污泥管道输送非均质流动阻力预测及费用模型研究

发布时间：2018-03-06 09:44

本文选题：城市污泥　切入点：管道输送　出处：《哈尔滨工业大学》2014年博士论文　论文类型：学位论文

【摘要】：活性污泥法因其高效、低耗等优点而成为城市污水处理的最主要方法，但随之产生的大量污泥却是污水处理厂面临的一大难题。对污泥的处理处置有分散处理和集中处理两种模式，其中后者因占用城市面积小且对周边环境污染轻而成为污泥处理与处置的首选模式。实践表明，在可供选择的污泥输送方式中，传统的卡车输送、驳船输送运行费用高，输送效率低，并且严重影响城市环境卫生。相比之下，城市污泥的管道输送方式因其运行费用省、自动化控制程度高及清洁卫生等优点而成为污泥输送方式的最佳选择。对城市污泥管道输送阻力特性进行研究，并对输送管道的设计参数进行优化，不但能够保障污泥输送管道的安全可靠运行，同时还对保障其经济运行并节省输送成本具有重要意义。测定了质量浓度分别为2.38%，3.94%和5.39%的污泥的流变性，结果表明其具有显著剪切稀化特性，在剪切速率足够大时表现出较稳定的极限粘度，三种质量浓度污泥在温度T=293K时的极限粘度分别为2.60mPa s，3.21mPa s和5.95mPa s；T=298K时分别为2.45mPa s，2.91mPa s和5.78mPa s；T=303K时分别为2.32mPa s，2.78mPa s和3.69mPa s，表明极限粘度随污泥质量浓度的升高而增大，同时随温度的升高而降低。污泥流变曲线符合宾汉模型，表现出宾汉伪塑性的流变特征。基于污泥的流变特性，经阻力模型比选，采用广泛应用的Turian-Yuan非均质模型对城市污泥在管道内的流动阻力进行了预测，并结合试验数据对其参数进行了优化。对于敏感参数污泥体积浓度CV的指数m1和污泥颗粒沉降阻力系数CD的指数m2的优化结果为：m1=0.887，m2=-0.162，由此确定改进Turian-Yuan20.694非均质阻力模型为i i0.551C0.887C0.162(v)(s movD)1.2gD i0。经实际输泥管道实测数据验证，改进Turian-Yuan非均质模型精度高且预测效果稳定，满足对污泥流动阻力预测的精度要求，同时对该模型预测误差的来源进行了分析。推导了基于相似理论的输泥管道原型和物理模型主要参数之间的关系，实现了基于试验结果的实际原型流动参数的模拟，，并将该方法所获得的阻力模拟值与改进Turian-Yuan模型的模拟值进行了分析比较，进一步验证了改进Turian-Yuan模型的精度和安全性。建立了污泥管道输送系统年折算总费用模型，并将污泥浓度Cw和输送速度v确定为待优化变量，同时利用高效并行且具有全局寻优能力的遗传算法对复杂非线性的污泥管道输送系统费用模型进行了参数优化求解，为污泥管道输送系统的安全经济运行提供了可参考的优化设计参数。计算实例表明，污泥流量Q=0.226~0.045m3/s（污泥浓度Cw=0.8~4.0%），输送距离L=4.5103m条件下的最优设计参数为：污泥浓度2.32%，输送流速1.10m/s，管径300mm，年折算总费用W=52.83万元。污泥管道输送系统年折算总费用构成的分析结果表明，输送系统年折算总费用由年折算建设费用和年运行费用构成，后者主要表现为维持系统运行的动力费用且在总费用中占主要部分，因此应在满足输送流速约束条件的前提下通过降低输送流速来控制年运行费用的剧增，从而降低年折算总费用。同时，对实用的污泥浓度进行了分区，并对计算实例建立了比年折算总费用偏离率曲线以用于对不同污泥浓度分区内的运行方案进行优选，优选结果为：在第Ⅲ浓度分区内，基准值W0’(300)=1.77E-06，且在Cw=2.32%时偏离率达到最小值，与计算实例中优化结果吻合。
[Abstract]:The activated sludge process because of its high efficiency, and has become the most important method of city sewage treatment and low consumption, but a major problem resulting in a large number of sludge is a sewage treatment plant. The disposal of sludge is decentralized and centralized treatment of two modes, which accounted for by the latter due to the small area of the city and the surrounding environment pollution the light has become the preferred mode of sludge treatment and disposal. The practice shows that the choice of sludge conveying way, the traditional transportation truck, barge transport high operating costs, low transport efficiency, and seriously affect the city environmental sanitation. In contrast, the pipeline of city sludge transport due to its operating cost, the advantages of automation a high degree of control and clean and become the best choice of transportation mode. The sludge resistance characteristics of sludge pipeline transportation of city is studied, and design parameters of the pipeline is optimized. It not only ensures the safe and reliable operation of the sludge conveying pipeline, but also is of great significance to ensure its economic operation and save the transportation cost.
Determination of the mass concentration were 2.38%, 3.94% and 5.39% of the rheological properties of sludge, the results showed that it has obvious shear thinning characteristics, showing a stable limit viscosity when the shear rate is large enough, the limiting viscosity of three kinds of quality concentration of sludge at a temperature of T=293K were 2.60mPa s, 3.21mPa s and 5.95mPa s; T=298K s 2.91mPa s were 2.45mPa, 5.78mPa and S; T=303K were 2.32mPa s, 2.78mPa s and 3.69mPa s, showed that the limiting viscosity increases with increase of sludge concentration, and decreases with the increase of temperature. The sludge rheological curve accords with the Bingham model, exhibited pseudo plastic rheological characteristics of Bingham.
Based on the rheological properties of sludge, the resistance model selection, the widely used Turian-Yuan heterogeneous model to predict the flow resistance of city sludge in pipeline, and combined with the optimization of the parameters of the test data. The sensitive parameters of sludge volume concentration of CV refers to the optimized index M2 drag coefficient CD M1 and sludge settling the result of particles: m1=0.887, m2=-0.162, the improved Turian-Yuan20.694 heterogeneous resistance model for I i0.551C0.887C0.162 (V) (s movD) 1.2gD i0. after the actual mud
The measured data show that the improved Turian-Yuan pipeline, unsteady homogeneous model with high precision and prediction results meet the requirements of the accuracy of prediction of flow resistance of sludge, while the source of the forecasting error of the model is analyzed. The relationship between the main parameters of dredging pipeline prototype and physical model based on similarity theory is deduced to simulate the actual prototype flow based on the parameters of test results, and this method has the resistance value and the simulation value of the modified Turian-Yuan model are analyzed and compared, further verify the accuracy and safety of the improved Turian-Yuan model.
The sludge pipeline transportation system of annual total cost model, and the sludge concentration of Cw and V to determine the transmission speed of variables to be optimized, while the genetic algorithm is efficient and parallel with global optimization ability of sludge pipeline delivery system for complex nonlinear cost model for parameter optimization solution, provided the optimum design parameters for reference the safety and economic operation of transportation system for sludge pipeline. The calculation examples show that the sludge flow Q=0.226~0.045m3/s (sludge concentration Cw=0.8~4.0%), the optimal design parameters of the transmission distance under the condition of L=4.5103m: the sludge concentration 2.32%, conveying velocity 1.10m/s, diameter 300mm, annual total cost of W=52.83 million yuan.
The analysis results of sludge pipeline transportation system annual total cost that annual total cost of transportation system consists of annual construction cost and operation cost, the latter is mainly for power system operation and maintenance costs accounted for the major part of the total cost, therefore should meet the premise of transportation rate constraints by reducing to control operating cost of conveying velocity increase, thereby reducing the annual total cost. At the same time, the sludge concentration practical is partitioned, and the calculation example is established in the total cost of conversion rate curve to optimize the deviation in operation scheme of different sludge concentration areas, and the results were: the concentration of Division III in the reference value W0 '(300) =1.77E-06, and at Cw=2.32% when the deviation rate reaches the minimum value, and an example of calculation in optimization results.

【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU992.2

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