Use of biomass in domestic cookstoves leads to the release of oxides of nitrogen (NO<sub>x</sub>), nitric oxide (NO), nitrogen dioxide (NO<sub>2</sub>), carbon monoxide (CO) and hydrocarbons C&...Use of biomass in domestic cookstoves leads to the release of oxides of nitrogen (NO<sub>x</sub>), nitric oxide (NO), nitrogen dioxide (NO<sub>2</sub>), carbon monoxide (CO) and hydrocarbons C<sub>x</sub>H<sub>x</sub> that can be detrimental to health of the public and the environment. Attainment of complete combustion is the best strategy for mitigating the release of these emissions. This study sought to experimentally determine the effects of secondary air injection on the emission profiles of NO<sub>x</sub> (NO & NO<sub>2</sub>), CO and C<sub>x</sub>H<sub>x</sub> in a charcoal operated cookstove. Charcoal from Eucalyptus glandis was bought from Kakuzi PLC. Composites from three batches were analyzed for chemical composition and the stoichiometric air equivalent. Proximate analysis data show that the charcoal composed 58.72% ± 3.3% C, 15.95% ± 1.2% Volatile Matter, 4.69% ± 0.55% Moisture, 20.7% ± 0.8% Ash, High heat value (HHV) of 30.5 ± 1.1 and 29.3 ± 1.3 Low heat value (LHV) (MJ/kg) with a chemical formula of C<sub>18</sub>H<sub>2</sub>O and a stoichiometric air requirement of 5.28 ± 0.6 with a fuel flow rate of 1 kg fuel/hr. Emission profiles for CO and C<sub>x</sub>H<sub>x</sub> reduced significantly by 70% and 80% respectively with secondary air injection whereas those of NO<sub>x</sub> increased by between 15% and 20% for NO<sub>2</sub> and NO. The study reveals that secondary air injection has potential to mitigate on emission release, however other measures are required to mitigate NO<sub>x</sub> emissions.展开更多
Mesophilic biogas production and substrate decomposition is one of the significant limiting steps in biogas generation. The rate of generation and quality often affect the viability of biogas systems. This study asses...Mesophilic biogas production and substrate decomposition is one of the significant limiting steps in biogas generation. The rate of generation and quality often affect the viability of biogas systems. This study assessed the potential for biogas process catalysis using powdered Sorghum bicolor L., Zea mays, and Pennisetum glaucum. The kinetics and biogas generation processes were studied. Experiments were conducted in 1 m<sup>3</sup> tubular batch reactors, where batches were dosed with various organic biomolecules. Results show that the use of P. glaucum L. and S. bicolor L. reduced the biogas retention times significantly. Biogas generation commenced after the first day for digesters fed with S. bicolor L. and P. glaucum L. while one with Z. mays and control occurred on day two. The rate of biomethanation and methane content were enhanced. S. bicolor L. led to the highest methane content. Findings reveal that locally available organic biomolecules improved biogas quality and quantity.展开更多
文摘Use of biomass in domestic cookstoves leads to the release of oxides of nitrogen (NO<sub>x</sub>), nitric oxide (NO), nitrogen dioxide (NO<sub>2</sub>), carbon monoxide (CO) and hydrocarbons C<sub>x</sub>H<sub>x</sub> that can be detrimental to health of the public and the environment. Attainment of complete combustion is the best strategy for mitigating the release of these emissions. This study sought to experimentally determine the effects of secondary air injection on the emission profiles of NO<sub>x</sub> (NO & NO<sub>2</sub>), CO and C<sub>x</sub>H<sub>x</sub> in a charcoal operated cookstove. Charcoal from Eucalyptus glandis was bought from Kakuzi PLC. Composites from three batches were analyzed for chemical composition and the stoichiometric air equivalent. Proximate analysis data show that the charcoal composed 58.72% ± 3.3% C, 15.95% ± 1.2% Volatile Matter, 4.69% ± 0.55% Moisture, 20.7% ± 0.8% Ash, High heat value (HHV) of 30.5 ± 1.1 and 29.3 ± 1.3 Low heat value (LHV) (MJ/kg) with a chemical formula of C<sub>18</sub>H<sub>2</sub>O and a stoichiometric air requirement of 5.28 ± 0.6 with a fuel flow rate of 1 kg fuel/hr. Emission profiles for CO and C<sub>x</sub>H<sub>x</sub> reduced significantly by 70% and 80% respectively with secondary air injection whereas those of NO<sub>x</sub> increased by between 15% and 20% for NO<sub>2</sub> and NO. The study reveals that secondary air injection has potential to mitigate on emission release, however other measures are required to mitigate NO<sub>x</sub> emissions.
文摘Mesophilic biogas production and substrate decomposition is one of the significant limiting steps in biogas generation. The rate of generation and quality often affect the viability of biogas systems. This study assessed the potential for biogas process catalysis using powdered Sorghum bicolor L., Zea mays, and Pennisetum glaucum. The kinetics and biogas generation processes were studied. Experiments were conducted in 1 m<sup>3</sup> tubular batch reactors, where batches were dosed with various organic biomolecules. Results show that the use of P. glaucum L. and S. bicolor L. reduced the biogas retention times significantly. Biogas generation commenced after the first day for digesters fed with S. bicolor L. and P. glaucum L. while one with Z. mays and control occurred on day two. The rate of biomethanation and methane content were enhanced. S. bicolor L. led to the highest methane content. Findings reveal that locally available organic biomolecules improved biogas quality and quantity.
