Papers by Keyword: Agglomeration

Abstract: Through nation-wide and various provinces and regions of the country's gross national product and software industry data Investigation. Combined with industrial concentration index method and location entropy method on the cluster development of software industry and software industry in Jilin province has carried on the empirical research, analysis the software industry in Jilin province while keeping the sustainable development. But the agglomeration development is weak. The software business income, agglomeration degree and the speed of converging in the software industry are below the national average.

Abstract: The impacts of operation parameters on agglomeration characteristics during biomass gasification in fluidized bed were studied experimentally in a 0.02MWt CFB gasifier using cotton stalk pellet as fuel. The experimental results indicated that among the temperature range (600 °C-800 °C), bed agglomeration would occur after a period running with sand, high alumina bauxite or periclase as the bed material, and potassium gathered on the surface of bed materials. In the process of the fluidized-bed gasification of biomass, air velocity affected the degree of bed agglomeration, and the agglomeration problem in return valve was more serious than that in main bed.

Abstract: We have used molecular dynamics and first-principles calculations to investigate the structure and agglomeration of Ti nanoparticles. The results indicate that Ti nanoclusters undergo a phase transition with a change of point group symmetry. In addition, we found that titanium nanocluster growth occurred along the [0001] direction.

Abstract: In order to control the FePO₄ particles size, the reaction precipitation between Fe (NO₃)₃ and H₃PO₄ was performed by the controlled crystallization technique. The influences of the feed concentration, stirring speed and reaction temperature on the agglomeration size of FePO₄ were investigated. The particles produced were amorphous and can be crystallied to pure phase FePO₄ after calcining at 550 °C for 5 hours. The agglomerates size and morphology were characterized by the laser granulometer and scanning electron microscope, respectively. The results showed that the products were spherical and the agglomerate size was in the range of 2~9 μm at the solution PH 2.30 and the other experiment conditions were as follows, the reactant concentration was ranged from 0.5 to 1.0mol/L, stirring speed from 500 to 3000 rpm and reaction temperature from 15 to 80°C. It was found that the agglomerates size increased with the increase of the reaction temperature, decreased with the increase of the feed concentration and stirring speed. Based on the discretized population balance, the particle size distribution model was developed. There was a good agreement between the calculated values and the experimental data, which indicated that this model can be used for predicting the agglomerates size distribution at any desired levels of the variables studied.

Abstract: The article is devoted to the questions of the intermodal transport hubs (ITH) siting on the example of Moscow agglomeration. Big variety of ITH types forming a transport system on the agglomeration territory, proposes to use the territorial principle in determining the main directions of system development, in accordance with the purposes and objectives of the functioning of the ITH in each zone. Also in the article discusses the issues of park-and-Ride facilitiy as an important part of each ITH.

Abstract: The European Directive 2002/49/EC on the assessment and management of environmental noise obliges European Union Member states to draw noise maps of communities with more than 100,000 inhabitants (agglomerations) and of areas near the major transport infrastructures for the assessment of noise outdoors. The Latvian law On Pollution and the Cabinet Regulation No 597 Procedures for Noise Assessment and Management (Adopted 13 July 2004) were harmonized with this European Directive to provide the legislative background for the local authorities to draw noise maps to be used as a basis for noise reduction plans. Riga Agglomeration strategic noise map was calculated using software IMMI 6.3. The map shows Riga City as rather noisy city because major roads and railway lines cross the city center and close to it. Riga Freeport, located on the banks of river Daugava, with its supply roads and branch-ways also add to contribute in the total noise levels. The European Directive 2002/49/EC on the assessment and management of environmental noise also obliges European Union Member states to draw Noise reduction Action plans. In Latvia, Capital Riga and Daugavpils are required to have the Action Plans. Action Plans must be completed by 18 July 2008. Much to our regret the Riga City noise reduction Action Plan is still under consideration and in process of development because it touches the interests of many parties.

Abstract: Titanium dioxide (TiO₂) possesses excellent photocatalytic activity and provides UV protection for polymeric materials. The nanosized TiO₂ particles with larger surface area to volume ratio and an increased surface reactivity shall impart better photocatalysis and UV protection efficiency to the rubber compounds, compared to the use of conventional micron-sized particles. Direct incorporation of TiO₂ nanoparticles (n-TiO₂) into non-polar rubbers faces incompatibility problem between the two phases. One of the solutions to overcome this problem is to treat the nanoparticle surface by using silane coupling agent such as bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT). This work prepared n-TiO₂ from commercial micron sized-TiO₂ by ultrasonication technique. Particle size of TiO₂ was measured by laser light scattering particle size analyzer. The morphology of TiO₂ nanoparticles was characterized by field emission scanning electron microscope (FESEM). The grafting reaction of silane on TiO₂ nanoparticles surface was studied at varying reaction temperatures and times. The purified grafted materials were characterized by energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). The characterization data confirm a presence of grafted silane on the TiO₂ nanoparticles surface. The result shows that ultrasonication technique can effectively decrease particle size and the grafting reaction of silane coupling agent onto TiO₂ nanoparticles can be successfully carried out at 140°C for 8 h.

Abstract: The population balance equation (PBE) was solved numerically by using the sectional method to investigate the effect of breakage on the agglomeration between bipolarly charged particles. Calculations showed that breakage results in the increase of small particles and the decrease of large particles bipolarly charged, compared to the case with only agglomeration effect. The breakage effects are important when simulating the agglomeration dynamics.

Abstract: High temperature CO₂ capture via a CaO-based sorbent was investigated in a fluidized bed. The sorbents tested included natural limestone, pellets made from powdered lime with a calcium aluminate cement binder, mixtures of natural limestone and alumina with a ratio of 1:1 and 2:1. Air-combustion flue gas with a composition of 15% CO₂ + 6% H₂O + 3% O₂ + 76% N₂ at 680°C and oxy-combustion flue gas with a composition of 80% CO₂ + 16% H₂O + 3% O₂ + 1% N₂ at 950°C were used as a carbonation and calcination atmosphere separately to simulate real CFB running conditions. Results showed that pellets have a lower carrying capacity (g CO₂/g calcined limestone or pellets) than nature limestone for the first few cycles mainly due to the existence of calcium aluminate cement (CaAl₂O₄) binder, while pellets have better cyclic activity than natural limestone. Solids agglomeration was found to be a big problem in the application of using Ca-based sorbent to capture CO₂. The solids was not powdery as original ones and tended to clump together after few cycles, making it difficult to fluidize and some dead areas form in the fluidized bed. Agglomeration became severer as cycle number increase and pellets had a much slighter agglomeration than nature limetone due to large particle size. The two mixtures were run in different conditions and H₂O was speculated to accelerate agglomeration.

Abstract: The occurrence of agglomeration in gas-solid fluidized bed can have a very negative impact on the efficiency of reactor operation. In order to overcome the agglomeration problem, an Agglomeration Early-Warning System (AEWS) is proposed. AEWS is able to detect the event of such undesired behavior and make it possible to operate more efficiently. The sensitivity and selectivity of AEWS is illustrated with experimental results. In order to minimize the false alarm, both moving time window method and minimizing value method were analyzed. The experimental results have shown that agglomeration can be recognized 30-60min earlier with AEWS than that with conventional methods based on changes in pressure drop or temperature difference over the bed.