Development of Novel Synthetic Amine Absorbents for CO2 Capture

AbstractIn the present paper, we investigated five synthetic amine based absorbents, including three formulated solvents. Aqueous solutions of the amines (mass fraction; 30% for single amine and >30% for blended solvents) were used to evaluate the performance for CO2 capture. Gas scrubbing, vapor-liquid equilibrium (VLE), and reaction calorimetry experiments were conducted in the laboratory to obtain the absorption rate, the amount of CO2 absorbed, cyclic CO2 capacity, and heat of reaction for each absorbent. The results of these absorbents were compared with the conventional absorbent monoethanolamine (MEA). Three high performing synthetic absorbents (IPAE, IPAP and IBAE) were found, and these had lower heats of reaction, higher cyclic capacities, and comparable absorption rates compared with MEA. All formulated absorbents showed excellent cyclic CO2 capacity and keeping moderately good absorption rate and lower heats of absorption. Some blended solvents were already demonstrated with real blast furnace gas at pilot test plants with capacities of 1 ton-CO2/day and 30 ton-CO2/day and showed promising results in terms of reducing absorbent regeneration energy

エイセイ チキュウ カンソク ニ ヨル コクサイ レジーム ノ カンシ : グンシュク カラ キコウ ヘンドウ マデ

京都大学0048新制・課程博士博士(地球環境学)甲第14802号地環博第56号新制||地環||11(附属図書館)UT51-2009-D514京都大学大学院地球環境学舎地球環境学専攻(主査)教授 松下 和夫, 教授 田村 正行, 准教授 小畑 史子学位規則第4条第1項該当Doctor of Global Environmental StudiesKyoto UniversityDA

Combustion Techniques in Remote CC-HDR Process

The remote CC-HDR process went into operation at Yawata Works, Nippon Steel, in June 1987. The new process is an advanced version of the proximate CC-HDR process in which the continuous caster is located adjacent to hot rolling mill, as represented by Nippon Steel's Sakai Works. In this remote CC-HDR process, the new insulater with the luminous wall burners and the slab edge heater by the jet gas impinging were developed and installed in order to keep the slab edge temperature high enough to be rolled at the hot strip mill. These important combustion technologies that made great contributions to the realization of the remote CC-HDR process are described

Satellite Earth Observations and Their Impact on Society and Policy

The result of a workshop bringing together an international advisory board of experts in science, satellite technologies, industry innovations, and public policy, this book addresses the current and future roles of satellite Earth observations in solving large-scale environmental problems. The book showcases the results of engaging distinct communities to enhance our ability to identify emerging problems and to administer international regimes created to solve them. It also reviews the work of the Policy and Earth Observation Innovation Cycle (PEOIC) project, an effort aimed at assessing the impact of satellite observations on environmental policy and to propose a mission going forward that would launch an “innovation cycle”. The achievements of such a mission would feed back to innovations in next-generation observation technology, thus contributing to global policy demand for policy-relevant information

Synthesis and selection of hindered new amine absorbents for CO2 capture

AbstractThis work focuses on synthesizing and selecting hindered new amine absorbents to reduce the regeneration energy cost for CO2 capture. To achieve this target we synthesized seven secondary and two tertiary amine based CO2 absorbents with systematic modification of their chemical structures by an appropriate placement of substituent functional groups especially the alkyl functions (e.g. methyl, isopropyl, isobutyl, secondary butyl etc.), relative to the position of the amino group. Performances evaluations of these new absorbents in aqueous solutions were carried out based on their CO2 absorption rate, absorption capacity and heat of reaction measurements. Particular attention was paid to absorbents with a potential for high absorption rate and low heats of reaction. The results for the synthesized amino alcohols were then compared with conventional absorbents AMP and MDEA which were chosen as the base case for all comparisons. We found three high performance absorbents with advantages of high absorption rate and low heats of reaction compared with AMP and MDEA. Absorbents higher CO2 absorption rate and lower heat energy consumption characteristics will reduce the regeneration energy cost of CO2 during stripping

Ab Initio Study of CO2 Capture Mechanisms in Monoethanolamine Aqueous Solution: Reaction Pathways from Carbamate to Bicarbonate

AbstractAb initio calculations combined with the continuum solvation model have been conducted to obtain complete reaction pathways involved in the CO2 capture into monoethanol (MEA) aqueous solution. We have investigated the reaction pathways for the decomposition of MEA carbamate into bicarbonate. Although the already known pathways invoke a generation of free CO2(aq), we are concerned with another mechanism which does not involve such an intermediate. The neutral hydrolysis of the MEA carbamate was found to be a slow reaction that has an essentially two-step nature. We propose an alternative pathway that involves the carbamic acid as an intermediate that undergoes an alkaline hydrolysis leading to the formation of bicarbonate. Taking account of the novel reaction pathways elucidated here as well as the established routes for the formation of carbamate and bicarbonate may lead to a comprehensive understanding and a better prediction of the chemical CO2 capture process under specific conditions including pH (concentration of amine) and partial pressure of CO2

Ab Initio Study of CO₂ Capture Mechanisms in Aqueous Monoethanolamine: Reaction Pathways for the Direct Interconversion of Carbamate and Bicarbonate

Ab initio molecular orbital calculations combined with the polarizable continuum model (PCM) formalism have been carried out for a comprehensive understanding of the mechanism of carbon dioxide (CO₂) absorption by aqueous amine solutions. CO₂ is captured by amines to generate carbamates and bicarbonate. We have examined the direct interconversion pathways of these two species (collectively represented by a reversible hydrolysis of carbamate) with the prototypical amine, monoethanolamine (MEA). We evaluate both a concerted and a stepwise mechanism for the neutral hydrolysis of MEA carbamate. Large activation energies (ca. 36 kcal/mol) and lack of increase in catalytic efficiency with the inclusion of additional water molecules are predicted in both the mechanisms. We also examined the mechanism of alkaline hydrolysis of MEA carbamate at high concentrations of amine (high pH). The addition of OH^– ion to carbamate anion was theoretically not allowed due to the reduction in the nucleophilicity of the former as a result of microsolvation. We propose an alternative pathway for hydrolysis: a proton transfer from protonated MEA to carbamate to generate the carbamic acid that initially undergoes a nucleophilic addition of OH^– and subsequent low-barrier reactions leading to the formation of bicarbonate and free MEA. On the basis of the calculated activation energies, this pathway would be the most efficient route for the direct interconversion of carbamate and bicarbonate without the intermediacy of the free CO₂, while the actual contributions will be dependent on the concentrations of protonated MEA and OH^– ions