Effect of ultrasonic field treatment on degassing of 2024 alloy

The 2024 aluminum alloy was prepared with different ultrasonic processes.Effects of ultrasonic treatment parameters including ultrasonic power,treatment time,treatment temperature,and frequency resonance,as well as C_(2)Cl_(6) degasser on degassing of the 2024 aluminum alloy were investigated.Results indicate that increasing ultrasonic power at the same ultrasonic treatment time can improve the degassing effect.The optimum degassing efficiency can be obtained under the resonant ultrasound condition.With the combination of 1%C_(2)Cl_(6) addition and 150 W ultrasonic treatment for 40 s,the hydrogen content of the alloy is decreased by 52.9%.At the same time,the tensile strength and elongation are increased by 28.3%and 92.3%,respectively,and the yield strength is slightly increased by 6.7%.The degassing mechanism is also discussed.

耦合CO_(2)脱气的岩溶地热水结垢趋势定量分析

岩溶地热系统是最具开发潜力的水热型地热系统之一,在水热型地热资源利用中,地热水结垢(尤其是井下结垢)是目前面临的最普遍、最重要的问题之一,制约着地热水资源可持续利用。针对岩溶地热水结垢趋势分析方法存在的不足,在重点考虑CO_(2)脱气这一重要过程对结垢趋势影响的基础上,利用化学热力学模拟技术构建了一种耦合CO_(2)脱气过程的结垢趋势定量分析的改进方法,并将其应用于南京汤山岩溶地热区。结果表明汤山地区地热水不具有发生SiO 2结垢的趋势;在井口有发生碳酸盐结垢趋势,主要成分为CaCO_(3);井筒中下部有发生不同程度的硫酸盐结垢趋势,主要成分为CaSO_(4),SrSO_(4),BaSO_(4)。本研究在改进结垢趋势分析方法不足的同时,为防垢除垢工作提供了理论基础和方法指导,可有力促进地热水资源的可持续利用。

CO2 degassing and melting of metasomatized mantle lithosphere during rifting-Numerical study

:Reactivation of metasomatized mantle lithosphere may occur during continental extension,which is an important component of plate tectonics.The lower most part of the metasomatized domains in the subcontinental mantle lithosphere can be locally enriched in CO2.Therefore,partial melting of these metasomatized domains may play a crucial role in the global carbon cycle.However,little is known about this process and up until now few numerical constraints are available.Here we address this knowledge gap and use a 2-D high resolution petrological-thermomechanical model to assess lithospheric rifting.CO2 degassing and melting.We test 4 lithospheric thicknesses:90,110,130 and 200 km with a 10 km thick metasomatized layer at the base using CO2 of 2 wt.%in the bulk composition.The carbonate enriched layer is stable below^3 GPa(>110 km)for a temperature of 1300℃;therefore,we only observe degassing patterns for lithospheric models that are 130 km and 200 km thick.The metasomatized layer for the 130 km thick lithosphere mostly comprises carbonatite melting,whereas in the 200 km thick scenario propagation of melt development from kimberlites to carbonatites occurs as the metasomatic mantle is exhumed during extension.The numerical models fit well into natural rifting zones of the European Cenozoic Rift System for young(shallow)and of the North Atlantic Rift for old(thick)lithosphere.

Calculation of the CO2 Degassing during Contact Metamorphism and Its Geological Significance:The Model and Example from the Shuanshan Area of the South Tan-Lu Fault Belt

The paper studies CO2 degassing and controlling factors under the condition of contact metamorphism in the Shuangshan area, southern Tan-Lu fault belt and the method of calculating the amount of CO2 degassing. The results show that the amount of CO2 degassing is controlled by the characteristics of the country rocks, including the thermal conductivity, penetrability, porosity and connectivity. Compositions, size and depth of intrusive rock also have an important influence on CO2 degassing, i.e., they generated numerous cracks in the country rocks, and thus allowed the easy flow and accumulation of fluids. The amount of CO2 flux in contact metamorphism is calculated quantitatively based on the metamorphic reaction and time-integrated fluid flux. The value （0.729- 2.446×10^4 mol/cm^2） of CO2 flux suggests that CO2 was provided mainly by the contact metamorphic reaction. The generation and releasing of CO2 are positively correlated with the degree of metamorphism, and XCO2 in fluids gradually increases from dolomite zone to calcite zone, but in the zone of grossular, fluid flux is the largest and XCO2 sharply decreases due to involvement of magmatic water. This study presents evidence that a large amount of industrial-scale CO2 can be produced during contact metamorphism. On the basis of theoretical and practical studies, a cone model has been proposed to response CO2 degassing for the contact metamorphism, and it can be used to explore CO2 accumulations beyond the oil-gas basins. This model can also be applied to the study of inorganic genesis of CO2 accumulations.

康定榆林宫水热区CO_2研究

本文探讨康定榆林宫水热区水热ＣＯ２气的来源、区内主要水热点的ＣＯ２气释放强度及释放模式。稳定同位素分析结果表明，该水热区水热ＣＯ２气为深部成因，且有６０％以上为变质成因；估算得区内主要水热点的ＣＯ２气释放强度为１０８ｇ／ａ。结合研究区地质条件做出了水热ＣＯ２气释放模式示意图。

北京西部活动断裂CO_(2)与Rn脱气特征及其环境影响

利用跨断层土壤气测量方法,连续两年对北京西部黄庄—高丽营断裂、八宝山断裂和南口山前断裂CO_(2)与Rn的脱气浓度与通量进行了测量,分析了研究区断裂带脱气特征及产生的环境影响。结果表明:黄庄—高丽营断裂北段的西王路测区土壤气浓度平均值及KQ值最大,反映了该断裂北段构造活动性较强;研究区3条断裂的土壤气浓度均值及构造活动性呈现东高西低的特征,与首都圈土壤气地球化学背景场特征一致。3条断裂脱气对大气CO_(2)的年贡献量约为0.45×10^(6) t。西王路测区土壤气Rn平均浓度高于20 kBq/m^(3),其附近建筑物应采取相应的底层地面抗开裂措施,部分测点浓度高于30 kBq/m^(3)及50 kBq/m^(3),其附近建筑应采取防水处理或综合防氡措施。

The CO_2 absorption and desorption performance of the triethylenetetramine + N,N-diethylethanolamine + H_2O system

Post-combustion CO_2 capture(PCC) process faces significant challenge of high regeneration energy consumption.Biphasic absorbent is a promising alternative candidate which could significantly reduce the regeneration energy consumption because only the CO_2-concentrated phase should be regenerated. In this work, aqueous solutions of triethylenetetramine(TETA) and N,N-diethylethanolamine(DEEA) are found to be efficient biphasic absorbents of CO_2. The effects of the solvent composition, total amine concentration, and temperature on the absorption behavior, as well as the effect of temperature on the desorption behavior of TETA–DEEA–H2 O system were investigated. An aqueous solution of 1 mol·L-1 TETA and 4 mol·L-1 DEEA spontaneously separates into two liquid phases after a certain amount of CO_2 is absorbed and it shows high CO_2 absorption/desorption performance.About 99.4% of the absorbed CO_2 is found in the lower phase, which corresponds to a CO_2 absorption capacity of 3.44 mol·kg-1. The appropriate absorption and desorption temperatures are found to be 30 °C and 90 °C,respectively. The thermal analysis indicates that the heat of absorption of the 1 mol·L-1 TETA and 4 mol·L-1 DEEA solution is-84.38 kJ·(mol CO_2)-1 which is 6.92 kJ·(mol CO_2)-1 less than that of aqueous MEA. The reaction heat, sensible heat, and the vaporization heat of the TETA–DEEA–H2 O system are lower than that of the aqueous MEA, while its CO_2 capacity is higher. Thus the TETA–DEEA–H2 O system is potentially a better absorbent for the post-combustion CO_2 capture process.

河流水气界面CO_(2)脱气时间尺度变化研究进展

河流作为连接陆地和海洋碳库之间的通道,是全球内陆水体碳排放最主要的载体,在全球碳循环中发挥着至关重要的作用。全球河流水气界面二氧化碳(CO_(2))脱气显著的时间异质性特征研究有助于深入理解其碳循环过程与机制,也为准确评估碳通量以及完善碳循环模型提供了科学支撑。本文系统梳理了国内外的相关研究成果,总结了目前河流CO_(2)脱气通量在昼夜、季节以及多年尺度上的动态变化及其影响因素,指出其昼夜变化与季节变化存在一定的周期性,并对不同空间尺度上CO_(2)脱气通量的时间差异进行讨论。同时分析当前研究中的不足,认为缺乏河流二氧化碳分压(p CO_(2))与CO_(2)脱气系数(k)高分辨率且长期连续的直接测量,限制了河流CO_(2)脱气通量时间尺度变化的周期性及相互之间关系的厘定,使得气候变化与人类活动对河流CO_(2)脱气时间动态的影响仍然难以量化与预测。最后,根据目前存在的问题,展望了未来的研究重点,为全球河流水气界面碳循环过程与机制、模型研究提供新的思路与方向,以及可以更准确地评估和预测未来河流碳排放的变化趋势。

Influence of Operating Parameters on NO_(x)and SO_(2)Emissions in Circulating Fluidized Bed with Post-Combustion

Post-combustion technology of circulating fluidized bed can largely reduce the emission of nitrogen oxides(NOx)in the process of combustion and succeed in meeting the ultra-low NO_(x)standard for some fuels like Shenmu coal.Exploring the potential of synergistic control of the emissions of NO_(x)and sulphur dioxide(SO_(2))under post-combustion technology has become a direction that needs further study.The experiments were conducted on a 0.1 MW(thermal)circulating fluidized bed(CFB)test platform,composed of a CFB main combustor and post-combustion chamber(PCC).The paper focuses on the effects of air distribution ratio and temperature in CFB and limestone addition on NO_(x)and SO_(2)emissions.The experimental results showed that compared with traditional CFB combustion,post-combustion technology can reduce NO_(x)emission largely,but lead to a slight increase in SO_(2)emission.The higher SO_(2)emissions at post-combustion can lead to less NO_(x)emission.With the decrease inλ_(CFB),NO_(x)emission first decreased and then increased;by contrast,SO_(2)emission withλ_(CFB)first increased and then decreased.Under post-combustion,whenλ_(CFB)was 0.9,NO_(x)emission was the minimum,while the SO_(2)emission was the largest.Combustion temperature and limestone addition has less adverse effects on NO_(x)emission under post-combustion,compared with traditional CFB combustion.Limestone injection into the furnace is applicable under post-combustion,and the sulfur removal efficiency under post-combustion is very high,almost equivalent to that under traditional combustion.

Mantle-derived CO_(2) in Hot Springs of the Rehai Geothermal Field,Tengchong,China

Gas concentrations and isotopic compositions of He and CO2 were determined on free gas samples from ten hot springs of the Rehai geothermal field, Tengchong, China. The results showed that hot-spring CO2 gas, together with He, was derived mainly from the mantle, indicating the accumulation of mantle-derived volatiles beneath the survey area. The δ 13C values of CO2, higher than those of the typical mantle-derived carbon and the isotopic composition of hot-spring-free CO2 in unequilibrium with dissolved CO2, are recognized only in the Rehai geothermal field, suggesting that there seems to be a still-degassing magmatic intrusion at depths, which provides mantle-derived volatiles to the hydrothermal system above. The accumulation of those volatiles has probably played an important role in triggering earthquakes in this region. In addition, the isotopic characteristics of He and C also indicate that the magmatic intrusion seems to have been derived from the MORB source, and could be contaminated by crustal materials during its upwelling through the continental crust.

CO_(2) capture RD&D proceedings in China Huaneng Group

CO_(2) capture is an important carbon management route to mitigate the greenhouse gas emission in power sector.In recent years,China Huaneng Group(CHNG)has paid more attention on CO_(2)capture technology development and launched a series of R&D and demonstration projects.In the area of pre-combustion CO_(2) capture technology,GreenGen project initiated by CHNG is the first integrated gasification combined cycle(IGCC)power plant in China.Located in Tianjin,GreenGen aims at the development,demonstration and promotion of a near-zero emissions power plant.An IGCC plant of 250 MW has successfully passed full-scale trial operation.In the next phase,a pre-combustion CO_(2) capture unit will be integrated into the system.Pre-combustion process based on coal chemical process has been developed with lower costs successfully.Regarding to post-combustion CO_(2) capture(PCC),in 2008,CHNG built a 3,000 tpa CO_(2) capture plant,which was the first CO_(2) capture demonstration plant in China.In 2009,CHNG launched a PCC project in Shanghai with a capture capacity of 120,000 tpa CO_(2).Recently,Huaneng Clean Energy Research Institute(CERI)and Powerspan formed a joint venture,Huaneng-CERI-Powerspan(HCP).HCP has completed the technology qualification program to supply carbon capture technology for the CO_(2)capture Mongstad project.Besides these activities mentioned above,feasibility studies and system design for large scale PCC system,have been undertaken by CERI and its partners from Australia,US and Europe.

Coupling between the Changes in CO₂Concentration and Sediment Biogeochemistry in Mudflat of Salinas de San Pedro, California, USA

We investigated the effects of elevated carbon dioxide (CO2) on biogeochemistry of marsh sediment including speciation of selected heavy metals in Salinas de San Pedro mudflat in California. The Salinas de San Pedro mudflat has higher carbon (C) content than the vast majority of fully-vegetated salt marshes even with the higher tidal action in the mudflat. Sources for CO2 were identified as atmospheric CO2 as well as due to local fault degassing process. We measured carbon dioxide, methane, total organic carbon, dissolved oxygen, salinity, and heavy metal concentration in various salt marsh locations. Overall, our results showed that CO2 concentration ranging from 418.7 to 436.9 (ppm), which are slightly different in various chambers but are in good agreement with some heavy metal concentrations values in mudflat at or around the same location. The selected metal concentration values (ppm) ranging from 0.003 - 0.011 (As);0.001 - 0.005 (Cd);0.04 - 0.02 (Cr);0.13 - 0.38 (Cu);0.11 - 0.38 (Pb);0.0009 - 0.020 (Se);and 0.188 - 0.321 (Zn). The low dissolved oxygen (ppm) in the pore water sediment indicated suboxic environment. Additionally, CO2 (ppm) and loss on ignition (LOI) (%) correlated inversely;the higher CO2 content, the lower was the LOI (%);that is to say the excess CO2 causes higher rates of decomposition and therefore it leads to lower LOI (%) on the mudflat surface. It appears that the elevated CO2 makes changes in salt marsh pore water chemistry for instance the free ionic metal (Cu2+, Pb2+, etc.) speciation is one of the most reactive form because simply assimilated by the non-decayed or alive organisms in sediment of salt marsh and/or in water. This means that CO2 not only is a sign of improvement in plant productivity, but also activates microbial decomposition through increases in dissolved organic carbon availability. CO2 also increases acidification processes such as anaerobic degradation of microorganism and oxidation of reduced components. The heavy metal concentrations in sediment samples were slightly higher in suboxic layer, yet it appears that salt marsh sediments in Salinas de San Pedro act like a sink for nutrient and carbon by maximizing carbon sequestration.

喀斯特小流域地表水碳酸盐系统化学平衡对酸性矿山废水的缓冲作用

Revelle因子不仅能反映弱碱性水体对吸收大气CO_(2)的缓冲能力,还能体现水体酸化过程中CO_(2)去气对H^(+)的缓冲作用。本研究通过对多个缓冲因子的分析,探讨喀斯特中高硫煤矿区地表水碳酸盐系统对酸性矿山废水的缓冲作用,有助于进一步理解喀斯特地区流域水体中DIC循环过程和CO_(2)源汇关系特征。结果表明,地表水碳酸盐系统内车田河流域Revelle因子变化区间在1.00~51.96之间,能有效揭示地表水碳酸盐系统内CO_(2)去气对H^(+)的缓冲过程,其敏感区间为pH=7.0~8.38的弱碱性水体。γDIC、βDIC、ωDIC、γAlk、βAlk、ωAlk等缓冲因子是基于pH和DIC浓度的二元方程。这些因子进一步细化了CO_(2)(aq)、H^(+)和CO_(3)^(2-)等组分对DIC浓度和碱度的相对变化关系。在pH>7.0的DIC碳酸盐体系内,6个缓冲因子对水体酸化过程中碳酸盐组分的动态转化具有很好的响应。当pH<7.0以后,水−气界面和水−岩界面的碳传输过程增强,当CO_(2)去气过程占主导,则缓冲因子绝对值变大;当H^(+)对碳酸盐岩溶蚀过程占主导,则缓冲因子绝对值变小。

Integrated adsorption and absorption process for post-combustion CO_(2) capture

This study explored the feasibility of integrating an adsorption and solvent scrubbing process for postcombustion CO_(2) capture from a coal-fired power plant.This integrated process has two stages:the first is a vacuum swing adsorption(VSA)process using activated carbon as the adsorbent,and the second stage is a solvent scrubber/stripper system using monoethanolamine (30 wt-%) as the solvent.The results showed that the adsorption process could enrich CO_(2) in the flue gas from 12 to 50 mol-% with a CO_(2) recovery of >90%,and the concentrated CO_(2) stream fed to the solvent scrubber had a significantly lower volumetric flowrate.The increased CO_(2) concentration and reduced feed flow to the absorption section resulted in significant reduction in the diameter of the solvent absorber,bringing the size of the absorber from uneconomically large to readily achievable domain.In addition,the VSA process could also remove most of the oxygen initially existed in the feed gas,alleviating the downstream corrosion and degradation problems in the absorption section.The findings in this work will reduce the technical risks associated with the state-of-the art solvent absorption technology for CO_(2) capture and thus accelerate the deployment of such technologies to reduce carbon emissions.

Dynamic modelling and simulation of a post-combustion CO_(2) capture process for coal-fired power plants

Solvent-based post-combustion capture technologies have great potential for CO_(2)mitigation in traditional coal-fired power plants.Modelling and simulation provide a low-cost opportunity to evaluate performances and guide flexible operation.Composed by a series of partial differential equations,first-principle post-combustion capture models are computationally expensive,which limits their use in real time process simulation and control.In this study,we propose a first-principle approach to develop the basic structure of a reduced-order model and then the dominant factor is used to fit properties and simplify the chemical and physical process,based on which a universal and hybrid post-combustion capture model is established.Model output at steady state and trend at dynamic state are validated using experimental data obtained from the literature.Then,impacts of liquidto-gas ratio,reboiler power,desorber pressure,tower height and their combination on the absorption and desorption effects are analyzed.Results indicate that tower height should be designed in conjunction with the flue gas flow,and the gas-liquid ratio can be optimized to reduce the reboiler power under a certain capture target.

Post-combustion slipstream CO_(2)-capture test facility at Jiangyou Power Plant, Sichuan, China: performance of a membrane separation module under dynamic power-plant operations

Membrane-based separation technologies have the potential to lower the cost of post-combustion CO_(2) capture from power-plant flue gases through reduced energy and capital costs relative to conventional solvent approaches.Studies have shown promise under controlled conditions,but there is a need for data on performance and reliability under field conditions.Coal-fired power plants in China operate in a dynamic manner,with increases and decreases in output causing changes in flue-gas composition.In this paper,we describe the first field test of a membrane-based post-combustion CO_(2)-capture system connected to a dynamically operating power plant in China.We report the performance of a Membrane Technology Research,Inc.(MTR)Polaris^(TM) membrane-based capture system over a range of plant operating loads ranging from 54%to 84%and conducted an operational stability test over a 168-h period during which the power plant was operating at an average load of 55%,but ramped as high as 79%and as low as 55%.Our results confirm the ability of a membrane capture system to operate effectively over a wide range of host-plant operating conditions,but also identity several issues related to plant integration,system control and resilience in the face of host-plant upsets that require attention as membrane separation systems move towards commercial use.

Advancement and new perspectives of using formulated reactive amine blends for post-combustion carbon dioxide (CO_(2)) capture technologies

Chemical absorption using amine-based solvents have proven to be the most studied,as well as the most reliable and efficient technology for capturing carbon dioxide(CO_(2))from exhaust gas streams and synthesis gas in all combustion and industrial processes.The application of single amine-based solvents especially the very reactive monoethanolamine(MEA)is associated with a parasitic energy demand for solvent regeneration.Since regeneration energy accounts for up to threeequarters of the plant operating cost,efforts in its reduction have prompted the idea of using blended amine solvents.This review paper highlights the success achieved in blending amine solvents and the recent and future technologies aimed at increasing the overall volumetric mass transfer coefficient,absorption rate,cyclic capacity and greatly minimizing both degradation and the energy for solvent regeneration.The importance of amine biodegradability(BOD)and low ecotoxicity as well as low amine volatility is also highlighted.Costs and energy penalty indices that influences the capital and operating costs of CO_(2) capture process was also highlighted.A new experimental method for simultaneously estimating amine cost,degradation rate,regeneration energy and reclaiming energy is also proposed in this review paper.

幔源岩浆去气形成富二氧化碳含金流体——可能性与现实性

综合国内外研究资料并结合笔者的研究成果 ,评述了幔源岩浆去气形成富二氧化碳含金流体的可能性和现实性。笔者认为 ,在地幔熔融和富集交代过程中可以形成富金和二氧化碳的岩浆 ,进一步在岩浆去气过程中金可以气相形式随二氧化碳排出 ,而一个由深部稳定热源驱动、富含幔源岩浆去气带入的二氧化碳和金并与地壳浅部流体混合的热液环流系统是形成重要金矿化的必要条件。

桂林漓江水体溶解无机碳迁移与水生光合碳固定研究

河流溶解无机碳含量昼夜变化主要受碳酸盐反向沉积、水生光合利用和脱气作用控制,被水生光合利用的溶解无机碳是岩溶碳汇的组成部分,脱气作用比例的大小是影响碳汇稳定性的决定因素。本文以漓江中游省里—冠岩之间15 km长河段为研究对象,开展昼夜高分辨率水化学自动化监测与高频取样,分析水生植物光合作用利用HCO^(-)_(3)及相关钙沉降过程。结果表明,监测河段水生光合利用的无机碳转化通量为859 kgC·d^(-1),单位流程光合作用溶解无机碳转化量和钙沉降量分别为2.06 t·(d·km)^(-1)和0.78 t·(d·km)^(-1)。光合作用与钙沉降消耗DIC约占总转化量的70%,以光合有机碳和CaCO3形式储存于河床,成为岩溶碳汇组成部分。无机碳转化量约占输入DIC总量的6.0%(其中1.7%以CO_(2)形式返回大气),说明夏季低水位期间强烈的水生植物光合利用溶解无机碳,可有效遏制白天水气界面CO_(2)脱气过程发生,低脱气比例证实漓江水体的溶解无机碳还是比较稳定的。

二氧化碳成因、成藏主控因素及脱气模式研究综述

高纯度的CO_(2)气藏不仅具有重要的资源意义,同时也有很重要的地质意义,CO_(2)气藏成因及主控因素研究已成为世界范围内地球科学领域广为关注的重要课题。对CO_(2)气藏的成因、鉴别方法、成藏主控等进行了系统的论述。结果表明:CO_(2)气藏的成因可以分为无机成因和有机成因,且以前者为主;CO_(2)气藏成因的判别主要是综合多种地球化学指标,结合天然气成藏地质条件来分析;高地温场、深大断裂和岩浆活动是CO_(2)气运聚成藏最重要、最直接的三大主控因素;幔源CO_(2)进入沉积盆地中具有4种脱气模式,即沿岩石圈断裂直接脱气模式、热流底辟体脱气模式、壳内岩浆房-基底断裂组合脱气模式和火山岩吸附气后期脱气模式。但在CO_(2)对油气运移聚集的影响、CO_(2)释放机理、脱气模式等方面的研究尚存一定的争议,将是未来主要的研究方向。