Emissions of SO2, NO and N2O in a circulating fluidized bed combustor during co-firing coal and biomass

This paper presents the experimental investigations of the emissions of SO2, NO and N2O in a bench scale circulating fluidized bed combustor for coal combustion and co-firing coal and biomass. The thermal capacity of the combustor is 30 kW. The setup is electrically heated during startup. The influence of the excess air, the degree of the air staging, the biomass share and the feeding position of the fuels on the emissions of SO2, NO and N2O were studied. The results showed that an increase in the biomass shares resulted in an increase of the CO concentration in the flue gas, probably due to the high volatile content of the biomass. In co-firing, the emission of SO2 increased with increasing biomass share slightly, however, non-linear increase relationship between SO2 emission and fuel sulfur content was observed. Air staging significantly decreased the NO emission without raising the SO2 level. Although the change of the fuel feeding position from riser to downer resulted in a decrease in the NO emission level, no obvious change was observed for the SO2 level. Taking the coal feeding position R as a reference, the relative NO emission could significantly decrease during co-firing coal and biomass when feeding fuel at position D and keeping the first stage stoichiometry greater than 0.95. The possible mechanisms of the sulfur and nitrogen chemistry at these conditions were discussed and the ways of simultaneous reduction of SO2, NO and N2O were proposed.     

Pd/activated carbon sorbents for mid-temperature capture of mercury from coal-derived fuel gas

Higher concentrations of Hg can be emitted from coal pyrolysis or gasification than from coal combustion, especially elemental Hg. Highly efficient Hg removal technology from coal-derived fuel gas is thus of great importance. Based on the very excellent Hg removal ability of Pd and the high adsorption abilities of activated carbon（AC） for H2 S and Hg, a series of Pd/AC sorbents was prepared by using pore volume impregnation, and their performance in capturing Hg and H2 S from coal-derived fuel gas was investigated using a laboratory-scale fixed-bed reactor. The effects of loading amount, reaction temperature and reaction atmosphere on Hg removal from coal-derived fuel gas were studied. The sorbents were characterized by N2 adsorption, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）. The results indicated that the efficiency of Hg removal increased with the increasing of Pd loading amount, but the effective utilization rate of the active component Pd decreased significantly at the same time. High temperature had a negative influence on the Hg removal. The efficiency of Hg removal in the N2-H2S-H2-CO-Hg atmosphere（simulated coal gas） was higher than that in N2-H2S-Hg and N2-Hg atmospheres, which showed that H2 and CO, with their reducing capacity, could benefit promote the removal of Hg. The XPS results suggested that there were two different ways of capturing Hg over sorbents in N2-H2S-Hg and N2-Hg atmospheres.     

SCR催化剂对汞的催化氧化研究进展

文章综述了目前国内外选择性催化还原(SCR)催化剂催化氧化燃煤烟气中汞的研究现状。介绍了钒基、铜基、铁基、锰基、铈基以及贵金属SCR催化剂对汞的催化氧化性能;分别分析了烟气温度、烟气组分(Cl2、HCl、SO2、NH3等)、空速等因素对各催化剂汞氧化性能的影响;最后运用文献对比方法综合概括了燃煤烟气条件对汞氧化的影响,并结合我国燃煤电厂现状,对SCR催化脱汞技术的发展方向提出建议:利用SCR催化剂实现燃煤烟气中汞的氧化,结合现有污染物控制设备实现汞的脱除,是一种经济、高效的燃煤烟气脱汞技术;当前应深入研究SCR催化剂对汞的催化氧化机理,开发能够实现NOx与汞协同控制的,稳定、高效、普适性强的低温SCR催化剂。     

大面积推广天然气发电的难点何在

从英美等国能源转型的实践看,用天然气替代煤炭是战胜雾霾的一大途径.但对“富煤贫油少气”的中国来说,被各地寄予厚望并强力推进的“煤改气”真是一剂治霾良方吗？在治霾压力倒逼之下,中国天然气产业会迎来什么样的机遇和挑战？     

高水压载荷下软硬原煤瓦斯渗流试验研究

采用二次成型法成功地制作同一煤矿的硬煤和软煤原煤样,并在高水压加载前后使用自行设计的瓦斯渗流试验装置对两种典型原煤煤样的瓦斯渗透率的变化规律进行研究。结果表明:高水压加载前后,两种原煤样的瓦斯渗透率的变化规律差异较大,硬煤原煤样在高水压作用下,煤体内部发生脆性变形,其裂隙得到充分扩张、衍生,形成贯通裂隙网,有效孔隙度增加,煤样瓦斯渗透率较加载前大幅提高;相反,软煤原煤样在高水压作用下,煤体内部发生塑性变形,煤体被水压实,其原生裂隙也被堵塞,瓦斯的流动性更进一步弱化,煤样瓦斯渗透率较加载前大大降低。     

流化床O2/CO2气氛燃煤痕量元素的排放特性及控制

通过平顶山烟煤在小型流化床中的燃烧实验,采用X-射线荧光光谱仪(XRF)对低压撞击器(LPI)收集到的细颗粒物元素组成进行定量测定,研究了O2/CO2气氛下硅藻土对煤粉燃烧痕量元素的排放控制.结果表明,Zn、Mn和Ni的含量随粒径呈双峰分布,峰值分别在0.1μm和2μm附近,Hg和Co的含量在0.1μm附近有一峰值;Hg和Zn在亚微米颗粒上有一定程度的富集,Mn、Ni和Co在亚微米和超微米颗粒上的含量基本相当;当颗粒物粒径一定时,随着硅藻土含量的增加,5种元素的富集因子呈减小的趋势;随着添加剂粒径的减小,颗粒物中Hg、Mn、Zn、Ni和Co的含量呈减少的趋势;当颗粒物粒径一定时,5种元素含量顺序为MnZnNiCoHg.     

我国规划建12条治霾跨区送电通道

日前,国家电网公司推行“以电代煤、以电代油、电从远方来”．我国将规划建设12条治霾跨区送电通道．让雾霾频发的东中部地区少燃煤多用“远方来的电”、国网公司将负责建设运营其中11条输电通道,     

浅谈陶瓷炉窑“煤改气”工程节能减排效益分析

通过一家陶瓷企业"煤改气"工程实例,分析比较工程改造前后的燃料消耗、污染物排放、产品质量、成本费用等情况,认为陶瓷炉窑煤"煤改气"后企业降低了能源消耗、减少污染物排放、提高资源利用率、提高产品质量,具有较好的环境效益和社会效益,天然气作为陶瓷行业燃料,是大势所趋。     

地质动力区划预测煤与瓦斯突出

为了确定煤与瓦斯突出矿井的突出危险区域,威胁区域和安全区域,提出基于地质动力区划的多因素模式识别概率预测方法预测煤与瓦斯突出的新思路。以鸡西滴道矿立井为研究对象,利用地质动力区划方法确定不同尺度和级别构造运动的特征,建立板块构造学说与矿井工程实际的联系,将对矿井煤与瓦斯突出产生影响的因素为参数,采用多因素模式识别概率预测方法划分研究区域内的危险区域。研究表明该方法对煤与瓦斯突出区域预测的合理性与有效性,可以在实际工程中应用推广。     

职业病加重后的工伤认定

正【案情】2008年,刘某在共和煤业有限公司从事采煤期间被诊断为一期尘肺,并被认定为工伤。自2010年2月起,刘某开始在狮子山煤业有限公司从事采煤工作,刘某在入职前体检和工伤保险参保体检时均未查出患尘肺病。2013年刘某被诊断为煤工尘肺三期,经重庆市大足人社局认定,确认刘某所患尘肺三期为工伤。2014年11月25日,大足人社局以"同一受伤部位不能进行重复认定"的原则为由,作出了撤销刘某尘肺三期的工伤认定通知。刘某对此不服,于2014年