Abstract

Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People’s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and Cn Hm of electrified railways, and analyzed their dynamic characteristics during the period of 1975–2007. The results show that during this period, the annual mean values of energy saving is 1.23×106 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and Cn Hm are 4.267×106 t, 20.5×103 t, 3.0×103 t, 9.6×103 t, 67.9×103 t, and 6.9×103 t per year, respectively. The annual average increasing rates of energy saving is 139×103 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and Cn Hm are 483×103 t, 2.3×103 t, 0.34×103 t, 1.1×103 t, 7.7×103 t and 0.78×103 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China’s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China’s railway transportation. He, J., and Y. Xu, 2011: Energy saving and emission reduction estimations of electrified railways in China. Adv. Clim. Change Res., 2 (4), doi:10.3724/SP.J.1248.2011.00211.

Abstract

Three total column dry-air mole fractions of CO2 (XCO2 ) products from satellite retrievals, namely SCIAMACHY, NIES-GOSAT, and ACOS-GOSAT, in the Northern Hemisphere were validated by ground data from the Total Carbon Column Observing Network (TCCON). The results showed that the satellite data have the same seasonal fluctuations as in the TCCON data, with maximum in April or May and minimum in August or September. The three products all underestimate the XCO2 . The ACOS-GOSAT and the NIES-GOSAT products are roughly equivalent, and their mean standard deviations are 2.26 × 10−6 and 2.27 × 10−6 respectively. The accuracy of the SCIMACHY product is slightly lower, with a mean standard deviation of 2.91 × 10−6 .

Abstract

This paper reviews the CO2 emissions data for China provided by various international organizations and databases (namely IEA, BP, EDGAR/PBL/JRC, CDIAC, EIA and CAIT) and compares them with China’s official data and estimation. The difference among these data is due to different scopes, methods and underlying data, and particularly the difference in fossil fuel consumption. Compared with data from other databases, IEA and CAIT data have the best comparability with China’s official data. The paper recommends that China enhance its coal statistics, raise the frequency of official data publication and improve the inventory completeness. Zhu, S.-L., 2014: Comparison and analysis of CO2 emissions data for China. Adv. Clim. Change Res ., 5(1), doi: 10.3724/SP.J.1248.2014.017.

Abstract

International audience; The scale of proposed carbon dioxide (CO2) capture and storage (CCS) chains also draws attention to the hazards posed by the transport mode, enabling the link from source to sink. As such, the adverse consequences of an accidental release from transport pipelines or other equipment containing CO2 at high pressure in a dense-phase (supercritical or liquid) state are (re)considered in theory and in practice. Several experimental observations of large-scale CO2 releases have been made, and yet the physics and thermodynamics involved are not fully understood. The work presented here provides a database focused on the specificities of the release and the dispersion of the carbon dioxide cloud in case of substantial variations of storage (temperature and pressure) and discharge conditions (nozzle size). Document type: Conference object

Abstract

This paper presents a review of research and models regarding sustainability of railway passenger services. In order to take into account all relevant aspects in terms of environmental impacts of a railway passenger service, a holistic system perspective is required, that includes a whole life cycle assessment. A life cycle approach is important since comparison of for instance only the exhaust emissions of an electric vehicle with a petrol vehicle is misleading, due to neglecting the emissions of for instance electrical energy production process. Thus, all stages in energy carrier, vehicle and infrastructure life cycles are to be considered. Existing models are analyzed, as well as possible developments, focusing on diesel and electrical traction as the most common traction options in use, and on GHG emissions, especially on CO2, which takes the greatest part in all emissions. Issues and challenges in improving the environmental impact of railway passenger services are addressed. Additionally, several areas are indicated where environmental aspects could be included in future assessment models. The main challenge is answering how the existing partial assessments can be brought together and, together with filling the identified gaps, allow to conduct a comprehensive LCA which will produce real-world emissions estimations. Results of this paper will be used as an input in developing a framework for quantifying and improving overall environmental impacts of a railway passenger service.

Abstract

International audience; Without a clear understanding of the hazards associated with the failure of CO2 pipelines, carbon capture and storage (CCS) cannot be considered as a viable proposition for tackling the effects of global warming. Given that CO2 is an asphyxiant at high concentrations, the development of reliable validated pipeline outflow and dispersion models are central to addressing this challenge. This information is pivotal to quantifying all the hazard consequences associated with the failure of CO2 transportation pipelines, which forms the basis for emergency response planning and determining minimum safe distances to populated areas. This paper presents an overview of the main findings of the recently completed CO(2)PipeHaz project [1] which focussed on the hazard assessment of CO2 pipelines to be employed as an integral part of CCS. Funded by the European Commission FP7 Energy programme, the project's main objective was to address this fundamentally important issue. Document type: Conference object

Abstract

This paper presents a review of research and models regarding sustainability of railway passenger services. In order to take into account all relevant aspects in terms of environmental impacts of a railway passenger service, a holistic system perspective is required, that includes a whole life cycle assessment. A life cycle approach is important since comparison of for instance only the exhaust emissions of an electric vehicle with a petrol vehicle is misleading, due to neglecting the emissions of for instance electrical energy production process. Thus, all stages in energy carrier, vehicle and infrastructure life cycles are to be considered. Existing models are analyzed, as well as possible developments, focusing on diesel and electrical traction as the most common traction options in use, and on GHG emissions, especially on CO2, which takes the greatest part in all emissions. Issues and challenges in improving the environmental impact of railway passenger services are addressed. Additionally, several areas are indicated where environmental aspects could be included in future assessment models. The main challenge is answering how the existing partial assessments can be brought together and, together with filling the identified gaps, allow to conduct a comprehensive LCA which will produce real-world emissions estimations. Results of this paper will be used as an input in developing a framework for quantifying and improving overall environmental impacts of a railway passenger service.

Abstract

CO2 captured from fossil-fueled power generation plants is said to be economically transported via pipelines over long distances. The CO2 must be compressed to pipeline specifications using compressors and pumps that are driven by gas turbine (GT) or other prime movers. This paper presents the evaluation of actual work transfer or required prime power by modeling the governing equations of compression using the Peng–Robinson equation of state (PR-EOS). A computer code was developed to carry out the modeling and subsequent simulation of the compression power requirement. The simulation of prime mover power was carried out for different technology (head per stage) of the compressor ranging from 10-staged compression to double stage compression. The results show that the current technology of the centrifugal compressor could require as much as 23MW of prime mover power to compress 1.5 million tonnes per year of CO2—a projected equivalent CO2 released from a 530MW combined cycle gas turbine (CCGT) power generation plant. Document type: Article

Abstract

This paper describes the development and experimental validation of a three-phase flow model for predicting the transient outflow following the failure of pressurised CO2 pipelines and vessels. The choked flow parameters at the rupture plane, spanning the dense-phase and saturated conditions to below the triple point, are modelled by maximisation of the mass flowrate with respect to pressure and solids mass fraction at the triple point. The pertinent solid/vapour/liquid phase equilibrium data are predicted using an extended Peng–Robinson equation of state. The proposed outflow model is successfully validated against experimental data obtained from high-pressure CO2 releases performed as part of the FP7 CO2PipeHaz project (www.co2pipehaz.eu). The formation of solid phase CO2 at the triple point is marked by a stabilisation in pressure as confirmed by both theory and experimental observation. For a fixed diameter hypothetical pipeline at 100 bar and 20 °C, the flow model is used to determine the impact of the pipeline length on the time taken to commence solid CO2 discharge following its rupture.