Atmospheric Chemistry Modelling of Amine Emissions from Post Combustion CO2 Capture Technology

Emissions from post combustion CO2 capture plants using amine solvents are of concern due to their adverse impacts on the human health and environment. Potent carcinogens such as nitrosamines and nitramines resulting from the degradation of the amine emissions in the atmosphere have not been fully investigated. It is, therefore, imperative to determine the atmospheric fate of these amine emissions, such as their chemical transformation, deposition and transport pathways away from the emitting facility so as to perform essential risk assessments. More importantly, there is a lack of integration of amine atmospheric chemistry with dispersion studies. In this work, the atmospheric chemistry of the reference solvent for CO2 capture, monoethanolamine, and the most common degradation amines, methylamine and dimethylamine, formed as part of the post combustion capture process are considered along with dispersion calculations. Rate constants describing the atmospheric chemistry reactions of the amines of interest are obtained using theoretical quantum chemistry methods and kinetic modeling. The dispersion of these amines in the atmosphere is modeled using an air-dispersion model, ADMS 5. A worst case study on the UK's largest CO2 capture pilot plant, Ferrybridge, is carried out to estimate the maximum tolerable emissions of these amines into the atmosphere so that the calculated concentrations do not exceed guideline values and that the risk is acceptable

Life cycle assessment of recycling options for automotive Li-ion battery packs

Ramping up automotive lithium-ion battery (LIB) production volumes creates an imperative need for the establishment of end-of-life treatment chains for spent automotive traction battery packs. Life Cycle Assessment (LCA) is an essential tool in evaluating the environmental performance of such chains and options. This work synthesises publicly-available data to expand upon previously reported LCA studies for LIB recycling and holistically model end-of-life treatment chains for spent automotive traction battery packs with lithium nickel cobalt manganese oxide positive electrodes. The study provides an in-depth analysis of unit process contributions to the environmental benefits and burdens of battery recycling options and integrates these with the battery production impacts to estimate the net environmental benefit achieved by the introduction of recycling in the value chain. The attributional LCA model accounts for the whole recycling chain, from the point of end-of-life LIB collection to the provision of secondary materials for battery manufacturing. Pyrometallurgical processing of spent automotive traction battery cells is predicted to have a larger Global Warming Potential (GWP), due to its higher energy intensity, while hydrometallurgical processing is shown to be more environmentally beneficial, due to the additional recovery of lithium as hydroxide. The majority of the environmental benefits arise from the recovery of aluminium and copper fractions of battery packs, with important contributions also arising from the recovery of nickel and cobalt from the battery cells. Overall, the LCA model presented estimates a net benefit in 11 out of 13 environmental impact categories based on the ReCiPe characterisation method, as compared to battery production without recycling. An investigation of the effect of geographic specificity on the combined production and recycling indicates that it is as a key source of GWP impact variability and that the more climate burdening chains offer a significantly higher potential for GWP reductions through battery recycling. The sensitivity analysis carried out shows that impacts related to air quality are higher when recovering lower grade materials. This study provides a quantitative and replicable inventory model which highlights the significance of the environmental benefits achieved through the establishment of circular automotive battery value chains

Development of a life cycle assessment tool for the assessment of food production systems within the energy, water and food nexus

© 2015 The Institution of Chemical Engineers.As the demand for services and products continues to increase in light of rapid population growth, the question of energy, water and food (EWF) security is of increasing importance. The systems representing the three resources are intrinsically connected and, as such, there is a need to develop assessment tools that consider their interdependences. Specifically when evaluating the environmental performance of a food production system, it is necessary to understand its life cycle. The objective of this paper is to introduce an integrated energy, water and food life cycle assessment tool that integrates EWF resources in one robust model and at an appropriate resolution. The nexus modelling tool developed is capable of providing an environmental assessment for food production systems utilising a holistic systems approach as described by a series of subsystems that constitute each of the EWF resources. A case study set in Qatar and characterised by an agriculture sub-system, which includes the production and application of fertilisers and the raising of livestock, a water sub-system represented by mechanical and thermal desalination processes and an energy sub-system, which includes fossil fuel in the form of combined cycle natural gas based energy production and solar renewable energy is used to illustrate the model function. For the nexus system analysed it is demonstrated that the food system is the largest contributor to global warming. The GWP can be reduced by up to 30% through the utilisation of solar energy to substitute fossil fuels, which, however, comes with a significant requirement for land investment

Gas-driven rapid fracture propagation and gas outbursts under unloading conditions in coal seams

Copyright © 2018 ARMA, American Rock Mechanics Association. Coal and gas outbursts have long posed a serious risk to safe and efficient production in coal mines. It is recognised that the coal and gas outbursts are triggered by excavation unloading followed by gas-driven rapid propagation of a system of preexisting or mining-induced fractures. Gas-filled fractures parallel to a working face are likely to experience opening first, then expansion and rapid propagation stages under unloading conditions. This research aimed to identify the key factors affecting outburst initiation and its temporal evolution during roadway developments. Specifically, the response of pre-set fractures in a coal seam sandwiched between rock layers to roadway development is simulated using a geomechanical model coupled with fracture mechanics for fracture opening and propagation. In addition, kinetic gas desorption and its migration into open fractures is considered. During simulations outburst is deemed to occur when the fracture length exceeds the dimension of a host element. The findings of this research suggests that the simulated coal and gas outburst may be considered as a dynamic gas desorption-driven fracture propagation process. The occurrence of coal and gas outbursts is found to be influenced mainly by the coal properties, fracture attributes, and initial gas pressure and the in situ stress conditions

Discrete element modelling of hydraulic fracture interaction with natural fractures in shale formations

Research presented in this paper aimed at establishing a better understanding of natural fracture (NF)/hydraulic fracture (HF) interaction mechanisms and fracture network development in naturally fractured and nonhomogeneous shale formations through numerical modelling using the two-dimensional particle flow code (PFC2D). Hydraulic fracture propagation was firstly modelled in a 30 m x 30 m model representing intact rock by bonded particle method (BPM), which served as a base case in the research. Then a single, deterministic natural fracture was embedded into the same model by a smooth joint contact model (SJM) to investigate different NF/HF interaction mechanisms under a range of different conditions by varying the angle of approach, differential horizontal stress, and the mechanical properties of a fracture within the model. Based on the parametric research findings, number and diversity of natural fractures in the model were increased both deterministically and stochastically, and the results are compared and discussed

Multiple-panel longwall top coal caving induced microseismicity: Monitoring and development of a statistical forecasting model for hazardous microseismicity

Continuous microseismic monitoring was carried out around 9 producing longwall top coal caving (LTCC) panels with concurrently recorded daily face advance rates at Coal Mine Velenje in Slovenia over a 27-month monitoring period. The monitoring results suggested that spatial and magnitude characteristics of microseismicity are dominated by those of underlying fractures, while microseismic event rate is under the combined effects of local natural fracture abundance and mining intensity. On this basis, a data-driven yet physics-based forecasting methodology was established for LTCC induced hazardous microseismicity, which is above a given threshold of energy magnitude and within a certain distance to the longwall face. Statistical analyses were first conducted to characterise temporal, magnitude and spatial characteristics of long-term recorded microseismicity, based on which a short-term forecasting model was developed to calculate the probability of hazardous microseismicity considering the three characteristics. The model developed was employed to forecast the likelihood of hazardous microseismicity at one of these LTCC panels, and the forecasted results were supported by the monitoring. This statistical model has important implications in the evaluation of mining-induced hazards, and it can be used to optimise longwall face advance rates to minimise the risk of hazardous microseismicity in burst-prone deep-level mining sites

Parametric analysis of slotting operation induced failure zones to stimulate low permeability coal seams

The main constrain for effective gas drainage in coal mines is the low permeability nature of coal reservoirs. As coal mining activities are extending to deeper subsurface, the ever-increasing in situ stress conditions is anticipated to result in much lower permeability and more challenges for gas emission control in coal mines. In recent years, hydraulic slotting using high-pressure waterjet along underground gas drainage boreholes, as a general solution to stimulate low permeability coal seams, has become increasingly favourable. This paper presents a systematic investigation into the sensitivity of borehole slotting performance to a number of field and operational parameters. A wide range of geomechanical properties, in situ stress conditions, slot geometry and spacing of multiple slots were considered in a series of numerical simulations. The relations between these key parameters and the failure zone size/volume induced by slotting were quantified. The effect of different parameters in improving slotting performance has also been ranked, which provides theoretical base for mine operators to optimise slotting operations

Gas-driven rapid fracture propagation under unloading conditions in coal and gas outbursts

Coal and gas outbursts have long posed a serious risk to safe and efficient production in coal mines. It is recognised that coal and gas outbursts are triggered by excavation unloading followed by gas-driven rapid propagation of a system of pre-existing or mining-induced fractures. Gas-filled fractures parallel to a working face are likely to experience opening first, then expansion and rapid propagation stages under unloading conditions. The fracture opening is driven by the effective stress inside the fracture, while the fracture expansion and rapid propagation is propelled by the pressure build-up of desorbed gas in the vicinity of the fracture. Based upon this understanding, this research aimed to identify the key factors affecting outburst initiation and its temporal evolution during roadway developments. Specifically, the response of pre-set fractures in a thin coal seam sandwiched between rock layers to roadway development is simulated using a geomechanical model coupled with fracture mechanics for fracture opening and propagation. In addition, kinetic gas desorption and its migration into open fractures is considered. During simulations outburst is deemed to occur when the fracture length exceeds the dimension of a host element. The findings of this research suggest that the simulated coal and gas outburst caused by roadway development may be considered as a dynamic gas desorption-driven fracture propagation process. The occurrence of coal and gas outbursts is found to be influenced mainly by the coal properties, fracture attributes, and initial gas pressure and the in situ stress conditions. Furthermore, the model predictions in terms of dome-shaped erupted-zone and layer-by-layer coal breakage are consistent with the field reports. In addition, the model results suggest that delayed occurrence of coal and gas outbursts, especially after sudden exposure of a coal seam or after blasting disturbance, reported in the literature may be related to the gas desorption behaviour

Mediterranean Diet and Workplace Health Promotion

Analytical and experimental studies confirm relationships between the consumption of certain foods and cardiovascular disease, diabetes, and cancer. Mediterranean diet patterns have long been associated with a reduced risk of major diseases and many favorable health outcomes. Data from observational, longitudinal, and randomized controlled trials have demonstrated that Mediterranean-style diets can improve body mass index and body weight, reduce the incidence of diabetes mellitus and metabolic syndrome risk factors, decrease cardiovascular morbidity and coronary heart disease mortality, as well as decrease all-cause mortality. Recently, efforts have attempted to improve dietary habits in the workplace, by modifying food selection, eating patterns, meal frequency, and the sourcing of meals taken during work. Evidence supporting the Mediterranean diet and the potential cardioprotective role of healthier diets in the workplace are reviewed here, and promising strategies to improve metabolic and cardiovascular health outcomes are also provided