Methods for measuring gas emissions from naturally ventilated livestock buildings: Developments over the last decade and perspectives for improvement

[EN] The objectives of this paper are: 1) to give an overview of the development of methods for measuring emission rates from naturally ventilated livestock buildings over the last decade, 2) to identify and evaluate strengths and weaknesses, 3) to summarise and conclude the current state-of-art of available measurement concepts and their perspectives for improvement. The methods reviewed include determination of concentration and air exchange rate separately, tracer gas ratio, passive flux samplers, flux chambers, and combined downwind measurement and dispersion modelling. It is concluded that passive flux samplers, flux chambers and combined measurement and dispersion modelling are useful, but for limited fields of application only and require further development and validation against reference methods. The most robust method to investigate emission rates available at this stage is the tracer gas ratio method, but improvements are required. They include more detailed estimates of CO2 release rates (when using CO2 as a tracer) and research into optimising dosing performance of tracer gas release systems. The reliability of tracer gas ratio methods applied in buildings with large ventilation openings needs to be improved by a more profound understanding of tracer-pollutant ratios and their spatial variability, and the development of improved sampling methods for concentration ratios. There is a need for a field reference method against which other methods can be evaluated. None of the diicussed measurement methods can be marked as a solid reference for all conditions; tracer gas ratio methods are the most likely candidate but need further improvement. (C) 2012 IAgrE. Published by Elsevier Ltd. All rights reserved.The contribution to this paper of N. Ogink and J. Mosquera was financially supported by the Netherlands Ministry of Infrastructure and Environment.Ogink, NWM.; Mosquera, J.; Calvet Sanz, S.; Zhang, G. (2013). Methods for measuring gas emissions from naturally ventilated livestock buildings: Developments over the last decade and perspectives for improvement. Biosystems Engineering. 116(3):297-308. https://doi.org/10.1016/j.biosystemseng.2012.10.005S297308116

Ammonia emissions from anaerobic swine lagoons : model development

Concentrated animal production may represent a significant source for ammonia emissions to the environment. Most concentrated animal production systems use anaerobic or liquid/slurry systems for wasteholding; thus, it is desirable to be able to predict ammonia emissions from these systems. A process model was developed to use commonly available measurements, including effluent concentration, water temperature, wind speed, and effluent pH. The developed model simulated emissions, as measured by micrometeorological techniques, with an accuracy that explains 70% of the variability of the data using average daily emissions and explains 50% of the variability of the data using 4-h average data. The process model did not show increased accuracy over a statistical model, but the deviations between model and measurement were distributed more evenly in the case of the process model than in the case of the statistical model

P-graph approach to planning biochar-based carbon management networks

Biochar application to soil is a potentially scalable carbon sequestration strategy. In practice, the amount of biochar that can be added to soil is constrained by the presence of contaminants such as salts, heavy metals, or dioxins. Process Systems Engineering (PSE) and Process Integration (PI) methods can be developed to optimize the reduction of greenhouse gas (GHG) emissions in such biochar-based Carbon Management Networks (CMNs). Previous works have proposed Mathematical Programming (MP) and Pinch Analysis (PA) approaches to the planning of these systems but are subject to the inherent methodological limitations. In this work, an alternative approach using Process Graph (P-graph) is developed, based on the source-sink matching problem being treated as a special Process Network Synthesis (PNS) problem. A case study is solved to illustrate the P-graph approach. In particular, optimal and near-optimal solutions are generated for the problem, which in real applications presents improved flexibility for purposes of practical decision support

P-graph approach to planning biochar-based carbon management networks

Biochar application to soil is a potentially scalable carbon sequestration strategy. In practice, the amount of biochar that can be added to soil is constrained by the presence of contaminants such as salts, heavy metals, or dioxins. Process Systems Engineering (PSE) and Process Integration (PI) methods can be developed to optimize the reduction of greenhouse gas (GHG) emissions in such biochar-based Carbon Management Networks (CMNs). Previous works have proposed Mathematical Programming (MP) and Pinch Analysis (PA) approaches to the planning of these systems but are subject to the inherent methodological limitations. In this work, an alternative approach using Process Graph (P-graph) is developed, based on the source-sink matching problem being treated as a special Process Network Synthesis (PNS) problem. A case study is solved to illustrate the P-graph approach. In particular, optimal and near-optimal solutions are generated for the problem, which in real applications presents improved flexibility for purposes of practical decision support. Copyright © 2018, AIDIC Servizi S.r.l

Synthesis of optimal and near-optimal biochar-based carbon management networks with P-graph

The application of biochar to soil is a potentially significant way to achieve negative net emissions. Photosynthesis fixes carbon from the atmosphere during plant growth; subsequently, pyrolysis stabilizes the carbon in biomass into recalcitrant form, which results in long-term storage when the carbonized product is put in soil. However, effective planning of such Biochar-based Carbon Management Networks is needed to ensure that benefits are maximized, and that adverse consequences are mitigated. The objective of this work is to develop a P-graph methodology for planning Biochar-based Carbon Management Networks, where pyrolysis plants act as sources, while the agricultural lands that receive the biochar act as sinks. Two problem variants are considered. In the first case study, the allocation of biochar is constrained by the presence of contaminants that exist naturally in the biomass or are formed during pyrolysis, such that only 72.5% of the available biochar is applied to soil. In the second case study, the distribution of biochar is limited both by the ultimate soil carbon limit, as well as annual application rates at each site; 88.9% of the available biochar is used in the optimal solution. The P-graph framework also generates near-optimal network topologies, which present alternative solutions that can be useful for the large-scale implementation of Biochar-based Carbon Management Networks. © 2019 Elsevier Lt