7.5　Dust Precipitators

7.5.1　Before the erection of the dust precipitator equipment，the construction preparation shall include the following contents:

1　The complete erection technical documents shall be ready.The counting and inspection shall be carried out according to the manufacturer's equipment drawings and equipment lists，and the equipment maintenance shall be carried out.

2　The foundation re-inspection shall be carried out according to the related requirements of the manufacturer's drawings and GB 50204（Code for acceptance of constructional quality of concrete structures）.

7.5.2　The erection of electrostatic precipitators shall meet the following requirements:

1　When the pillars below the bottom grider are steel pillars，the pillar erection allowable deviation is listed as follows:

1）The erection allowable deviation shall be 1/1000 of the spacing between different pillars and not exceed 10mm.

2）The pillar verticality shall be 1/1000 of the pillar height，and not exceed 10mm.

3）The pillar top elevation shall be±5mm，and the mutual deviation between different columns shall not exceed 2mm.

2　The erection of supports shall meet the following requirements:

1）The erection direction of supports in the design drawing shall be checked carefully so as to ensure it free expansion.

2）The erection allowable deviation of supports is listed as follows:

The center distance deviation for two adjacent supports is±2mm.

The diagonal deviation for two adjacent supports is±3mm.

The elevation deviation of supports is±3mm.

The surface flatness of supports shall not exceed 1mm.

3　The erection allowable deviationof bottom griders is listed as follows:

1）The upper plane of bottom grider shall be in the same horizontal plane，whose allowable deviation in levelness is 5mm.

2）The allowable deviation in horizontal distance of bottom grider center lines for each electric field is 5 mm，and the allowable deviation in size for two diagonal lines is 7 mm.

3）The allowable deviation in horizontal distance of the complete bottom griders is 5mm，and the allowable deviation in size for two diagonal lines is 9mm.

4　The erection allowable deviation of columns is listed as follows:

1）The erection allowable deviation shall be 1/1000 of the spacing between different columns and shall not exceed 10mm.

2）The column verticality shall be 1/1000 of the column height and shall not exceed 10mm.

3）The top elevation of columns is±5mm.

5　The erection allowable deviation of the girder is listed as follows:

1）The allowable deviation in elevation of the girder is±5mm.

2）The allowable deviation of the longitudinal center spacing between two adjacent girders is 5mm.

6　The assembly and erection of the anode plates shall meet the following requirements:

1）The lifting and carrying of the anode plate container must be carried out according to the marking position.If there is no marking，the cushion position and the sling shall ensure no deformation of the anode plates.

2）When the assembly of the anode plate arrays is carried out，the single sheet inspection shall be carried out to the anode plates.The flatness deviation shall not exceed 5mm and the distortion deviation shall not exceed 4mm.The plate surface shall be smooth and flat，and there shall be no burr，obvious scar and rust.

3）After the assembly of the anode plates has been completed，the plane bending deviation shall not exceed 10mm.The length deviation for two diagonal lines shall not exceed 5mm.If any size is found to be out of limits，the corresponding correction shall be carried out.

4）The special measures shall be taken to lift the anode plates so that there shall be no permanent deformation in any anode plate array.

5）When two ends of the anode plate arrays are tightened with bolts，the tightening pieces and tightening torque shall meet the requirements of equipment technical documents.The locking measures shall be taken to the nuts after tightening and there shall be no burr and sharp edge.

7　The erection of the cathode suspension system shall meet the following requirements:

1）Before the erection of the support casings in the cathode system，inspection shall be carried out carefully.There shall be no crack or other defects.Tapping and prying are not allowed during erection.The packing should be filled in time if the packing material is needed for the sleeves.

2）The support casings in the same group shall be adjusted in the same plane，and the allowable deviation in flatness shall not exceed 1mm.

3）The center line of the support casing shall coincide with the center line of the hanger rod，and the deviation between two center lines shall not exceed 10mm.

8　The erection of the cathode large frame shall meet the following requirements:

1）The cathode large frame shall be vertical to the horizontal plane.The allowable deviation in verticality shall be 1/1000 of the frame height and not exceed 10mm.

2）The center lines of two adjacent large frames in the same electric field shall be in the center plane along the air flow direction in this electric field.The flatness deviation shall not exceed 5mm，and the spacing deviation shall be 2.5mm.

3）In the same electric field，the corresponding section steel for hanging the same cathode small frame in two large frames shall be in the same horizontal plane，the flatness shall be 5mm and the spacing limit deviation shall be 5mm.

4）The verticality between the straight lines，which are formed between the upper and lower notches of the small frame hung in the large frame，and the horizontal plane shall be 5mm.

5）When the porcelain sleeve is used，the flexible pad shall be equipped below the sleeve.The upper plane of each porcelain sleeve shall be in the horizontal location，with 2mm of the flatness.

9　The erection of the cathode small frame shall meet the following requirements:

1）After the cathode small frame is assembled and welded，the flatness deviation shall not exceed 10mm.The length deviation for two diagonal lines shall not exceed 5mm.If any size is found to be more than the standard size，the corresponding correction shall be carried out.

2）The pre-tention force of the cathode line shall be distrubted uniformly so as to ensure that there is no deformation out of tolerance for the small frame.

3）After assembly，the locking measures shall be taken for all the bolts and nuts in the small frame and the cathode line，and there shall be no burr and sharp edge.

10　The erection of the anode plates and the cathode small frame shall be vertical to the horizontal plane.The verticality deviation shall be 1/1000 of the height and not exceed 10mm.The homopolar spacing deviation and the heteropolar spacing deviation within all channels shall not exceed 10mm.After the erection of the cathode and anode systems，all locating pieces and fixing parts shall be fixed firmly and reliably.

11　The erection of the rapping system shall meet the following requirements:

1）The rapping devices shall be fixed firmly.The top rapping components shall be lifted freely，with the flexible unhooking.The rapping hammer shall act in the hammering seat center，with 3mm of allowable deviation.For the side rapping mode，the rapping shaft horizontal deviation shall not exceed 1.5mm，and the coaxiality deviation shall be 1mm between the adjacent two bearing seats and 3mm for the whole length.

2）The deviations for the contact position between the side rapping hammer and the striking anvil in the horizontal direction and in the vertical direction shall be±2mm and±5mm，respectively.

3）There shall be no spot contact between the hammer head and the striking anvil.The line contact length shall be more than 2/3 of the thickness of hammer head.

4）The hammer head shall be rotated flexibly without jam fault and collision.

12　The erection of the shell and the ash hopper shall meet the following requirements:

1）After the arrival of block plates and airflow uniform distribution devices（guide plates，uniform distribution boards and so on）of the electrical precipitator，the overall dimensions and opening holes shall be inspected to meet the drawing and design requirements.The plane curvature deviation shall not exceed 3mm.The installation positions of block plates shall be correct.The welding shall be firm and shall not affect the free expansion of the cathode and anode plates.

2）The welding in the shell，the ash hopper and other locations shall be carried out according to the design requirements.The quality acceptance to the pressure welds in the ash hopper shall be carried out by the personnel including the manufacturer representative.The seal welding shall be inspected by the oil leak test，and also involved in the the boiler flue gas and air system whole pressure decay test.

3）The inlet/outlet flanges and all kinds of access holes shall be tight.

4）The ash hopper shall be equipped with the electric heating device，and the energizing test shall be carried out before the insulation construction.When the steam heating device is used，hydrostatic test shall be carried out under the pressure equal to or greater than 1.25times the work pressure.

5）After completing all work and tests inside of insulation layers，the insulation can be carried out.

13　The erection of the steel platforms，ladders and rails shall meet the related requirements of GB 4053 Safety Requirements for Fixed Steel Ladders and Platform.

14　After the pressure decay test for the electrostatic precipitators has been qualified，the cold state gas flowing distribution test shall be carried out according to the requirements of the manufacturer's technical documents.

15　After the erection of the electrostatic precipitators，the following requirements shall apply:

1）There shall be no sundries.The temporary reinforcement part shall be cut and burnished completely.The internal cleanness inspection shall be qualified，and then the closing shall be carried out after the certification has been handled.

2）The polar distance deviation shall meet the requirements.The tightening degree for the cathode line erection shall be proper and uniform.

3）The position and direction of rapping hammer shall be correct.The actuator shall be in the flexible rotation mode.

4）The complete performances of electrical precipitators shall meet the requirements of DL/T 514 Electrostatic Precipitators and the requirements of equipment technical documents.

7.5.3　The erection of bag filters shall meet the following requirements:

1　The erection requirements for steel supports，platforms，ladders，rails，supports，bottom griders，shells and ash hoppers of bag filters shall meet the requirements of Article 7.6.2 in this Part.

2　The assembly and erection of the tubesheets shall meet the following requirements:

1）The protection measures shall be taken to prevent any damage and deformation in the tubesheet storage，erection and welding processes.

2）The allowable deviation of the erection center position in the tubesheet shall not exceed 1.5mm.

3）All welds shall be tight without any leakage，and welding slags and burrs in the tubesheet shall be removed completely in time.

3　The erection of the rotating injection equipment shall meet the following requirements:

1）In the erection of the rotating injection equipment，the allowable deviation of center line and the allowable deviation in elevation shall be±5mm and±10mm，respectively.The distance between the nozzles and the tubesheet shall be ensured.The allowable deviation in concentricity for all nozzle centers and the tubesheet hole centers shall be±10mm.

2）The inspection to the reducer shall be carried out according to the requirements of equipment technical documents.The overall inspection shall be carried out to ensure its flexible and smooth rotation after the erection.

3）The coupling alignment allowable deviations shall not exceed 0.10mm in the radial direction and not exceed 0.05mm in the end.The coupling protection cover shall be fixed firmly and beautifully.

4　The erection of the vibration driving equipment shall meet the following requirements:

1）The allowable deviation of the equipment longitudinal and transverse center lines shall be±5mm，and the allowable deviation of the shaft center shall be±3mm.The levelness deviation of the shaft shall meet the manufacturer's requirements，and it shall not exceed 0.5/1000 of the shaft length.

2）The erection of the reducer shall meet the requirements of Article 10.4.4-3 in this Part.

3）The erection force of the triangle belt shall be uniform and the tightening shall be proper.The deviation for two wheel centers shall not exceed 1mm.The parallelism for two shafts shall not exceed 0.5/1000.

4）The erection of the coupling shall meet the requirements of the manufacturer's drawings.The safety protection cover of the coupling shall be fixed firmly，with the convenient assembly and disassembly.

5　The erection of the filter bag shall meet the following requirements:

1）The inspection shall be carried out to the filter bag geometry sizes and appearance quality before the erection，and the requirements of Appendix M shall be met.

2）The erection of the filter bag shall meet the requirements of the manufacturer's technical documents.The measures shall be taken to prevent filter bag from damage during the erection and trial operation.

3）The verticality deviation of the short pipes shall not exceed 2mm.

4）The filter bag shall not be distorted and wrinkled during erection.The bag mouth shall be sealed tightly，and the bag surface shall be tight.The internal filter bag with the clip ring shall be clamped tightly.The verticality shall be inspected according to Appendix M after erection，and the tensile force shall be adjusted.

5）Before the pre-spraying，the filter bag shall be ensured to not contact with the raw flue gas.

6　The erection of the pulse air tank shall be carried out under the vertical state，and the rotating component shall be in the free rotation mode.

7　The erection of the compressed air pipe shall be carried out according to the related requirements of DL 5190.5 Technical Specification for Thermal Power Erection and Construction-Part 5:Piping and System.

8　The following inspection shall be carried out after the erection of bag filters:

1）The internal and external sundries，collection ash and oil contamination in the dust precipitators shall be removed completely.

2）The tightness degree for hanging filter bag shall meet the requirements，and the filter bag shall be bound firmly and reliably.

3）The valves，pipes，suction hoods，grid wheels and so on shall be sealed tightly.

4）The valves and local instruments shall be complete，and the actuators and so on shall be flexible and reliable.The dust removing equipment shall be in normal operation.