微生物好氧高效繁殖的堆肥茶涡流混合反应装置设计及应用

该装置的发酵罐底部为圆锥体,发酵罐外部安装有循环泵,用于将发酵液从罐底循环至顶部,热交换器用于控制发酵过程中所需的温度,该设备包括一个或多个雾化喷管,雾化喷管安装在涡流混合室内,用于发酵液的精细雾化,同时,还可与发酵罐内部发酵液上方空间内的氧气混合,确保在酿造堆肥茶过程中能够提供足够的氧气供应促进微生物的繁殖。整个发酵过程中,发酵罐下部的发酵液没有受到任何机械搅拌,一直处于静止状态。

涡流混合增效器在哈拉哈塘油田掺稀生产中的应用

随着世界经济的发展,能源供求日趋紧张的矛盾日益突出,我国稠油资源丰富,如何高效开发利用稠油资源是我们面临的难题。哈拉哈塘油田东北部为稠油油藏,粘度大,流动性差,主要采用掺稀降粘的工艺,由于稀油和稠油在井筒内混合不均匀,出现了一些稠油上返现象,同时导致机采井出现卡泵、欠载停泵、过载停泵等问题,制约了检泵周期的提高,影响了油田正常生产。涡流混合增效器设计原理是利用涡流和惯性原理,实现稀油和稠油的的均匀混合,避免出现段塞状稠油。本文以某15-2井为例,简要介绍了涡流混合增效器在哈拉哈塘油田掺稀生产中的成功应用。

涡流混合式SCR脱硝系统喷氨优化调整试验研究

针对脱硝系统氨逃逸量大造成除尘器无法投运的问题,对涡流混合式脱硝系统进行喷氨优化试验。试验发现,脱硝出口NOx浓度在烟道宽度方向分布不均。通过调整喷氨支管手动蝶阀降低了脱硝出口NOx浓度分布的不均匀度。满负荷下,烟道A侧出口不均匀度由48.3%降低到19.4%;B侧出口不均匀度由62.7%降低到21.8%。经过调整,NOx分布不均匀度显著下降。两侧烟气流量在高低负荷下不存在明显的偏差,流场分布也较为均匀。电厂采用新型涡流静态混合器,有助于解决脱硝出口NOx浓度沿烟道深度方向分布不均的问题。利用SIS数据分析发现脱硝出口NOx浓度CEMS测点不准确,导致喷氨自动投运时喷氨量过大,氨逃逸量变大。CEMS测点取样不具代表性,建议采用网格法取样,并对CEMS测点进行定期标定。喷氨控制策略中,喷氨量跟随性差,导致喷氨量与脱硝入口NOx浓度变化存在一定的延迟,建议优化喷氨控制逻辑。净烟气NOx排放浓度值不宜设置得过低,设定值越低,氨逃逸量越大。综合环保性和经济性,推荐净烟气NOx排放浓度控制在25~35 mg/m3。经过喷氨优化后,整体的氨逃逸量控制在3×10^-6以下。

一种基于喷氨涡流混合器流场设计及应用

随着燃煤火电机组超低排放的全面实施,脱硝系统安全稳定运行是火电机组生产的重要工艺环节。本文结合工程项目脱硝喷氨首次采用大口径涡流混合器,通过CFD模拟计算,全过程优化喷氨格栅入口、出口侧速度场、浓度场,保证了氨氮混合均匀,各项指标优于相关规范要求,为后续推广应用喷氨涡流混合器、提升脱硝设计准则提供了借鉴建议。

涡流混合式SCR系统喷氨特性试验研究

对涡流混合式脱硝系统进行喷氨优化试验。通过喷氨支管手动蝶阀的调节,脱硝出口A侧不均匀度下降了4%;B侧脱硝出口不均匀度下降了24.8%。试验发现,NO_(x)浓度沿烟道深度方向分布不均。分析可能的原因,一是涡流盘结构限制导致的氨浓度分布不均;二是烟道结构导致的流场不均,从而影响脱硝反应进行得不够均匀。综合考虑经济与环保,推荐净烟气NO_(x)排放浓度控制在40mg/m^(3)左右。

脱硝系统新型涡流喷氨混合装置流场数值模拟

SCR脱硝系统的性能取决于进入脱硝反应器的氮氧化物与还原剂氨气混合的均匀程度和烟气速度分布。提出了一种新型的涡流喷氨混合装置,并对其流场进行了三维数值模拟。分析表明,涡流喷氨混合装置能够使进入第1层催化剂的烟气与氨气均匀混合,催化剂入口截面氨气浓度偏差小于10%,混合效果良好;在2个烟道转弯处等距离布置4块导流板,反应器上部等距离布置11块导流板后,烟气速度场达到偏差小于15%的设计要求,因此该新型涡流喷氨混合装置完全能够替代传统的喷氨格栅。

涡流三相混合气浮工艺在某海上平台小型试验研究

为解决渤海油田生产水处理面临的难题,开展了涡流三相混合气浮水处理小型试验研究,以节约海上平台占地面积和减少质量。分析了涡流三相混合气浮工艺原理及设备结构,针对某渤海油田海上平台进行现场调研,提出试验设备连接方案和试验方案,开展了海上平台现场小型试验。试验结果表明,试验装置在添加药剂2后除油效果显著,处理指标能够满足该平台生产水处理需求。根据试验结果结合渤海海上平台生产水处理需求,提出了优化改进措施。

330MW机组涡流混合SCR脱硝装置性能分析及诊断

针对某电厂330 MW火电机组SCR脱硝系统氨气喷射管易堵塞、反应器内氨气浓度分布均匀性差、催化剂磨损严重等问题,基于试验和数值模拟研究对其进行了性能分析和诊断,找出了产生上述问题的根源,对同类型SCR的优化设计和改造具有一定的借鉴意义。

混合式永磁涡流耦合器有限元振动特性研究

介绍了永磁涡流耦合器的结构、工作原理及混合式永磁涡流耦合器的结构;分析了混合式永磁涡流耦合器振动产生的原因,建立了混合式永磁涡流耦合器有限元数学模型,并给出了r≥2阶力波作用下固有频率的表达式;利用有限元仿真软件分别对混合式永磁涡流耦合器的导体转子、永磁体转子、外壳进行仿真。由分析仿真结果可知,通过优化混合式永磁涡流耦合器的结构,可以抑制振动,提高混合式永磁涡流耦合器的使用寿命,减少设备故障率。

关于浮式半潜平台生产水处理的高效涡流三相混合气浮选选用

本文指出了海上平台生产水处理目前面临的困难,结合本项目浮式半潜平台的生产水特点、本设备的原理、特点和此前的应用效果进行分析选型。涡流三相混合气能浮选系统的原理新颖,体积小,重量轻,此前在海上试验结果表明,该技术可以快速、高效地去除生产水中的石油类和悬浮物,系统出水的石油类和悬浮物的含量均可以达到20mg/L以下。

基于模糊输出反馈的永磁涡流耦合器调速系统研究

混合式永磁涡流耦合器具有复杂的控制系统,受到外扰和内扰都会对混合式永磁涡流耦合器控制产生影响,增加控制的难度。为了提高混合式永磁涡流耦合器的鲁棒性与控制精度,提出了基于模糊输出反馈控制器的混合式永磁涡流耦合器控制方案。通过仿真验证和对比发现,该控制系统较传统PID系统具有更强的动态性能和稳态性能,表明该控制方法提高了混合式永磁涡流耦合器调速控制系统的鲁棒性与控制精度。

SCR烟气脱硝装置烟气流场数值模拟

采用FLUENT软件对某6OO MW燃煤机组SCR脱硝系统进行数值模拟,获得了3种方案的速度场。结果表明:烟气和NH3在反应器内速度场和浓度场分布是否均匀直接影响SCR技术的脱硝效果。加装导流叶栅和整流格栅,反应器内第一层催化剂入口断面烟气速度不均匀性小于15%。在获得最佳流场的前提下,涡流混合器保证了氨与烟气在反应器中的充分掺混。数值计算结果为导流板、混合器的设计及合理配置等提供重要参考依据。

GEM气浮在半潜式生产储油平台的应用

某半潜式生产储油平台上的富乙二醇(MEG)经乙二醇再生系统(MRU)处理后回收乙二醇,处理过程中分离出的生产水除含有少量的污油外,还含有高浓度的一价盐溶液和二价盐固体颗粒。固体颗粒可造成下游除油聚结滤器的堵塞而影响生产水处理系统的作业效率。常规气浮可除掉生产污水中的污油,但针对大量的固体颗粒的处理效果较差。新型的GEM气浮为涡流三相混合原理的溶气气浮,利用流体旋转产生的涡流效应将污水、固体、药剂、压缩气体高效混合,使其形成大块、比重极轻的絮状漂浮物,利于在气浮内快速脱除。避免固体颗粒堵塞系统中的聚结过滤器,将生产污水处理至排海指标。

600MW电站锅炉SCR脱硝系统冷态试验研究

SCR反应器中催化剂入口截面气体速度和反应物（NH3和NOx）浓度分布的均匀性直接影响脱硝效率和机组的安全性。采用冷态模拟的方法对600MW燃煤机组SCR脱硝系统进行速度场和反应物（NH3和NOx）浓度分布优化。结果表明：通过涡流混合器、整流格栅及整流格栅上方倾斜顶板附近安装导流钢管，优化调整后速度偏差测定值在5％-6％之间。通过优化涡流混合器的圆盘直径和定位方式，以及调整5个喷甲烷（氨）管的流量，获得达到了NH3／NOx混合的目的，混合不均匀性为5．06％。为指导SCR脱硝系统的设计奠定基础，

HYBRID SCHEME FOR COMPRESSIBLE TURBULENT FLOW AROUND CURVED SURFACE BODY

A hybrid central-upwind scheme is proposed. Two sub-schemes, the central difference scheme and the Roets flux difference splitting scheme, are hybridized by means of a binary sensor function. In order to examine the capability of the proposed hybrid scheme in computing compressible turbulent flow around a curved surface body, especially the flow involving shock wave, three typical eases are investigated by using detached-eddy simulation technique. Numerical results show good agreements with the experimental measurements. The present hybrid scheme can be applied to simulating the compressible flow around a curved surface body involving shock wave and turbulence.

Improvement of Prandtl mixing length theory and application in modeling of turbulent flow in circular tubes

In order to correctly predict tube cross section time-smoothed velocity distribution, friction factor and mass transfer behavior, two models for turbulent flow in circular tubes based on classical Prandtl mixing length theory and a modified mixing length were established. The results show that the modified mixing length includes the introduction of a damping function for the viscous sublayer and the second-order derivative to approximate eddy velocity. The calculated dimensionless time-smoothed velocity from the model based on Prandtl mixing length is much better than the result from the concept of eddy viscosity. The calculated eddy viscosity from the model based on modified mixing length is much better than the result from the model based on the classical Prandtl mixing length theory. And the friction factor calculated from the model based on the modified mixing length agrees well with the reported empirical relationships.

A modified method to estimate eddy diffusivity in the North Pacific using altimeter eddy statistics

The method proposed by Stammer (1998) is modified using eddy statistics from altimeter observation to obtain more realistic eddy diffusivity (K) for the North Pacific. Compared with original estimates, the modified K has remarkably reduced values in the Kuroshio Extension (KE) and North Equatorial Counter Current (NECC) regions, but slightly enhanced values in the Subtropical Counter Current (STCC) region. In strong eastward flow areas like the KE and NECC, owing to a large difference between mean flow velocity and propagation velocity of mesoscale eddies, tracers inside the mesoscale eddies are transported outside rapidly by advection, and mixing length L is hence strongly suppressed. The low eddy probability (P) is also responsible for the reduced K in the NECC area. In the STCC region, however, L is mildly suppressed and P is very high, so K there is enhanced. The zonally-averaged K has two peaks with comparable magnitudes, in the latitude bands of the STCC and KE. In the core of KE, because of the reduced values of P and L, the zonally-averaged K is a minimum. Zonally-integrated eddy heat transport in the KE band, calculated based on the modified K, is much closer to the results of previous independent research, indicating the robustness of our modified K. The map of modified K provides useful information for modeling studies in the North Pacific.

Gas–liquid hydrodynamics in a vessel stirred by dual dislocated-blade Rushton impellers

Towards the objective of improving the gas dispersion performance, the dislocated-blade Rushton impeller was applied to the gas-liquid mixing in a baffled stirred vessel. The flow field, gas hold-up, dissolved oxygen, power consumption before and after gassing were studied using the computational fluid dynamics （CFD） technique. Dispersion of gas in the liquid was modelled using the Eulerian-Eulerian approach along with the dispersed k-e turbulent model. Rotation of the impeller was simulated with the multiple reference frame method. A modified drag coefficient which includes the effect of turbulence was used to account for the momentum exchange. The predictions were compared with their counterparts of the standard Rushton impeller and were validated with the experimental results. It is concluded that the dislocated-blade Rushton impeller is superior to the standard Rushton impeller in the gas-liquid mixing operation, and the findings obtained here lay the basis of its application in process industries.

不同型式AIG对喷氨性能影响的试验研究

为了缓解脱硝反应器内局部氨氮摩尔比不匹配,介绍了喷氨优化调整方法,并结合某厂600MW超临界燃煤机组喷氨格栅(AIG)改造,给出涡流静态混合式AIG和分区控制式AIG下烟气脱硝系统喷氨支管喷氨覆盖面与出口测点位置的对应关系。试验结果表明,500MW负荷下,烟囱出口NO_(x)质量浓度值控制在40mg/m^(3)左右,通过对涡流静态混合式AIG进行喷氨优化调整,脱硝反应器两侧出口NO_(x)质量浓度分布不均匀度分别由72.8%、90.3%下降至39.3%、40.2%;氨逃逸体积浓度分别由2.39μL/L、2.97μL/L下降至0.97μL/L、0.96μL/L。通过对分区控制式AIG进行喷氨优化调整,脱硝反应器两侧出口NO_(x)质量浓度分布不均匀度分别由36.2%、45.4%下降至13.2%、18.8%;氨逃逸体积浓度分别由0.78μL/L、1.05μL/L下降至0.57μL/L、0.68μL/L。结果表明,分区控制式AIG效果优于涡流静态混合式AIG,研究结果为燃煤机组脱硝系统喷氨格栅改造提供参考和借鉴。

Subduction/obduction rate in the North Pacific diagnosed by an eddy-resolving model

Ventilation in the North Pacifi c is examined using data from the eddy-resolving 1/12° global HYbrid Coordinate Ocean Model(HYCOM) and Quik SCAT wind stress data. For the period January 2004 to December 2006 and area 20°–40°N, the total annual subduction rate is estimated at 79 Sv, and the obduction rate 41 Sv. Resolving the small-scale and high-frequency components of the eddy fi eld can increase the subduction rate by 42 Sv, and obduction by 31 Sv. Lateral induction is the dominant contributor to enhancement of subduction/obduction, and temporal change of mixed layer depth has a secondary role. Further analysis indicates that the high-frequency components of the eddy fi eld, especially those with timescale shorter than 10 days, are the most critical factor enhancing subduction/obduction.