FCC DeSO_x and DeNO_x additive technology

The fluid catalytic cracking(FCC) is the principal gasoline producing process in the refinery. Considerable amounts of harmful sulfur oxides and nitrogen oxides (SO x and NO x) are generated with the FCC operation. Impacted by strengthening environmental regulations and the current global emphasis on environmental protection and pollution abatement, refiners have been meaning to look for effective ways to control and reduce SO x and NO x emissions. FCC DeSO x and DeNO x additives is the most promising measure. The present paper reviews the developments in FCC DeSO x and DeNO x additive technology based on the respective authors' works, the future directions of the technology are also discussed.

煤粉燃烧中NO_x和SO_x生成的详细反应机理模拟

采用详细化学反应机理与CFD方法耦合的煤粉燃烧数值模拟程序,计算了煤粉燃烧过程中CO,NO_x和SO_x等的浓度分布特性.通过与实验对照,验证了数值模拟方法的可靠性,并分析了燃烧温度和煤粉细度等因素对于NO生成的影响.结果表明温度对于NO的生成影响较大,随着温度的增加,NO的生成浓度明显增加;对于不同煤种,可能存在一个温度点,这时NO的生成速率将非常快;在计算范围内,温度对SO_2的最终生成浓度没有明显影响,而只影响SO_2的释放过程.煤粉细度对于NO生成有较小的影响.

Catalytic performance of Ag/Co-Ce composite oxides during soot combustion in O_2 and NO_x:Insights into the effects of silver

The composite oxides xAg/Co_（0.93）Ce_（0.07）（x=Ag/（Co＋Ce） molar ratio）,intended for use as high performance catalytic materials,were successfully prepared via citric acid complexation.The effects of silver on the performance of these substances during soot combustion were subsequently investigated.Under O_2,the 0.3Ag/Co_（0.93）Ce_（0.07） catalyst resulted in the lowest ignition temperature,T_（10）,of197 ℃,while the minimum light-off temperature was obtained from both 0.2Ag/Co_（0.93）Ce_（0.07） and0.3Ag/Co_（0.93）Ce_（0.07） in the NO_x atmosphere.These materials were also characterized by various techniques,including H_2,soot and NO_x temperature programmed reduction,X-ray diffraction,and electron paramagnetic resonance,Raman,X-ray photoelectron,and Fourier transform infrared spectroscopic analyses.The results demonstrated that silver significantly alters the catalytic behavior under both O_2 and NO_x,even though the lattice structure of the mixed oxide is not affected.Surface silver oxides generated under the O_2 atmosphere favor soot combustion by participating in the redox cycles between soot and the silver oxide,whereas the AgNO_3 that forms in a NO_x-rich atmosphere facilitates soot abatement at a lower temperature.The inferior activity of AgNO_3 relative to that of Ag_2O results in the different catalytic performance in the presence of NO_x or O_2.

亚洲地区能源消费结构与SO_X、NO_X、CO_2排放量动态分析

1 引言亚洲人口占世界总人口约60％,人口增加和经济发展使该地区能源消耗量持续增加。人们估计,这个地区是世界上对地球环境压力最大的地区之一。同时,这个地区也是人们对资料掌握情况最不完备的地区之一。本文总结了对阿富汗和巴基斯坦以东的25个国家和地区的能源消耗结构与SOx、NOx、CO2排放量的调查。

Combustion and NO_x Emission Behavior of Chinese Coals

Seven Chinese coals ranking from anthracite to sub-bituminous fromthe Shanxi province were selected for study to forecast thecombustion and NO_x emission behavior. Three UK, one Indonesia andone South Africa coal was included in the study for reference. A flatflame-turbulent jet apparatus was employed to assess flame stability,ignition performance and NO_x emission behavior for the initial stageof devolatilization and combustion. This apparatus can simulateparticle heating rates, maximum temperatures and the influence of theturbulent Fluid interactions on the fate of volatiles.

基于物理信息神经网络的燃煤锅炉NO_x排放浓度预测方法

准确的NO_(x)浓度预测对保障燃煤锅炉安全运行和降低污染物排放具有重要意义。基于机器学习的NO_x排放浓度预测方法计算速度快、拟合精度高,但缺少可解释性,且过度依赖训练样本,在样本不充分的情况下模型泛化能力差。为此,该文提出一种基于物理信息神经网络的燃煤锅炉NO_x排放浓度预测方法,将煤量、氧量、分离燃尽风(separated overfireair,SOFA)开度与NO_x排放浓度之间的单调关系嵌入到神经网络中,促使模型服从机理约束,避免机器学习过拟合或欠拟合,提升模型在锅炉宽工况条件下的准确性。以某660 MW燃煤锅炉为研究对象,算例分析表明,提出的预测方法明显优于随机森林、支持向量机和神经网络等常规机器学习方法,即使在未知工况下也能遵循参数间单调性关系,具有较好的可解释性和泛化能力。

Advances in reduction of NO_x and N_2O emission formation in an oxy-fired fluidized bed boiler

Fossil fuel combustion is one of the major means to meet the mounting global energy demand. However, the increasing NO_x and N_2 O emissions arising from fossil fuel combustion process have hazardous effects. Thus, mitigating these gases is vital to attain a sustainable environment. Interestingly, oxy-fuel combustion in fluidized bed for carbon capture and minimized NO_x emissions is strongly sustainable compare to the other approaches. It was assessed that NO_x formation and fuel-N conversion have significant limitation under oxy-fluidized bed compared to air mode and the mechanism of NO_x formation is still deficient and requires further development. In addition, this review paper discussed the potential of primary measure as low emission process with others supplementary techniques for feasible NO_x reduction. The influences of combustion mode, operating parameters, and reduction techniques such as flue gas recirculation, oxygen staging, biomass co-firing, catalyst, influence of fluidized bed design and structure, decoupling combustion and their merges are respectively evaluated. Findings show that significant minimization of NO_x emission can be achieved through combination of primary and secondary reduction techniques.

Study on NO_x Decomposition by Unbalanced Plasma Under Low Temperature and Normal Pressure

Experimental mechanism of decomposing NOx througb catalytic activation, using the high energy unbalanced plasma technology to form an activation center on the metal oxide surface under low temperature and normal pressure is introduced. The results show that the low temperature normal pressure uubalanced plasma technology has provided a new method to solve NOx pollution problem with the decomposing rate over 70%.

Impacts of Future NO_x and CO Emissions on Regional Chemistry and Climate over Eastern China

A coupled chemical/dynamical model （SOCOL-SOlar Climate Ozone Links） is applied to study the impacts of future enhanced CO and NO_x emissions over eastern China on regional chemistry and climate. The result shows that the increase of CO and NOx emissions has significant effects on regional chemistry, including NOx, CO, O_3, and OH concentrations. During winter, the CO concentration is uniformly increased in the northern hemisphere by about 10 ppbv. During summer, the increase of CO has a regional distribution. The change in O_3 concentrations near eastern China has both strong seasonal and spatial variations. During winter, the surface O_3 concentrations decrease by about 2 ppbv, while during summer they increase by about 2 ppbv in eastern China. The changes of CO, NO_x, and O_3 induce important impacts on OH concentrations. The changes in chemistry, especially O_3, induce important effects on regional climate. The analysis suggests that during winter, the surface temperature decreases and air pressure increases in central-eastern China. The changes of temperature and pressure produce decreases in vertical velocity. We should mention that the model resolution is coarse, and the calculated concentrations are generally underestimated when they are compared to measured results. However, because this model is a coupled dynamical/chemical model, it can provide some useful insights regarding the climate impacts due to changes in air pollutant emissions.

Simultaneous Removal of Soot and NO_x over Precious Metal Catalysts O_2-Rich Atmospheres and in the Presence of H_2O and SO_2

The activities of ZrO_2-supported precious metal catalysts for simultaneous removal of soot and NO_x in the presence of rich O_2and H_2O as well as SO_2 have been studied by keeping loose contact between catalyst and soot.The results show that only Ru,Ir and Rh have catalytic activity for simultaneous removal of soot and NO_x and the order of catalytic activity is Ru > Ir > Rh.Pt has the catalytic activity only for the removal of soot,and Ag,Pd,and Au have hardly any catalytic activities for the removal of soot and NO_x.The relationships between catalytic activity of precious metal catalysts and various reaction conditions were discussed.

SO_x和NO_x的脱除方法

美国R.M.Parsons公司开发了一种脱除SO3和NOx的方法,几乎可将SOx和NOx完全脱除。正准备1989年在Ohio州的圣马里斯地方火电厂对10000立方英尺/小时的旁气流上进行中间试验。

Simulation of the Influence of Ion-Produced NO_X and HO_X Radicals on the Antarctic Ozone Depletion with a One-Dimensional Model

A one -dimensional time-dependent photochemical model is used to simulate the influence of ion-produced NOx and HOx radicals on the Antarctic ozone depletion in polar night and polar spring at a latitude of 73 degrees south.Vertical transport and nitrogen-oxygen (NOx). hydrogen-oxygen (HOx) production by ionic reactions have been introduced into the model.NOx and HOx produced by precipitating ions are transported into the lower stratosphere by vertical motion and have some effects in the development of the Antarctic ozone depletion.From winter through spring the calculated ozone column decreases to 269.4 DU. However, this value is significantly higher than the total ozone observed at several Antarctic ozone stations.

基于动态相关向量回归的燃煤锅炉烟气NO_x浓度预测模型

针对NO_x的生成过程的高度非线性、强相关性以及动态特征,提出一种基于互信息和动态相关向量回归的烟气NO_x浓度预测模型。依托某660 MW燃煤锅炉的历史运行数据,建立动态相关向量回归模型。通过和相关向量回归、人工神经网络、极限学习机模型以及动态支持向量回归模型对比分析,提出的NO_x浓度预测模型动态跟踪性能好,预测准确性高,为锅炉燃烧参数调整和SCR系统动态优化提供了基础。

低NO_x煤粉燃烧器技术的研究进展与前景展望

针对日益严格的氮氧化物排放标准,从直流燃烧和旋流燃烧两个方面,介绍了目前国内外较先进的低NOx煤粉燃烧器的技术特点、应用状况及其优缺点,从而提出进一步研究的方向,以开发适应我国国情的低NOx煤粉燃烧器。

不同温度下炉内喷射氨水脱除NO_x的模拟与试验研究

在一台小型沉降炉上进行了氨水喷射还原烟气中NOx的SNCR(SelectiveNon CatalyticReduction)实验研究,同时结合化学反应动力学模型研究了NH3还原NO过程中的关键影响因素,结果发现,过高的温度引起氨水的氧化,过低的温度不利于NO的还原,存在一个单一的温度区间,在该试验台上最佳的氨水喷射温度范围为850℃～1100℃,最高达到了82%的NO还原率;采用均相反应模型与试验结果进行了对比,在高温区吻合情况较好;当温度高于950℃时,NH3残留量可以忽略;NH2的两类支链反应对于整个反应起重要作用。

钼硅酸化学吸收同时去除气流中的SO_2和NO_x

对钼硅酸溶液脱除废气中的ＳＯ２和ＮＯ２及其吸收机理进行了研究．实验结果表明，钼硅酸能十分有效地吸收ＳＯ２并使杂多酸还原为杂多兰；而杂多兰则能还原ＮＯｘ为Ｎ２，从而达到同时去除ＳＯ２和ＮＯｘ的目的．

基于优化粗粒级固体燃料赋存形态的铁矿烧结过程NO_x减排

铁矿烧结工序作为钢铁行业NO_x排放的主要来源,在当前高压环保态势下减少其NO_x排放迫在眉睫.烧结过程NO_x主要产生于固体燃料燃烧过程,而粗粒级燃料的赋存形态会影响其NO_x排放.基于此,本研究采用可视化微型烧结燃烧装置研究裸露型和被覆型粗粒级焦粉的燃烧行为,以及优化其配加模式对NO_x排放和烧结固结强度的影响规律,并烧结杯实验研究兼顾NO_x减排和烧结产质量指标的适宜粗粒级燃料赋存形态.结果表明,相比裸露型粗粒级焦粉,表面被覆铁酸钙细粉时其NO_x排放降低约56%;分加粗粒级焦粉以调控其为裸露型时,NO_x排放增加约10%,且烧结矿强度降低,而控制粒度为0.5~3.15 mm以调控其为被覆型时,NO_x最大体积分数和N元素转化率分别降低约8%和27%,且烧结各项产质量指标均得到改善.

煤燃烧中NO_x的来源和抑制其生成的有效措施

煤燃烧中产生的ＮＯ＿ｘ是不可忽视的大气污染源。根据其生成机理，它主要来自煤中氮的氧化以及高温下空气中Ｎ＿２和Ｏ＿２的反应。烟气中ＮＯ＿ｘ的浓度范围很宽，从２００至２５００ｍｇ／ｍ￣３，影响因素有燃烧温度、空气过剩系数、煤种和燃烧器类型等。在煤燃烧中采取适当措施，可以有效地降低ＮＯ＿ｘ浓度，如降低燃烧温度、分段燃烧、优化空气过剩系数、烟气部分循环和选用含氨量低的煤等。

造纸污泥与废水污泥流化床焚烧时NO_x和SO_2的排放特性研究

The experimental studies on the formation of NOx and SO2 during incineration of sewagesludge and paper mill sludge are reported. The test result indicates that: (1) The conversionof fuel-S into SO2 and fuel-N into NOx is mainly determined by sludge characteristics;(2) Emission of NOx and SO2 decreases with increasing sludge moisture content, increaseswith increasing bed temperature and excess air; (3) The conversion of fuelN into NOxincreases with increasing excess air; (4) The conversion of fuel-S into SO2 increases with bedtemperature and excess air increasing, decreases with sludge moisture increasing.

我国SO_2和NO_X排放强度地理分布和历史趋势

根据我国燃料消费、燃料的含硫量和硫与氮氧化物排放因子，计算我国各地区ＳＯ_２和ＮＯ_Ｘ排放强度地理分布。结果指出，我国原煤含硫量为１．１２％。１９９０年全国ＳＯ_２和ＮＯ_Ｘ的排放量分别为１７５１．８万ｔ和８４２．２万ｔ，排放强度最大的地区是中东部地区，即辽宁、河北、山东、山西和浙江。这些地区平均排放强度大于７ｔ／ｋｍ￣２·ａ。还估算了全国１９５０～１９９０年ＳＯ_２和ＮＯ_Ｘ历年的排放量。