粒子反应器技术及其聚烯烃工业应用

综述了粒子反应器技术,包括 Catalloy技术、多催化剂粒子反应器技术等,并对该技术在聚烯烃工业中的应用前景作了介绍。

粒子系太阳能反应器气固两相流与温度场特性

为粒子系太阳能反应器的设计与制造提供理论指导,利用CFD方法对粒子系反应器内的流动与传热过程进行了数值模拟,建立了能够合适的描述反应器内气固两相流动与传热的数学模型。在特定的流动状态下给反应器壁面施加不同的热流得到不同的温度场特性,并对不同的流动状态和温度场进行了对比。研究结果表明:双流体模型和k-ε湍流模型能够很好的描述粒子系反应器内的流动情况;空气速度0.1 m/s、颗粒粒径0.09 mm时反应器内流动状态为环-核流动,且反应器中气固两相的环-核流动状态要优于悬浮状态;在相同热流条件下,环-核流动状态的出口温度比悬浮状态的出口温度高50 K,但是无论是哪种热流,反应器出口的空气温度随时间的增加趋于定值。

应用单粒子扩散反应器对甲烷在4A沸石中扩散的研究

本文利用单粒子扩散反应器对甲烷在4A沸石中的扩散系数进行了测量。首先由沸石的吸附柱的一级矩得到吸附平衡常数Ka,即: △μ=μ_1~c-μ_1^(in)=x/u·(1-a)/aρ_pK_a然后由单粒子扩散反应器的一级矩得到甲烷在4A沸石中的大孔扩散系数,即: μ_1~'=L^2/(6D_a)[(ε_a+ε_i)+(1-ε_a)ρK_a利用以上结果及单粒子扩散反应器的二级矩则可得到甲烷在4A沸石中的微孔扩散系数,即: μ'_2=(L^4)[(ε_a+ε_i)+(1-ε_a)ρK_a]~2)/(90D^2_a+(L^2(ε_i+ρK_a)~2·γ_0~2)/(45D_a·D_i(1-ε_a))得到的实验条件下的微孔扩散系数在3.34×10^(-11)-3.90×10^(-11)cm^2/s范围内,扩散活化能为2.1kJ/mol。

催化合金研究进展

催化合金技术代表了Ziegler Natta催化剂催化聚丙烯的先进技术和工艺。详细描述了催化合金和催化合金技术 ,介绍了催化合金的性能。

Effect of Injecting Inert Particles on Coking Prohibition and Particle Velocity Uniformization in Downer Reactors

The coking observation and particle flow behaviour in both thermal plasma and cold plexiglas downers were investigated in a binary particle system formed by injecting coarse inert particles (carrying coke away and scouring wall) and fine coal powders into the downer reactor. The results demonstrate that this scheme is a rational selection to prevent coking on downer walls and improve particle velocity distribution along the radial direction. When injected coarse particles mixed with fine powders in downers, the fluctuation of local particle velocity in the radial direction becomes smaller and two peaks in the radial distribution of local particle velocity occur due to the improved dispersing character and flow structure, which are beneficial to the thermo-plasma coal cracking reaction and coking prevention.

Studies of Photocatalytic Kinetics on the Degradation of Bisphenol A （BPA） by Immobilized ZnO Nanoparticles in Aerated Photoreactors

The photocatalytic kinetics of BPA （4, 4＇-isopropylidenediphenol）, a representative endocrine disruptor, was explored using immobilized ZnO nanoparticles as a photocatalyst in a laboratory scale photocatalytic reactor. The conditions of photocatalytic degradation were optimized. Direct photocatalytic degradation of BPA was undertaken in an aqueous solution containing ZnO nanoparticles under the optimized experimental conditions. The effects of various factors, such as initial BPA concentrations, initial pH values and various anions （CI, NO3, COa2, SO42-, HCO3＂） were investigated. In the case of the nanoparticles derived films, the photocatalytic efficiency was found not to be remarkably related with the calcination temperature employed in the coating process. Screen-printed ZnO nanoparticles films obtained in the optimal processing conditions showed that the photocatalytic activity is comparable to ZnO nanoparticles in aqueous suspensions. Over 90% degradation efficiency of BPA was achieved under the optimum conditions. The degradation rates in all photocatalytic experiments were linear with the degradation efficiencies of BPA by regression analysis （r ≥ 0.99）. The results showed that the degradation kinetics of BPA in the reactor with immobilized nano-ZnO film as photocatalyst was in agreement with a pseudo-first order rate law.

Effects of extracellular polymer substances on aerobic granulation in sequencing batch reactors

The effects of extracellular polymeric substances (EPS) on aerobic granulation in sequencing batch reactors (SBR) were investigated by evaluating the EPS content, and the relationship between EPS composition and surface properties of glucose-fed aerobic granules. The results show that aerobic granular sludge contains more EPS than seed sludge, and it is about 47 mg/gMLSS. Corresponding to the changes of EPS, the surface charge of microorganisms in granules increases from -0.732 to -0.845 meq/gMLSS, whereas the hydrophobicty changes significantly from 48.46% to 73.16%. It is obviously that changes of EPS in sludge alter the negative surface charge and hydrophobicity of microorganisms in granules, enhance the polymeric interaction and promote the aerobic granulation. Moreover, EPS can serve as carbon and energy reserves in granulation, thus the growth between the interior and exterior bacteria is balanced, and the integrality of granules is maintained. SEM observation of the granules exhibits that EPS in granules are ropy; by mixing with bacteria, compact matrix structure can be formed. The distribution of EPS in granules profiles the importance of EPS storage. It can be concluded that EPS play a crucial role in aerobic granulation.

Advanced functional nanomaterials with microemulsion phase

Significant progress has been made in the formulation of the functional nanomaterials with microemulsion phase.Microemulsion phase can be considered as true nanoreactors,which can be used to synthesize nanomaterials.Properties and the mechanism of nanoparticle formation with microemulsion phase are reviewed in this paper.Preparation of the various nanomaterials,such as metal nanomaterials,oxide nanomaterials,magnetic nanoparticles,inorganic and inorganic compounds nanomaterials,metallic-organic composite nanomaterials,and other composite nanomaterials,are investigated with different microemulsion phases.The possible formation mechanisms are presented with the schematic diagram.

A Miniature Droplet Reactor Built on Nanoparticle-Derived Superhydrophobic Pedestals

The capability to design and modulate materials, shapes, heat transfer, and mass mixing during the process of developing chemical reactors has allowed researchers to explore millions of chemical reactions and assays. However, despite the advantages in engineering array-based microreactors or microfluidic systems, the wetting attachment between solutions of reagents/products and the glass or polymer substrates of containers leads to difficulties in collecting products effectively and preventing channel blockage. Herein we present a miniature droplet reactor which takes advantage of the anti-wetting and low-adhesive properties of nanoparticle-derived superhydrophobic pedestals, allowing aqueous droplets to be manipulated freely but also providing a confined environment for performing a series of aqueous phase chemical reactions on a small scale. Gas- or precipitate- forming reactions can also be performed inside this miniature reactor. Most importantly, reaction products in liquid, solid or gaseous states can be collected effectively, which allows the harvesting of valuable products formed in limited amounts. Such a miniature reactor built on superhydrophobic pedestals provides a new way of performing common chemical reactions and may open the door to the design of next-generation microreaction systems.

Effect of Swirl Cup's Secondary Swirler on Flow Field and Ignition Performance

In a gas turbine engine combustor, highly swiding combustion is usually adopted to stabilize flame and reduce pollutant emissions. Swirl cup, as an air blast atomizer, is widely used to provide a uniform presentation of fuel droplets to the combustor dome. This paper investigated the effect of secondary swirler on the flow field down- stream of the swirl cup using particle image velocimetry （PIV）. Three swirl cups＇ non-reacting flow field were studied： case A, B and C with secondary swirler vane angle 53°, 60° and 68° respectively. Detailed mean and transient velocities and vorticity in the center plane were obtained. From the PIV results, a sharp contrast flow field was obtained for case A to other two cases due to the lower secondary swirling intensity. The recirculation zone is collapsed in disorder for the case A. Ignition tests of the three cups were completed in a single cup com- bustor. In general, the ignition performance increases with the increasing of the secondary swirling intensity. For case A, the ignition performance is very unstable and has much randomness and there is no clear lean ignition boundary can be generated. This work can further understand the swirl behavior and ignition mechanism.

Pore-scale lattice Boltzmann simulation of flow and mass transfer in bioreactor with an immobilized granule for biohydrogen production

The photo bioreaction combined with flow and mass transfer is simulated with pore-scale lattice Boltzmann （LB） method, which is the scenario of a bioreactor filled with a porous granule immobilized photosynthetic bacteria cells for hydrogen production. The quartet structure generation set （QSGS） is used to generate porous structure of the immobilized granule. The effects of porosity of the immobilized granule on flow and concentration fields as well as the hydrogen production performance are investi- gated. Higher porosity facilitates the substrate solution smoothly flowing through the porous granule with increasing velocity, and thus results in higher product concentration inside the immobilized gran- ule. Additionally, the substrate consumption efficiency increases, while hydrogen yield slightly decreases with increasing porosity, and they tend to stable for the porosity larger than 0.5. Furthermore, the LB numerical results have a good agreement with the experimental results. It is demonstrated that the pore-scale LB simulation method coupling with QSGS is available to simulate the photo hydrogen produc- tion in the hioreactor with porous immobilized granules.