研究报告
阎维平,李海新,鲁晓宇.基于碳捕集的富氧燃煤烟气联合脱硫脱硝试验研究[J].环境科学学报,2013,33(5):1382-1388
基于碳捕集的富氧燃煤烟气联合脱硫脱硝试验研究
- Experimental study on desulfurization and denitration of oxygen-enriched coal-fired flue gas with CO2 capture
- 基金项目：国家高技术研究发展(863)计划项目(No.2009AA05Z310)
- 作者
- 单位
- 阎维平
- 华北电力大学 能源动力与机械工程学院, 保定 071003
- 李海新
- 华北电力大学 能源动力与机械工程学院, 保定 071003
- 鲁晓宇
- 华北电力大学 能源动力与机械工程学院, 保定 071003
- 摘要：富氧燃煤烟气压缩液化CO2的高压低温工况为NO氧化为易溶于水的NO2提供了十分有利的条件.基于小型高压吸收试验装置,采用配制的富氧燃煤模拟烟气,在高压常温下进行了NO、SO2、O2与H2O的吸收反应试验.根据反应前后的气液产物分析,测定了不同组分比例与不同压力下混合气体中NO与SO2的转化率.NO氧化与吸收试验表明,NO转化为HNO3的比率随压力升高而增加,在0.5~2 MPa之间增加很快,在2~3 MPa之间增速趋于平缓,压力达3 MPa以上时,90%以上的NO均转化为稀硝酸,且初始NO浓度越高,NO的转化率越大.混合气体中同时存在SO2与NO的联合吸收试验发现,只有少量的NO转化成了NO3-,SO2向H2SO4的转化率随压力升高而增加,初始SO2浓度越大,转化率越高.分析表明,SO2与NO同时存在时SO2先行转化为SO3,NO充当了催化剂,但SO2转化为SO3的一次转化率小于35%,反应酸液产物的多次循环能使SO2的转化率达到90%以上.建议的工艺流程中需采用两座吸收反应塔顺序脱除SO2与NO并回收稀酸溶液,有望在富氧燃煤发电捕集CO2系统中降低脱硫脱硝成本,部分地弥补富氧燃烧机组发电成本的增加.
- Abstract：The high pressure and low temperature conditions of the CO2 compressing and cooling process of oxygen-enriched coal-fired flue gas offer favorable conditions in accelerating the NO oxidation to NO2.Based on the small scale high-pressure absorption experimental rig, the chemical reaction and absorption tests of different gas mixtures of NO, SO2, O2 and H2O balanced with CO2 were conducted under different high pressure and low temperature conditions. Both the gas and liquid products before and after reaction were sampled and analyzed, and the conversion ratios of NO to NO2 and SO2 to SO3 for different gas mixtures were measured and estimated under different pressures. Without SO2 in the gas mixtures, the NO oxidation and absorption results showed that the conversion ratio of NO to HNO3 increased quickly with pressure ranging 0.5~2 MPa, and slowed down as pressure reached 2~3 MPa. When the reaction pressure exceeded 3 MPa, 90% of NO were converted to HNO3, and high initial NO concentration led to higher NO conversion ratios. The combined absorption experiments of SO2 and NO indicated that only a small proportion of NO were converted to NO3-, and the conversion ratio of SO2 to H2SO4 increased with higher pressure and initial SO2 concentration. Analysis showed that in the co-existence of SO2 and NO, SO2 was firstly converted to SO3 with nitric oxide as a catalyst. However, the primary conversion ratio of SO2 to SO3 was lower than 35%, the multi-circulation of the reacted acid liquid products can promote the SO2 conversion to SO3 to over 90%. In the proposed engineering process for recovering H2SO4 and HNO3 solutions from oxygen-enriched coal-fired flue gas, the two reaction columns would be necessary to remove SO2 and NO separately. Desulfurization and denitration costs can hopefully be reduced and the CO2 capture cost of oxygen-enriched coal-fired power generation can partly be compensated.
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