激光诱导白炽光（LII）烟气分析仪

胺洗工艺中气溶胶的清除是一项重要的指标。相位多普勒粒子干涉仪可以准确地在线测量气溶胶粒径，速度和浓度。对于是优化工业过程的重要而有效的工具

Current liquid propellants are either cryogenic (storage constraints), either extremely toxic (handling problem). For this purpose, alternative storable propellant are currently being investigated in this work. The sprays generated by a like-impingement configuration have to be ignited. Because the couple of propellants chosen is non hypergolic, the energy of ignition was brought by a torch igniter. The injection conditions of both the propellants and the torch proved to be compatible to ignite the reactants quickly and stabilize the combustion downstream of the impingement point.

During the last decade particulate matter emission regulation have mandated lower emissions. Future regulations (e.g. EURO 5) will require even lower vehicle emissions. A large reduction in total particulate mass will also create new problems in accurate measurement. Further the calibration of engine maps to interface with soot trap optimisation will require transient data which is certainly beyond current gravimetric procedures. Laser-Induced Incandescence is a technique capable of measuring accurately and near instantaneously particulate matter mass and soot primary particle diameter. LII offers as well the ability to operate in raw exhausts where hydrocarbon loading and vapours often affect other instruments. This poster presents the self-calibrated LII technique invented by the National Research Council, Canada and currently under development in collaboration with Cranfield University. We present measurements taken at Millbrook Proving Ground Emission Test Chamber on a Vauxhall Frontera® and a Dennis Dart® bus following the Euro 4 cycle procedure and the Millbrook London Bus Transport Cycle Procedure. This poster includes also a demonstration of real-time raw exhaust measurement between the exhaust and the particulate trap of a London Bus and a comparison with instruments available within the test facility. The

There are many industrial pollutants produced from coal fired power generation plants. Recent legislation is pushing to reduce these emissions. Greenhouse gasses as well as nitrous oxides (NOX) and sulfur dioxide (SO2) are the targeted pollutants. Governmental legislation outlined by Environmental Protection Agency (EPA) through its Maximum Achievable Control Technology (MACT) guideline is a major thrust.

Sulfur dioxide is the major environmental contaminant that contributes to smog and soot. The reduction of air pollu-tants is a worldwide goal that has become a focus for sustainable environmental development strategies. As emission standards increase, the waste gas cleaning system will be required to adapt or be upgraded. Wet FGD is character-ized as one of the most reliable and effective SO2 removal techniques, with the added benefit of low operating cost. However, implementation and maintenance is considered high. Spray towers are essential elements in the emission cleaning system. Control of the droplets throughout the tower geometry is critical to ensuring maximum reduction and minimal scaling. In order to improve the scrubber, nozzle characteristics and placement must be optimized to reduce the cost of the system implementation and mitigate risks of inadequate pollution removal. A series of large flow rate, hydraulic full and hollow cone injectors were investi-gated for this study. Computational Fluid Dynamics (CFD) simulations were used to examine a standard industrial-size wet scrubber design for injection system optimization. ANSYS Fluent solvers were used with Lagrangian particle tracking meth-od for heat and mass transfer between gas and liquid. The alkaline sorbent material and SO2 reaction was modeled to determine uniformity and efficacy of the system. Surface chemical mechanisms were used to simulate the reaction rate. Drop size, liquid rheology, and injector array layout were examined to achieve SO2 removal above 90%. Wall impingement and flow pattern results were evaluated, due to their impact in minimizing equipment corrosion and plugging.

In 2011, NASA Glenn’s Icing Research Tunnel underwent a major modification to it’s refrigeration plant and heat exchanger. This paper presents the results of the subsequent full cloud calibration. Details of the calibration procedure and results are presented herein. The steps include developing a nozzle transfer map, establishing a uniform cloud, conducting a drop sizing calibration and finally a liquid water content calibration. The goal of the calibration is to develop a uniform cloud, and to build a transfer map from the inputs of air speed, spray bar atomizing air pressure and water pressure to the output of median volumetric droplet diameter and liquid water content.

High-level Nitrogen oxides (NOx) released to the atmosphere cause health and environmental hazards. Conventional power plants are required to have NOx emission control systems to abide by local environmental regulations. Com-mon post-combustion techniques include selective non-catalytic reduction (SNCR) or selective catalytic reduction (SCR) techniques. SNCR is a proven technology that can be implemented virtually without affecting existing indus-trial operations with low capital cost. SNCR is a method involving either aqueous ammonia or urea as the reagent injected into flue gas in the boiler/furnace within specific temperature range. This method commonly reduces the emission of NOx by 30-50%. However, high reductions can be achieved by system optimization. Placement within the proper temperature window, distribution within the cross section and residence time of reagent significantly in-fluence performance of an SNCR system. Therefore, spray lance and nozzle design is crucial for assurance of oper-ating efficiency and ammonia utilization. In this paper, an SNCR system in a circulating fluidized bed (CFB) boiler was studied with using Computational Fluid Dynamics (CFD) simulations, as it relates to spray technology. The simulation solves Navier-Stokes equa-tions with heat and mass transfer using ANSYS Fluent SNCR model with Lagrangian multiphase models and spe-cies transport model. CFD was used to diagnose the gas phase behavior and thermal distribution, to determine opti-mal spray placement and maximum penetration. The focus of this work was the parameters of the injection, which were determined based on test data acquired through in-house laboratory equipment. Temperature profile, pollutant reduction, ammonia slippage and wall impingement were used from the CFD results to assist determining the best spray design to achieve the greatest efficiency.

High-level Nitrogen oxides (NOx) released to the atmosphere cause health and environmental hazards. Conventional power plants are required to have NOx emission control systems to abide by local environmental regulations. Com-mon post-combustion techniques include selective non-catalytic reduction (SNCR) or selective catalytic reduction (SCR) techniques. SNCR is a proven technology that can be implemented virtually without affecting existing indus-trial operations with low capital cost. SNCR is a method involving either aqueous ammonia or urea as the reagent injected into flue gas in the boiler/furnace within specific temperature range. This method commonly reduces the emission of NOx by 30-50%. However, high reductions can be achieved by system optimization. Placement within the proper temperature window, distribution within the cross section and residence time of reagent significantly in-fluence performance of an SNCR system. Therefore, spray lance and nozzle design is crucial for assurance of oper-ating efficiency and ammonia utilization. In this paper, an SNCR system in a circulating fluidized bed (CFB) boiler was studied with using Computational Fluid Dynamics (CFD) simulations, as it relates to spray technology. The simulation solves Navier-Stokes equa-tions with heat and mass transfer using ANSYS Fluent SNCR model with Lagrangian multiphase models and spe-cies transport model. CFD was used to diagnose the gas phase behavior and thermal distribution, to determine opti-mal spray placement and maximum penetration. The focus of this work was the parameters of the injection, which were determined based on test data acquired through in-house laboratory equipment. Temperature profile, pollutant reduction, ammonia slippage and wall impingement were used from the CFD results to assist determining the best spray design to achieve the greatest efficiency.

During the course of a hypothetical severe accident in a nuclear Pressurized Water Reactor (PWR), hydrogen may be produced by the reactor core oxidation and distributed into the containment. Spray systems are used in order to limit overpressure, to enhance the gas mixing to avoid hydrogen accumulation, and to wash out the fission products. In order to simulate these phenomena with CFD codes, it is first necessary to know the droplet size and velocity distributions close to the outlet nozzle. Furthermore, since most of the phenomena relative to droplets (condensation, gas entrainment, collision) are of particular importance in the region below the nozzle, accurate input data are needed for real-scale PWR calculations. The objective is therefore to determine experimentally these input data. Experimental measurements were performed on a single spray nozzle which is routinely used in many PWRs. This nozzle is generally used with water at a relative pressure supply of 350 kPa, producing a mass flow rate of approximately 1 kg/s. At a distance of 20 cm, where atomization is just achieved, it is found that geometric mean diameter varies from 305 to 366 μm, Sauter mean diameter from 430 to 600 μm and mean axial velocity from 14.1 to 18.4 m/s.

During the course of a hypothetical severe accident in a nuclear Pressurized Water Reactor (PWR), hydrogen may be produced by the reactor core oxidation and distributed into the containment. Spray systems are used in order to limit overpressure, to enhance the gas mixing to avoid hydrogen accumulation, and to wash out the fission products. In order to simulate these phenomena with CFD codes, it is first necessary to know the droplet size and velocity distributions close to the outlet nozzle. Furthermore, since most of the phenomena relative to droplets (condensation, gas entrainment, collision) are of particular importance in the region below the nozzle, accurate input data are needed for real-scale PWR calculations. The objective is therefore to determine experimentally these input data. Experimental measurements were performed on a single spray nozzle which is routinely used in many PWRs. This nozzle is generally used with water at a relative pressure supply of 350 kPa, producing a mass flow rate of approximately 1 kg/s. At a distance of 20 cm, where atomization is just achieved, it is found that geometric mean diameter varies from 305 to 366 μm, Sauter mean diameter from 430 to 600 μm and mean axial velocity from 14.1 to 18.4 m/s.

In this work the authors have added an additional sensor to the traditional Phase Doppler Interferometry (PDI) configuration yielding three independent measures of phase shift between detectors. This seemingly minor enhance-ment has a profound impact on the limitations of the PDI technique in two important areas: the minimum laser beam diameters and the ability of the technique to discriminate liquid droplets from solid particles. Phase Doppler measurements can be impacted by reflection/refraction errors in which a droplet’s measured diameter is substantially different from its actual size. This is most critical when small droplets are measured as very large but the converse is possible as well. Consideration for this error source places a major constraint on the minimum laser beam diameter at the measurement volume. The addition of a third independent measure of phase shift effectively eliminates reflection/refraction errors allowing PDI measurements with smaller laser beams than would ordinarily be recommend-ed. The authors demonstrate this ability by measuring the same location of a spray with decreasing laser beam waists. Since the droplet number density limit of the Phase Doppler technique scales inverse to the square of the laser beam diameter, such an optical configuration would substantially enhance the instrument’s performance in dense sprays ap-plications. For applications such as icing cloud measurements, the ability to discriminate and size only liquid droplets in a mixed-phase environment is an important capability of the PDI technique. The relationship between the phase shifts of Phase Doppler signals can be used to differentiate liquid droplets or other spherical particles from irregularly-shaped solids. The authors demonstrate that the addition of a third independent measure of phase shift reduces the number of false positives (solids measuring as droplets) by a large factor – from 11.7% to 0.33% in one example.

The ability of airborne particles to take up water may be enhanced by surface-active components, but the importance of this effect is controversial because direct measurement of the surface tension of microscopic droplets has not been possible. Here we infer droplet surface tension from water uptake measurements of mixed organic-inorganic particles at relative humidities just below saturation (99.3–99.9%). The surface tension of droplets formed on particles composed of NaCl and a-pinene ozonolysis products was reduced by 50–75%, but only when enough organic material was present to form a film on the droplet surface at least 0.8 nm thick. This study suggests that if atmospheric particles are predominantly (?80%) composed of surface-active material, their influence on cloud properties and thus climate could be enhanced, and their atmospheric lifetimes could be reduced. Citation: Ruehl, C. R., P. Y. Chuang, A. Nenes, C. D. Cappa, K. R. Kolesar, and A. H. Goldstein (2012), Strong evidence of surface tension reduction in microscopic aqueous droplets,