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AbstractDue to the strong interest in geochemical CO2-fluid-rock interaction in the context of geological storage of CO2 a growing number of research groups have used a variety of different experimental ways to identify important geochemical dissolution or precipitation reactions and – if possible – quantify the rates and extent of mineral or rock alteration. In this inter-laboratory comparison the gas-fluid-mineral reactions of three samples of rock-forming minerals have been investigated by 11 experimental labs. The reported results point to robust identification of the major processes in the experiments by most groups. The dissolution rates derived from the changes in composition of the aqueous phase are consistent overall, but the variation could be reduced by using similar corrections for changing parameters in the reaction cells over time. The comparison of experimental setups and procedures as well as of data corrections identified potential improvements for future gas-fluid-rock studies.

AbstractPipeline transport of gas has several advantages and is also an attractive approach for CO2 transport from the existing experience. The transport cost is a key index for people to make decisions on the selection of transport means of CO2. However, the pipeline transport cost is obviously market sensitive and the existing cost models in USA, EU, etc. can’t be directly used in the cost evaluations in China. A localized assessment methodology for onshore pipeline transport cost is valuable. This paper developed a new cost estimate methodology for onshore pipeline transport of CO2 which can reflect the price level of pipe in China's market. For two transport routes of 300km with the transport amount 1.46Mt/y CO2, the transport costs are respectively 47.0 and 68.5RMB/t. A comparison with existing research work in China was conducted, which showed the validity of the methodology presented.

The performances of a 2984-kW (4,000-hp) gas turbine–powered passenger locomotive fueled with different biofuels are compared with the performance of the same locomotive fueled with Diesel #2. The process of selecting a small number of biofuels from a detailed evaluation of 13 readily available biofuels is explored. A simulation of operation in an actual high-speed corridor is used to develop exhaust emission values in terms of tonnes (tons)/year for a complete service, and then in terms of g (lb)/trip of primary smog-producing pollutants. Energy use and cost per trip are developed from the same simulation. All of these values are compared with Diesel #2 values developed in previous research. Bio-fuel use in respect to turbine maintenance costs is discussed. Explored are the implications of carrying and delivering the biofuels on a locomotive in terms of ( a) projected range with a given fuel tank size and ( b) the minimum fuel tank size required to serve a typical corridor.

This work is focused on results from a recent controlled sub-seabed in situ carbon dioxide (CO2) release experiment carried out during May–October 2012 in Ardmucknish Bay on the Scottish west coast. Three types of pCO2 sensors (fluorescence, NDIR and ISFET-based technologies) were used in combination with multiparameter instruments measuring oxygen, temperature, salinity and currents in the water column at the epicentre of release and further away. It was shown that distribution of seafloor CO2 emissions features high spatial and temporal heterogeneity. The highest pCO2 values (∼1250 μatm) were detected at low tide around a bubble stream and within centimetres distance from the seafloor. Further up in the water column, 30–100 cm above the seabed, the gradients decreased, but continued to indicate elevated pCO2 at the epicentre of release throughout the injection campaign with the peak values between 400 and 740 μatm. High-frequency parallel measurements from two instruments placed within 1 m from each other, relocation of one of the instruments at the release site and 2D horizontal mapping of the release and control sites confirmed a localized impact from CO2 emissions. Observed effects on the water column were temporary and post-injection recovery took <7 days. A multivariate statistical approach was used to recognize the periods when the system was dominated by natural forcing with strong correlation between variation in pCO2 and O2, and when it was influenced by purposefully released CO2. Use of a hydrodynamic circulation model, calibrated with in situ data, was crucial to establishing background conditions in this complex and dynamic shallow water system.

Abstract We detected a controlled release of CO2 (g) with pH eddy covariance. We quantified CO2 emission using measurements of water velocity and pH in the plume of aqueous CO2 generated by the bubble streams, and using model predictions of vertical CO2 dissolution and its dispersion downstream. CO2 (g) was injected 3 m below the floor of the North Sea at rates of 5.7–143 kg d − 1. Instruments were 2.6 m from the center of the bubble streams. In the absence of injected CO2, pH eddy covariance quantified the proton flux due to naturally-occurring benthic organic matter mineralization (equivalent to a dissolved inorganic carbon flux of 7.6 ± 3.3 mmol m − 2 d − 1, s.e., n = 33). At the lowest injection rate, the proton flux due to CO2 dissolution was 20-fold greater than this. To accurately quantify emission, the kinetics of the carbonate system had to be accounted for. At the peak injection rate, 73 ± 13% (s.d.) of the injected CO2 was emitted, but when kinetics were neglected, the calculated CO2 emission was one-fifth of this. Our results demonstrate that geochemical techniques can detect and quantify very small seafloor sources of CO2 and attribute them to natural or abiotic origins.