Numerical Simulation Analysis Of Upflow Anaerobic Sludge Blanket

As an important component of Upflow Anaerobic Sludge Blanket(UASB),The structure of water distributor and three-phase separator have a great influence on the UASB treatment effect. Water distributor is set on the bottle of UASB, which provides the function: Water distribution and blender. Scientific design of Water distributor can improve uniformity of water distribution,avoid orifices jammed,increase the efficiency of uniformity and achieve a steady treatment effeciency. The three-phase separator is an equipment can separates gas,solid and liquid from mixture. The gas could able to separate effectively under an optimum structure, also acceptable fluid state will be bring about when precipitate is carrying on.Aim at the disadvantages of grid pipe water distributor, in this paper, firstly, the improved branch system was adopted, and hydraulics design was taken. By using the Fluent software, the paper reported the numerical modeling of flow field in UASB, analyzed the influence of flow pattern and gained optimum combination scheme, according to water distribution manner, gas-liquid height of three phase separator and the structure of three phase separator. At last, the charts of gas volume fraction in UASB at the different time were showed through simulation of gas-liquid flow, the rule of gas-liquid separation was also discussed.The following conclusions are obtained: 1.The effect of head loss for water distribution must be considered when we design the water distributor.2. The using of Branch network of pipes can save tube length, eliminate note of pipe cross, effectively reduce head loss. 3.The logical water distribution is based on specific size and form of anaerobic reactor, trapezoidal water distribution was adopted with high center separator and low circumjacent separator adopt.4.Normal Turbulence modeling can simulate the interior flow field of UASB.5.The internal flow depends on the water distribution pattern,the structure of UASB and specific formal of three-phase separator. by means of increasing the position of fluid level in the center separator can largen valid reactor volume, also raise the abilities and effects of sewage disposal. At the same time, without prejudice to reinforce dead area, reactor volume can be effectively used when a lower position of fluid level in the periphery separator is designed. 6. The numerical simulation method was carried out and showed the discipline of gas development and aggregation at the different time. Center separator with a lower position has a big influence on gas-liquid separating process.The conclusion of this paper can help people have a fully realize on the influence factors and rules of interior flow field in the UASB anaerobic sludge bed, it can not only provide useful reference basis and technical support for the optimization design and efficient operation in practical example, but also promote the design level of the UASB anaerobic sludge bed.