Purpose Of CO Research Articles

CO2solubility measurements in brine under reservoir conditions: A comparison of experimental and geochemical modeling methods

The dissolution of CO 2 in brine (solubility trapping) is one of the most secure and permanent trapping mechanisms when considering CO 2 geological storage. In addition, CO 2 dissolution in brine is an important mechanism of CO 2 enhanced oil recovery as it improves sweep efficiency and increases oil displacement. Currently, there is a range of experimental methods that has been used to measure CO 2 solubility in brine and a critical review of these methods is presented here. Several different geochemical models that can be used to calculate CO 2 solubility in brine are also reviewed and the importance of selecting the correct equation of state (EoS) is addressed. Furthermore, the validity of the experimental results was ascertained through a comparison of the published experimental results with those produced through geochemical modeling. The geochemical modeling software, HydraFLASH, can be used to accurately calculate CO 2 solubilities under a number of conditions provided the correct EoS is selected. For the purpose of CO 2 ‐water systems, the Valderrama‐Patel‐Teja EoS is the most accurate as it is designed to be used for systems containing polar and non‐polar compounds. The published experimental results were compared with those obtained through the geochemical modeling, to ascertain the most accurate means of measuring CO 2 solubility. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd

Parameters affecting Mg(OH)2 extraction from serpentinites in lithuania for the purpose of CO2 reduction by mineral carbonation

Mineral sequestration has a great potential for abating CO2 emissions, especially at locations where no opportunities for CO2 geological storage exist. This article focuses on the mineral carbonation of magnesium silicates, that is, serpentinites, which offers an attractive option for CO2 emission mitigation in Lithuania. Mineral CO2 carbonation in a staged gas/solid process route is one of the most prospective approaches. The process was conducted in several steps. Firstly, extraction of the magnesium hydroxide from serpentinite via a solid/solid reaction between serpentinite and ammonium sulfate salt at a temperature interval of 500–540°C was carried out. The maximum Mg extraction (53.70 %) was obtained with the mass ratio of reactants of 2 g serpentinite/3 g ammonium sulfate, reaction temperature, and time of 520°C and 20 min, respectively. Secondly, the process of precipitation of Mg(OH)2 took place. The effect of precipitation of the Fe‐containing compounds (first step) and the Mg(OH)2 (second step) was analyzed. At the pH of 8–10 and 10–12, compounds of Fe and Mg precipitated, respectively. The optimal Fe removal and Mg extraction was achieved at the pH of the ∼9.5 for the first step and at the pH of ∼11.50 for the second step. Finally, the carbonation of extracted magnesium hydroxide was accomplished and reached the effectiveness of 65 % after 15 min at 535°C, 51 bar. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 512–518, 2014

Process simulation and optimal design of membrane separation system for CO 2 capture from natural gas

Abstract Membrane process, a relatively new technology among other available techniques, can be used for the purpose of CO 2 capture from natural gas. Over the decades, membrane performance has been described by different mathematical models, but there is limited work done in the field of process simulation where membrane models can be incorporated with other unit operations using commercially available simulator. In this paper, a two dimensional cross flow mathematical model for membrane separation has been incorporated with Aspen HYSYS as a user defined unit operation in order to optimize and design the membrane system for CO 2 capture from natural gas. Parameter sensitivities, along with process economics, have been studied for different design configurations (including recycle streams and multiple stages). It has been observed that double stage with permeate recycle system gives the optimum design configuration due to minimum process gas cost involved with it.

Carbon capture and storage policy in the United States: A new coalition endeavors to change existing policy

Carbon capture and storage (CCS) is considered by some to be a promising technology to reduce greenhouse gas emissions, and advocates are seeking policies to facilitate its deployment. Unlike many countries, which approach the development of policies for geologic storage (GS) of carbon dioxide (CO2) with nearly a blank slate, the U.S. already has a mature policy regime devoted to the injection of CO2 into deep geologic formations. However, the existing governance of CO2 injection is designed to manage enhanced oil recovery (EOR), and policy changes would be needed to manage the risks and benefits of CO2 injection for the purpose of avoiding GHG emissions. We review GS policy developments at both the U.S. federal and state levels, including original research on state GS policy development. By applying advocacy coalition framework theory, we identify two competing coalitions defined by their beliefs about the primary purpose of CO2 injection: energy supply or greenhouse gas (GHG) emission reductions. The established energy coalition is the beneficiary of the current policy regime. Their vision of GS policy is protective: to minimize harm to fossil energy industries if climate policy were to be enacted. In contrast, the newly formed climate coalition seeks to change existing GS policy to support their proactive vision: to maximize GHG reductions using CCS when climate policy is enacted. We explore where and at what scale legislation emerges and examine which institutions gain prominence as drivers of policy change. Through a detailed textual analysis of the content of state GS legislation, we find that the energy coalition has had greater success than the climate coalition in shaping state laws to align with its policy preferences. It has enshrined its view of the purpose of CO2 injection in state legislation, delegated authority for GS to state agencies aligned with the existing policy regime, and protected the EOR status quo, while creating new opportunities for EOR operators to profit from the storage of CO2 The climate coalition's objective of proactively putting GS policy in place has been furthered, and important progress has been made on commonly held concerns, such as the resolution of property rights issues, but the net result is policy change that does not significantly revise the existing policy regime.

Northwest McGregor field CO2 Huff ‘n’ Puff: A case study of the application of field monitoring and modeling techniques for CO2 prediction and accounting

Northwest McGregor field CO2 Huff ‘n’ Puff: A case study of the application of field monitoring and modeling techniques for CO2 prediction and accounting

Seismic Monitoring and Verification for the CO2CRC Otway Basin Project, Part 2: acquisition and analysis of borehole seismic data

Abstract The Otway Project conducted under the Australian Cooperative Research Centre for Greenhouse Gas Technologies (CO 2 CRC) is the first of its kind, where CO 2 is injected into a depleted gas reservoir. The use of depleted fields for CO 2 storage is likely to become widely adopted globally and, therefore, the project will provide important experience for monitoring under these conditions. However, such scenario is not favorable for the application of geophysical techniques for the purpose of CO 2 monitoring and verification (M&V) because the injection of CO 2 into a CH4 depleted reservoir is modeled to produce very subtle changes in elastic properties of the reservoir rock which may be very difficult to measure. Consequently geophysical program for the Otway site was design according to the expected time-lapse effects. It combines both surface and borehole seismic methods. Surface seismic should provide a global vision of the underground and an indirect confirmation of the CO 2 containment by recording no differences between the successive time-lapse experiments. Vertical Seismic Profile (VSP) surveys are expected to provide an improved characterization of the reservoir and hopefully a direct indication of the fluid distribution and/or its potential upward migration along the reservoir bounding fault pattern. Indeed the results of the current analysis of both pre-base line (test) and base-line 2D and 3D VSP data are encouraging. The availability of vector wave field (three-component) data recorded in VSP surveys should significantly improve the outcomes of M&V program at Naylor site.

Chemical modification of rutile TiO 2(1 1 0) surface by ab initio calculations for the purpose of CO 2 adsorption

The interaction energy between rutile TiO 2 (1 1 0) surface and CO 2 molecule has been investigated by ab initio quantum chemical calculations in order to increase the adsorption energy between the surface and the adsorbate by a chemical modification of the surface. In this work, we propose a novel approach for chemical modifications by utilizing the ab initio calculations. The interaction energy between a surface and a molecule can be decomposed into several physically meaningful terms such as electrostatic, polarization and charge transfer interactions by the Kitaura-Morokuma analysis. In the case when the charge transfer interaction from the molecule to surface is dominant, replacing several Ti atoms by the element that has larger electron negativity than the Ti atom will be appropriate. Such modification will promote the charge transfer from molecule to surface, which will leads to the increase in the stabilization energy. We represent TiO 2 surface by a Ti 7 O 22 H 16 cluster in which dangling bonds are terminated by hydrogen atoms. Geometry optimizations as well as the Kitaura-Morokuma analysis are performed within the RHF level for the CO 2 and Ti 7 O 22 H 1 6 system. In the CO 3 form adsorption geometry, the charge transfer interaction energy from the cluster to CO 2 is found to be dominant among the component interactions. It is demonstrated that replacement of two Ti atoms by two Ca atoms drastically promotes the charge transfer in accord with our proposal and consequently, the total adsorption energy increases. The mechanism of the increase in the charge transfer interaction as well as CO 2 adsorption on the TiO 2 cluster is discussed by investigating the spacial distribution of the HOMO electron density of the cluster.

Cobalt irradiation box ejection accident of ETRR-2

Abstract The new Egyptian Test and Research Reactor Number 2 ETRR-2, MTR type, is now under operational tests. It has a main central irradiation channel for the purpose of Co 60 isotope production with an intended rated capacity of 50 000 Ci per year. The reactivity introduced in the reactor due to accidental ejection of the Co 60 irradiation box (CIB) should be discussed. This reactivity insertion accident (RIA) may be fast or slow with maximum reactivity worth 2.9428 $. The CIB may move with constant speed or variable acceleration according to its initial speed and the applied forces. This results in a linear, parabolic or sinusoidal motion, which in turn affects the reactivity insertion rate (RIR). The present work analyzes this type of perturbation during normal operating conditions: 22 MW full power and 1900 kg s −1 forced core cooling flow. The work serves as a part of the safety evaluation process applicable to similar MTR cores. The RIA code TRANSP20 is developed for this study. It simulates various types of RIR, fast or slow resulting from different CIB ejections. Scram signal due to power, period, inlet and outlet temperatures, or temperature difference is expected to activate the shutdown system. The work presents five case studies, two for fast ejection and three for slow. The transient behavior of the reactor during this is illustrated. The results show that the reactor can withstand slow ejection if the scram is available. However, for fast ejection the scram system does not prevent the clad temperature from exceeding safety limits. Recommendations to prevent or mitigate this accident are highlighted.