Pilot CO Research Articles

ExxonMobil to pilot CO2-capture fuel cells

ExxonMobil to pilot CO₂-capture fuel cells

Effect of Pilot Injection Strategy on Performance of Diesel Engine under Ethanol/F-T Diesel Dual-Fuel Combustion Mode

To reduce emissions and save energy, alternative fuel and dual-fuel mode have been widely applied in the field of diesel engines. The pilot injection has potential to reduce engine vibration noise and pollutant emissions. The effects of a diesel fuel pilot injection strategy on the performance of an ethanol/F-T diesel dual-fuel engine were experimentally investigated on a four-cylinder four-stroke common rail diesel engine modified with an ethanol injection system. The results indicate that the variation in the combustion characteristic parameters with pilot injection timing is nonlinear and the difference is small, while soot, NOx, and CO tend to decrease, with an increase in pilot injection timing. With the increase in pilot injection amount, pmax, combustion duration, CO and soot increased; pmax phase and CA50 were closer to TDC; HRRmax and the ignition delay period decreased. The BSFC tends to increase with the increase in pilot injection timing and the increase in pilot injection amount, while the BTE shows the opposite trend. The value and the variation range of COVpmax are small. The effect of the pilot injection amount on ethanol/F-T diesel dual-fuel engine is more significant. The research presented in this paper can provide reference directions for the formulation of a fuel injection strategy of ethanol/F-T diesel dual-fuel combustion mode to reduce NOx without worsening the combustion process and presenting an insufficient fuel economy.

Experimental study the effect of injection strategies on combustion and emission characteristics in gasoline compression ignition engines using gasoline/hydrogenated catalytic biodiesel blends

A new type of fuel named hydrogenated catalytic biodiesel blended with gasoline is proposed to apply in a gasoline compression ignition engine for low-temperature combustion. However, the higher maximum pressure rise rate and retarded combustion phasing under high loads of single injection mode are the main problems. Hence, the double injection strategy is proposed to solve the above problems and to find the optimal injection conditions for this tested fuel. The combustion and emission characteristics are tested at high load by varying different pilot injection ratio from 20 to 30% and pilot injection timing from −60 to −40 °CA aTDC for this test fuel. The results show that increasing pilot injection ratio can advance the combustion phasing, while it increases the maximum pressure rise rate. −50 °CA aTDC of pilot start of injection timing has advanced combustion phasing and higher maximum pressure rise rate than that of −40 and −60 °CA aTDC conditions. Moreover, the NOx emission is mainly effect by pilot ratio, while PM, THC and CO emissions are controlled by pilot start of injection timing. 30% of pilot ratio with −50 °CA aTDC of pilot start of injection timing is an optimal injection strategy for G80H20 and G70H30 blends considering combustion and emission characteristics.

The first post‐injection seismic monitor survey at the Ketzin pilot CO2 storage site: results from time‐lapse analysis

ABSTRACTThe injection of CO2 at the Ketzin pilot CO2 storage site started in June 2008 and ended in August 2013. During the 62 months of injection, a total amount of about 67 kt of CO2 was injected into a saline aquifer. A third repeat three‐dimensional seismic survey, serving as the first post‐injection survey, was acquired in 2015, aiming to investigate the recent movement of the injected CO2. Consistent with the previous two time‐lapse surveys, a predominantly west–northwest migration of the gaseous CO2 plume in the up‐dip direction within the reservoir is inferred in this first post‐injection survey. No systematic anomalies are detected through the reservoir overburden. The extent of the CO2 plume west of the injection site is almost identical to that found in the 2012 second repeat survey (after injection of 61 kt); however, there is a significant decrease in its size east of the injection site. Assessment of the CO2 plume distribution suggests that the decrease in the size of the anomaly may be due to multiple factors, such as limited vertical resolution, CO2 dissolution, and CO2 migration into thin layers, in addition to the effects of ambient noise. Four‐dimensional seismic modelling based on dynamic flow simulations indicates that a dynamic balance between the newly injected CO2 after the second repeat survey and the CO2 migrating into thin layers and being dissolved was reached by the time of the first post‐injection survey. In view of the significant uncertainties in CO2 mass estimation, both patchy and non‐patchy saturation models for the Ketzin site were taken into consideration.

Experimental investigations of the effects of pilot injection on combustion and gaseous emission characteristics of diesel/methanol dual fuel engine

A diesel engine with 6-cylinder, turbocharged intercooling and common rail system was modified to operate on diesel/methanol dual fuel (DMDF). To optimize combustion process at high methanol substitution ratio (MSR) and further decrease exhaust emissions of DMDF engine at low load condition, pilot injection strategy was applied on it and the combustion, regulated and unregulated gaseous emission (included NOx, CO, THC, carbon dioxide (CO2), nitrous oxide (N2O), unburned methanol (CH3OH), formaldehyde (HCHO), formic acid (HCOOH), 1,3-butadiene (1,3-C4H6), benzene (C6H6) and toluene (C7H8)) characteristics were experimentally investigated. Experimental results reveal that the application of pilot injection could improve combustion stability and fuel economy at high MSR, and it can also reduce regulated emissions CO, THC except NOx, and unregulated emissions tested in this study except CO2 on M0 and M10 mode and toluene on M50 mode when compared with single injection cases. Increase pilot injection quantity and advance pilot injection timing both cause an increase in in-cylinder temperature and pressure before main combustion. The variations of pilot injection quantity and timing have less effect on regulated and unregulated gaseous emissions except NOx on M0 and M10 mode than higher MSR mode. With the rise of pilot quantity and the advance of pilot injection timing, HC and CO emissions decrease gradually but NOx emissions ascend; almost all unregulated emissions tested in this study on M30 mode reduce gradually; but when the MSR continues to rise to 50%, increasing emissions in unburned methanol, 1,3-butadiene and benzene are observed.

The investigation of CO2 storage potential in the Zululand Basin in South Africa

Abstract Carbon capture and storage (CCS) is seen as one of the technical approaches that can be used to mitigate global climate change in fossil fuel dominated countries such as South Africa. Approximately 90% of primary energy in South Africa is derived from fossil fuels, with coal providing 92% of electricity production in the country. The South African Centre of Carbon Capture and Storage (SACCCS) was established in 2009 (by the South African government with the assistance from international governments and industry) to investigate the potential of CCS in the country. SACCCS is addressing its mandate in line with the South African CCS Roadmap, which has been endorsed by the South African government. SACCCS's role in the South African CCS Roadmap is as follows: 2004 Assessment of the potential for CCS in South Africa 2010 Development of a South African CO 2 Geological Storage Atlas 2017 Commencement of a Pilot CO 2 Storage Project (10,000 - 50,000t CO 2 stored) 2020 Facilitate the commencement of a CCS demonstration plant (in the order of 100,000t CO 2 /year) 2025+ Inform the implementation of commercial CCS deployment (over 1,000,000t CO 2 /year) Ongoing: Provide support to other CCS activities in South Africa The results from the assessment of CCS potential in South Africa were summarised and documented in the Atlas (which was published in 2010) with the majority of storage potential occurring in Mesozoic basins of South Africa. There is 150 Gt of theoretical storage capacity is identified, of which 98% occurs offshore. After the completion of the Atlas the next stage on the Roadmap, the Pilot CO 2 Storage Project (PCSP), has become the focus of SACCCS activities. The scope and available funding of the PCSP led to the decision to focus on the onshore portions of the Algoa and Zululand basins as possible sedimentary basins for the PCSP programme. This paper will discuss the progress associated with the ongoing investigation of CO 2 storage potential in the Algoa basin which forms the onshore extension of the offshore Outeniqua basin. The middle Jurassic (Kimmeridgian) to lower Cretaceous (Hauterivian) Uitenhage Group constitutes the syn-rift basin-fill succession with stratigraphy dominated by the fluviatile Kirkwood Formation, and shallow marine Sundays River Formation. Due to limited and reasonably poor data availability, the need for new data and more tests on existing data to confirm any potential storage areas/sites was cited. SACCCS is now planning additional analysis of data to potentially allow for reinterpretation of the older data. The results from the analysis and reinterpretation will inform the next stage of the PCSP.

The First Brazilian Field Lab Fully Dedicated to CO2 MMV Experiments: From the Start-up to the Initial Results

Abstract Currently one of the main challenges in CO 2 storage research is the development, testing and validation of accurate and efficient Measuring, Monitoring and Verification (MMV) techniques to be deployed at geological sequestration sites that are cost effective yet help minimize risk. This perspective motivated PETROBRAS, the National Oil Major in Brazil, through its R&D investments portfolio to prioritize research projects that would contribute to decreasing the technological gap in the area. The Company's periodic surveys indicated the lack of infrastructure, as well as expertise in CO 2 MMV, as two of the most critical issues at the national level. In order to bridge that gap, initial steps were taken in 2010 for the start-up and development of the first CO 2 MMV Field Lab in Brazil, fully sponsored by PETROBRAS, with a long term goal of enabling the ranking of the best, most cost- effective MMV technology alternatives to be deployed at commercial large scale CCGS sites scheduled to be installed in the country. In addition to providing basic infrastructure to carry out the CO 2 injection and controlled release experiments, the facility was designed for the simultaneous testing of multiple measuring methodologies. Additional benefits of the initiative are the creation of expertise and the acceleration of the know-how in MMV in Brazil, as well as the development of a deeper and more practical knowledge of CO 2 dynamics and impacts in a real world, open air scenario. Under the full support of the PETROBRAS R&D Center (CENPES), through its Climate Change Mitigation Technological Program (PROCLIMA), the Brazilian Pilot CO 2 MMV Lab was made possible through a joint 4-year research Project, conceived and carried out by PETROBRAS and local academia in Brazil, in close cooperation with international experts. An overview of the Project and the multiple research areas encompassed will be presented, together with the preliminary results of the first CO 2 injection campaign, which took place in 2013.

Post-Injection monitoring of stored CO2 at the Nagaoka pilot site: 5 years time-lapse well logging results

Abstract Monitoring is the major challenge in CO 2 geological sequestration. At the first Japanese pilot CO 2 injection site (Nagaoka), CO 2 was injected into a thin permeable zone at a depth of 1100 m and the total amount of injected CO 2 was 10,400 tons during the injection period from July 2003 to January 2005. After ceasing of CO 2 injection, well loggings which mainly consist of neutron logging, sonic logging and induction logging have been continued for 5 years. The Nagaoka site may provide the first field data set of post-injection monitoring and essential information on long-term CO 2 behaviour in a saline aquifer. In this paper reports the results of formation pressure, well logging and fluid sampling aiming to improve understanding of CO 2 long term behaviour in the reservoir. The results of time-laps well logging provide the evidences of the solubility trap and residual trap in progress at Nagaoka, suggesting CO 2 is stored safely in a complex sandstone reservoir.

Experimental study on CO 2 monitoring and quantification of stored CO 2 in saline formations using resistivity measurements

This paper reports CO 2 saturation estimations based on resistivity data obtained from laboratory measurements and induction logging results at the Nagaoka pilot CO 2 injection site. The laboratory experiments put in evidence that the presence of clay content tends to reduce the increase of resistivity caused by the displacement of brine by less conductive CO 2. As a result, CO 2 saturations estimated from resistivity measurements without any correction for the clay effect are considerably lower than the actual saturations. The resistivity index ( RI) provides better estimates of CO 2 saturations than the Archie's equation because it requires the determination or assumption of only one rock parameter: the saturation exponent. CO 2 saturations estimated from the induction logging data acquired at Nagaoka are considerably lower than the neutron porosity changes due to displacement between brine and CO 2 in the reservoir. Even in the case of considering the De Witte's equation and the Poupon's to account for the clay effect, it was still difficult to get a good agreement with the neutron logging results. New relations based on the resistivity index with correction factors for the clay effect are developed and implemented in this study. One of these relations has proved to be effective to estimate CO 2 saturations in saline formations with high clay content.

2D modeling of salt precipitation during the injection of dry CO2 in a depleted gas reservoir

The precipitation of halite around a CO 2 injection well has been studied to investigate the possible effects on well injectivity for a pilot test of CO 2 injection in a depleted gas reservoir. The numerical simulations performed with the TMGAS simulator, using both 1D and 2D radial grids, show that the injection of dry supercritical CO 2 vaporizes the formation brine promoting NaCl concentration and the precipitation of halite. Different behaviors are observed depending on the initial liquid saturation: when the brine has a low mobility, the evaporation front advances with limited halite precipitation and only minor effects on well injectivity. On the other hand, when the brine has sufficient mobility, the precipitation front is recharged by the brine flowing towards the wellbore, due to the capillary pressure gradient driven by the evaporation. In this case the concentrated precipitation can strongly reduce the formation permeability. These effects depend on formation properties and on the porosity–permeability relationship which describes the effects of halite precipitation on permeability reduction. In the attempt to improve the prediction of halite precipitation effects, an extension of the so-called tube-in-series model of Verma and Pruess was developed, with pore-size distribution evaluated from the measured grain-size distribution of the sandy formation considered for the execution of the pilot CO 2 sequestration test.

The Symmetry Properties of Linear Combination Coefficients for Molecular Orbitals of Diatomic Molecules

In this paper, the symmetry properties of linear combination coefficients for molecular orbitals of diatomic molecules, using Slater type orbitals, are presented with the help of the symmetry operations in group theory. In order to test the presented symmetry properties, the linear combination coefficients of molecular orbitals for the ground electronic state of pilot molecules F2 and CO are calculated using constructed computer programs for Hartree-Fock-Roothaan equation. It is seen that the obtained computing results satisfy the presented symmetry properties.

Mechanistic model for prediction of structured packing mass transfer performance in CO 2 absorption with chemical reactions

A mechanistic model based on liquid irrigation feature is proposed for predicting mass transfer performance of sheet-metal structured packings. The model was used to simulate mass transfer performance of Gempak 4A structured packings for CO 2 absorption using NaOH aqueous solutions. A very good agreement between the simulation results and the experimental data acquired from a pilot CO 2 absorption unit was found under ranges of process parameters including liquid load, initial liquid distribution pattern, and liquid temperature. In comparison with published mass transfer correlations, the proposed model can effectively handle the prediction in a wider range of the liquid load.

Effect of CO 2 flood on geochemistry of McElroy oil

Geochemical characterization has been completed on a series of oil samples collected over time from the McElroy Field, Texas, where a pilot CO 2 flood project was initiated a few years ago. A non-waxy, 31 gravity ( oAPI) oil is produced from carbonate reservoirs within the Permian Grayburg Formation. The samples were taken from various wells over a time span of one and one half years for monitoring changes in oil composition induced by CO 2 injection over time. The oil samples taken from about 40 wells shortly after the start of CO 2 injection showed a marked reduction (∼50%) in the asphaltene content, indicating CO 2-induced asphaltene deposition had occurred. Mapping asphaltene reduction could provide information on the flow direction of CO 2 in the reservoir. Hydrocarbon profiles of the oils from some wells also showed a significant reduction in the heavy paraffin content (i.e. > C 25), suggesting deposition of heavy hydrocarbons within the reservoir. The observation of a slight increase in oil API gravity is also consistent with precipitation of heavy components from the oil phase due to CO 2 injection. The organic deposits (or flocs) which can cause restriction of fluid flow in the reservoir by reducing porosity and permeability have probably contributed to reduction in injectivity experienced by some injection wells shortly after the start of CO 2 injection. Field observations have been duplicated in laboratory core flood experiments to mimic the field recovery process. The experiments show that most of heavy organics were deposited near the CO 2 injection port, suggesting organic deposition in the field occurs near the injection wells rather than producing wells. Despite the continued CO 2 flood, some molecular properties such as sterane and hopane distributions remain relatively unchanged. These geochemical parameters are commonly derived from ratios of compounds with similar molecular properties and are generally not affected by the CO 2 flood as precipitation of heavy hydrocarbons causes little fractionation among these compounds. Thus, oil samples from fields under the gas flood are still viable for correlation, source evaluation and maturity determination.