基准年法水泥企业未来CO2排放测算模型构建

本文提出了一个基于水泥企业历史CO₂排放数据而构建的企业未来CO₂排放测算模型。从熟料产量减少、原料替代、低碳熟料与新型胶凝材料、能源效率提升、能源替代、固碳用碳、非熟料工序减碳共七个水泥企业可能采取的低碳措施入手,逐一分析每项措施中存在的会导致企业CO₂排放总量发生变化的变量,以碳元素来源及流向为基础梳理变量与最终CO₂排放之间的函数关系,并以公式体系予以表达。该模型可以输出水泥企业未来年度序列CO₂排放总量、熟料生产CO₂排放强度和各降碳措施的贡献比例等结果,为水泥企业评估自身低碳转型进程、做好相关规划和管理提供指导。     

“双碳”目标下我国能源转型路径

2020年9月,习近平主席在第75届联合国大会的一般性辩论上提出“中国要力争在2030年前实现碳达峰,在2060年前实现碳中和”的目标。我国是CO₂排放大国,“双碳”目标是我国对世界作出的承诺。实现“双碳”目标的关键是有效进行碳减排,而我国大部分CO₂的产生来自能源领域。对我国的CO₂排放情况和能源消耗现状进行研究分析,分别从能源结构、生产、消费等方面提出了加大能源型方面人才的培养,减少化石能源的使用,同时大量发展可再生能源和出台碳税政策的具体改革建议。     

O2/CO2和O2/N2氛围下煤粉富氧燃烧数值模拟

在目前煤炭依然作为能源主体的背景下，控制燃煤污染物排放有着重要意义。基于CFD数值模拟，建立伴流燃烧器模型，控制燃料、氧化剂入口流量恒定，设计了O₂/CO₂、O₂/N₂氧化剂氛围中O₂浓度在21%～40%内的多种工况，对煤粉燃烧特性及燃烧产生的污染物进行了研究。分析了不同工况下煤粉燃烧的温度分布、燃烧速率、碳烟、NO_x的生成情况。结果显示，在O₂/CO₂、O₂/N₂两种氧化剂氛围中，随着O₂浓度的上升，煤粉燃烧温度升高、燃烧速率增大，碳烟生成量均增加，同等O2浓度条件下，O₂/CO₂氛围的煤粉燃烧温度和燃烧速率均高于O₂/N₂氛围，碳烟生成量小于O₂/N₂氛围，且O₂/CO₂...     

广东能源消费碳排放趋势与前景展望

能源消费是人类活动排放CO₂等温室气体的主要来源,碳减排已成为我国能源发展的一个重要约束因素。2012年全世界能源消费排放3.173 4×1010 t CO₂,中国能源消费排放的CO₂已占世界总排放量的26.0%。2012年全世界人均CO₂排放量4 510 kg,而中国人均CO₂排放量达到了6 093 kg。同年广东省人均CO₂排放量为5 224 kg,高于世界平均水平,低于全国平均水平。随着节能减排和应对气候变化工作的推进,广东的单位产值能耗水平逐年降低,能源结构不断改善,使得全省化石能源消费带来的CO₂排放量的增长势头得到抑制,2012年的排放量比2011年略有减少。按目前的发展趋势预测,到2020年,广东CO₂排放总量将达到1.606 2×108 t碳当量,比2012年增加9.69×106 t碳当量,人均CO₂排放量将达到5 287 kg,略高于2012年的5 224 kg。如果在“十三五”期间加快第三产业发展,则到2020年广东省化石能源消费总量将比2012年下降2.7%,CO₂排放总量将比2012年下降3.5%,人均CO₂排放量将由2012年的5 224 kg下降到2020年的4 795 kg,接近世界平均水平。     

二氧化碳捕集技术研究进展

CO₂是造成温室效应的主要气体,如何有效解决CO₂引起的气候问题越来越受到人们的关注。近年来,通过大力发展可再生能源和清洁能源试图从源头上降低碳排放,但由于短期内人类生产生活离不开对能源的消耗,要做到完全脱碳是不现实的。事实上,二氧化碳不仅是一种温室气体,也是一种潜在的碳资源。因此,如何捕集并有效利用CO₂成为业界一直在探索关注的研究方向。通过介绍和分析化学吸收法、多孔固体吸附法、膜分离法、深冷分离法、水合物法和微生物法等各类CO₂捕集技术的研究现状、适用场景和技术发展重点,总结对比不同CO₂捕集方法的优点和局限性,并针对不同技术的未来前景和建议方向进行了展望。以期为CO₂捕集和利用途径提供有益的借鉴和参考,推动CO₂捕集技术实现大规模商业化应用。     

O2/CO2气氛下煤燃烧NOx排放特性的实验研究

利用管式电阻炉在O₂/CO₂气氛和O₂/N₂气氛下对煤粉燃烧过程中NO_x排放特性进行实验,研究在不同停留时间、炉内燃料/氧化学当量比、温度、氧浓度等因素对燃煤过程中NO_x放特性的影响,并对这两种燃烧方式下NO_x的排放特性进行对比。结果表明:在O₂/CO₂气氛下NO_x的生成量要远远低于O₂/N₂气氛下NO_x的生成量。随着停留时间的延长,NO_x沿程释放特性是先增大后减少。随着燃料/氧化学当量比的增加,NO_x排放浓度也呈现出先增加后降低的趋势。随着炉内温度的增加,2种气氛下NO_x的排放浓度均增加。随着氧浓度的提高,NO_x排放浓度增大。     

高炉煤气碳捕集对钢铁联合企业碳排放的影响

为了探究高炉煤气碳捕集对钢铁联合企业碳排放的影响,通过建立钢铁联合企业的CO₂排放核算模型,用来计算钢铁产品以及企业的CO₂排放量。最后以高炉煤气CO₂捕集率作为情景假设,计算不同情景下高炉煤气CO₂排放系数及高炉煤气的热值,分析不同情景下钢铁产品以及企业CO₂的减排效果。结果表明捕集率为75%时,高炉煤气的热值提高了17.6%,钢铁联合企业的CO₂减排幅度约为14.5%,钢铁产品中的铁水的碳减排幅度最大,降低了15.33%。高炉煤气的碳捕集可以有效降低钢铁联合企业的CO₂排放,对钢铁联合企业碳中和提供有效的实施路径。     

基于熵权法的广东省核电节能减排效果综合评价研究

以广东省为例分析发展核电以来节能减排的综合效益,通过1993-2010年广东省统计数据,应用熵权法,从能源消耗强度、污染物排放、污染物治理与利用和经济效益四方面对广东省核电节能减排效果进行综合评价。结果表明,1993-2010年期间,广东省核电节能减排综合效果呈上升趋势;单位GDP煤炭和石油消耗总量、火电生产和CO₂排放总量、单位GDP综合能耗呈下降趋势;单位GDP核电和水电生产总量变化幅度不大,但是核电和水电在电力供应中所占比例较小。     

水合物法分离CO2工艺研究进展

随着温室效应加剧,CO₂减排行动已迫在眉睫。水合物法分离CO₂工艺作为一种发展前景广阔的新型CO₂分离技术,为CO₂减排提供了一种解决思路。水合物法分离CO₂工艺相比于化学吸收、物理吸附、深冷分离和膜分离等技术具有分离效率高、过程简单无副产物、条件温和的优势,为减缓CO₂排放增加对环境造成的影响提供了一个中短期解决方案,以此为前提将允许人类继续使用化石燃料直至可再生能源技术广泛应用。本文综合分析了国内外的相关文献,介绍了水合物法分离CO₂工艺的基本原理,并比较了水合物法分离CO₂不同工艺的优劣之处,为进一步优化水合物法分离CO₂工艺提供指导。     

关于固体替代燃料燃烧CO2排放量的测算

本文通过对固体替代燃料的定义、标准、性质、指标的研究，用类比的方式得出其燃烧CO₂排放量的测算公式，再以某项目的样品为实例，通过样品间的横向对比，不同种类燃料间的纵向对比，研究固体替代燃料燃烧CO₂排放问题，可为今后企业制定减碳方案提供与借鉴。     

Coal gasification system using nuclear heat for ammonia production

Utilization of nuclear energy is an effective way of solving the global warming resulting from CO₂ emissions. Thermal energy accounts for more than two thirds of total energy utilization at present and therefore it is significant to extend the utilization of nuclear heat for the effective reduction of CO₂ emissions in the world. This paper describes a coal gasification system using HTGR nuclear heat in an ammonia production plant in terms of industrial utilization of the nuclear heat. The system uses the nuclear heat directly in addition to generating electricity. A steam reforming method using a two-stage coal gasifier is employed: it improves the heat utilization efficiency of the secondary helium gas from the HTGR. Finally, the paper clarifies that the nuclear gasification system can reduce CO₂ emissions by about five hundred thousand tons per year from that of a conventional system using fossil fuel.     

Mitigation assessment results and priorities for China''s energy sector

Energy-related CO₂ emission projections of China up to 2030 are given. CO₂ mitigation potential and technology options in main fields of energy conservation and energy substitution are analyzed. CO₂ reduction costs of main mitigation technologies are estimated and the multi-criteria approach is used for assessment of priority technologies.

The results of this study show (1) Given population expansion and high GDP growth, energy-related CO₂ emissions will increase in China. (2) There exists a large energy conservation potential in China. (3) Adjustment of industry structure and increase of shares of products with high added value have and will play a very important role in reducing energy intensity of GDP. (4) Energy conservation and substitution of coal by natural gas, nuclear power, hydropower and renewable energy will be the key technological measures in a long-term strategy to reduce GHG emission. (5) Identification and implementation of GHG mitigation technologies is consistent with China's targets of sustainable development and environmental protection. (6) Energy efficiency improvement is a “no-regret” option for CO₂ reduction, whereas an incremental cost is needed to develop hydropower and renewable energy.     

Will Germany move into a situation with unsecured power supply?

Together with a huge number of other countries, Germany signed the Paris Agreements in 2015 to prevent global temperature increase above 2°C. Within this agreement, all countries defined their own national contributions to CO₂ reduction. Since that, it was visible that CO₂ emissions in Germany decreased, but not so fast than proposed in this German nationally determined contribution to the Paris Agreement. Due to increasing traffic, CO₂ emissions from this mobility sector increased and CO₂ emission from German power generation is nearly constant for the past 20 years, even a renewable generation capacity of 112 GW was built up in 2017, which is much higher than the peak load of 84 GW in Germany. That is why the German National Government has implemented a commission (often called “The German Coal Commission”) to propose a time line: how Germany can move out of coal-fired power stations. This “Coal Commission” started its work in the late spring of 2018 and handed over its final report with 336 pages to the government on January 26th, 2019. Within this report the following proposals were made: ① Until 2022: Due to a former decision of the German Government, the actual remaining nuclear power generation capacity of about 10 GW has to be switched off in 2022. Besides, the “Coal Commission” proposed to switch off additionally in total 12.5 GW of both, hard coal and lignite-fired power plants, so that Germany should reduce its conventional generation capacity by 22.5 GW in 2022. ② Until 2030: Another 13 GW of German hard coal or lignite-fired power plants should be switched off. ③ Until 2038: The final 17 GW of German hard coal or lignite-fired power plants should be switched off until 2038 latest. Unfortunately the “Coal Commission” has not investigated the relevant technical parameter to ensure a secured electric power supply, based on German’s own national resources. Because German Energy Revolution mainly is based on wind energy and photovoltaic, this paper will describe the negligible contribution of these sources to the secured generation capacity, which will be needed for a reliable power supply. In addition, it will discuss several technical options to integrate wind energy and photovoltaic into a secured power supply system with an overall reduced CO₂ emission.     

A coal-fired power plant integrated with biomass co-firing and CO2 capture for zero carbon emission

A promising scheme for coal-fired power plants in which biomass co-firing and carbon dioxide capture technologies are adopted and the low-temperature waste heat from the CO₂ capture process is recycled to heat the condensed water to achieve zero carbon emission is proposed in this paper. Based on a 660 MW supercritical coal-fired power plant, the thermal performance, emission performance, and economic performance of the proposed scheme are evaluated. In addition, a sensitivity analysis is conducted to show the effects of several key parameters on the performance of the proposed system. The results show that when the biomass mass mixing ratio is 15.40% and the CO₂ capture rate is 90%, the CO₂ emission of the coal-fired power plant can reach zero, indicating that the technical route proposed in this paper can indeed achieve zero carbon emission in coal-fired power plants. The net thermal efficiency decreases by 10.31%, due to the huge energy consumption of the CO₂ capture unit. Besides, the cost of electricity (COE) and the cost of CO₂ avoided (COA) of the proposed system are 80.37 $/MWh and 41.63 $/tCO₂, respectively. The sensitivity analysis demonstrates that with the energy consumption of the reboiler decreasing from 3.22 GJ/tCO₂ to 2.40 GJ/ tCO₂, the efficiency penalty is reduced to 8.67%. This paper may provide reference for promoting the early realization of carbon neutrality in the power generation industry.     

Nuclear power and the environment: comparative assessment of environmental and health impacts of electricity-generating systems

This paper deals with comparative assessment of the environmental and health impacts of nuclear and other electricity-generation systems. The study includes normal operations and accidents in the full energy chain analysis. The comparison of environmental impacts arising from the waste-management cycles associated with non-emission waste are also discussed. Nuclear power, while economically feasible and meeting 17% of the world's demand for electricity, is almost free of the air polluting gases that threaten the global climate. Comparing nuclear power with other sources for electricity generation in terms of their associated environmental releases of pollutant such as SO₂, NOX, CO₂, CH₄ and radioisotopes, taking into account the full fuel chains of supply option, nuclear power will help to reduce environmental degradation due to electricity generation activities. In view of CO₂ emission, the ranking order commences with hydro, followed by nuclear, wind and photovoltaic power plants. CO₂ emissions from a nuclear power plant are by two orders of magnitude lower than those of fossil-fuelled power plants. A consequent risk comparison between different energy sources has to include all phases of the whole energy cycle. Coal mine accidents have resulted in several 1000 acute deaths over the years. Then came hydropower, also resulting in many catastrophes and loss of human lives, followed by the oil and gas energy industries, last in the list is commercial nuclear energy, which has had a “bad” press because of the Chernobyl accident, resulting officially in 31 acute fatalities, and at least 145 latent fatalities. The paper offers some findings and conclusions on the role of nuclear power in protecting the global environment.     

Natural gas fired combined cycle power plant with CO2 capture

A natural gas (NG) fired power plant is designed with virtually zero emissions of pollutants, including CO₂. The plant operates in a gas turbine-steam turbine combined cycle mode. NG is fired in highly enriched oxygen (99.7%) and recycled CO₂ from the flue gas. Liquid oxygen (LOX) is supplied by an on-site air separation unit (ASU). By cross-integrating the ASU with the CO₂ capture unit, the energy consumption for CO₂ capture is significantly reduced. The exergy of LOX is used to liquefy CO₂ from the flue gas, thereby saving compression energy and also delivering product CO₂ in a saleable form. By applying a new technique, the gas turbine efficiency is increased by about 2.9%. The net thermal efficiency (electricity out/heat input) is estimated at 45%, compared to a plant without CO₂ capture of 54%. However, the relatively modest efficiency loss is amply compensated by producing saleable byproducts, and by the virtue that the plant is pollution free, including NO_x, SO₂ and particulate matter. In fact, the plant needs no smokestack. Besides electricity, the byproducts of the plant are condensed CO₂, NO₂ and Ar, and if operated in cogeneration mode, steam.     

The efficiency-renewable synergism

Improving energy efficiency is the most effective and least expensive way to reduce carbon dioxide (CO₂) emissions in most industrialized nations— including the UK. A report from the UKAEA's own Energy Technology Support Unit concludes that energy efficiency can displace nearly four times more CO₂ than nuclear power can - more quickly and more cost-effectively. Each pound invested in efficient lighting can displace four to five times as much CO₂ as a pound invested in new nuclear power. Meanwhile, given recent dramatic progress in renewable energy technologies, the most promising long-term CO₂-abatement strategy may be a synergistic combination of energy efficiency and renewable energy.     

集成小型堆和可再生能源的超临界CO2循环发电系统

  [目的]  小型模块化压水堆(小型堆)核电站由于温度参数低,其发电效率不到30%,为了提高小型堆的核能利用效率,可将小型堆与可再生能源组合,并以先进的超临界CO₂循环作为热能转换为电能的装置。  [方法]  基于简单回热模式的超临界CO₂循环,并在此基础上增加一次间冷和一次再热,将小型堆与太阳能、生物质能热源集成为新型混合发电系统,对其发电效率进行了分析。  [结果]  结果表明:对于高压透平入口温度390 ℃的系统,发电效率34.13%,对于高压透平入口温度550 ℃的系统,发电效率41.22%。此外,对系统的安全性分析表明:CO₂本身是具备核安全属性的工质,并且超临界CO₂循环还可以作为反应堆的非能动余热排出系统,确保在严重事故工况下,反应堆持续排出衰变热。  [结论]  集成小型堆和可再生能源的超临界CO₂循环发电系统具备良好的发电效率和核安全性。     

Mitigation technologies and measures in the energy sector of Kazakstan

An important commitment in the UN Framework Convention on Climate Change is to conduct mitigation analysis and to communicate climate change measures and polices. In major part reducing CO₂ as well as the other greenhouse gas emissions in Kazakstan can be a side-product of measures addressed to increasing energy efficiency. Since such measures are very important for the national economy, mitigation strategies in the energy sector of Kazakstan are directly connected with the general national strategy of the energy sector development. This paper outlines the main measures and technologies in energy sector of Kazakstan which can lead to GHG emissions reduction and presents the results of current mitigation assessment.

The mitigation analysis addressed to energy production sector. A baseline and six mitigation scenarios were developed to evaluate the most attractive mitigation options, focusing on specific technologies which have been already included in sustainable energy programs. According to the baseline projection, Kazakstan's CO₂ emissions will not exceed their 1990 level until 2005. The potential for CO₂ emission reduction is estimated to be about 11% of the baseline emission level by the end of considered period (in 2020). The main mitigation options in the energy production sector in terms of mitigation potential and technical and economical feasibility include rehabilitation of thermal power plants aimed to increasing efficiency, use of nuclear energy, and further expansion in the use of hydro energy based on small hydroelectric power plants.     

The Carbon-tax debate

This paper discusses recent topics related indirectly to energy production and marketing and related highly to energy policy and economy. These topics are: (1) background to carbon taxes including environmental issues — global warming and CO₂ emissions, fuel substitution and the encouragement of non-hydrocarbon fuel use; (2) climate-change convention and related conferences including those at Rio de Janeiro — objectives and achievements, and Kyoto-objectives; (3) carbon-tax proposals, including implications for oil, coal and gas: (4) The OECD view including evolution of general taxes on hydrocarbons, the carbon tax as a government revenue-raising objective, CO₂ emissions in the OECD; (5) the oil-producer's view including discrimination against oil, the impact on the incentives to use oil and gas; (6) the developing countries' view, including the need to increase fuel use for industrialisation, financial constraints on energy use, and CO₂ emissions in the developing countries.