含硫油品储罐腐蚀产物自燃性的研究

通过模拟储油罐中硫铁化物的生成方式, 分析和研究了H2S气体在无氧条件下,与不同相对湿度的Fe2O3、Fe3O4和Fe(OH)3反应所生成的硫铁化物的自燃性.不同相对湿度的试样经6 h硫化后,其自燃性明显不同.以Fe2O3试样为例,相对湿度为0的硫化产物氧化升温最高为256 ℃,平均升温速率为10.8 ℃/min; 相对湿度为5%、10%和15%的硫化产物,氧化升温最高温度分别为474 ℃、408 ℃和388 ℃,平均升温速率分别为20.5 ℃/min、18.3 ℃/min和13.5 ℃/min.实验结果表明, 不同相对湿度、不同物质的硫化产物,其自燃性有显著差异,样品的相对湿度对硫化产物的自燃性有重要影响.对各种干燥样品的硫化产物进行电镜分析发现,由不同物质硫化所生成的硫化产物结构不同,致使其自燃性有较大差异.硫铁化物氧化反应放热是引发油罐着火的主要因素.     

纳米TiO2催化臭氧化对松花江水中氨氮的影响

研究了以负载于陶粒、硅胶、沸石表面的纳米TiO₂作为催化剂时,催化臭氧化松花江水过程中氨氮浓度的变化.结果表明,在单独臭氧化过程中,氨氮浓度先升高后下降,反应30 min后的氨氮浓度与初始浓度相近.在以TiO₂/陶粒、TiO₂/硅胶为催化剂的催化臭氧化过程中,氨氮浓度也是先升高后下降,但反应过程中氨氮的平均浓度要高于单独臭氧化过程.以TiO₂/沸石为催化剂时,催化臭氧化过程中氨氮浓度先下降,然后略有升高,继而又下降,30 min时对氨氮的去除率接近80%.单独臭氧化和催化臭氧化过程中,增大臭氧投量,氨氮浓度最大值出现的时间提前,并且反应过程中氨氮浓度平均值降低.增大催化剂TiO₂/陶粒、TiO₂/硅胶的投量,催化臭氧化过程中氨氮浓度平均值升高.增大TiO₂/沸石投量,有利于氨氮的去除,但投量增大到50g以上时,对氨氮的去除效果影响很小.温度从10℃升高到30℃,对TiO₂/陶粒、TiO₂/硅胶催化臭氧化过程中氨氮浓度的变化影响不大.而以TiO₂/沸石为催化剂时,温度升高有利于催化臭氧化过程中氨氮的去除.     

Kinetics of selective catalytic reduction of NO by NH3 on Fe-Mo/ZSM-5 catalyst

The catalyst of Fe-Mo/ZSM-5 has been found to be more active than Fe-ZSM-5 and Mo/ZSM-5 separately for selective catalytic reduction (SCR) of nitric oxide (NO) with NH3. The kinetics of the SCR reaction in the presence of O2 was studied in this work. The results show that the observed reaction orders were 0.74-0.99, 0.01-0.13, and 0 for NO, O2 and NH3, respectively, at 350-450℃. And the apparent activation energy of the SCR was 65 kJ/mol on the Fe-Mo/ZSM-5 catalyst. The SCR mechanism was also deduced. Adsorbed NO species can react directly with adsorbed ammonia species on the active sites to form N2 and H2O. Gaseous O2 might serve as a reoxidizing agent for the active sites that have undergone reduction in the SCR process. It is also important to note that a certain amount of NO was decomposed directly over the Fe-Mo/ZSM-5 catalyst in the absence of NH3.     

珠江三角洲人为氨源排放清单及特征

根据收集的珠江三角洲(珠三角)人为氨源的活动水平数据,采用合理的估算方法和排放因子,建立了该地区2006年人为氨源分类别和分城市的排放清单.结果表明:①2006年珠三角地区人为氨源NH3排放总量约为194.8kt;②农业源是珠江三角洲地区人为氨源的主要排放贡献源,其中畜禽源排放的NH3占总排放量的62.1%,其次是氮肥施用源,其贡献率为21.7%;③畜禽源中肉鸡是NH3排放最大贡献源,占畜禽源NH3排放总量的43.4%,其次是肉猪,其贡献率为32.1%;④广州是珠三角地区2006年人为氨源排放量最大的城市,其次是江门,分别占NH3总排放量的23.4%和19.1%,主要的排放源均为畜禽和氮肥施用源.     

加油站油气回收系统分析与关键技术研究

深入分析了加油站平衡式油气回收系统、真空泵辅助式油气回收系统的美国模式和德国模式的油气回收效率和关键技术问题,揭示了密封性是平衡式失败和美国模式低效的根本原因,解决了困扰业界的罐压不高、罐压保持、后处理装置是否必要等困惑和争议,提出高效率、低密封性要求的"低罐压真空泵辅助式油气回收系统"技术方案和实施方案。     

Effect of C/N ratio, aeration rate and moisture content on ammonia and greenhouse gas emission during the composting

Gaseous emission (N₂O, CH₄ and NH₃) from composting can be an important source of anthropogenic greenhouse gas and air pollution. A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio, aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system. The results showed that about 23.9% to 45.6% of total organic carbon (TOC) was lost in the form of CO₂ and 0.8% to 7.5% of TOC emitted as CH₄. Most of the nitrogen was lost in the form of NH₃, which account for 9.6% to 32.4% of initial nitrogen. N₂O was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it. Statistic analysis showed that the aeration rate is the most important factor which could affect the NH₃ (p = 0.0189), CH₄ (p = 0.0113) and N₂O (p = 0.0493) emissions significantly. Higher aeration rates reduce the CH₄ emission but increase the NH₃ and N₂O losses. C/N ratio could affect the NH₃ (p = 0.0442) and CH₄ (p = 0.0246) emissions significantly, but not the N₂O. Lower C/N ratio caused higher NH₃ and CH₄ emissions. The initial moisture content can not influence the gaseous emission significantly. Most treatments were matured after 37 days, except a trial with high moisture content and a low C/N ratio.     

大型溞母溞暴露于氨氮所产子代对氨氮毒性的耐受性

采用大型溞(Daphnia magna)作为受试生物,在测定了氨氮对大型溞的急慢性毒性效应的基础上,进一步研究了在慢性毒性试验中暴露于氨氮环境下的母溞所产子代对氨氮的毒性响应.急性毒性试验结果表明,氨氮对大型溞的24 h和48 h的LC50分别为165.97和69.54 mg/L.21 d慢性试验结果表明:大型溞的生长指标——脱皮数是对氨氮最为敏感的毒性参数;其慢性毒性下限值(LCL)和慢性毒性上限值(UCL)分别为1.88和3.75 mg/L;据此计算出的慢性毒性值(CHV)为2.66 mg/L,急慢性比(ACR)为26.14.在慢性试验中,暴露于毒物的母体所产的子代幼溞,与对照组相比,其48 h LC50都有所增大(增幅为13.7%～56.2%),说明对毒物的适应性有所增强.     

有关斜管沉淀池的上升流速讨论

文章从理论上了分析斜管沉淀池上升流速对沉淀池处理效果的影响,及原水特性与斜管沉淀池上升流速取值的关系。讨论分析斜管沉淀池设计时,应根据原水特性不同选择不同的斜管沉淀池上升流速。     

控制游离氨实现单级自养生物脱氮的研究

通过实时调控SBR反应器内的游离氮浓度的控制策略,实现以亚硝化作用和厌氧氨氧化作用协同的单级自养生物脱氮工艺.实验分成亚硝酸菌富集和厌氧氨氧化菌混合接种2个阶段,SBR内的温度始终保持在(31±2)℃.亚硝酸菌富集阶段,pH值稳定在7.8左右,通过调节进水氩氮浓度(56～446 mg·L-1)实现FA浓度的变化,从而实...     

曝气生物滤池的短程硝化特性

通过控制进水pH值实现曝气生物滤池的短程硝化。工艺运行结果表明,对于进水pH值为8.22~8.57,NH4+-N平均容积负荷为0.5 kg/(m3.d),水温为17.5~20.2℃,曝气生物滤池溶解氧质量浓度平均为4.5 mg/L的条件下能够同步实现95%的NH4+-N去除率和80%的NO2--N积累率。通过分析FA和FNA沿滤池高度的变化特征,发现滤池底部(0~5 cm)区域短程硝化反应主要由FA控制,中部(5~15 cm)区域是由FA和FNA共同掌控;而上部区域(15~50 cm)则是由FNA控制,FNA沿滤池高度的快速增加是确保工艺实现稳定亚硝酸盐积累的重要原因。