全部
  • 全部
  • 产品管理
  • 新闻资讯
  • 介绍内容
  • 企业网点
  • 常见问题
  • 企业视频
  • 企业图册
+
  • 隔绝.jpg

Flue gas duct isolation door

key word:Heat exchange element


Product description

Flue gas duct isolation door

 

1. Introduction

1.1. Application

It is mainly used for boiler flue gas and air duct.

1.2. Model meaning

R(L)GM × – A×L

R (L) GM --- RGM stands for hot air door; LGM stands for cold air door

×--- D is electric and Q is pneumatic

A × L --- length × width

1.3. Structural features

1.3.1. See Fig. 25-1 for the structure of isolating door.

1.3.2. Sealing parts of isolating door. The isolation valve plays the role of isolating working fluid in flue, so it must ensure the tight sealing performance. In practice, both shaft end seal and frame seal should be used to ensure the sealing performance of the isolating valve.

1.3.3. Locking parts. The locking parts can ensure that the sealing materials of the frame work in place, so as to play a good sealing role.

1.3.4. Shaft end sealing and cooling parts. The shaft end sealing parts can ensure that the positive pressure smoke and air of the damper will not leak out from the shaft end. Generally, the packing seal is used, and if necessary, the air sealing device can be added; the shaft end cooling device is mainly used in the pneumatic valve to ensure that the piston rod of the cylinder works in high temperature for a long time without deformation.

1.3.5. Control system. According to the requirements of the site, the control system of the isolation door can be divided into two types: electric and pneumatic. In structure, worm mechanism needs to be designed, while pneumatic isolation door only needs to be connected with cylinder piston rod with long rod.

1.4. Technical level

It has been many years since SPERI introduced the technology development products of CE company in the United States. According to the actual operation situation of various power plants and the practical experience of our Institute for many years, we have made corresponding improvements on the isolation door based on CE technology, such as the door plate structure, sealing structure, control reliability and so on. After the improvement, the isolation door has been greatly improved in the sealing performance and operation reliability High.

According to the actuator, there are pneumatic valve and electric valve. According to the layout position, there are hot air door and cold air door. Generally, the hot air door can be pneumatic or electric, while the cold air door is generally electric.

The isolating valve is generally used as the working medium for intercepting the flow in the flue gas and air system of the boiler in the power plant. The door plate has the function of fully opening and closing along the straight line, and is not used for regulating the working medium. In the flue gas and air system, the isolation door is often arranged at the inlet and outlet of the coal mill, and it is of frame structure, with light structure, flexible operation, fast speed and good sealing performance.

The pressure and working temperature of the system are the basic parameters for the performance design of the isolation valve. Generally, the maximum pressure is 15000Pa, and the maximum working (medium) temperature is 450 ℃. If the ambient temperature exceeds the normal operating conditions, it is also one of the design parameters. If other performance parameters exceed the specified range, special design is required.

CE imported isolating valve is introduced along with 300 MW and 600 MW units, and has been applied in many large units in China. However, there are many defects in the operation of this kind of isolating valve, such as the need to seal the air, the unbalanced action of two cylinders when opening and closing, and the problem of internal leakage and external leakage has not been fundamentally solved. Because the position of the air duct of the hot air isolating valve is positive pressure, the leakage of hot air and the ash trapped in the hot air will also have a certain impact on the surrounding environment. In view of these problems of CE isolation valve and other problems reflected in operation of isolation valve, the following improvement measures can be taken. First of all, the frame door body with its own sealing structure is adopted. When the isolation door is closed, multiple linear cams are used to press the door body onto the sealing surface through the sealing structure to basically solve the internal leakage problem. The insulation extends to the outer part of the air duct, and the frame is sealed with steel plate through bolt connection, so as to solve the leakage problem. Since the cover plate on the outside can be removed, it is more convenient to replace the sealing material. In addition, the guide mechanism is set on the isolating door and the ash hopper is set on the frame of the door, so that the opening and closing of the isolation door is relatively stable, and the dust accumulation in the door is easy to be removed. In addition, depending on the installation position of the isolation door, soot blowing device can also be installed on the isolation door. Through the above improvements, the isolating valve can meet the operation requirements of the power plant.

 

2. Main technical parameters

See Fig. 25-2 and table 25-1 for the overall dimensions and main technical parameters of smoke and air duct isolation door.

Table 25-1 main technical parameters of smoke and air duct isolation door (mm)

Unit capacity (MW) W L D
330 660 1430 500
660 1000 1000 500


 

3. Selection method

If the user wants to use SPERI's hot air isolation door, the following parameters should be provided:

3.1. Performance parameters

The following data, if available, shall be included in the user's inquiry:

3.1.1. Flue gas flow direction, such as whether the flow direction is vertical or horizontal.

3.1.2. The number of hot air isolating valves for one boiler.

3.1.3. Temperature and pressure of hot air passing through hot air isolation door.

3.1.4. Allowable pressure loss of hot air isolating valve.

3.1.5. The maximum allowable air leakage rate is required.

3.1.6. Opening and closing time of hot air isolating valve and relevant requirements of control system. For example, the driving mode of hot air isolating door: electric or pneumatic.

3.1.7. Control requirements. Such as electrical control input voltage, pneumatic solenoid valve coil voltage and protection level.

3.2. Site conditions (if provided)

3.3. Supply requirements

 

4. Selection examples

4.1. Typical hot air isolating door material

Typical hot air isolating door materials are shown in table 25-2.

Item Material
Frame Q235B
Baffle material 304
Shaft 1Cr18Ni9Ti
Bearing box Cast iron or cast steel
Bearing Self lubricating and high temperature resistant
Frame sealing material Graphite metal braiding
Rotor sealing material Graphite Packing
Driving type Pneumatic

4.2. Typical supporting examples of hot air isolating valve of 300 MW and 600 MW Units

4.2.1. See table 25-3 for working medium parameters and technical requirements of hot air isolation valve of 330MW unit.

Item Data
Hot primary air temperature () 400
Hot primary air pressure (kPa) 15
Air duct dimensions (mm*mm) 600*1300
Ambient temperature () 35
Driving type Pneumatic
Driving air source pressure (Mpa) 0.4-0.8
Opening and closing time of damper (s) <8
Electrical control input voltage (V) 220

4.2.2. Selection results:

4.2.2.1. Design mass of damper: 3000kg

4.2.2.2. According to the mass, the parameters of active cylinder and locking cylinder can be calculated.

4.2.2.3. The type of active cylinder is C95SDB200-700, and the matching active solenoid valve is VF5210-06

4.2.2.4. The locking cylinder is selected as C95SDB100-600, and the matching locking solenoid valve is VFS4310-04

4.2.2.5. Other pneumatic accessories can be selected according to the above selection.

 

5. Scope of supply and order requirements

5.1. Scope of supply (typical scope, which can be increased or decreased according to user's demand)

The scope of supply includes product design, procurement, manufacturing, factory testing, installation and commissioning drawings, operation and maintenance manuals.

5.1. Equipment:

5.1.1. Damper body.

5.1.2. Supporting pneumatic control cabinet.

5.1.3. Packing.

5.1.4. Name plate.

5.1.5. Standard surface protective paint.

5.1.6. Special tools.

5.2. Connector:

5.2.1. Counter flange of damper body.

5.2.2. Metal hose from control cabinet to control cylinder (hard metal pipe shall be arranged by power plant itself on site).

5.2.3. Connecting wire from limit switch to control cabinet.

5.2. Specification for isolating doors

5.2.1. Overview. The function of isolating door is to separate various working fluids of smoke and air duct. The specific specifications are as follows:

5.2.1.1. The supplier shall evaluate the design of various isolation, and consider the operation conditions and the most important economic factors, so as to select the most suitable model.

5.2.1.2. The supplier shall provide a tender in accordance with the specification and shall include in the tender the information required in the inquiry so that the tender can be correctly evaluated.

In addition, the documents required above shall be provided.

5.2.2. Air leakage performance. The isolation door is required to be able to achieve zero leakage when there is a sealed air system. The supplier shall describe the sealing system in the bidding document and provide performance proof materials of air leakage performance.

5.2.3. Equipment maintenance. The isolation gate shall be designed to minimize the need for regular maintenance of the equipment, state the recommended overhaul period, and specify the spare parts and maintenance time for each overhaul during the first 5-year operation period. The supplier shall point out the key points and the most economical maintenance method for the hot air isolating door.

5.2.4. Reliability. The supplier shall provide the feasibility and reliability description of the isolation valve in the quotation, and especially point out any means to improve and optimize the performance parameters of the isolation valve.

5.2.5. Equipment life. The design life of the equipment shall be guaranteed to be at least 15 years. Any parts with service life less than 15 years shall be listed and the expected replacement time shall be given.

5.2.6. Mechanical design:

5.2.6.1. Materials. The selected materials shall be suitable for the working environment, and the materials of main components shall be listed in the quotation.

5.2.6.2. Control instrument. Icons indicating control and instrumentation functions shall be listed in the offer.

5.2.6.3. Standards. The manufacture of isolating doors shall comply with internationally recognized standards.

5.2.7. Complete technical specification of isolating door shall be provided with quotation.

5.3. Technical specifications

5.3.1. Frame plate. The frame plate is made of steel plate.

5.3.2. Shaft. The shaft is generally made of stainless steel.

3.3. According to the design temperature, the material of door panel is generally SS304, and the design temperature that can withstand is 450 ℃.

5.3.4. Locking block. The material of locking block used in air duct for a long time is usually cast.