Efficient MgO-doped CaO sorbent pellets for high temperature CO2 capture

Novel MgO-doped CaO sorbent pellets were prepared by gel-casting and wet impregnation. The effect of Na⁺ and MgO on the structure and CO₂ adsorption performance of CaO sorbent pellets was elucidated. MgO-doped CaO sorbent pellets with the diameter range of 0.5-1.5 mm exhibited an excellent capacity for CO₂ adsorption and adsorption rate due to the homogeneous dispersion of MgO in the sorbent pellets and its effects on the physical structure of sorbents. The results show that MgO can effectively inhibit the sintering of CaO and retain the adsorption capacity of sorbents during multiple adsorption-desorption cycles. The presence of mesopores and macropores resulted in appreciable change of volume from CaO (16.7 cm³∙mol⁻¹) to CaCO₃ (36.9 cm³∙mol⁻¹) over repeated operation cycles. Ca2Mg1 sorbent pellets exhibited favorable CO₂ capture capacity (9.49 mmol∙g⁻¹), average adsorption rate (0.32 mmol∙g⁻¹∙min⁻¹) and conversion rate of CaO (74.83%) after 30 cycles.     

CCUS in a net-zero U.S. power sector: Policy design,rates, and project finance

Carbon capture utilization and storage is an important technology option to rapidly and profoundly decarbonize the power sector, but will not deploy without substantial incentives or regulation. Assessment of U.S. policy options reveals that current incentives only partially close the finance gap and are most sensitive to fuel type and ownership structure. Recent proposed legislation would in some designs attract private investment for many projects, leading to widespread deployment of CCUS in the power sector. Additional constraints and concerns (including technology options and presence of CO₂ infrastructure) could play an important secondary role. This study discusses the specific US incentive policies that can provide investors and lenders with net cash flows that are adequate to attract private capital to CCUS power projects in the US.     

Environmental and climate justice and technological carbon removal

Environmental justice (EJ) and climate justice are becoming central foci of climate policy. Awareness is also growing on the need for some amount of carbon dioxide removal (CDR) to curb warming to 1.5 °C. In this paper we map dimensions of environmental and climate justice that stakeholders and communities will need to consider -- from local to global scales. Mapping issues is a step towards developing frameworks to undertake CDR in an environmentally just way.     

先进控制技术在波浪发电系统中的应用

由于波浪储量丰富,具有随机性,如何控制波能转换系统捕获最大波能和控制并网电能质量成为波浪发电的核心问题。简述了波能转换装置实现最大波能捕获的方法,综述了滑模变结构控制、自适应控制、最优控制、智能算法、模糊控制、无源控制在控制最大波能捕获以及改善电能质量方面的研究成果。并提出未来的控制算法应是多种先进控制算法相结合。     

A large-scale experimental study on CO2 capture utilizing slurry-based ab-adsorption approach

The increasing concentration of CO_2 in atmosphere is deemed the main reason of global warming.Therefore,efficiently capturing CO_2 from various sources with energy conservation is of great significance.Herein,a series of experiments were carried out to successfully test the slurry-based ab-adsorption method for continuously capturing CO_2 in the large-scale cycled separation unit with cost-effect taking into account the scale-up criteria.A bubble column(with height 4900 mm and inner diameter 376 mm) and a desorption tank(with volume 310 L) are the essential components of the separation unit.The novel slurry used in this study was formed with zeolitic imidazolate framework-8 and 2-methylimidazole-water solution.The influence of operation conditions was investigated systematically.The results show that increasing sorption pressure and slurry height level,decreasing gas volume flow and sorption temperature are beneficial for separation processes.The volume fraction of CO_2 in the feed gas was also studied.Although the scale-up effect had been observed and it was found that it exerted a negative effect on CO_2 capture,depending on experimental conditions,CO_2 removal efficiency could still reach 85%-95% and the maximum CO_2 loading in the recycled slurry could be up to0.007 mol·L~(-1)·kPa~(-1).Furthermore,the slurry-based method could be operated well even under very moderate regeneration conditions(333 K and 0.05 MPa),which means that the novel approach shows greater energy conservation than traditional amine absorption methods.     

Reactivity study and kinetic evaluation of CuO-based oxygen carriers modified by three different ores in chemical looping with oxygen uncoupling (CLOU) process

In the chemical looping with oxygen uncoupling (CLOU) process,CuO is a promising material due to the high oxygen carrier capacity and exothermic reaction in fuel reactor but limited by the low melting point.The combustion rate of carbon is faster than the decoupling rate of oxygen carrier (OC).Hence,high tem-perature tolerance and rapid oxygen release rate of CuO modified by three different ores were investi-gated in this study.The kinetics analysis of oxygen decoupling with Cu-based oxygen carriers was also evaluated.Results showed that CuO modified by chrysolite had faster oxygen release rate than that of CuO.Limestone showed obvious positive effect on the oxidization process.The selected OCs could keep stable in at least 20 cycles,for about 1200 min.Shrinking core model (SCM) fitted well for the decoupling process in the temperature range of 1123-1223 K.Reduction rate kinetic information may aid in the development of chemical looping with oxygen uncoupling (CLOU) technologies during reactor design and process modeling.Ternary doped copper oxide with chrysolite and limestone could improve the reactivity of CuO in decoupling and coupling process and also improve the high temperature tolerance.     

低温洗涤法烟气脱硫脱碳工艺模拟研究

本文提出了一种通过低温戊烷液体洗涤烟气将CO2和SO2同时冷凝脱除的烟气处理工艺。该工艺采用2塔喷淋冷却方式冷却烟气,第1个喷淋塔采用冷冻水喷淋降温至接近冰点,第2个喷淋塔采用低温正戊烷液体喷淋降温至SO2和CO2的凝华温度,洗涤冷凝得到的SO2、CO2和H2O等组分不溶于正戊烷,故而从洗涤液分离出来。本文基于ASPEN PLUS软件建立600 MW 燃煤机组低温冷凝法脱硫脱碳工艺模型,通过物料和能量平衡计算,对SO2和CO2脱除效率和系统能耗进行了分析。结果表明:将烟气降温至–116 ℃时,CO2捕集率达到90%,SO2脱除率接近100%;当捕集的CO2以气态形式存在时,系统能耗约为80.25 MW（188.6 kW·h/t）,当捕集的CO2以液态形式存在时,系统能耗约为114.56 MW（269.2 kW·h/t）,比传统醇胺吸收法脱碳能耗降低30%左右。     

纳米颗粒强化胺法吸收CO2研究进展

碳捕集、利用与封存（CCUS）技术是缓解全球气候变化的重要措施之一。纳米颗粒因具有良好表面效应和体积效应,能够强化CO2捕集传质性能而备受青睐,其可增大胺法吸收CO2过程中的传质系数并减少溶剂再生所需的能量,有望进一步提高CO2捕集效率、降低能耗。本文从纳米颗粒强化胺法吸收CO2过程出发,讨论了纳米颗粒强化吸收的3种机理（抑制气泡聚并机理、传输机理、边界层混合机理）,总结了近年来国内外最新研究进展,论述了纳米颗粒强化CO2吸收过程中的主要影响因素,指出纳米颗粒对CO2吸收过程的强化是多重因素共同作用的结果,并对该技术的未来研究方向作了展望。     

碳酸酐酶在功能化Fe3O4-SiO2核壳纳米颗粒上的固定及其性能表征研究

以Fe3O4纳米颗粒为核,正硅酸乙酯（TEOS）为前驱体,通过St?ber法合成了Fe3O4-SiO2核壳纳米颗粒。以γ-缩水甘油醚氧丙基三甲氧基硅烷（GPTMS）为改性剂对纳米颗粒进行改性,得到了环氧基功能化的Fe3O4-SiO2核壳纳米颗粒,随后将碳酸酐酶（carbonic anhydrase,CA）共价固定到纳米颗粒上,以实现CA固定化。采用傅立叶红外（FTIR）、透射电镜（TEM）等手段对载体材料进行表征;以对硝基苯酚乙酸酯（p-NPA）为底物,采用紫外分光光度仪测试酶活力,并对固定化酶进行了性能表征。试验结果表明,固定化酶的热稳定性、贮藏稳定性和循环使用性均优于同等条件下的游离酶,其在循环使用10次后仍保持84.2%的相对酶活力。     

中国煤电生命周期二氧化碳和大气污染物排放相互影响建模分析

煤电在中国电力供应结构中占据主导地位,其环境影响是研究热点之一。建立中国煤电生命周期二氧化碳和大气污染物排放分析模型,基于文献调研构建参数数据库,测算中国煤电的单位发电量排放。结果表明,近年来中国煤电生命周期单位发电量的CO₂、SO₂、NO_x和PM_2.5排放分别为838.6 g/（kW·h）、0.34 g/（kW·h）、0.32 g/（kW·h）和0.08 g/（kW·h）。其中煤电单位发电量大气污染物排放,比实施超低排放改造前,下降幅度超过90%。研究发现,增大单机机组规模和进行超低排放改造能够有效降低煤电发电过程的大气污染物排放,采用煤电燃烧后碳捕集和存储(carbon capture and storage, CCS)处理技术能够使煤电CO₂排放下降到144 g/（kW·h）,助力碳中和目标实现。如果不采用更加严格的大气污染物排放标准和处理方式,CCS技术可能会使煤电大气污染物排放强度上升30%~40%,这与碳捕集过程使用的技术有关。