As the leading industry of economic development, safety, efficiency and environmental protection are the most basic requirements for the electric power production industry. Rotary air preheater (short air preheater) is the main type of large capacity generating units in China. The corrugated plate type heat storage element of the rotary air preheater is tightly placed in the fan-shaped compartment. Because of the narrow circulation space, it is easy to cause the deposition of dust. In particular, during the "12th Five-Year" development of the national economy, with the increase of environmental emission pressure, the state provided a complete set of denitrification facilities for the active service coal-fired units of 200 thousand kilowatts and above the capacity of 20 years. Although the air preheater and soot blowing system have been revamping in the modification of denitrification technology, the effect of the operation of the denitrification system on increasing the ash plugging of the air preheater is still very obvious. Air preheater ash blocking not only affects the safety of boiler equipment, but also increases the energy consumption of the equipment and reduces the efficiency of the power plant. The air preheater plugging ash leads to an increase in the current of the three large fans (sending, induced draft fan and primary fan), increasing the exhaust gas temperature, reducing the boiler efficiency and increasing the power consumption rate. At the same time, it also increases the possibility of the surge of the air fan and even the RB accident of the boiler. When the ash plugging is serious, it may cause the unit to be unable to run full load, even force the unit to stop and repair. It has a serious effect on the economy of the power plant. The traditional steam soot blowing or sonic soot blowing system can not play a significant role when the differential pressure reaches a certain value due to the aggravation of ash blockage in the running hollow preheater. Using the high pressure flushing water to wash the air preheater online and reduce the differential pressure of the air preheater becomes the main feasible means of on-line treatment. This paper gives a brief introduction to the reasons for the dust plugging of the air preheater of the Tianjin Datang International Panshan Power Generation Company (hereinafter referred to as the Panshan Power Generation Company) and the successful experience of the on-line high pressure water flushing.

1. 设备概述

An overview of 1. equipment

1.1机组概述

Summary of 1.1 unit

盘山发电公司2×600 MW火电机组是我国华北地区建设投产最早的600 MW等级火电机组，工程于1998年10月开工，其中3号机组于2001-12-18正式投产，4号机组于2002-06-05日正式投产，是京津唐电网的主力机组。锅炉为哈尔滨锅炉有限责任公司制造HG-2023/17.6-YM4 型锅、亚临界压力、一次中间再热、固态排渣、单炉膛、Π型布置、全钢构架悬吊结构、半露天布置、控制循环汽包炉。采用三分仓回转式空气预热器，平衡通风， 6 套制粉系统为正压直吹式制粉系统，配置ZGM-123 型中速磨煤机。

The 2 x 600 MW thermal power unit of Panshan Power Generation Company is the earliest 600 MW grade thermal power unit in North China Construction and put into operation. The project was started in October 1998, of which unit 3 was formally put into operation in 2001-12-18, and unit 4 was formally put into operation on 2002-06-05 day, which is the main force of Beijing Tianjin Tangshan power grid. The boiler for Harbin Boiler Co., Ltd. makes HG-2023/17.6-YM4 type pot, subcritical pressure, once reheat, solid slag discharge, single furnace, layout, whole steel frame suspension structure, semi open layout, and www.zibobanjia.com.cnwww.zidongmenz.cn www.shensuomenw.cnwww.weifangbanjia.com.cnwww.canjinzhiji.net.cnwww.weishengzhiji.cncontrol circular drum furnace. Adopting three compartment rotary air preheater and balancing ventilation, 6 sets of pulverizing system are directly pressurized direct coal pulverizing system, and ZGM-123 type medium speed coal pulverizer is equipped.

1.2脱硝空预器改造概述

Summary of 1.2 denitrification air preheater

脱硝SCR反应器投运后，由于氨逃逸的存在，会加剧空预器中温段和冷端的腐蚀和堵灰。因此需要对下游的空预器在防止堵塞和冷段清洗方面作特殊设计和改造。改造范围主要包括：

After the denitration SCR reactor is put into operation, the ammonia escaping will aggravate the corrosion and ash blocking of the middle and the cold ends of the air preheater. Therefore, it is necessary to make special design and transformation for the downstream air preheater to prevent clogging and cold section cleaning. The scope of the transformation mainly includes:

1） 改造后总的换热面积由45032平米增加到47189平米，约增加4.8%；蓄热元件仍维持原来的三段布置，总高度由860mm增加到1910mm，增加约2.7%；

1) the total heat transfer area is increased from 45032 square meters to 47189 square meters, with an increase of about 4.8%, and the regenerative element still maintains the original three sections, the total height is increased from 860mm to 1910mm, and the increase is about 2.7%.

2） 改造后空预器的转动重量计算值（含驱动装置及顶部轴承箱、驱动轴等）由373.12吨增加为423.23吨，增加约13%；驱动电机功率由9KW增加至11KW；

2) the calculation value of the rotating weight of the air preheater (including the driving device and the top bearing box, the driving shaft, etc.) increased from 373.12 tons to 423.23 tons, with an increase of about 13%, and the driving motor power increased from 9KW to 11KW.

3） 热段元件采用高吹灰通透性的HS7板型替代原DU板型，高度由原来的780mm减少到300mm；

3) the high temperature soot blowing HS7 plate is used instead of the original DU plate, and the height is reduced from the original 780mm to 300mm.

4） 中温段采用利旧原中温段，保持HS7板型不变，高度780mm不变；

4) in the middle temperature section, the original intermediate temperature section is used to maintain the HS7 shape and the height 780mm remains unchanged.

5） 冷段层采用HS8板型脱碳钢度搪瓷表面传热元件，高度由原300mm增加到830mm。冷端采用搪瓷表面传热元件可以隔断腐蚀物（硫酸氢铵和由SO3吸收水分产生的H2SO4）和金属接触，而且表面光洁，易于清洗干净。搪瓷层稳定性好，耐磨损，使用寿命长；

5) the cold plate section uses HS8 plate decarbonization steel enamel surface heat transfer element, and the height is increased from original 300mm to 830mm. The cold end uses the enamel surface heat transfer element to cut off the corrosion (ammonium hydrogen sulfate and H2SO4 produced by the SO3 absorption of water) and metal contact, and the surface is smooth and easy to clean. Enamel layer has good stability, wear resistance and long service life.

6） 空预器热端新增加一台普通蒸汽吹灰器。冷端吹灰器采用双介质吹灰器，采用蒸汽/高压水做为吹灰介质，新增加一套以高压柱塞泵为核心设备的高压水泵系统两台空预器共用，设计上可以在线隔离/非隔离以及离线水冲洗。

6) an ordinary steam soot blower is added to the hot end of the air preheater. The cold end soot blower adopts a double medium soot blower, using steam / high pressure water as the soot blowing medium. A new set of high pressure plunger pumps is used as the core equipment of the high pressure water pump system two air predevices. The design can be online isolation / non isolation and off-line water irrigation.

1.3空预器高压水冲洗系统概述

A summary of high pressure water washing system for 1.3 air preheater

由于高压水射流集中，剪切强度大，对灰垢的清扫能力比蒸汽大的多，同时高压水的流速远小于蒸汽，动能的破坏作用比蒸汽小的多，因此大部分脱硝空预器配有高压水冲洗装置供在线或离线对空预器进行冲洗。豪顿华公司为空预器选择通洁公司的3D2A型高压冲洗水泵组,该泵组在现场集成安装，具有结构紧凑体积小的特点。

Because of the concentration of high pressure water jet, the shear strength is large and the cleaning ability of ash scale is much larger than that of steam. At the same time, the flow velocity of high pressure water is much smaller than that of steam, and the damage of kinetic energy is much smaller than that of steam. Houghton Hua company chose the 3D2A high pressure washing water pump group of Tong Jie company for the air preheater. The pump group is installed in the field and has the characteristics of compact structure and small volume.