The effect of membrane pores wettability on CO_2 removal from CO_2/CH_4 gaseous mixture using NaOH, MEA and TEA liquid absorbents in hollow fiber membrane contactor

The present paper renders a modeling and a 2D numerical simulation for the removal of CO_2from CO_2/CH_4gaseous stream utilizing sodium hydroxide(NaOH),monoethanolamine(MEA)and triethanolamine(TEA)liquid absorbents inside the hollow fiber membrane contactor.Counter-current arrangement of absorbing agents and CO_2/CH_4gaseous mixture flows are implemented in the modeling and numerical simulation.Non-wetting and partial wetting modes of operation are considered where in the partial wetting mode,CO_2/CH_4gaseous mixture and liquid absorbents fill the membrane pores.The deteriorated removal of CO_2in the partial wetting mode of operation is mainly due to the mass transfer resistance imposed by the liquid in the pores of membrane.The validation of numerical simulation is done based on the comparison of simulation results of CO_2removal using Na OH and experimental data under non-wetting mode of operation.The comparison illustrates a desirable agreement with an average deviation of less than 5%.According to the results,MEA provides higher efficiency for CO_2removal in comparison with the other liquid absorbents.The order for CO_2removal performance is MEAN Na OHN TEA.The influence of non-wetting and partial wetting modes of operation on CO_2removal are evaluated in this article as one of the novelties.Besides,the percentage of CO_2sequestration as a function of gas velocity for various percentages of membrane pores wetting ranging from 0(non-wetting mode of operation)to 100%(complete wetting mode of operation)is studied in this research paper,which can be proposed as the other novelty.The results indicate that increase in some operational parameters such as module length,membrane porosity and absorbents concentration encourage the removal percentage of CO_2from CO_2/CH_4gaseous mixture while increasing in membrane tortuosity,gas velocity and initial CO_2concentration has unfavorable influence on the separation efficiency of CO_2.

Simulation and energy performance assessment of CO_2 removal from crude synthetic natural gas via physical absorption process

The paper presents an energy performance assessment of CO2 removal for crude synthetic natural gas （SNG） upgrade by Selexol absorption process. A simplified process simulation of the Selexol process concerning power requirement and separation performance was developed. The assessment indicates that less pressure difference between crude SNG and absorption pressure favors the energy performance of CO2 removal process. When both crude SNG and absorption pressures are 20 bar, CO2 removal process has the best energy performance. The optimal specific power consumption of the CO2 removal process is 566 kJ/kgCO2. The sensitivity analysis shows that the CO2 removal efficiency would significantly influence the total power consumption of the removal process, as well as higher heating value （HHV） and CO2 content in SNG. However, the specific power consumption excluding crude SNG and SNG compressions changes little with the variance of CO2 removal efficiency. If by-product CO2 is compressed for CO2 capture, the process would turn into a CO2-sink for the atmosphere. Correspondingly, an increase of 281 kJ/kgCO2 in specific power consumption is required for compressing the separated CO2.

Hierarchical Reduced Graphene Oxide-MnO_(2)@Polypyrrole Coaxial Nanotube Composite Hydrogel as a Potential Adsorbent for Cr(Ⅵ)Removal

A hierarchical reduced graphene oxide-MnO_(2)@polypyrrole coaxial nanotube composite hydrogel was prepared via oxidative polymerization of pyrrole in the presence of MnO_(2)nanotubes,followed by the hydrothermal treatment of graphene oxide and MnO_(2)@polypyrrole coaxial nanotubes.The stable composite hydrogel with a hierarchical network was composed of one-dimensional MnO_(2)@polypyrrole coaxial nanotube and two-dimensional graphene nanosheet and characterized by scanning electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction,Brunauer-Emmett-Teller surface,and X-ray photoelectron spectroscopy measurements.The composite hydrogel can be used as an efficient adsorbent for Cr(Ⅵ)removal due to the synergistic interaction between graphene and MnO_(2)@polypyrrole and the hierarchical structure of the hydrogel.Moreover,the composite hydrogel is easily separated because of its stable monolith,and it is reusable(76.8%of removal ability remaining after five adsorption-desorption cycles).The simple fabrication and cost-effective separation process together with the excellent absorption performance endow the composite hydrogel with great potential for practical wastewater treatment.

Efficient removal of Al(Ⅲ)and P507 from high concentration MgCl_(2)solution based on in-situ reaction strategy

For a highly efficient recycling of a wastewater containing a high concentration of MgCl_(2),Al(Ⅲ)and P507 were scheduled to be removed in advance.In this study,the in-situ removal of Al(Ⅲ)and P507 from a high concentration MgCl_(2)solution at different pH values and Al/P molar ratios was investigated.The results showed that P507 formed organic complexes of Al_(x)(OH)_y^(Z+)-P507 at pH of 2.0-4.0.At pH of 4.0-5.0,Al(Ⅲ)precipitated and transferred into Al(OH)_(3)with a flocculent amorphous morphology.Active sites on the Al(OH)_(3)surface enhanced the removal efficiency of P507.At pH of 6.0-6.5,Al(Ⅲ)and Mg(Ⅱ)formed layered crystalline Al(OH)_(3)and MgAl_(2)(OH)_(8with)small pore channels and fewer active sites,resulting in a reduced removal efficiency of P507.When the Al/P molar ratio exceeded 13 and the pH was between 4.0 and 5.0,the removal rates of both Al(Ⅲ)and P507 were higher than98%,while the concentration loss of Mg(Ⅱ)was only 0.2%-0.9%.

TiO2-PES Fibrous Composite Material for Ammonia Removal Using UV-A Photocatalyst

This study focused on the development and characterization of TiO2-PES composite fibers with varying TiO2 loading amounts using a phase inversion process. The resulting composite fibers exhibited a sponge-like structure with embedded TiO2 nanoparticles within a polymer matrix. Their photocatalytic performance for ammonia removal from aqueous solutions under UV-A light exposure was thoroughly investigated. The findings revealed that PeTi8 composite fibers displayed superior adsorption capacity compared to other samples. Moreover, the study explored the impact of pH, light intensity, and catalyst dosage on the photocatalytic degradation of ammonia. Adsorption equilibrium isotherms closely followed the Langmuir model, with the results indicating a correlation between qm values of 2.49 mg/g and the porous structure of the adsorbents. The research underscored the efficacy of TiO2 composite fibers in the photocatalytic removal of aqueous under UV-A light. Notably, increasing the distance between the photocatalyst and the light source resulted in de-creased hydroxyl radical concentration, influencing photocatalytic efficiency. These findings contribute to our understanding of TiO2 composite fibers as promising photocatalysts for ammonia removal in water treatment applications.

PRP点注联合CO_2点阵激光治疗烧伤后增生瘢痕的效果观察

观察自体富小板血浆(PRP)点注技术与CO_2点阵激光技术联合治疗烧伤后增生瘢痕的临床疗效和安全性。方法 将在本院烧伤整形科就诊的烧伤后并发瘢痕增生患者列为本次研究对象,依据访谈和研究知情同意书签署结果将知情同意参与本次研究的30例患者纳为观察组,并选择未参与本研究,接受常规治疗的30例患者作为对照组。对照组按照瘢痕增生常规给予CO_2点阵激光治疗;观察组采用自体PRP微针点注技术联合CO_2点阵激光治疗。每2个月治疗一次,连续治疗3次为一疗程,观察并记录治疗前后两组的皮损治疗效果、温哥华瘢痕量表(VSS)评分以及治疗过程中的不良反应发生率。结果 观察组统计共90.00%的治疗有效率高于对照组统计66.67%的治疗有效率,组间统计学差异明显(P<0.05);两组到诊时的首次VSS测试结果,平均得分相近(P>0.05),一疗程后,两组的VSS评分均有明显下降,观察组的下降幅度大于对照组(P<0.01);治疗过程中,观察组的不良反应发生率明显低于对照组(P<0.05)。结论 自体PRP点注技术联合CO_2点阵激光治疗烧伤后瘢痕增生,不仅疗效显著,且安全性高,还能有效改善VSS评分,值得临床推广用。

Effects of CO_2 enrichment and spikelet removal on rice quality under open-air field conditions

The increase of atmospheric carbon dioxide（CO_2） concentration adversely affect several quality traits of rice grains, but the biochemical mechanism remains unclear. The objectives of this study were to determine how changes in the source-sink relationship affected rice quality. Source-sink manipulation was achieved by free-air CO_2 enrichment from tillering to maturity and partial removal of spikelet at anthesis using a japonica rice cultivar Wuyunjing 23. Enrichment with CO_2 decreased the head rice percentage and protein concentration of milled rice, but increased the grain chalkiness. In contrast, spikelet removal resulted in a dramatic increase in the head rice percentage and protein concentration, and much less grain chalkiness. Neither CO_2 enrichment nor spikelet removal affected the starch content, but the distribution of starch granule size showed distinct treatment effects. O n average, spikelet removal decreased the percentage of starch granules of diameter 〉10 and 5–10 μm by 23.6 and 5.6%, respectively, and increased those with a diameter of 2–5 and 〈2 μm by 4.6 and 3.3%, respectively. In contrast, CO_2 elevation showed an opposite response： increasing the proportion of large starch granules（〉5 μm） and decreasing that of 〈5 μm. The starch pasting properties were affected by spikelet removal much more than by CO_2 elevation. These results indicated that the protein concentration and starch granule size played a role in chalkiness formation under these experimental conditions.

A novel application of the SAWD-Sabatier-SPE integrated system for CO_2 removal and O_2 regeneration in submarine cabins during prolonged voyages

To improve the working and living environment of submarine crews, an integrated system of CO2 removal and O2 regeneration was designed to work under experimental conditions for 50 people in a submarine cabin during prolonged voyages. The integrated system comprises a solid amine water desorption （SAWD） unit for CO2 collection and concentration, a Sabatier reactor for CO2 reduction and a solid polymer electrolyte （SPE） unit for O2 regeneration by electrolysis. The performances of the SAWD-Sabatier-SPE integrated system were investigated. The experimental results from the SAWD unit showed that the average CO2 concentration in the CO2 storage tank was more than 96% and the outlet CO2 concentration was nearly zero in the first 45 min, and less than 1/10 of inlet CO2 after 60 min when input CO2 was 0.5% （1000 L）. About 950 L of CO2 was recovered with a recovery rate of 92%-97%. The output CO2 concentration was less than 0.2%, which showed that the adsorption-desorption performance of this unit was excellent. In the CO2 reduction unit we investigated mainly the start-up and reaction performance of the Sabatier reactor. The start-up time of the Sabatier reactor was 6, 8 and 10 rain when the start-up temperature was 187.3, 179.5 and 168 ℃, respectively. The product water was colorless, transparent, and had a pH of 6.9-7.5, and an electrical conductivity of 80μs/cm. The sum of the concentration of metal ions （Ru^3＋, Al^3＋, Pb^2＋） was 0.028% and that of nonmetal ions （Cl^-, SO4^2-） was 0.05%. In the O2 regeneration unit, the O2 generation rate was 0.48 m^3/d and the quantity was 2400 L, sufficient to meet the submariners＇ basic oxygen demands. These results may be useful as a basis for establishing CO2-1evel limits and O2 regeneration systems in submarines or similar enclosed compartments during prolonged voyages.

Controllably partial removal of thiolate ligands from unsupported Au_(25) nanoclusters by rapid thermal treatments for electrochemical CO_(2)reduction

Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.

Highly Selective Electrocatalytic CuEDTA Reduction by MoS_(2) Nanosheets for Efficient Pollutant Removal and Simultaneous Electric Power Output

Electrocatalytic reduction of ethylenediamine tetraacetic acid copper(CuEDTA),a typical refractory heavy metal complexation pollutant,is an environmental benign method that operates at mild condition.Unfortunately,the selective reduction of CuEDTA is still a big challenge in cathodic process.In this work,we report a MoS_(2) nanosheet/graphite felt(GF)cathode,which achieves an average Faraday efficiency of 29.6%and specific removal rate(SRR)of 0.042 mol/cm^(2)/h for CuEDTA at−0.65 V vs SCE(saturated calomel electrode),both of which are much higher than those of the commonly reported electrooxidation technology-based removal systems.Moreover,a proofof-concept CuEDTA/Zn battery with Zn anode and MoS_(2)/GF cathode is demonstrated,which has bifunctions of simultaneous CuEDTA removal and energy output.This is one of the pioneer studies on the electrocatalytic reduction of heavy metal complex and CuEDTA/Zn battery,which brings new insights in developing efficient electrocatalytic reduction system for pollution control and energy output.

二氧化碳-水-岩作用机理及微观模拟方法研究进展

系统综述CO_(2)-水-岩复杂作用机理、多孔介质反应输运(溶解、沉淀及沉淀运移)微观模拟、CO_(2)-水-岩系统微观模拟3个方面的研究进展,指出目前研究存在的主要问题并提出了关于未来研究方向的建议。CO_(2)注入储集层后,不仅存在常规渗流体系的流动和传质作用,还会产生溶解、沉淀及沉淀运移等特殊物理化学现象,其耦合作用导致多孔介质的孔渗参数变化规律复杂。孔隙尺度的微观渗流模拟,可以得到孔喉三维空间内的详细信息,且能显性观察到多孔介质流-固界面随反应的变化。目前研究主要在复杂作用机理解耦合、多矿物差异性反应表征、沉淀生成机理及表征(晶体成核和矿物脱落)、沉淀-流体相互作用模拟方法、多物理化学过程耦合渗流机制等方面存在局限。未来研究中,需要创新实验方法对“溶解—沉淀—沉淀运移”解耦合,提高矿物地球化学反应相关参数实验测试的准确度,在不同沉淀机理可靠表征的基础上,建立沉淀-流体相互作用模拟方法,并有机耦合各个物理化学过程,最终实现对CO_(2)-水-岩系统中“溶解—沉淀—沉淀运移”的耦合渗流模拟。

煤矿充填固碳理论基础与技术构想

在国家“双碳”目标背景下,如何减少煤炭行业的碳排放、实现碳封存已成为亟待解决的难题。煤炭行业作为高碳化石能源生产者和主体碳排放源提供者,在生产和消费过程中引发的大宗固废堆存、大型采空区形成和大量CO_(2)排放是制约煤炭可持续开发利用与绿色健康发展的瓶颈所在。为协同解决二氧化碳封存与矿山固废消纳问题,将大宗固废处置、固废高值化利用、CO_(2)封存、采空区利用有机结合,提出了二氧化碳充填的理念,从碳汇能力评估角度界定了二氧化碳充填的3种类型。具体开展工作包括:①分析了CO_(2)充填料浆输运过程和矿化反应过程涉及到的基础理论,给出了各个过程的数学方程以及碳封存量计算公式,指出了温度、湿度等因素对矿化反应机理、碳封存量和充填体强度的影响规律。②总结了现阶段CO_(2)矿化的工艺方法、主要碱性工业固废的CO_(2)封存能力和CO_(2)矿化强化措施。在此基础上提出了基于直接湿法矿化和间接矿化的2种CO_(2)充填材料制备工艺,满足矿井充填的流动性、凝固特性和强度要求。③针对CO_(2)充填过程中的CO_(2)物理封存问题,提出了窄条带式胶结充填和综采架后胶结充填2种技术路径,前者通过在弱充填条带中构筑多贯通孔隙的充填体CO_(2)物理封存,后者借助充填支架和链式自行充填挡板在长壁工作面采空区中间断构筑充填带,控制顶板垮落,形成CO_(2)物理化学封存空间。④为了评估CO_(2)充填的碳平衡效果,依据全生命周期法界定了CO_(2)充填中碳足迹及碳消纳的计算边界。然后,梳理了CO_(2)充填过程中的碳足迹及碳消纳,分别考虑了CO_(2)的来源、用量、损耗、转化等因素。给出了包括原料运输、充填料浆制备、井下注入与充填等过程中的碳足迹及碳消纳计算方法。研究成果有望降低CO_(2)封存的能耗及成本,对煤炭绿色开采及其可持续开发利用具有深远的意义。

Estimation of actual carbon dioxide removal in burned forests using satellite data:A case study in South Korea

With the increasing impact of climate change,carbon emissions and removals have become major issues.Forests are major carbon pools,and forest fires are an essential part of the carbon cycle.This study introduces a model for estimating the detailed actual CO_(2)removal in burned forests using burn severity and tree survivability.Actual CO_(2)removal was estimated from empirical yield tables without using the standard carbon removal provided by the national inventory.The primary CO_(2)calculation method followed the guidelines of the International Panel on Climate Change.The burn severity was mapped using Sentinel-2 multispectral instrument data,and the survivability of each forest type was estimated according to burn severity.The survivability was applied to the pre-fire CO_(2)removal of each forest to estimate post-fire CO_(2)removal.In our case study,the burned forest area was 1,034 ha,and the CO_(2)removal before the fire was 8,615.3t/year.After the fire,removal decreased by 81.2%to 1,618.4 t/yr.In particular,the decrease in coniferous forests was high,more than 86%.The lack of survivability data on burned trees was a major limitation of our study.Systematically accumulating field monitoring data of post-fire forests will be necessary for future research and could serve as a reference for devising immediate countermeasures against forest fires.

胜利油田GF84区块CCUS气窜封堵技术及其应用

胜利油田GF84区块为低渗透油藏,采出程度较低,CO_(2)驱是提高该区块采收率的有效措施之一。在前期开发中注采井之间已形成明显的气窜通道,现阶段亟需进行气窜封堵,提高CO_(2)驱波及系数,实现均衡驱替。通过分析GF84区块气窜特征与开发矛盾,将气窜类型划分为“裂缝型气窜”和“基质型气窜”,并制定了“裂缝封堵”和“基质调剖”的治理策略。在明确气窜特征的基础上,通过室内实验研发了硅盐树脂堵剂、CO_(2)气溶性发泡剂和高温冻胶堵剂,并形成了“硅盐树脂裂缝封堵+CO_(2)气溶性发泡剂、高温冻胶基质调剖”化学封堵分级调控技术。结果表明,该技术在GF84区块成功应用4口井,其中硅盐树脂裂缝封堵2口井,CO_(2)气溶性发泡剂基质调剖2口井,措施有效率100%,有效期在0.5 a以上。研究成果可为低渗透油田CO_(2)驱开发提供技术支撑。

油气田刺激响应性材料应用现状及前景展望

油田化学品在钻井完井、压裂酸化、调剖堵水、乳化降黏、油水分离等环节发挥关键作用,但低渗透、高温、高盐、极端pH及使用过程中温度、pH变化等苛刻油气藏环境,给应用于油田化学品的聚合物和表面活性剂的研发带来了严峻的挑战。引入磺酸基等抗温抗盐基团或增大驱油剂相对分子质量等传统方式已难以满足油田需求。该文介绍了温度敏感聚合物、pH敏感聚合物、磁响应聚合物、CO_(2)敏感聚合物及表面活性剂、盐度敏感聚合物响应环境变化的刺激响应原理和性能;综述了5种刺激响应性材料在钻井完井、提高采收率、乳化破乳、压裂酸化、调剖堵水、油水分离等方向的应用,展望了刺激响应性材料在油气开采中的发展前景。

新能源用钢管的应用现状、需求分析及思考

“双碳”战略下新能源及相关产业发展给钢管带来新的应用场景,对钢管的功能和性能提出新的需求。聚焦于碳捕获、利用与封存技术领域中的CO_(2)输送用管、氢能领域中的氢气输送用管和储能领域中的盐穴压缩空气储能用注采管,总结了新能源用钢管的应用现状和研究进展,分析了各领域用管需求,并就“双碳”背景下新能源用钢管的基础理论研究、关键技术开发和标准体系建设等方面进行了思考,提出了建议。

海洋CO_(2)地质封存研究进展与发展趋势

CO_(2)捕集、利用和封存是中国实现“双碳”目标的核心技术,也是全球研究的热点。CO_(2)地质封存是其中的关键环节,特别是海洋CO_(2)地质封存是今后的重点发展方向。以国内外海洋CO_(2)地质封存的发展历程为基础,结合典型CO_(2)海洋封存示范项目案例,系统梳理了国内外海洋CO_(2)地质封存理论研究进展,分析了CO_(2)在井筒流动、相变与传热、CO_(2)流体运移与储层物性参数展布规律、海洋地质封存机制及封存潜力、地质封存盖层完整性及安全性评估等方面的研究现状。认识到中国目前对海底地质结构中CO_(2)注入过程的多相态转化、溶解、捕获传质特征及动力学特性认识尚浅,对海洋封存机制及不同封存机制之间的相互作用机理尚不明确,未来应开展海洋CO_(2)动态地质封存空间重构机制研究,解决地质封存相态转化及流体动态迁移机理等关键科学问题,揭示海洋CO_(2)地质封存机制的相互作用机理,形成适用于中国海洋地质封存CO_(2)高效注入和增效封存方法。

二氧化碳置换法开采天然气水合物研究进展

应用CO_(2)置换法开采天然气水合物被认为是一种极具潜力的提高CH_(4)采收率和CO_(2)埋存率的技术。论述了CO_(2)及其混合气置换法开采天然气水合物的机理,梳理了CO_(2)混N_(2)/H_(2)及地热辅助CO_(2)提高水合物中CH_(4)采收率的技术进展。研究表明:①应用纯CO_(2)置换开采天然气水合物时,CH_(4)的采收率较低,而将CO_(2)与N_(2)、H_(2)以不同比例混合后注入天然气水合物藏中进行CH_(4)开采,能够有效提高CH_(4)的采收率。②CO_(2)与N_(2)或H_(2)混合注入水合物层时,多种气体分子在竞争吸附作用下降低了CH_(4)分子与水合物分子笼之间的范德华力,同时降低了混合气中CO_(2)的分压,导致水合物相平衡曲线上移,抑制了置换过程中CO_(2)水合物的生成速率,减轻了包裹作用的不利影响,从而提高CH_(4)采收率。③CO_(2)混合N_(2)注入开采水合物时,N_(2)的混入虽然能够减轻包裹作用的影响,但新形成的N_(2)水合物会堵塞CO_(2)进入水合物分子笼的通道,因此提高CH_(4)采收率效果有限。④在水合物层条件下H_(2)并不会形成新的水合物,而且混入少量的H_(2)又会与N_(2)发生吸附竞争,从而抑制N_(2)水合物的形成,故将低浓度的H_(2)气混入CO_(2)与N_(2)的混合气中能够进一步提高对水合物中CH_(4)的置换率,从而提高CH_(4)的采收率。因此,混入H_(2)被认为是提高CO_(2)置换开发水合物效果的重要途径。⑤混合气周期注气方式可明显提高水合物中CH_(4)的采收率和CO_(2)水合物藏封存率。⑥应用地热辅助CO_(2)开采水合物的方法也能够降低新形成水合物的包裹作用,同时实现CO_(2)在地热层和水合物层的两次埋存,在提高CH_(4)采收率的同时,大大提高CO_(2)在地层中的埋存率。

黄铁矿在CO_(2)气氛下非等温氧化转化及动力学分析

针对煤中常见含铁矿物黄铁矿在富氧燃烧典型气氛下转化特性,通过同步热分析结合烟气分析研究了黄铁矿在CO_(2)气氛下的转化行为.结果发现,黄铁矿在CO_(2)气氛下主要经历5个失重阶段且均为吸热过程,首先是黄铁矿颗粒表面硫脱除的起始热解段(相界面反应,n=1/2),活化能低于其在N_(2)气氛下近30 kJ/mol,为220.27 kJ/mol,随后裂解成磁黄铁矿(三维扩散,n=1/2)活化能与其在N_(2)(177.27 kJ/mol)下接近为178.1 kJ/mol;温度高于690℃,随着升温磁黄铁矿缓慢失硫,CO_(2)逐渐参与磁黄铁矿转化且释放SO_(2)和CO;820~1150℃经历双峰失重峰阶段,820~1020℃,氧化气体产物SO_(2)大量生成且在约1000℃达到体积浓度峰值;最后1020~1150℃,坩埚中残留物大量与CO_(2)持续氧化反应失重形成SO_(2)和CO,坩埚中形成复杂物相体系,铁硫化物和铁氧化物共存(或共融).CO_(2)参与黄铁矿产物转化失重阶段活化能分别为180.94 kJ/mol、229.69 kJ/mol和243.46 kJ/mol,动力学机制均为成核与生长(n=1).

大型燃煤发电机组低碳技术进展

当前我国碳排放总量约110亿t,其中约40%的CO_(2)由燃煤机组产生,如何降低燃煤发电机组的碳排放是实现双碳目标的关键。针对燃煤发电机组大规模减碳技术,重点介绍低碳/零碳燃料替代技术(生物质、污泥、氢/氨等)和CCUS技术的研究进展:燃煤电厂耦合生物质包括直接耦合和间接耦合,但均受制于生物质原料供应和价格,生物质“种植—收割—转运—储存—预处理—燃烧”全链条控制掺烧模式可有效解决上述问题。660 MW机组掺烧试验表明,CO_(2)排放可减少77.25万t/a;市政污泥含水率高达80%,进入锅炉前需干化处理,目前蒸汽或烟气干化均存在投资运行成本高、干化后的污泥水分较大且有臭气等问题,导致掺烧比例一般低于8%。基于生物质热源的污泥炭化技术可直接在污水厂生产无臭污泥炭,热值达10.26 MJ/kg左右,电厂掺烧比例可提高至20%~30%;掺烧氢/氨燃料需解决大比例掺烧下氨逃逸和NOx排放问题,国内已开展皖能集团300 MW和国家能源集团600 MW氨煤掺烧实验,通过燃烧调控可在NOx排放略微增加的情况下实现较高的NH3燃烬率,但商业化推广还受制于氢/氨成本;燃烧前脱碳技术(IGCC电站)的商业化运行案例极为有限,由于高居不下的成本,国外多个示范项目均已停运,推动该技术商业化需解决建设成本、发电成本和设备可靠性等问题。燃烧中碳捕集包括富氧燃烧和化学链燃烧,由于空分、再循环等过程能耗,常压富氧发电效率比空气燃烧低8%~12%,从常压富氧到加压富氧可进一步提高净发电效率;我国已建成全球最大的4 MW化学链燃烧示范装置,该技术也有望应用于气化领域;燃烧后碳捕集目前以溶液吸收技术为主,固体吸附技术的再生能耗更低,但大规模商业化需要继续降低能耗和成本。