Electrochemical reduction of carbon dioxide to produce formic acid coupled with oxidative conversion of biomass

Electrochemical reduction of CO_(2)(CO_(2)RR)has become a research hot spot in recent years in the context of carbon neutrality.HCOOH is one of the most promising products obtained by electrochemical reduction of CO_(2) due to its high energy value as estimated by market price per energy unit and wide application in chemical industry.Biomass is the most abundant renewable resource in the natural world.Coupling biomass oxidative conversion with CO_(2)RR driven by renewable electricity would well achieve carbon negativity.In this work,we comprehensively reviewed the current research progress on CO_(2)RR to produce HCOOH and coupled system for conversion of biomass and its derivatives to produce value-added products.Sn-and Bi-based electrocatalysts are discussed for CO_(2)RR with regards to the structure of the catalyst and reaction mechanisms.Electro-oxidation reactions of biomass derived sugars,alcohols,furan aldehydes and even polymeric components of lignocellulose were reviewed as alternatives to replace oxygen evolution reaction(OER)in the conventional electrolysis process.It was recommended that to further improve the efficiency of the coupled system,future work should be focused on the development of more efficient and stable catalysts,careful design of the electrolytic cells for improving the mass transfer and development of environment-friendly processes for recovering the formed formate and biomass oxidation products.

New Problems of Boiler Corrosion after Coupling Combustion of Coal and Biomass and Anti-Corrosion Technologies

This study explores the corrosion issues arising from the coupled combustion of coal and biomass and proposes potential solutions.Biomass,as a renewable energy source,offers advantages in energy-saving and carbon reduction.However,the corrosive effects of alkali metal compounds,sulfur(S)and chlorine(Cl)elements in the ash after combustion cannot be underestimated due to the high volatile content of biomass fuels.We investigate the corrosion mechanisms,as well as the transfer of Cl and alkali metal elements during this process.Comparative corrosion analyses are conducted among coal-fired boilers,pure biomass boilers and boilers with coupled combustion.Various biomass types in co-firing are studied to understand different corrosion outcomes.The main factors influencing corrosion include the physicochemical properties of biomass feedstock,furnace temperature and heating surface materials,with the chemical composition and ash content of biomass playing a dominant role.Currently,the methods used for anti-corrosion include water washing pretreatment of biomass feedstock,application of novel alloys and coatings and the development of additives to inhibit fouling,ash deposition and corrosion.Efficient inhibitors are economical and easy to produce.Additionally,biomass can be converted into biomass gasification gas,although challenges related to tar still need to be addressed.

Simulated biomass tar removal mechanism by a Quench Coupled with ADsorption Technology(QCADT)

Tar removal is a bottleneck in the smooth commercialization of biomass gasification technology. Based on introducing adsorption process into Quench Coupled with ABsorption Technology(QCABT) previously proposed by the author’s group, Quench Coupled with ADsorption Technology(QCADT) has been developed to narrow this gap. Additionally, benzene and naphthalene, which are more similar to the real tar for containing aromatic ring structures, were adopted as light and heavy simulated tar, respectively. Also their removal behavior by QCADT was investigated. The results show that the removal mechanism of QCADT is similar to that of QCABT, except for the higher overall tar removal rate due to adsorption effect. Adsorbents with both micro-and narrow mesopores exhibit a better benzene removal performance, while narrow mesopores play dominant roles in naphthalene removal. Penetration adsorption loading of benzene and naphthalene on AC-1 can reach0.38 g·g^-1 and 0.34 g·g^-1, respectively. The sawdust hardly has any tar removal effect. Combined micro-and meso-pores, will benefit both deep tar removal and large adsorption rate, providing a high tar removal efficiency.

System Performance and Pollution Emission of Biomass Gas Co-Firing in a Coal-Fired Boiler

To reduce greenhouse gases emission and increase the renewable energy utilization portion in the world, the biomass gasification coupled with a coal-fired boiler power generation system is studied. It is a challenge to achieve optimum performance for the coupled system. The models of biomass gasification coupled with co-firing of coal in a boiler have been established. A comparative study of three kinds of biomass (Food Rubbish, Straw and Wood Pellets) has been done. The syngas produced in a 10 t/h gasifier is fed to a 330 MWe coal-fired boiler for co-combustion, and the co-firing performances have been compared with pure coal combustion case under the conditions of constant boiler load. Results show that co-firing decreases the furnace combustion temperature and raises the flue gas temperature for Food Rubbish and Straw, while, flue gases temperature decrease in case of Wood Pellets. At the same time NOx and SOx emissions have reduced. The system efficiencies at constant load for Food Rubbish, Straw and Wood Pellets are 83.25%, 83.88% and 82.56% when the optimum conditions of gasification and co-firing process are guaranteed.

Metal vacancy-enriched layered double hydroxide for biomass molecule electrooxidation coupled with hydrogen production

The electrochemical oxidation of biomass molecules coupling with hydrogen production is a promising strategy to obtain both green energy and value-added chemicals;however,this strategy is limited by the competing oxygen evolution reactions and high energy consumption.Herein,we report a hierarchical CoNi layered double hydroxides(LDHs)electrocatalyst with abundant Ni vacancies for the efficient anodic oxidation of 5-hydroxymethylfurfural(HMF)and cathodic hydrogen evolution.The unique hierarchical nanosheet structure and Ni vacancies provide outstanding activity and selectivity toward several biomass molecules because of the finely regulated electronic structure and highly-exposed active sites.In particular,a high faradaic efficiency(FE)at a high current density(99%at 100 mA cm^(-2))is achieved for HMF oxidation,and a two-electrode electrolyzer is assembled based on the Ni vacancies-enriched LDH,which realized a continuous synthesis of highly-pure 2,5-furandicarboxylic acid products with high yields(95%)and FE(90%).

电厂和政府行为策略演化博弈与仿真研究——基于农林生物质与煤耦合发电产业发展视角

“双碳”背景下,农林生物质与煤耦合发电成为煤电转型的新路径。政府如何制定有效的补贴和监管政策,以及电厂如何进行正确的策略选择是促进农林生物质与煤耦合发电产业发展的关键。通过构建政府和电厂的混合策略博弈模型,分析双方的博弈关系和行为策略动态演变过程,并运用系统动力学进行建模仿真,进一步探析关键因素对政府和电厂行为策略的影响路径。结果表明:政府和电厂的行为策略在较长时期里无法趋于稳定,而是在相互影响中波动变化。政府制定补贴和监管策略、提高耦合发电收益、降低耦合发电成本,都将促进更多电厂选择农林生物质与煤耦合发电,从而进一步促进产业发展。

全可再生能源多能互补系统优化配置与运行探索

在机组100%为全可再生能源的多能互补系统的基础上,通过部分市网供电及“隔墙售电”消纳改进其容量配置和调度优化模型并通过LINGO求解,考察市网供电和“隔墙售电”对系统经济性和碳排放参数的影响。结果表明:随着隔墙售电的电价增长,系统的运行费用及蓄电池的容量随之下降,在售电电价增至0.33元/kWh后蓄电池单元容量趋于稳定;在售电电价达到0.37元/kWh后系统不再因电价的上升而引起系统运行策略的改变;园区多能互补系统相比不参与“隔墙售电”的传统系统,系统年总费用降低25.9%,年运行成本降低37.8%,碳排放强度由76.9 kgCO_(2)/(m^(2)·a)降至52.3 kgCO_(2)/(m^(2)·a)。

适用于生物质直接耦合煤发电过程的温室气体核算方法优化

生物质与煤直接耦合燃烧发电作为降低火电行业碳排放的关键技术选择得到广泛关注,在双碳目标的推动下,准确量化生物质掺烧电力生产过程温室气体排放能有效提升发电行业碳排放数据的准确性与一致性,确保国内碳排放交易市场向更公平稳定的方向发展。介绍了国内外生物质耦合煤发电机组碳核算方法,提出生物质直接耦合发电机组温室气体核算边界、计算方法和核算参数的选取原则。结果表明:与现行核算法相比,基于生物质直接耦合煤发电的温室气体核算方法在核算边界、核算范围和计算方法上均有一定差异。对于核算边界,有必要新增燃料燃烧过程N_(2)O排放、新增设备资源带来的间接碳排放;针对常见生物质是否可视为零碳燃料进行评估,发现在各省份生物质的最佳经济运输半径内秸秆、城市垃圾、林类剩余物等常见生物质均达到温室气体减排要求,且合理运输范围(48 km)内均可视为零排放;在计算方法上,燃料消耗量建议根据碳排放量分层级选取测定方法,小比例掺烧时碳氧化率可直接选取缺省值99%,并且建议核算脱硫环节带来的碳排放,对循环流化床燃烧温度在1123 K以下的工况需要进行N_(2)O核算。

300 MW循环流化床锅炉燃煤耦合生物质燃烧及污染物排放特性试验研究

在碳达峰、碳中和背景下,发展燃煤与生物质耦合发电是加快电力转型升级、实现煤电低碳发展的重要途径之一。在某台300 MW循环流化床(CFB)锅炉上设计建设了一套燃煤直燃耦合生物质的燃烧发电系统,并利用该系统进行了燃煤直燃耦合生物质的燃烧特性试验研究。结果表明:该生物质直燃耦合系统运行稳定可靠;CFB锅炉在掺烧木屑颗粒燃料时,随着掺烧比的增加,混合燃料的飞灰含碳量下降、CO排放量降低,混合燃料的燃尽性得以改善;掺烧后经过锅炉燃烧配风优化,锅炉NOx排放量比纯烧原煤排放量略有降低。试验典型工况污染物测试表明:掺入木屑颗粒燃料后,锅炉烟气二噁英排放量为0.0088 ng TEQ/m^(3)(标准工况,φ(O_(2))=11%,下同),飞灰中二噁英排放量为0.0206 ng TEQ/m^(3);飞灰中重金属及P、As、Se等有害微量元素排放值总量为32.121mg/L;底渣中重金属及P、As、Se等有害微量元素排放值总量为3.918 mg/L,烟气和飞灰中的二噁英和重金属等有害物质排放均满足国家环保标准排放限值。

农村规模化养殖耦合生物质发电问题分析

通过对清洁能源使用问题的分析,将规模化养殖与清洁能源消费进行结合,完成对养殖-清洁能源系统耦合过程的论证,同时利用规模化养殖产生的废物进行生物质发电和种植肥的生产,为我国农牧场低碳、高效、清洁的养殖理念以及生物质能源的利用提供新思路。

电力市场环境下生物质气化耦合燃煤机组与风电场联合自调度优化策略

利用生物质气化耦合燃煤发电技术可以提升火电机组的燃料及运行灵活性,从而促进风电的高水平消纳,同时实现生物质能的有效开发利用。该文首先建立反映生物质气化耦合热电联产机组内部能流过程和外部出力特性的运行模型。然后,从能源供应商视角出发,给出耦合机组与风电场联合参与日前、日内和实时平衡市场的多阶段决策框架,提出反映联合体期望收益和条件风险价值的多目标自调度策略。最后,利用基于字典优化框架的增强ε约束法,给出构建帕累托前沿的多目标优化求解流程。以一台350 MW燃煤热电联产机组和一座600 MW风电场构成的联合体为例进行分析。结果可知,增设生物质气化子系统和联合运行能够使其经济效益提升6%左右,同时有利于降低能源供应商的运营风险。

Coupling effect of bifunctional ZnCe@SBA-15 catalyst in 1,3-butadiene production from bioethanol

A series of bifunctional Zn Ce@SBA-15 catalysts with different Zn/Ce ratios were prepared by a solid-state grinding strategy and used in the conversion of ethanol to 1,3-butadiene(ETB).For the supported metal oxides,Zn O serves as the active sites for the dehydrogenation of ethanol,and CeO_(2) promotes the aldolcondensation reaction.Based on the results of Py-FTIR and NH_(3)-TPD,it suggests that the yield of 1,3-butadiene is positively correlated with the number of weak Lewis acid sites on the catalyst surface,given their benefit for aldol-condensation reactions.The catalyst with an optimal Zn/Ce ratio of about 1:5 has the highest concentration of weak Lewis acid.Coupling with the Zn O sites,it contributes to a 98.4%conversion of ethanol and a 45.2%selective of 1,3-butadiene under relatively mild reaction conditions(375°C,101.325 k Pa,and 0.54 h^(-1)).

660 MWe机组煤粉炉耦合生物质气燃烧污染物排放分析

为分析煤粉炉掺烧生物质气对耦合锅炉运行性能的影响,基于660 MWe燃煤锅炉和30 t/h生物质气化炉,搭建生物质气化耦合燃煤锅炉系统模型。在额定工况下,选取松木、木屑、污泥3种生物质,研究气化过程;并将最佳气化条件下得到的生物质气引入锅炉进行混合燃烧,研究不同生物质气对锅炉运行及燃烧产物的影响规律。结果表明,生物质气化热效率在最佳空燃比下均可达90%以上。与纯煤燃烧工况相比,耦合工况的炉膛燃烧温度均有所下降,最高下降9.43℃;生物质气掺烧使锅炉效率略下降,而耦合系统的生物质利用效率均可达84%以上;且耦合燃烧减少了CO_(2)排放量,其中松木气掺烧时CO_(2)减排量最大,为2.62×10^(5)t/a。耦合系统中NO_(x)生成量与炉膛燃烧温度和生物质气中CH4含量明显相关,其中木屑气耦合燃烧生成的NO_(x)质量浓度下降最多,为167.16 mg/m^(3);而SO_(x)生成与生物质成分密切相关,其中松木气耦合燃烧生成的SO_(x)质量浓度最低,相比纯煤燃烧下降330.22 mg/m^(3)(标况下)。

燃煤机组耦合生物质直燃发电综合分析

燃煤机组耦合生物质发电能有效减少碳排放,是当前煤电实现低碳化的最佳途径。文章借助某电厂300 MW煤粉锅炉掺烧生物质的热力试验结果,从安全性、经济性、技术性和环保性等方面,综合分析了生物质直燃耦合对燃煤机组的影响,并对掺烧生物质可能引起的锅炉受热面的沾污和腐蚀、SCR脱硝催化剂的中毒、湿法脱硫石灰石活性的削弱、制粉系统出力和效率的下降、灰渣利用的限制以及燃煤机组运行经济性的下降等问题,提出了相应的建议和应对措施,为我国燃煤机组的低碳绿色转型提供了参考。

煤耦合生物质气化发电技术研究进展

煤电碳排放是我国能源消费碳排放的主要来源。生物质发电是一种零碳甚至可以是碳负排放的电力生产方式,因此发展煤耦合生物质气化发电技术可实现煤炭减量替代与碳减排效应,是一条煤电走向低碳化的可行路径。基于此,综述了煤耦合生物质发电的3种技术——直燃耦合发电技术、并联耦合发电技术和气化耦合发电技术,解析了3种技术的特点,提出了煤耦合生物质气化发电技术的优势,并基于气化耦合发电技术研究了原料的物理化学性质适应性及原料对气化炉的影响。重点解析了煤耦合生物质气化发电技术的工艺流程,包括生物质原料储存输送系统、气化炉(循环流化床(CFB)气化炉、双流化床(DFB)气化炉、下吸式固定床气化炉、上吸式固定床气化炉、横吸式固定床气化炉和链条炉)、燃气冷却降温系统、燃气加压输送系统、燃气耦合燃烧系统和气体净化系统,并进行了能源利用效率、经济性与环境效益分析,以期为煤耦合生物质发电技术的研究与应用提供理论参考与技术支持。此外,还综述了国家为推进煤耦合生物质气化发电技术出台的一系列政策及当前煤耦合生物质气化发电站的成功案例。最后对煤耦合生物质气化发电技术存在的挑战和未来的发展进行了展望。

新银合欢林土壤理化性质–微生物生物量耦合协调关系研究

研究采用空间代替时间序列的方法,通过方差分析、相关性分析和偏最小二乘路径模型探究向家坝工程扰动区6种不同龄级新银合欢林土壤理化性质与微生物生物量的耦合协调关系。结果表明:①原生草地群落(A1,无新银合欢群落)土壤含水量、养分水平和微生物生物量均最高,新银合欢入侵后在草灌阶段土壤含水量、养分水平和微生物生物量显著下降。新银合欢成为灌丛时(A3,新银合欢2 a群落)土壤含水率、有机碳、全氮、全磷、微生物生物量碳氮含量分别下降为A1群落的51.2%、33.9%、31.6%、27.1%、72.8%和61.5%,pH上升至8.16,使得土壤更为碱化。②土壤微生物生物量碳与土壤含水率显著相关(P<0.05),土壤微生物生物量碳氮比与pH呈显著相关;土壤含水率、养分水平和微生物生物量三者之间相互影响且作用显著,高土壤含水率有利于土壤养分与微生物生物量的存在和转化。③原生样地结构稳定,协调度D较高(0.7162);新银合欢入侵后,协调度随着新银合欢林龄增大呈现波动下降,至A4群落(新银合欢3~4 a)时协调度降至最小值(0.5012);在乔木阶段土壤养分与微生物生物量缓慢增加且趋于稳定,协调度缓慢上升,最终在新银合欢纯林时稳定趋于勉强协调发展类型。因此,针对不同龄级新银合欢林,要根据不同恢复阶段的土壤生境条件采取不同调控措施,在植被恢复的物种搭配选择上应注重草灌结合,促进土壤以及整个生态系统的健康发展。

燃煤机组直接耦合生物质的模型构建与碳减排分析

燃煤机组直接耦合生物质可以显著降低二氧化碳排放量,是燃煤电厂实现“双碳”目标的主要路径之一。通过Aspen Plus搭建的300 MW煤粉锅炉模型模拟生物质直接耦合煤燃烧发电流程,根据模拟结果以及建立的经济性模型和碳减排模型,分析了燃煤机组掺烧生物质的度电成本和碳排放变化。结果表明,随着生物质掺烧比例增大,燃煤机组的额外每度电成本逐渐升高,但考虑碳税因素后,额外每度电成本将会降低。因此合理设置碳税价格可以有效促进生物质的掺烧,通过调节碳税可以降低掺烧生物质带来的经济成本。燃煤机组耦合生物质可明显减少二氧化碳排放量,关键是降低生物质的含水量。研究结果为生物质直接耦合煤燃烧发电的技术实现和经济性评估提供了参考。

燃煤耦合生物质循环流化床锅炉设计

环保要求日趋严格,燃煤机组碳减排势在必行。燃煤耦合生物质发电,是一种高性价比的火力发电厂碳减排方式。因此,以某型循环流化床锅炉为基础,开展了对燃煤耦合生物质火电装备的探索。

Toward effective electrocatalytic C–N coupling for the synthesis of organic nitrogenous compounds using CO_(2)and biomass as carbon sources

Thermochemical conversion of fossil resources into fuels,chemicals,andmaterials has rapidly increased atmospheric CO_(2)levels,hindering global efforts toward achieving carbon neutrality.With the increasing push for sustainability,utilizing electrochemical technology to transform CO_(2)or biomass into value-added chemicals and to close the carbon cycle with sustainable energy sources represents a promising strategy.Expanding the scope of electrosynthesis technology is a prerequisite for the electrification of chemical manufacturing.To this end,constructing the C─N bond is considered a priority.However,a systematic review of electrocatalytic processes toward building C─N bonds using CO_(2)and biomass as carbon sources is not available.Accordingly,this review highlights the research progress in the electrosynthesis of organic nitrogen compounds from CO_(2)and biomass by C─N coupling reactions in view of catalytic materials,focusing on the enlightenment of traditional catalysis on C─N coupling and the understanding of the basis of electrochemical C─N coupling.The possibility of C─N bond in electrocatalysis is also examined from the standpoints of activation of substrates,coupling site,mechanism,and inhibition of hydrogen evolution reaction(HER).Finally,the challenges and prospects of electrocatalytic C─N coupling reactions with improved efficiency and selectivity for future development are discussed.

生物质气化耦合发电体系的合成气组分与能量分析

碳达峰碳减排目标实现过程中,充分挖掘生物质耦合发电是一项关键举措。通过Aspen Plus软件对生物质气化耦合发电体系中的气化过程进行了建模分析,重点研究了当量比和环境压力对合成气气体组分的影响,并结合计算结果探讨了合成气热值及能量的变化规律。结果表明,随着当量比的增加,H2体积分数由19.47%单调降低至5.19%;CO体积分数在当量比为0.3附近达到最大值22%;CH4体积分数随着当量比的增加呈现单调降低的状态,从1.3%降至0。依托理论研究的成果,合成气体热值的曲线与CO和H2表现出相同的变化规律,在当量比0.3~0.35时达到最高值,然后快速下降。考虑到带入炉膛的能量还有气体显焓,提出了一种热值+显焓的合成气能量评价方式,其在当量比为0.35时达到最大值,也是生物质耦合气化系统的最优当量比区间。