转炉是炼钢生产的主要方式，净化回收冶炼过程中产生的转炉煤气对于环境 保护、节能降耗有极其重要的意义。当前，转炉烟气净化及回收的技术主要有两 大类型，即日本的湿法系统 (OG 法) 和德国的干法系统 (LT 法)。但无论是 OG 法还是 LT 法，入柜煤气的粉尘含量均大于 10 mg/Nm 3 ，需在煤气柜后设置电除 尘器进行精除尘，才能供用户使用；另一方面，冶炼周期内大量不合格煤气因达 不到回收要求而在入柜前被放散掉，放散的烟气粉尘含量高，严重污染环境。为 了解决上述问题，本文结合现有 OG 法系统，提出将湿式电除尘应用在转炉煤气 柜前的新工艺，并对其可行性进行了理论和试验研究，研究结果可用于指导工业 设计。 首先，分析了湿式电除尘在转炉煤气柜前应用的可行性，研究了转炉煤气介 质在电除尘器中的电晕放电情况，得到了气体压力对煤气放电的影响规律，其伏 安特性曲线随气体压力的增加逐渐下移，当气压为4 kPa时，起晕电压低，火花放 电电压高，二次电流值基本保持最大，放电效果最好。 其次，研究了喷水对电除尘器伏安特性的影响规律，研究表明，随着喷水压 力的升高，电晕电流先增大后减小，起晕电压先减小后增大，火花放电电压有减 小的趋势。当水压为0.3 MPa~0.35 MPa时，电晕电流最大，起晕电压最低。即试 验条件下最佳雾化气压为0.3 MPa~0.35 MPa。 然后，试验研究了喷水压力对湿式电除尘器除尘效率的影响。结果表明，水 雾对颗粒的静电脱除效率有一定的促进作用，随着喷水压力的升高，粉尘的脱除 效率先增大后减小，水压为0.3MPa时除尘效率最高，比不喷水时提高约10 %。 最后，研究了水雾对微细颗粒物静电脱除的增强机理。对比原始粉尘和不喷 水时极板收集粉尘粒径分布，湿式电除尘器使粉尘的凝并效率提高，有效降低了5 μm以下尤其是亚微米颗粒物(减少73.9%)的含量，大幅度增加了10 μm以上颗粒物 的含量(增加4.4倍)。 关键词，转炉除尘；湿式电除尘器；气体放电；喷水压力；电晕电流；粉尘凝并- VII - Abstract The oxygen converter is the main way of the steelmaking production. Purification and recovery of converter gas generated in the process of smelting has great significance for environmental protection and energy saving. Currently, there are mainly two type of converter smoke cleaning and gas recovery technology: the Japanese wet system (OG method) and the German dry system (LT method). But both OG method and LT method, the dust content of the gas into the cabinet are greater than 10 mg/Nm 3 . In order to meet the high-quality gas use requirements, electrostatic precipitator should be set after the gas cabinet. On the other hand, in the smelting period a large number of unqualified gas is discharged before into the cabinet due to not reach the requirement of recovery. And the dust content of flue gas is high. This will cause serious environmental pollution. In order to solve the above situations, combining with the existing method of OG system, this paper put forward the new process of application of wet electrostatic precipitator in front of the converter gas tank, and its feasibility was studied experimentally and theoretically. The results can be used to guide the industrial design. Firstly, this paper analyzed the feasibility of application of wet electrostatic precipitator before the converter gas tank. And the discharge situation of converter gas was studied. Obtained the effect of gas pressure on the gas discharge. The rusults showed that the V-I characteristic gradually down with the increase of gas pressure. When the pressure was 4 kPa, the corona voltage was low, the spark discharge voltage was high, the secondary current remained substantially the maximum and the discharge effect was best. Secondly, the effect of water injection on the ESP V-I characteristics was studied. The research showed that with the increase of water pressure the corona current increasrd first and then decreased, the corona voltage decreased first and then increased, and the spark discharge voltage tended to decrease. When the nozzle pressure was 0.35 MPa~0.35 MPa, the corona current was biggest and the corona燕山大学工学硕士学位报告 voltage was lowest. That under the experimental conditions the best atomizing pressure was 0.3 MPa ~0.35 MPa. Then, the effect of nozzle pressure on the performance of ESP was experimentally studied. The results showed that water spray could promote the collection efficiency of particles. With the increase of the pressure, the collection efficiency increased first and then decreased. When the water pressure was 0.3 MPa, the collection efficiency was highest and the improvement was about 10 %. Finally, the enhanced mechanism of the collection efficiency of fine particles was studied. Compared the original dust and the particle size distribution of collected dust from the plates under the electrostatic effect only, wet electrostatic precipitator improved the coagulation efficiency of fine dust particles. Effectively reduced the content of the particulate under 5μm (73.9% reduction). Meanwhile, it also significantly increased the content of the particles more than 10μm, and the improvement was about 4.4 times. Keywords: converter gas recovery; wet electrostatic precipitator; gas discharge; nozzle pressure; corona current; particles coagulation目 录 - IX - 目 录 摘要........................................................................................................................I ABSTRACT ............................................................................................................. II 第 1 章 绪 论.........................................................................................................1 1.1 课题背景及研究的目的和意义 ................................................................ 1 1.2 转炉煤气回收净化系统的国内外研究现状 .............................................. 2 1.2.1 OG 法国内外研究现状 ............................................................................ 2 1.2.2 LT 法国内外研究现状 ............................................................................. 3 1.3 本文的主要研究内容 ............................................................................... 4 第 2 章 湿式电除尘器除尘机理..............................................................................6 2.1 气体放电原理 .......................................................................................... 6 2.1.1 场致发射 ................................................................................................. 6 2.1.2 碰撞电离 ................................................................................................. 7 2.1.3 气体的击穿.............................................................................................. 8 2.1.4 电晕放电过程.......................................................................................... 9 2.2 水雾形成原理 ........................................................................................ 10 2.3 尘粒荷电原理 ........................................................................................ 11 2.3.1 电场荷电 ............................................................................................... 12 2.3.2 扩散荷电 ............................................................................................... 13 2.4 湿式电除尘工作原理 ............................................................................. 13 2.4.1 除尘工作原理........................................................................................ 13 2.4.2 除尘效率 ................................................................................................ 14 第 3 章 湿式电除尘在转炉煤气柜前应用的可行性分析...................................15 3.1 工艺对比 ............................................................................................... 15 3.2 技术可靠性............................................................................................ 16 3.2.1 除尘效率高............................................................................................ 16 3.2.2 安全性高 ............................................................................................... 16 3.2.3 实践中运行良好.................................................................................... 17 3.3 经济效益 .....................................................................................