, the SWANA model showed better consistency with experimental data, with a coefficient of determination (R²) of 0.59 compared with the LandGEM model, which obtained a coefficient of 0.006. Thus, despite the low correlation values linked to the poor consistency of experimental data, the SWANA model models methane production much better than the LandGEM model. Thus, despite the low correlation values linked to the poor consistency of the experimental data, the SWANA model models methane production much better than the LandGEM V3.02 model. It was noted that the poor consistency of the experimental data justifies these low coefficients, and that they can be improved in the future thanks to ongoing in situ measurements. According to the SWANA model prediction, in 27 years of operation a biogas plant with 33% electrical efficiency using biogas from the Polesgo landfill would avoid 1,340 GgCO2e. Also, the evaluation of revenues due to electricity and carbon credit gave a total revenue derived from methane production of US$27.38 million at a cost of US$10.5/tonne CO2e.

Review on Thermocline Storage Effectiveness for Concentrating Solar Power Plant

In this paper, a literature review on thermocline storage performance for Concentrating Solar Power (CSP) plant storage systems has been conducted. The efficiency of materials to store heat depends on the storage process like sensible heat storage, latent heat storage and thermochemical one and also on their properties. This study has been focused on sensible heat storage materials especially thermocline storage system (DMT) using eco-materials which has a high potentiality (35%) to reduce CSP cost. There is a possibility to use natural rocks, industry waste and to develop also materials for a thermocline storage within a bed called packed bed using one tank. The thermal storage materials should have some optimum parameters (particle diameter less than 2 cm and good thermo-physical properties) to achieve better thermal storage performance (thermal cycle efficiency, extraction factor). However, the size and the shape of natural rocks are uncontrollable (big diameter) and can drive to thermocline degradation, catastrophic thermal ratcheting and poor thermal stratification due to the variability of the storage system porosity and the stress on the storage tank wall. Also a better thermal storage efficiency is achievable at low velocity and with good thermo-physical properties of the HTF. The ratio H/D, the height, the porosity, the shape and the position of the tank should be optimized to increase the storage efficiency.

Evaporation and Combustion of a Drop of Liquid Fuel—A Review

The accelerated depletion of oil reserves and the often exorbitant cost of fossil fuels contribute to the development of fuels from renewable sources. The objective of this work is to analyze the influence of the properties of renewable fuels on their evaporation in natural convection, their combustion and their use in internal combustion engines. A summary of the various numerical and experimental works from the literature has been presented in this work. This work focuses on the numerical modelling of the natural convection evaporation of an isolated drop of a liquid fuel in natural convection. The transfers in the liquid and vapour phases are described by the conservation equations of mass and species, momentum and energy. The main feature of this work is the consideration of advection, azimuthal angle and thickness of the vapour phase of the drop during evaporation of the drop.