O2／CO2气氛中生物质燃烧及 NO 排放特性研究

采用热重分析仪、管式炉试验研究了反应温度、燃料种类、氧浓度等操作参数对稻壳、稻杆、花生壳3种生物质在 O2／CO2气氛下的燃烧特性和 NO 排放特性。试验结果表明：随着 O2含量的增大,3种生物质的挥发分和固定碳的燃烧性能均随之增加;当反应温度由700℃增加到800℃时,NO 的平均排放量随温度升高迅速增加,当反应温度高于800℃,NO 平均排放量增幅趋于平缓;NO 平均排放量和氮转换率随着燃料中 N 含量的增加而减少;NO 平均排放量随氧气浓度变化较小,低于 NO 排放标准。增加 O2浓度有助于促进生物质在 O2／CO2气氛中的燃烧,同时对 NO 生成的影响较小。     

流化床空气和富氧燃烧气氛下 SO2的释放和脱除特性比较研究

在一个小型流化床试验台上比较了晋城无烟煤在空气和富氧燃烧下 SO2的释放和脱除特性,考察了燃烧气氛、氧浓度、床温和石灰石的添加等因素的影响．研究结果表明：在30％ O2的富氧燃烧条件下 SO2的释放量明显高于其在空气燃烧条件下的释放量;随着富氧燃烧气氛中 O2浓度的增加（从21％增至40％）,SO2的释放量显著增加,当氧浓度达到50％时,SO2的释放量有下降的趋势．床温860～920℃对SO2的释放没有明显的影响,但对其脱除有显著的影响．在空气和30％ O2富氧气氛下,SO2的最佳脱硫温度均为880～900℃．     

石油焦与煤在循环流化床中混合燃烧时SO2排放试验研究

在一热输入为0.6MW的循环流化床燃烧中试装置上进行了石油焦与煤混合燃烧和脱硫试验研究，得到燃料中石油焦与煤质量混合比、过量空气系数、床层温度、一次风率和钙硫摩尔比等参数对SO2排放的影响规律，结果表明，混合燃料中掺焦比例越大，混合燃料的硫含量越高，SO2排放浓度越高；纯烧石油焦时SO2排放浓度最高，对不同配比的混合燃料，随过量空气系数、一次风率和Ca／S摩尔比增大，SO2排放浓度降低，830-850℃的床温对脱硫最为有利，在燃用石油焦与煤质量混合比尺为1和3的混合燃料时可获得最低SO2排放。     

TiO2掺杂 Na2 CO3／Al2 O3吸收剂在流化床中的 CO2捕集特性

由于 Na2 CO3／Al2 O3吸收剂的活性成分 Na2 CO3与 CO2反应活性较低,选用 TiO2作为掺杂剂,采用浸渍法将其添加到 Na2 CO3／Al2 O3吸收剂中进行改性,研制一种新型具有高反应活性的钠基固体吸收剂。利用小型流化床反应器进行了14次循环脱碳／再生试验,并对吸收剂进行了 XRD 和氮吸附表征。结果表明：掺杂 TiO2后,吸收剂与 CO2的反应速率加快,特别是在碳酸化反应的前10 min 内;反应前后除 TiO2外无其他含 Ti 化合物生成;碳酸化反应产物为 NaHCO3和 Na5 H3（CO3）4;14次循环反应后吸收剂仍保持稳定的微观结构。采用 XPS 和 FTIR 分析了 TiO2对 Na2 CO3／Al2 O3吸收剂脱碳特性的改性机理。     

基于化学链制氧的 O2／CO2燃烧电站性能分析

采用 Aspen Plus 软件对基于化学链高温空分制氧技术（CLAS）的 O2／CO2燃烧电厂全过程进行建模,对化学链高温空分单元进行运行参数及功耗分析,并对化学链高温空分单元、锅炉热力发电系统和烟气冷却压缩单元（CCU）进行耦合并优化,确定高温烟气抽取温度及抽取流量．结果表明,O2／CO2燃烧系统的净效率为39．2％,仅比不能进行碳捕集的常规电厂低3．54％．然而,基于深冷空分技术的 O2／CO2燃烧系统会使得全厂净效率下降8％～10％．当采取优化措施后,O2／CO2燃烧系统效率能够提高1．65％．烟气冷却压缩单元能耗占总能耗的59．7％,泵能耗占27．1％．化学链制氧单元的供氧浓度为12．2％．     

富氧燃烧实验台及燃烧特性研究

富氧燃烧是节能、环保的一项重要技术.通过石油液化气在实验台中富氧燃烧的热工试验研究,通过控制助燃空气的含氧浓度来改变燃烧特性和火焰形状、温度,确保合理燃烧.助燃空气中的含氧浓度控制在24%～28%范围内,燃烧的技术性、经济性能较佳.根据燃烧火焰的流动特性和局部助燃富氧空气流动特性确定相关参数,能够得到较好的燃烧效果,较高的锅炉热工效率.采用该方法进行局部增氧助燃烧更为经济、实用.     

富氧燃烧循环流化床中石灰石煅烧／硫化反应模型

对富氧燃烧流化床下石灰石同时煅烧／硫化特性进行了研究,并与 CaO 硫化特性进行了比较。在石灰石煅烧阶段,CaO 与 SO2反应生成 CaSO4产物层覆盖在未煅烧 CaCO3的外层,降低了煅烧速率。同时煅烧／硫化过程中的硫化反应速率比 CaO 的硫化反应速率要缓慢,但是经过足够长的反应时间后,同时煅烧／硫化反应的钙转化率比 CaO 硫化反应的钙转化率要高。建立了一个包含石灰石同时煅烧、烧结和硫化反应的晶粒微晶粒模型用于描述流化床内同时进行的石灰石煅烧、烧结和硫化过程,实验证明所建立的模型能够反映流化床富氧气氛中石灰石的真实煅烧／硫化过程。     

N2和CO2稀释下的非预混甲烷燃烧特性

为研究N2、CO2稀释下的非预混甲烷燃烧特性,以工业锅炉常用的小型圆筒燃烧器为研究对象,基于数值模拟研究2种不同稀释气(CO2、N2)在不同稀释比(0、5％、10％、15％、20％、25％)工况下对天然气燃烧温度场、组分、燃料燃烧效率及主要污染物排放的影响规律.结果 表明:随着2种稀释气体的加入,燃烧速率、最高温度逐渐...     

RCCI发动机的燃烧及排放试验

为了研究天然气掺氢混合燃料对发动机燃烧及排放的影响,利用生物柴油作为燃料,在反应活性控制压燃(reactivity controlled compression ignition,RCCI)模式下进行对比试验。结果表明:天然气掺氢提高了柴油机的热效率,同时缩短了滞燃期和燃烧持续期;随着天然气掺氢混合燃料喷射量的增加,放热率峰值先增大后减小,着火时刻延迟;天然气掺氢燃料的HC、CO和烟度排放均低于天然气,但NO_x排放呈升高趋势,与传统柴油机相比,天然气掺氢能够显著降低CO和HC排放。     

垃圾焚烧发电厂燃烧控制及环保排放的研究

我国垃圾水分大、热值低、灰分大、成分复杂,焚烧炉燃烧控制不可控因素多,结合TIF-CFB特点,从垃圾品质、助燃煤成分、过量空气系数、负荷变化等参数分析影响垃圾燃烧稳定性的因素,对垃圾焚烧中产生的二恶英、重金属、酸性气体、固体废物等进行解析利于有针对性地防治,可实现垃圾发电最大的环境效益。     

利用流态化CVD技术在超细Al2O3粒子表面包覆SnO2薄膜的模型化研究

A theoretical treatment of simulating the morphology and content of SnO2 film coated on ultrafine Al2O3 particles in fluidized bed by chemical vapor deposition (CVD) was developed. The present model accounted for chemical reaction, coagulation, film coating, nucleation coating and gas entrainment of the coating process, which made it possible to predict the quality and quantity of the film coated. By means of Tenanor's method, the model was calculated numerically. Part of the numerical results were compared with the experimental data.     

Wavelet analysis of pressure fluctuation signals in a gas-solid fluidized bed

It has been shown that much dynamic information is hidden in the pressure fluctuation signals of a gas-solid fluidized bed. Unfortunately, due to the random and capricious nature of this signal, it is hard to realize reliable analysis using traditional signal processing methods such as statistical analysis or spectral analysis, which is done in Fourier domain. Information in different frequency band can be extracted by using wavelet analysis. On the evidence of the composition of the pressure fluctuation signals, energy of low frequency (ELF) is proposed to show the transition of fluidized regimes from bubbling fluidization to turbulent fluidization. Plots are presented to describe the fluidized bed's evolution to help identify the state of different flow regimes and provide a characteristic curve to identify the fluidized status effectively and reliably. Project (No. 60075003) supported by the National Natural Science Foundation of China.     

磁流化床铁磁颗粒的流化特性与磁稳区的确定

针对磁流化床可实现磁稳流化的特点,提出了一种确定和计算磁稳流化区域的方法.通过对4种不同粒径的铁磁颗粒(其平均粒径范围231 ~512μm)进行流态化实验研究,得到铁磁颗粒分别在磁场强度为0 ~7 330A/m时的流化曲线.实验中采用压降波动的方法测定最小鼓泡流化速度,进而确定磁稳流化区域的范围.基于铁磁颗粒的流化曲线,分析得到铁磁颗粒的流化特性,讨论了颗粒粒径、磁场强度对磁稳流化区域的影响;运用多元回归的方法得到磁稳流化区域与磁重势能比、阿基米德数以及雷诺数之间的实验关联式.与已有的研究相比,此式较为简单,具有较好的适用性,据此式可以方便地给出磁流化床磁稳流化状态运行时的合理参数.     

Hydrodynamics and oxygen transfer in a novel extra-loop fluidized bed bioreactor

In this paper, the characteristics of fluid mixing time in a novel extra-loop fluidized bed were studied. The results showed that the mixing time was shortened with the increase of fluid velocity. All the discrete numbers of the reactor were above 0.2. The serial number n was 2.5 -3.0. It was judged accordingly that the reactor fluid state was continous stirred tank reactor （CSTR） mainly. When the inspiratory capacity increased the mixing time of the reactor was shortened. Thus the air input was beneficial for the fluid mixing. During the three phases mixing process, the mixing time of the reactor could be decreased by the n increase of carrier and air loading together, but the change was not significant. The parameters affecting the reactor fluid state were fluid velocity, inspiratory capacity and carrier. KLa could be increased with the air loading increase, and at the same gas/liquid ratio when the pressure drop was high, KL~ value was increased. The amount of carrier complex influence on KLa. As the carrier loading continued to increase, its value had been dropped but the changes was not significant, and optimization condition was found at above 800 1 000 g carrier loading （pouzzolane） or 600 g PVC. Under gas/liquid ratio of 0.8% -5.2%, KLa was （0.62-1.37）×10^-2· s^-1.     

PCDD/FS emission in a 150T/D MSW and coal co-firing fluidized bed incinerator

Incineration as a method of reducing Municipal Solid Waste (MSW) volume and recovery of energy has been developed gradually in China. More attention is paid on polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, (PCDD/Fs) formed in MSW incineration process. This paper presents results of the analysis of PCDD/Fs in the residues of a fluidized bed incinerator co-firing MSW and coal in the Yuhang Thermal Power Plant. The effects of operation conditions and the wet scrubber system on PCDD/Fs formation were also analyzed. PCDD/Fs emitting from the smoke stack was 0.92 I-TEQ ng/Nm³. After the wet scrubber emission of dioxins increased and the shifting of homologue profiles in flue gas was also observed, PCDFs were not detected in the incinerator residues. From this, we can see that in the MSW incineration process, the formation mechanism of PCDFs was different from that of PCDDs. The results will benefit further research on the optimal operation of incinerator and control of PCDD/Fs emission from the MSW incinerator. Project supported by the Special Funds for Major State Basic Research Projects 973. (G1999022211), and Natural Science Foundation of China (No. 59836210, No. N1986 2598780472).     

液相燃烧合成LiMn_2O_4及其Mn平均价态的测定

以硝酸锂(锰)、醋酸锂(锰)、尿素和柠檬酸为原料,利用液相燃烧合成方法研究了两种不同酸根盐体系以及燃料尿素用量和柠檬酸对燃烧合成尖晶石型LiMn2O4的影响,并用氧化还原滴定法测定产物中Mn的平均化合价作为合成产物为LiMn2O4的辅证依据。XRD分析表明,液相燃烧合成可制备得尖晶石型LiMn2O4物质,锂和锰的醋酸盐体系燃烧合成LiMn2O4比硝酸盐体系好,燃料尿素比柠檬酸好;醋酸盐和尿素的燃烧体系可得纯相LiMn2O4产物,硝酸盐和尿素的燃烧体系中含有较多Mn2O3,但随尿素量增多,杂相Mn2O3的含量减少;产物LiMn2O4中Mn的价态为+3.5左右,与LiMn2O4中Mn的标准价态相同。