碳捕集与封存技术步骤

CCS技术可以分为捕集、运输以及封存三个步骤,商业化的二氧化碳捕集已运营了一段时间,已发展得较为成熟,而二氧化碳封存技术还在进行大规模的实验。二氧化碳的捕集方式主要有:燃烧前捕集、富氧燃烧和燃烧后捕集。     

碳捕集与封存

正碳捕集与封存(简称CCS)是指将大型发电厂所产生的二氧化碳(CO2)收集起来,并用各种方法储存以避免其排放到大气中的一种技术。这种技术被认为是未来大规模减少温室气体排放、减缓全球变暖最经济、可行的方法。CCS技术可以分为捕集、运输以及封存三个步骤,商业化的二氧化碳捕集已经运营了一段时间,技术已发展得较为成熟,而二氧化碳封存技术各国还在进行大规模的实验。二氧化碳的捕集方式主要有三种:燃烧前捕集、富氧燃烧和燃烧后捕集。燃烧前捕集主要运用于IGCC(整体煤气化联     

碳捕集与封存技术的现状与未来

全球气候变暖问题已经越来越严重,碳捕集与封存（CCS）技术被看作是最具发展前景的解决方案之一,随着研究的不断深入,CCS技术成本将进一步降低。碳捕集工艺按操作时间可分为燃烧前捕集、富氧燃烧捕集和燃烧后捕集,其中最有发展前景的是富氧燃烧捕集。CO2-EOR技术虽然不是直接针对性地封存二氧化碳,但其不仅可以解决二氧化碳的封存问题,还能提高油田采收率,近年来得到广泛应用。我国在CCS技术的研究上进行了大量工作,CCS技术已被列入＂973计划＂和＂863计划＂,北京高碑店热电厂二氧化碳捕集示范工程受到国内外的关注。虽然CCS技术取得了长足的进步,但仍面临着很多问题,如二氧化碳泄漏问题、技术难点、建设和运行成本高昂等。CCS技术项目投资较大,如果没有政府在立法和税收机制上的激励与优惠措施,很难真正进入商业化应用阶段。好在种种迹象表明,随着全球气候问题的加剧,各国政府越来越重视CCS技术的研发和利用。     

燃煤电站富氧燃烧及二氧化碳捕集技术研究现状及发展

本文对富氧燃烧和二氧化碳捕集技术的节能机理及其带来的社会效益进行了较为详尽的阐述,介绍了富氧燃烧及二氧化碳捕集技术的发展历程及现状,指出富氧燃烧及二氧化碳捕集技术在节能及环保方面将有广阔的前景。     

某燃煤电站锅炉富氧燃烧技术的可行性分析

本文针对某200MW燃煤电站锅炉进行富氧燃烧和CO_2减排改造技术的可行性分析,分析了该锅炉的本体改造和辅机改造的技术要点,以及富氧燃烧改造过程中存在富氧燃烧的热力计算方法、富氧燃烧的燃烧器设计开发、烟气再循环量的确定、制氧技术和二氧化碳后处理工艺等关键问题。     

增压富氧燃烧与捕集CO2电站的经济性分析

以300MW燃煤锅炉汽轮发电机组为研究对象,计算了其在6～8MPa压力下增压富氧燃烧的经济性,并与常压富氧燃烧下的经济性进行了对比分析．结果表明：由于系统压力的提高,烟气中水蒸气的凝结热得以回收,用于加热汽轮机低温凝结水,减少汽轮机抽汽,使汽轮机出力增加,电厂的毛输出功率接近320MW;增压富氧燃烧的空气深冷分离制氧（ASU）功耗大大增加,占毛输出功率的26％,而烟气压缩（CPU）的功耗大大降低,约为毛输出功率的0．2％;综合考虑电站其他辅机功耗后,6～8MPa下增压富氧燃烧的电厂净效率比常压富氧燃烧下提高了4．5％．与常压富氧燃烧发电机组相比,增压富氧燃烧在CO2的捕集、压缩液化与封存（CCS）技术中的经济性明显提高．     

富氧燃烧技术研究现状及发展

当前锅炉富氧燃烧技术正在逐步发展,其应用的规模和范围正在不断扩大,讨论了富氧燃烧技术的背景及意义,阐述了富氧燃烧技术的理论基础,详细介绍了国内外膜法制氧技术和富氧燃烧技术的发展历程及现状,最后对富氧燃烧技术的未来进行了展望,指出富氧燃烧技术在节能及环保方面将有广阔的前景.     

高压O2/CO2气氛下煤焦理论计算研究

研究表明在6MPa压力,富氧浓度为30%的条件下的增压富氧燃烧的经济性可以达到最佳。在此气氛下用一个简单的燃烧模型对碳球燃烧的情况进行理论计算,与空气气氛下的燃烧情况作对比,得到增压富氧燃烧在煤粉的燃烧时间和对烟气捕集回收二氧化碳上的优越性。从而为增压富氧燃烧的进一步发展提供理论基础。     

燃煤电站锅炉二氧化碳捕集封存技术经济性分析

阐述了我国燃煤电站采取二氧化碳捕集封存技术(CCS)的必要性,简述了各种二氧化碳捕集方案,并以350 Mw电站机组为例分析了采取各种方案的经济性,燃烧后捕集碳方法在碳交易费为138元/吨CO2时达到盈亏平衡点.纯氧燃烧在碳交易费为77元/吨CO2时达到盈亏平衡,燃烧后系统强化采油收益为0.06元/kwh,氧燃烧强化采油收益为0.10元/kwh.     

浅谈煤炭富氧燃烧减排的技术发展

大量使用矿物燃料所造成的地球温室效应现象越来越严重。近年来,火力发电领域CO_2的捕集、压缩液化及封存技术的研究与工程师范等已成为至关重要的任务。富氧燃烧减排技术是一种既能直接捕集高浓度CO_2,又可以综合控制燃煤污染物排放的新一代洁净煤发电技术。它又被称为O_2/CO_2燃烧技术,或者空气分离/烟气再循环技术。目前,国内外把它作为一种具有发展潜力的碳减排技术研究对象之一。未来将会加快对其研究步伐,围绕富氧燃烧锅炉本体、燃烧器技术、空分系统合理配置和动态调节特性、烟气净化技术来进行钻研。     

二氧化碳排放量化方法探讨

目前,通用的量化二氧化碳排放方法是IPCC排放因子法,但IPCC的排放因子是否适用于我国的排放源有待商榷。利用现场监测的烟道内的温度、压力、二氧化碳浓度、一氧化碳浓度、烟气流速、水蒸气体积百分比等参数,采用质量比法、时间比法、负荷法以及IPCC排放因子法等多种方法,对某企业不同时间段内的二氧化碳排放情况进行量化。结果表明,如果国内企业采用国际通用的量化二氧化碳排放方法,则得到的二氧化碳排放量偏大。为了能更准确地获得燃烧排放源的二氧化碳排放情况,需要采用现场监测的方法。质量比法与IPCC排放因子法的量化结果,其准确性严重依赖于燃料计量数据的准确性,不推荐采用。时间比法的量化结果虽然优于质量比法,但不适合用于量化较长时间段内的二氧化碳排放量。负荷法由于考虑了负荷的影响,其量化结果更为可靠。建议企业通过监测手段,采用负荷法量化燃烧排放源的二氧化碳排放量。为了尽可能减小由客观因素带来的排放量的不确定性,建议选择不同时间段、不同工况多次监测量化燃烧排放源某年度的二氧化碳排放量。     

柴油机富氧燃烧排放特性的试验研究

介绍了在S195柴油机上进行富氧燃烧的试验，对柴油机排放特性进行了比较与分析，目的是通过试验研究，找到在富氧条件下同时降低碳烟和NOx排放的方法。研究结果表明，增加进气氧的质量分数，碳烟排放大幅度下降，HC和CO也趋于下降，但NOx排放显增加；推迟供油提前角，可以使NOx排放降低，但碳烟有上升趋势，HC和CO排放增加。所以，采用富氧燃烧时必须同时推迟供油提前角，才能获得较低的排放量组合。     

Oxy-fuel combustion of solid fuels

Oxy-fuel combustion is suggested as one of the possible, promising technologies for capturing CO₂ from power plants. The concept of oxy-fuel combustion is removal of nitrogen from the oxidizer to carry out the combustion process in oxygen and, in most concepts, recycled flue gas to lower the flame temperature. The flue gas produced thus consists primarily of carbon dioxide and water. Much research on the different aspects of an oxy-fuel power plant has been performed during the last decade. Focus has mainly been on retrofits of existing pulverized-coal-fired power plant units. Green-field plants which provide additional options for improvement of process economics are however likewise investigated. Of particular interest is the change of the combustion process induced by the exchange of carbon dioxide and water vapor for nitrogen as diluent. This paper reviews the published knowledge on the oxy-fuel process and focuses particularly on the combustion fundamentals, i.e. flame temperatures and heat transfer, ignition and burnout, emissions, and fly ash characteristics. Knowledge is currently available regarding both an entire oxy-fuel power plant and the combustion fundamentals. However, several questions remain unanswered and more research and pilot plant testing of heat transfer profiles, emission levels, the optimum oxygen excess and inlet oxygen concentration levels, high and low-temperature fire-side corrosion, ash quality, plant operability, and models to predict NO_x and SO₃ formation is required.     

Future CO2 emissions from combustion of natural and synthetic gases

We assess the contribution of future gas combustion to the global emissions of carbon dioxide. Presently available natural gas resources are too small to make a significant contribution to the ultimate carbon emissions. However, if the production and combustion of synthetic gas becomes a major component of the global energy system, then carbon emissions from gas can become significant—in some cases, up to 50% of the total. Increased use of synthetic gas does not increase carbon emissions, unless the gas displaces electricity produced from nuclear power or solar energy.     

Oxygen efficiency with regard to carbon capture

Carbon capture is often discussed in the literature with the sole focus on power processes, despite the fact that carbon dioxide emissions from other sources are just as relevant for the impact on the atmosphere. Furthermore, some carbon capture methods are relatively inefficient when applied to power production processes. Carbon capture should preferably be performed where the cost is as low as possible, i.e. not necessarily from power production processes. As an example, carbon capture using combustion with pure oxygen is far more energy efficient if it is used together with lime kilns or cement kilns than together with power production processes. A new concept termed “oxygen efficiency” is introduced in this paper. It describes the amount of carbon dioxide that can potentially be captured per unit of oxygen. As such, the oxygen efficiency quantifies the value of a certain unit of oxygen for carbon capture reasons. The base concept is that the energy penalty for the production of one part of oxygen is the same no matter where it is produced; hence, if this unit of oxygen can be used to capture more carbon dioxide, it is more efficient. Typically, the oxygen efficiency would be five times greater for carbon capture when utilising pure oxygen together with cement kilns rather than together with methane-fired power plants. Furthermore, the concept of oxygen efficiency illustrates the importance of considering how carbon capture methods can be utilised in the most efficient way, in addition to evaluating which carbon capture method is the most suitable for a particular technology.     

The effects of changes in the UK energy demand and environmental legislation on atmospheric pollution by carbon dioxide

It has been demonstrated that the combustion of fossil fuel accounts for 97% of the carbon dioxide generated in the UK. The demand for primary energy over the 1970–1994 period has only marginally increased, however the demand for natural gas which has a significantly lower carbon content per unit of energy than other fuels accounts largely for the lowering of carbon dioxide emissions. The enactment UK/EU Environmental Legislation coupled with World Agreements accounts for a significant lowering of carbon dioxide emissions over this period. Future predictions suggest that a further downturn in carbon dioxide emissions will take place over the 1990–2000 period, followed by a pronounced increase over the 2000–2020 period. The expansion of the use of CCGT and/or the introduction of the IGCC and the SUPC in the power generating sector provides an opportunity for a further reduction in carbon dioxide emissions.©     

Combustion rate of carbon: Combustion of spheres in flowing gas streams

Data are presented on the rate of combustion of spheres of carbon in various nitrogen-oxygen mixtures, under conditions in which both the rate of chemical reaction at the surface and the rate of diffusion of oxygen to the surface are factors. A quantitative formulation of combustion rate is presented, predicting effects of temperature, gas velocity, and gas composition in agreement with the experimental measurements. The combustion-rate equation is able to establish limits within which the absolute magnitude of the combustion rate must lie, but these limits are rather broad because of the lack of data on gas diffusivities at high temperatures and of an inexact knowledge of the net products of the primary reaction between oxygen and carbon. From similar data for the rate of combustion in carbon dioxide it is concluded that carbon, when burned in air, is consumed by direct oxidation with oxygen rather than by a mechanism in which oxygen is pictured as reaching the surface chiefly in the form of carbon dioxide, there forming carbon monoxide.     

Oxy-fuel combustion technology for coal-fired power generation

The awareness of the increase in greenhouse gas emissions has resulted in the development of new technologies with lower emissions and technologies that can accommodate capture and sequestration of carbon dioxide. For existing coal-fired combustion plants there are two main options for CO₂ capture: removal of nitrogen from flue gases or removal of nitrogen from air before combustion to obtain a gas stream ready for geo-sequestration. In oxy-fuel combustion, fuel is combusted in pure oxygen rather than air. This technology recycles flue gas back into the furnace to control temperature and makeup the volume of the missing N₂ to ensure there is sufficient gas to maintain the temperature and heat flux profiles in the boiler. A further advantage of the technology revealed in pilot-scale tests is substantially reduced NO_x emissions. For coal-fired combustion, the technology was suggested in the eighties, however, recent developments have led to a renewed interest in the technology. This paper provides a comprehensive review of research that has been undertaken, gives the status of the technology development and assessments providing comparisons with other power generation options, and suggests research needs.     

汽车涂装烘干废气处理

在有燃料助燃的情况下，使汽车制造喷涂烘干过程有机废气在650—750℃燃烧，将有机物转换为二氧化碳和水，炉体采用蓄热式结构，燃烧的热量再用于加热待处理的有机废气，其净化率一般大于95％，达到节能、降耗、减污、增效的目的。