Cycle Greenhouse Gas Emissions Research Articles

Experimental Investigation of a Continuous Reactor for CO2 Capture and CaCO3 Precipitation

In a climate neutral world, the life cycle greenhouse gas (GHG) emissions of precipitated calcium carbonate (PCC) have to be reduced towards net-zero. Mineral carbonation processes allow to do so by replacing the carbon rich calcium source limestone by carbon free industrial mineral wastes. Various processes have been investigated in literature. They exhibit the benefit of little to no feedstock related emissions and high energy savings due to the avoidance of the CaCO3 calcination step. However, the nature of the process changes significantly, which requires a fundamental understanding of the new mechanisms controlling the process of CO2 absorption and CaCO3 precipitation. Within this work, a CO2 rich gas is contacted with a calcium rich aqueous feed in a continuous reactive crystallizor. The CO2 selectively absorbs and precipitates as either vaterite or calcite. The effect of the liquid and gas feed flow rates, of the feed stoichiometric ratio and of the residence time on key performance indicators, such as the CO2 capture efficiency the CaCO3 precipitation efficiency and the features of the final product, is studied experimentally. As expected, these feed characteristics determine the effective stoichiometric ratio of reactants in the liquid phase, ψ. The particle size increases strongly with ψ; vaterite represents the predominant solid phase at ψ < 1 while otherwise a mix of vaterite and calcite was formed, whereas the latter one accounted for 13%–90% in mass of crystals collected. Moreover, ψ of about one exhibits the highest CO2 capture efficiency exceeding 80%.

A case study on maintenance of bituminous concrete pavement considering life cycle cost analysis and carbon footprint estimation

Transport infrastructure has a huge impact on the social and economic scenario of any nation across the world. The selection of pavement maintenance should be based on sustainable concept meeting the sustainability and Long-term performance requirements. Bituminous concrete pavement maintenance with a bituminous concrete overlay is not a better option whereas the concrete overlay is having better performance across the globe. In this paper, an case study was conducted on a bituminous concrete pavement including its design, life cycle cost analysis and greenhouse gas emissions using life cycle approach with maintenance options of bituminous concrete overlay and a Ultra-thin cement concrete overlay. It is observed when compared with bituminous concrete overlay, the Ultra-thin white topping concrete overlay with sustainable materials is the better option as the life cycle cost analysis using net present value method greenhouse gas emission are little bit higher when compared with the other using life cycle analysis. The study concludes maintenance of bituminous concrete pavement with Ultra-thin white topping concrete overlay the inclusion of sustainable materials is the better option since it improves long-term performance of the pavement and further considering the economic and environmental point of view.

Economic and Environmental Optimisation Framework for Carbon Capture Utilisation and Storage Supply Chain

Carbon capture utilisation and storage (CCUS) is widely recognised as a key mitigation technology that can significantly reduce carbon dioxide (CO2) emission. This study develops an optimisation framework focused on the economic and environmental aspects of Northeast China CCUS supply chain. The overall network is economically optimised over a 20 years’ time horizon to provide the geographic location and scale of capture and sequestration sites as well as the most convenient transport routes. The resulting problem is a multi-objective mixed integer linear programming (MILP) problem, whose objectives include minimising its total annual cost and minimising life cycle greenhouse gas (GHG) emission. The economic and environmental performances are optimised by e-constraint method. To demonstrate the application of the proposed model, a realistic case study from Northeast China involving 16 sources and 3 sinks is illustrated. The results provide valuable insights to adopt more sustainable strategic alternatives in the design of CCUS supply chain.

Life Cycle Energy Consumption and Greenhouse Gas Emissions Analysis of Natural Gas-Based Distributed Generation Projects in China

In this paper, we used the life-cycle analysis (LCA) method to evaluate the energy consumption and greenhouse gas (GHG) emissions of natural gas (NG) distributed generation (DG) projects in China. We took the China Resources Snow Breweries (CRSB) NG DG project in Sichuan province of China as a base scenario and compared its life cycle energy consumption and GHG emissions performance against five further scenarios. We found the CRSB DG project (all energy input is NG) can reduce GHG emissions by 22%, but increase energy consumption by 12% relative to the scenario, using coal combined with grid electricity as an energy input. The LCA also indicated that the CRSB project can save 24% of energy and reduce GHG emissions by 48% relative to the all-coal scenario. The studied NG-based DG project presents major GHG emissions reduction advantages over the traditional centralized energy system. Moreover, this reduction of energy consumption and GHG emissions can be expanded if the extra electricity from the DG project can be supplied to the public grid. The action of combining renewable energy into the NG DG system can also strengthen the dual merit of energy conservation and GHG emissions reduction. The marginal CO2 abatement cost of the studied project is about 51 USD/ton CO2 equivalent, which is relatively low. Policymakers are recommended to support NG DG technology development and application in China and globally to boost NG utilization and control GHG emissions.

Carbon Footprint Analyses of Wastewater Treatment Systems in Puducherry

Carbon footprint analysis is a method to quantify the life cycle Greenhouse Gases (GHGs) emissions and identify the measure to reduce climate change impacts. The Intergovernmental Panel on Climate Change (IPCC) has identified that the global warming and climate change which is one of the most important issues in the domain of environment are caused by the excessive emission of Greenhouse Gases (GHG) mainly constituting Carbon dioxide (CO2), Methane (CH4) and Nitrous oxide (N2O). The municipal wastewater treatment plant receives wastewater for treatment and finally discharges the treated effluent. The emissions of GHG during the treatment of wastewater as well as during the treatment process of sludge and also for energy generation are known to be on-site GHG emissions. Off-site GHG emissions are generated due to transportation and disposal of sludge, off-site energy and chemical production. In Puducherry, the municipal wastewater is being treated using oxidation ponds, Upflow Anaerobic Sludge Blanket (UASB) and Sequencing Batch Reactor (SBR). Wastewater treatment using Sequencing Batch Reactor (SBR) technology is one of the state-of-the art wastewater management systems. In this technology equalization, biological treatment and secondary clarification are performed in a single reactor in a time control sequence. The emissions of GHG from the Oxidation ponds of 12.5 MLD, UASB reactor of 2.5 MLD and SBR of 17 MLD were assessed based on the IPCC guidelines and the total emissions of GHG in terms of equivalent of CO2 were compared. The performance of the SBR is more efficient and the emissions of GHG are less than the emissions in the UASB as well as in oxidation ponds. The emission of GHG in SBR is about 60% of the existing treatment systems of oxidation ponds and UASB thus a reduction of 40% GHG emission could be achieved.

Analysis on Influence Factors of Greenhouse Gas Emissions of Magnesium Production Process

Magnesium is a promising lightweight and green metallic engineering material, but the environmental impact of primary magnesium production stage, especially greenhouse gas (GHG) emissions cannot be ignored. In this study, the life cycle energy consumption and GHG emissions caused by the production of primary magnesium in the years of 2003-2013 in China were calculated; the factor decomposition was conducted to analyze the GHG emissions of magnesium production process by using logarithmic mean Divisia index method (LMDI), including energy GHG emission factors, energy structure, energy consumption per ton of primary magnesium, production, emissions per unit of dolomite and ferrosilicon, and dolomite and ferrosilicon consumptions per ton of primary magnesium. The results showed that GHG emissions of primary magnesium production increased 260.29*104 t CO2eq in total from 2003 to 2013. The variety magnesium production contributed the biggest part of GHG emissions, accounting for 418.17%. The energy structure took second place on the contribution of GHG emissions, accounting for-161.49%. The nest part was energy consumption per ton of primary magnesium, accounting for-138.97%. While, the contribution of energy GHG emission factors, emissions per unit of dolomite and ferrosilicon, and dolomite and ferrosilicon consumptions per ton of primary magnesium was relatively small, which were 0.88%, 0.00% -2.72% -4.73% and-11.13%, respectively. Thus, it is the key methods to reduce GHG emissions by optimizing the energy structure and decreasing the energy consumption.

Estimation of Carbon Footprints of Bituminous Road Construction Process

Carbon footprint is a term used to describe the total amount of carbon dioxide and other green house gas (GHG) emissions for which an individual/process/organization/activity is responsible. The challenge of global climate change has motivated state transportation agencies involved in the construction and maintenance of transportation infrastructure to investigate strategies that reduce the life cycle greenhouse gas (GHG) emissions associated with the construction and rehabilitation of highway infrastructure. The road sector is coming under pressure to review current practice and the potential to reduce carbon emissions. To reduce GHG emission, different approaches are adopted for road construction and maintenance such as Warm Mix and Cold Mix Technologies. Warm mix asphalt is produced at temperatures 20 to 40oC lower than hot mix asphalt (HMA). Cold Mix Asphalt is produced and paved at ambient temperature using bitumen emulsion. The immediate benefit of producing and placing asphalt mixes at a lower temperature is the reduction in energy consumption, greenhouse gas emissions, fumes, and odours generated at the plant and the paving site. The life cycle approach has been accepted as a robust method of measuring carbon footprint. Tools and data-sets have been developed to facilitate the measurement. Among them is the Calculator for Harmonised Assessment and Normalisation of Greenhouse-gas Emissions for Roads (CHANGER) developed by International Road Federation (IRF). This paper outlines the common methodology of road carbon foot printing, application of results in sustainable construction assessment schemes and resources available to undertake such analysis. Case studies of using CHANGER are provided in India for different technologies. The CO2 output of these projects is compared.

A method of production carbon footprint analysis in a supply chain based on life cycle assessment

As global warming becomes increasingly severe, environmental consciousness has become critical in the design and operation of globally integrated supply chain networks. Product Carbon Footprint is defined as the life cycle Greenhouse Gas (GHG) emissions of goods and services and it can be considered as a simplified life cycle assessment restricted to a single impact category. In order for companies to better confront GHG emission issues, calculating product carbon footprint and analysing how various parameters affect the carbon footprint over the entire life cycle of a product is necessary. This paper studies the carbon footprint across supply chains and proposes a method of production carbon footprint analysis in a supply chain based on life cycle assessment, including the following: taking product life cycle as the span of carbon footprint analysis, with all kinds of complex information system as objects and then carrying out the carbon footprint knowledge extraction according to the concept model format in physical database; building a carbon footprint analysis ontology, which is related to product life cycle in supply chain environment; calculating the quantification of carbon footprint through GHG emissions over the entire life cycle, and designing a tool for product carbon footprint in supply chain environment.

Energy Consumption and Greenhouse Gas Emission Studies of Jatropha Biodiesel Pathway by Life Cycle Assessment in India

In the present study, life cycle energy consumption, efficiency and greenhouse gas (GHG) emissions of Jatropha-based biodiesel was analysed by life cycle analysis method using GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transporta­tion) model. This study quantitatively explicates the life cycle energy saving and GHG emissions of Jatropha-derived biodiesel. The functional unit was defined as 1 mile distance driven by the vehicle and the fuel blend was about 20%. The results indicated that Jatropha biodiesel production and its usage in India have positive environmental performance at the current technical levels. Well-to-pump energy efficiency of Jatropha biodiesel production was found to be 75%. As compared with that of gasoline fuel, the use of 20% blended Jatropha biodiesel leads to the reduction of GHG emission about 22.3% and brings about energy saving 9%. Further improvement of production technology would reduce emissions and increase the energy saving markedly.

The life cycle energy demand and greenhouse gas emissions of high-capacity urban transport systems: A case study from Vienna's subway line U2

ABSTRACTThis article calculates the impact of three measures in order to reduce the global warming potential (GWP) and cumulative energy demand (CED) of Vienna's subway line U2. Results show that the increase of the train occupancy rate has the highest reduction impact (–30%/–30%), followed by new rolling stock (–26%/–34%), and a change in energy mix (–8%/–4%). The total reduction to be achieved with all measures combined is around –55% for GWP and CED, leading to a GWP of 91 [g] and 1.653 [MJ] per passenger kilometer traveled (PKT). With all these measures applied, the subway has lower GWP and CED than other modes of transport presented in the literature.

Reaching 10% renewable transportation fuels in 2020 by electric-vehicles in Styria/Austria

Electric-vehicles have the potential for a significant substitution of diesel and gasoline vehicles, and contribute to a reduction of greenhouse gas (GHG) and particulate matter emissions. According to the European Renewable Energy Directive, the share of renewable transportation fuels should be 10% in 2020. In the project “Styrian e-mobility in 2020” the potential for reaching the target of 10% renewable fuels in 2020 has been determined by analysing different implementation scenarios. Based on a life cycle analysis, GHG and particulate matter emissions from transport services have been calculated and their potential reductions in emissions by the introduction of electric vehicles by 2020 have been determined. Reaching the European target of 10% renewable fuels in the passenger car sector by 2020 is possible with 30,700 electric-vehicles (5% of passenger cars) if the share of the additional electricity is above 50% from renewable energy and the same amount of transportation biofuel of 7% used as today.

Impact of cultivation strategies and regional climate on greenhouse gas emissions from grass/clover silage

More than half the annual dry matter intake (DMI) of feed by dairy cows can be roughage. Its production and storage constitute a significant part of the life cycle greenhouse gas (GHG) emissions from milk production. This study estimated and analysed the impact of grass/clover silage production practices in five climatically different dairy production regions in Sweden on emitted GHG. GHG emissions calculated by the life cycle assessment method were 0.46–0.54 and 0.48–0.63 kg carbon dioxide equivalents per kg silage DMI for normal and higher silage nutrient quality, respectively. Crop cultivation for higher nutrient quality through an extra cut and increased nitrogen fertilisation rates increased GHG emissions by up to 16%. Varying the yield level by +/–20% decreased (11%)/increased (15%) GHG emissions per kg DMI. Improved management practices can reduce GHG emissions feed production, but accurate estimates of yield levels and feed losses are needed to reduce uncertainties.

The role of steel in reducing energy use and life cycle green house gas emissions

The role of steel in reducing energy use and life cycle green house gas emissions

The role of steel in reducing energy use and life cycle green house gas emissions

This article was submitted without an abstract, please refer to the full-text PDF file.

An analysis of a sustainable energy system taking resource depletion and environmental emissions into consideration

This paper aims at evaluating technologies to realise a sustainable energy system within the constraints of resources and environment. For this purpose, we first developed a database to estimate life cycle efficiencies and greenhouse gas emissions for various energy technologies. Then, on the basis of this life cycle assessment, we quantitatively define the concept of sustainability limitations on resource depletion and environmental emissions. From this concept, the present energy system of the world is judged to be unsustainable from both resource and environmental viewpoints. Then, various mitigation measures such as disposal of CO2 and solar power generation are evaluated utilising the concept. The evaluated result showed how sustainability influences cost–effectiveness of the measures. At the same time we clarified the key points to realise a sustainable energy scenario in ultra–long term.