Predictions of the impurities in the CO2 stream of an oxy-coal combustion plant
Predictions of the impurities in the CO2 stream of an oxy-coal combustion plant
复制标题
DOI：
10.1016/j.apenergy.2010.04.014
复制
发表时间：
2010-10
期刊：
影响因子：
11.2
通讯作者：
Hao Liu;Shao Yingjuan
中科院分区：
文献类型：
--
作者：
Hao Liu;Shao Yingjuan
虽然所有三种主要的碳捕获技术（燃烧后、燃烧前和富氧燃料燃烧）都可以产生以CO2为主的气流，但预计CO2气流中会存在其他杂质。CO2流中的杂质会对碳捕获和储存（CCS）链的其他过程产生不利影响，包括CO2流的纯化、压缩、运输和储存。CCS综合发电厂的CO2气流中预期存在的潜在杂质的性质和浓度不仅取决于发电厂的类型，还取决于所使用的碳捕获方法。本论文的重点是预测的杂质预计将存在于CO2流的氧煤燃烧厂。富氧燃烧CO2气流中的主要气体杂质为N2/Ar、O2和H2O。即使进入锅炉及其辅助设备的空气小到可以忽略，CO2流的N2/Ar浓度也可以在约100%至约100%之间变化。1%和6%，主要取决于空气分离单元的O2纯度，并且O2浓度可以在约. 3%和5%，主要取决于锅炉的燃烧化学计量。CO2流的H2O浓度可以从约100至约1000变化。10%到40%以上，主要取决于燃料水分和再循环烟气（RFG）在湿RFG和干RFG之间的分配。NOx和SO2是富氧煤燃烧装置的CO2流中的两种主要污染杂质，并且它们的浓度预期远高于空气煤燃烧装置的烟道气中发现的那些。富氧煤燃烧装置烟气中的NO浓度可高达约100%。相当于空气-煤燃烧装置的两倍。然而，预计富氧煤燃烧装置排放的NOx的量远小于空气煤燃烧装置。通过再燃机理和焦炭-NO反应减少燃烧炉内的再循环NOx是富氧煤燃烧装置NOx排放量较少的主要原因。如果循环烟气不进行脱硫，富氧煤燃烧装置的烟气中SO2浓度可达同等风煤燃烧装置的6倍。富氧煤燃烧装置的烟气体积流量比等效的空气煤燃烧装置的烟气体积流量小得多（<20%），这对于烟气的净化是显著的优势。
Whilst all three main carbon capture technologies (post-combustion, pre-combustion and oxy-fuel combustion) can produce a CO2dominant stream, other impurities are expected to be present in the CO2stream. The impurities in the CO2stream can adversely affect other processes of the carbon capture and storage (CCS) chain including the purification, compression, transportation and storage of the CO2stream. Both the nature and the concentrations of potential impurities expected to be present in the CO2stream of a CCS-integrated power plant depend on not only the type of the power plant but also the carbon capture method used. The present paper focuses on the predictions of impurities expected to be present in the CO2stream of an oxy-coal combustion plant. The main gaseous impurities of the CO2stream of oxy-coal combustion are N2/Ar, O2and H2O. Even the air ingress to the boiler and its auxiliaries is small enough to be neglected, the N2/Ar concentration of the CO2stream can vary between ca. 1% and 6%, mainly depending on the O2purity of the air separation unit, and the O2concentration can vary between ca. 3% and 5%, mainly depending on the combustion stoichiometry of the boiler. The H2O concentration of the CO2stream can vary from ca. 10% to over 40%, mainly depending on the fuel moisture and the partitioning of recycling flue gas (RFG) between wet-RFG and dry-RFG. NOxand SO2are the two main polluting impurities of the CO2stream of an oxy-coal combustion plant and their concentrations are expected to be well above those found in the flue gas of an air-coal combustion plant. The concentration of NOxin the flue gas of an oxy-coal combustion plant can be up to ca. two times to that of an equivalent air-coal combustion plant. The amount of NOxemitted by the oxy-coal combustion plant, however, is expected to be much smaller than that of the air-coal combustion plant. The reductions of the recirculated NOxwithin the combustion furnace by the reburning mechanism and the char-NO reactions are the main reason for a smaller amount of NOxemitted by the oxy-coal combustion plant. The concentration of SO2in the flue gas of an oxy-coal combustion plant can be up to six times to that of an equivalent air-coal combustion plant if the recycling flue gas is not desulphurized. The flue gas volume flow rate of an oxy-coal combustion plant is much smaller (<20%) than that of an equivalent air-coal combustion plant, which is a significant advantage for the purification of the flue gas.