A New Carbon and Oxygen Balance Model Based on Ecological Service of Urban Vegetation

The application of human induced oxygen consumption and carbon emission theory in urban region was summed up and on this base a new model of urban carbon and oxygen balance (UCOB) was constructed by calculating the carbon and oxygen fluxes. The purpose was to highlight the role of vegetation in urban ecosystems and evaluate the effects of various human activities on urban annual oxygen consumption and carbon emission. Hopefully,the model would be helpful in theory to keep the regional balance of carbon and oxygen,and provide guidance and support for urban vegetation planning in the future. To test the UCOB model,the Jimei District of Xiamen City,Fujian Province,China,a very typical urban region,was selected as a case study. The results turn out that Jimei′s vegetation service in oxygen emission and carbon sequestration could not meet the demand of the urban population,and more than 31.49 times of vegetation area should be added to meet the whole oxygen consumption in Jimei while 9.60 times of vegetation area are needed to meet the carbon sequestration targets. The results show that the new UCOB model is of a great potential to be applied to quantitative planning of urban vegetation and regional eco-compensation mechanisms.

Roles of urban vegetation on balance of carbon and oxygen in Guangzhou, China

The plant biomass and net primary production(NPP) of urban vegetation in Guangzhou were estimated by dimension analysis, tree truck volume, and harvest methods as well as relationship between biomass and NPP and so on. The biomass and NPP were respectively 2875150t and 1058122 t/a. They were respectively 392495t and 64948 t/a in the built-up area and 2482655t and 993147 t/a in the unbuilt-up area. It would make plant biomass, especially NPP decline obviously, if the unbuilt-up area were changed to the built-up area. The carbon content of plant was 1328649 for the total and 13.78 t/hm 2 for the mean, and amounts of carbon fixed and oxygen made by urban vegetation were respectively 4.80 t/(hm 2·a) and 12.79 t/(hm 2·a) for the mean and 462624 t/a and 1232430 t/a for the total, which were equal to 1.45 times and 1.04 times of those by human breathing. However, they were only equal to 7.61% and 4.97% of amount of carbon released and oxygen consumption in urban Guangzhou. The biomass and NPP of urban vegetation in Guangzhou only corresponded to 7.8% and 47.3% of those of southern subtropical evergreen broad-leaf forest in Dinghu Mountain. Therefore, the roles of Guangzhou urban vegetation in balance of carbon and oxygen would be increased greatly if it could be conserved and improved in some way.

Study on Ecological Land Demand of Shijiazhuang City Based on Carbon-Oxygen Balance Method

[Objective] The study aimed to analyze ecological land demand of Shijiazhuang City on the basis of carbon-oxygen balance method. [Method] Firstly, the release and absorption of CO2 and O2 in Shijiazhuang City during 2004 -2007 were studied by using carbon-oxygen balance method, and the ecological land area needed for carbon-oxygen balance was calculated, then the ecological land area needed for carbon-oxygen balance in 2015 was predicted. Finally, some measures to reduce the deficit of CO2 and O2 in Shijiazhuang were proposed. [Result] From 2004 to 2007, the unbalance between CO2 and O2 aggravated with the rapid development of Shijiazhuang City＇s economy, and the ecological land needed increased year by year. If the amount of CO2 released and 02 consumed grows constantly, the area of standard ecological land needed will be about doubled in 2015 compared with 2007 （ 1. 575 6 million hm2 ）, namely increasing to 3.566 million hm2. In addition, appropdately improving the area of mixed forest and other vegetation with higher net production, developing some green energy resources like nuclear energy and wind energy and controlling its population could be adopted to reduce the deficit of CO2 and 02 in Shijiazhuang City. ~ ConclusionJ The research could provide theoretical references for the overall plan of land utilization in Shijiazhuang City. Key words Shijiazhuang; Ecological land; Carbon-oxygen balance; Shijiazhuang City; China

铜冶炼过程碳排放及自热熔炼分析

“双碳”背景下,我国铜冶炼作为高耗能高排放行业需突破资源、能源、供求关系等多重制约因素,方能迈上铜工业低碳绿色创新可持续发展道路。采用熔炼系统能量流平衡模型研究其能源利用收支情况,有利于进一步挖掘节能潜力,实现富氧底吹熔炼过程的低碳可持续化高效生产。通过计算铜冶炼厂底吹熔炼体系各类热量的收入和支出行为,解析无碳质燃料投入工况下的热量收支平衡关系,继而提出无碳自热熔炼的优化改进方案。因此,从原料适配、操作制度、设备优化等多方式调控以实现富氧底吹无碳自热熔炼。从碳源上减少或避免煤粉的加入,从而降低过程碳排放,以期为铜冶炼的清洁生产提供有益的思路和建议。

“双碳”目标下中国社会——生态复合系统碳氧平衡时空格局分析

在“双碳”战略目标下,如何同步实现“稳增长”和“碳减排”,成为中国推进可持续发展、生态保护和高质量发展并重的焦点问题。论文基于碳氧平衡系数测算分析我国社会—生态复合系统2000—2020年排碳耗氧量、固碳释氧量以及碳氧平衡状况的时空格局。结果表明:2000年我国碳氧处于平衡状态,社会生态系统处于良性循环,随后,随着经济快速发展,排碳耗氧量剧增,同时,土地利用变化剧烈,林地和草地面积减少,固碳释氧量下降,导致碳氧处于失衡状态。进一步的碳氧平衡省际分析可知,2020年我国省际碳氧平衡差异明显,东部和中部大多数省份社会—生态复合系统处于碳氧失衡状态。测算分析社会—生态复合系统碳氧平衡时空格局,可为土地利用结构优化配置及不同区域间生态补偿和碳排放交易提供指导。

2025年京津冀陆地生态系统碳氧平衡分析

以2020年的京津冀地区数据为基准,测算出2020年释碳耗氧量、固碳释氧量,对2025年释碳耗氧量、固碳释氧量、生态用地需求面积进行预测。结果表明:2020年京津冀地区释碳量和耗氧量分别为125576.1万和143533.7万t。预测出2025年京津冀地区释碳量和耗氧量分别为135957.0万和163392.0万t。从2025年京津冀地区总体来看,维持碳平衡所需标准生态用地面积小于现有标准生态用地面积,说明不需要再另外增加面积。但分省(市)来看,北京、河北的生态用地面积均能够满足碳氧平衡需要,而天津还应增加标准生态用地,方能满足市内维持碳氧平衡的需要。在实际社会和经济发展过程中生态用地面积会略有调整,而且生态用地结构和质量也会发生变化,因此在实际生产和科研中,应根据每年生态用地的实际变化量来逐步修正。

湖南省碳排放空间分异与碳平衡分区治理研究

“双碳”战略目标涉及经济社会系统广泛而深刻的历史变革,而国土空间规划则是新时代实现“双碳”目标的必要途径和技术保障。基于碳氧平衡理论,以湖南省为例,通过分析湖南省122个县域单元碳排放空间分异特征,探索构建碳平衡主体功能区,提出“高碳控制区、低碳优化区、碳氧平衡区以及生态碳汇区”碳平衡功能分区。各功能区内部再根据地域特征进一步划分碳平衡治理管控单元,明确管控单元碳排放产权责任。针对各级主体功能区进行分区施策,制定相应的目标指标及调控措施,推动碳排放权交易平台的建设。促进“分区施策、分级传导、精准反馈、精细治理”,更好实现国土空间“双碳”目标的科学调控、高效传导、协调统筹、有效治理。

驱油用燃气锅炉富氧燃烧碳捕集方案研究

针对油田驱油用22t/h注汽天然气锅炉进行富氧燃烧碳捕集研究。燃气锅炉的烟气加补充纯氧作为锅炉的助燃气体,通过计算机软件模拟预测锅炉本体的热力学数值,考察这种碳捕集工艺流程对燃气锅炉热效率的影响及排放烟气中的最大CO_(2)体积分数。

氢气燃料与常规燃料对加热炉的影响分析

为探究氢气作为加热炉燃料的可行性,本文以国内某炼厂加热炉为实例,通过理论计算与FRNC5工程软件对氢气燃料传热效率进行研究,并对氢气燃料加热炉与常规燃料加热炉参数进行对比分析。最终得出氢气燃料在传热效率、燃料消耗、碳减排、富氧燃烧等方面的研究结论,为后续工程实践提供参考建议。

IF钢生产工艺优化

介绍了IF钢炼钢系统的装备,针对IF钢生产过程中转炉终点温度和终点活度氧偏高、钢液洁净度波动大、产品质量稳定性差等进行了工艺优化。通过研究转炉促进碳氧反应平衡的措施,优化了RH脱氧工艺和夹杂物控制工艺;分析了连铸水口结构对结晶器液面波动的影响,并提出按铸坯断面选用不同型号的水口。优化后,在转炉终点温度和终点氧含量相对较低的条件下,实现了IF钢的高效稳定生产,提高了冷轧板表面质量。

考虑光热电站及富氧燃烧捕集技术的电热气综合能源系统低碳运行优化

针对传统机组的运行约束及环境污染问题,引入富氧燃烧捕集技术对燃气机组进行改造,配置含热回收器的光热电站实现热电解耦与辅助供能,并结合电转气设备、燃气锅炉等能量转换设备组成综合能源系统,提出一种电热气综合能源系统低碳优化方法。首先,构建系统架构,并建立富氧燃烧捕集机组的电碳特性方程与光热电站模型;其次,计及反应余热利用与氧气回收,建立电转气设备模型;然后,引入奖惩阶梯型碳交易机制以限制碳排放量,建立以系统运行成本最小为目标的电热气综合能源系统低碳经济调度模型;最后,进行算例仿真,由仿真结果可知,该方案可兼顾减碳效果与运行效益,不仅可以提高燃气机组的运行调节能力与电转气设备的运行潜力,提升系统的运行效益,而且可以有效降低环境污染与制氧能耗。

Regulating metal-acid double site balance on mesoporous SiO_(2)-Al_(2)O_(3) composite oxide for supercritical n-decane cracking

The balance between metal and acid sites directly affects the preparation of high-performance cracking catalysts with high heat sink and low coking.Nevertheless,how to control acid-metal sites balance and its relationship with cracking performance are reported scarcely.In this work,a series of Pt/Al_(2)O_(3)-SiO_(2) dual sites catalysts with different metal to acid active sites ratio(C_(M)/C_(SA))were constructed by ethanolassisted impregnation method and the impact on n-decane cracking under supercritical conditions was systematically and deeply investigated.The results showed that the conversion and carbon deposition increased gradually with varied C_(M)/C_(SA)and reached the balance at C_(M)/C_(SA)of 0.13.The proper ratio C_(M)/C_(SA)(0.13)can balance the deep dehydrogenation coking over metal active sites and high heat sink of cracking over acid active sites,the chemical heat sink reaches amazing 1.75 MJ/kg and carbon deposition is only22.03 mg/cm^(2) at 750℃.Meanwhile,the few metal sites at low C_(M)/C_(SA)and the few strong acid sites at high C_(M)/C_(SA)are the main factors limiting the cracking activity.Low C_(M)/C_(SA)limit the activation of C-H bond and deep dehydrogenation of coking precursor,resulting in relative low cracking activity and carbon deposition,while high C_(M)/C_(SA)limit the activation of C-C bond and increase the deep dehydrogenation.In this contribution,design and construction of metal-acid dual sites can not only provide the technical solution for the preparation of high heat sink and low coking cracking catalyst,but also deepen the understanding of the cracking path of hydrocarbon fuel.

不同冷却方式对激光加工CFRP的影响研究

为了探索不同冷却方式对激光加工的影响,采用水、气体以及水气复合3种不同冷却方式辅助激光加工碳纤维复合材料进行了对比研究,同时采用单因素实验研究了不同工艺条件对加工质量的影响,并分析了作用机理。结果表明,在3种冷却方式下,热影响区、槽深均随着功率、频率的降低而降低,随着扫描速率的增加而降低;在相同工艺参数下,水气复合辅助激光加工产生的热影响区最小,气体辅助激光加工产生的热影响区次之,水辅助激光加工产生的热影响区最大;当激光功率为2250 W、频率为1200 Hz、速率为120 mm/s时,水、气体以及水气复合3种不同冷却方式的热影响区分别为378μm,283μm,196μm,槽深分别为401μm,789μm,647μm;采用水气复合辅助激光加工可以在加工过程中实现较好的冷热平衡,获得最好的加工质量。该研究为更好地实现碳纤维复合材料低损伤加工提供了参考。

常减压装置全产品碳足迹评价研究与应用

石油化工生产过程具有投入1种原料生产多个产品的特点,碳足迹评价中以产品质量来分配共生过程的碳排放量,其结果不能体现生产过程碳排放的来源。石油化工装置能量利用状况是影响碳排放的重要因素,依据产品在生产过程中的能量变化过程进行碳足迹评价,其结果可以反映产品生产所导致碳排放的根源和本质。对某10 Mt/a常减压装置的换热网络和分馏塔进行能量核算,确定产品的能量变化过程,依据用能系统的碳排放计算碳足迹。结果显示:其减压塔顶油气碳足迹最高,达到43.748 kgCO_(2)/t,常一线碳足迹最低,为11.546 kgCO_(2)/t;由所有产品碳足迹计算的碳排放与装置碳排放吻合。因此基于能量平衡的产品碳足迹评价方法,可以按照产品在生产过程中的能量变化将装置的碳排放分配到所有产品中,产品碳足迹结果与碳排放的来源相一致。

Comprehensive Evaluation of OxyCup Process for Steelmaking Dust Treatment Based on Calculation of Mass Balance and Heat Balance

Through the mass balance and thermal balance calculation for a typical OxyCup （or OxiCup） furnace process featuring a capacity of 380 kt/a of steel plant residuMs, the material flow and thermal flow diagrams were firstly obtained. Then, the performance of the main fuel in the OxyCup process, i.e. coke and carbon dust, was ana lyzed, and the results indicated that coke was mainly used as the stock column skeleton for the furnace and exothermal agent with a weak reduction ability; whereas carbon dust was mixed in the C-brick to reduce the iron oxide. In addition, the comparison between OxyCup process and traditional blast furnace process indicated that the reduction and melting processes in the OxyCup process were relatively isolated, while in the traditional blast furnace process, they were mixed with each other in the high temperature zone. Moreover, oxidizing atmosphere is necessary in part of the OxyCup furnaces to ensure the complete combustion of part of the coke, while only reducing atmosphere is al lowed in traditional blast furnaces. Finally, it was confirmed that oxygen enrichment can make a remarkable increase of the energy income and high temperature blast makes oMy a small contribution to energy income as the energy from the combustion of carbon takes up nearly 90% of the total income.

基于固废微波快速制备泡沫碳负载CoO_(x)纳米片及电催化析氧性能

开发性能稳定、成本低廉的电催化剂对于电催化水分解实现大规模制氢至关重要。以固体废弃物三聚氰胺泡沫为原料,采用微波选择性加热的方法在碳化后的三维氮掺杂碳骨架上快速生长均匀分布的CoO_(x)纳米片多孔包覆层(CoO_(x)/N-C)。微波反应过程仅需45 s,反应速率比传统化学沉淀—热解法(制备时间6-8 h)提高了两个数量级。电化学测试结果表明,当电流密度为10 mA cm^(-2)时,CoO_(x)/N-C电极在1M KOH电解液中过电位仅为340 mV;经过10 h循环测试,其电催化性能保持率高达97%。这主要归因于三维氮掺杂碳作为电子传输通道有效地提高了CoO_(x)的导电性,且CoO_(x)纳米片多孔层为电催化析氧反应(OER)提供了足够多的活性位点。研究为快速制备高性能OER电催化材料提供了一种新方法,为固体废弃物高价值再利用提供了一种有效途径。

General heat balance for oxygen steelmaking

Energy balances are a general fundamental approach for analyzing the heat requirements for metallurgical processes.The formulation of heat balance equations was involved by computing the various components of heat going in and coming out of the oxygen steelmaking furnace.The developed model was validated against the calculations of Healy and McBride.The overall heat losses that have not been analyzed in previous studies were quantified by back-calculating heat loss from 35 industrial data provided by Tata Steel.The results from the model infer that the heat losses range from 1.3%to 5.9%of the total heat input and it can be controlled by optimizing the silicon in hot metal,the amount of scrap added and the postcombustion ratio.The model prediction shows that sensible heat available from the hot metal accounts for around 66%of total heat input and the rest from the exothermic oxidation reactions.Out of 34%of the heat from exothermic reactions,between 20%and 25%of heat is evolved from the oxidation of carbon to carbon monoxide and carbon dioxide.This model can be applied to predict the heat balance of any top blown oxygen steelmaking technology but needs further validation for a range of oxygen steelmaking operations and conditions.

量热仪中的氧弹热传导不确定性影响因素研究

量热仪的热容量稳定性是准确获得煤炭可靠热值的基本前提,而氧弹是量热仪中供样品燃烧用的核心容器,其热传导性对量热仪的测量精准度有着较大的影响,因而研究量热仪中氧弹的热传导不确定性则可为提升量热仪的热容量稳定性及其测量精度提供支撑依据。针对量热仪中的氧弹部件,结合量热仪的工作原理及试验室环境要求,从氧弹的材质与弹筒壁厚及容积、氧弹芯内部组件的合理设计、氧弹整体清洁度3个角度分析影响氧弹热传导性的影响因素,并对2款不同型号的氧弹进行热传导性比对,以期有助于提高量热仪测试数据的稳定性。经燃烧试验发现,氧弹的热传导存在不确定性时会使仪器热容量不稳定,从氧弹整体清洁度进行试验分析则得出氧弹内、外表面油膜会导致热容量测试数据存在离散度变大的结论,由此提出减少氧弹热传导不确定性的措施,主要包括选择合适的氧弹材质、弹筒壁厚、氧弹容积,如氧弹材质宜选择镍铬或镍铬钼合金钢,氧弹容积一般为250~350 mL,弹筒壁厚宜为5~6 mm;优化氧弹芯结构中的陶瓷套、绝缘套等导热性能差的组件,氧弹结构尽可能简单且避免热传导路径过长;彻底清洁氧弹筒、氧弹盖、氧弹芯的内外表面,以清除油脂等异物对实验测定结果的干扰。

电石生产过程中石灰窑尾气余热利用工艺

论述了电石生产过程中石灰窑高温尾气的产生及尾气性质,将石灰窑高温尾气用作兰炭烘干热源进行可行性研究,对兰炭烘干热量及用空气量进行核算,实施石灰窑尾气烘干兰炭技术改造项目,余热利用达到了节能降碳的目的。

某燃料型炼油厂低碳发展路径分析

分析了某燃料型炼油厂近3 a来的用能结构、二氧化碳排放量和碳排放强度,提出了“双碳”行动方案。通过对低温热综合利用技术、碳捕集利用技术、光伏发电技术、加热炉优化、绿色氢能建设及二氧化碳的利用和转换技术的应用前景分析,力争十四五末期,该炼油厂碳排放总量控制在800 kt以内,二氧化碳排放强度控制在0.16 t/t以内,终端电气化率提高至15%左右,为燃料型炼油厂的能源结构调整探索节能减排路径,为炼化企业的低碳发展转型提供发展思路,最终实现燃料型炼油厂向“油气热电氢”综合能源公司转型。