【作者】 李娟；

【导师】 徐依吉；

【作者基本信息】 中国石油大学 ， 油气井工程， 2009， 硕士

【摘要】 水射流技术是近几十年来得以迅速发展的一项新技术,可用于清洗、除锈、切割、破岩等作业,具有清洁、能量集中、效率高、成本低、操作安全方便等特点,因此水射流技术在湿法除尘领域中被普遍采用,是湿法除尘中的一项重要技术。由于湿法除尘所造成的二次污染,使其应用受到一定限制,但是各企业采用的干法除尘效率低、使用和运行维护成本高,不适合中小型企业使用。从我国国情出发,湿法除尘在中小煤炉黑烟污染控制中具有极高的推广价值和应用前景。本文在对湿法除尘技术广泛调研的基础上,着重分析了文丘里湿式除尘器的优缺点,从降低能量损耗、提高除尘效率、降低运行以及维护成本的角度出发,改变除尘介质、改进除尘设备结构。通过对烟尘颗粒表面活性的研究以及表面活性剂作用机理的分析,从改变炭黑的润湿效果和沉降状态入手,将传统的除尘介质——纯水改为表面活性剂的混合溶液,通过对表面张力最低的几组溶液进行炭黑去除率实验,优选出最优配方,结果显示,除尘效果最好的除尘介质为2.9mmol/L十二烷基硫酸钠、20mmol/L硅酸钠、50mg/L絮凝剂B组分和7.1mmol/L磷酸三丁酯的混和溶液,加入后炭黑去除率可高达93.67%。改进除尘设备结构,通过比较不同文丘里风筒各结构参数下喉管处产生负压的大小来优化风筒结构;将12种出口直径、长径比不同的直射式雾化喷嘴和空心锥形雾化喷嘴的除尘量进行对比,优选雾化喷嘴。实验结果表明,空心锥形雾化喷嘴除尘效果最好。经过优选比较,文丘里风筒喉管直径80mm,喉管长度400mm,扩散管锥度10o时配合出口直径1.25mm的引射喷嘴可以获得最高的负压,烟尘吸入效果最好。此外,本文还对最优泵压、炭黑去除率随烟尘速度、浓度的变化规律进行了实验研究,在实验数据的基础上拟合出最优泵压随着烟尘浓度、速度变化的函数关系式,为该设备在不同现场实际应用提供了理论指导。研究结果表明,最优泵压的取值最大为10.4MPa;随着烟尘速度、浓度的增大,除尘效率随之提高,炭黑去除率均大于88.5%。所以无论从降低能耗、节约成本的角度看还是从除尘效率、性能稳定性来看,此种文丘里除尘装置都是满足要求的,具有广泛的工业应用前景。更多还原

【Abstract】 The development of water jet technology is gaining rapid momentum in recent decades. Water jet technology can be used for engineering situations like surface cleaning, descaling, cutting, rock breaking and dust removal, etc. As a wet dust removal method, water jet technology is widely used for its outstanding features including environmentally friendliness, concentrated energy, high efficiency, cost-effectiveness, safe and convenient operation, etc. Though to some extent the secondary pollution caused by water jet dust removal restricts its application, the dry dedusting method is not preferred by small and medium enterprise for its low efficiency and high operation and maintenance cost. From the perspective of China’s national conditions, the water jet dust removal method has great potential in black smoke control of small and medium coal stove.Based on the literature survey of wet dust removal techniques, its advantages and disadvantages are reviewed. In order to reduce energy consumption, enhance dedusting efficiency and lower operation and maintenance cost, the dedusting media and dedusting equipment are optimised in this paper. The tensiometric property of dust particle is firstly studied and the mechanism of surfactant is analyzed. Aiming to change the wetting property of dust particle, the traditional dedusting media, water, is transferred to the surfactant solution. Dust removal experiments are conducted using surfactant solutions with the lowest surface tension and the best surfactant solution for dust removal is determined. The best solution has 2.9mmol/L of sodium dodecyl sulfate, 20mmol/L of sodium silicate, 50mg/L of flocculating agent B and 7.1mmol/L tributyl phosphate. The dedusting experiment using this solution can result in up to 93.67% of dust removal rate.The structure of dedusting equipment is modified. The subpressure values under different structural parameters of Venturi air funnel are experimentally measured in order to optimize the structure of Venturi air funnel. The spraying nozzle that has the best performance of dust removal is determined by comparing the dust removal rate of cylindrical jet nozzles with 12 different values of outlet diameter and slenderness ratio and hollow tapered spraying nozzle. The experiments results show that the best dedusting performance can be obtained using hollow tapered spraying nozzle. The subpressure value and the quantity of inhaled dust can reach maximum using the dedusting equipment which has 80mm of Venturi throat diameter, 400mm of Venturi throat length, 10o taper of diffusion tube and 1.25mm of nozzle diameter. Besides, the effect of dust velocity and dust concentration on the optimal pump pressure and dust removal rate is studied experimentally. It’s found that the optimal pressure is a function of dust velocity and dust concentration. The expression of the optimal pressure with varing dust velocity and dust concentration is obtained, which offers theoretical guide for different engineering scenarios. The experiment results demonstrate that the maximum value of the optimal pressure is 10.4 MPa and the increase of both dust velocity and dust concentration leads to the enhancement of dust removal rate which all exceed 88.5%. This type of Venturi dedusting equipment shows great prospect in industrial applications of dust removal as it can dramatically reduce energy consumption, save cash inputs, enhance dedusting efficiency and work steadily.更多还原