8.2　Flue Gas Desulfurization

8.2.1　The erection of the metal structures shall meet the following requirements:

1　The erection of the framework，platforms and staircases of the desulfurization system shall be implemented according to the related requirements of Chapter 4 in this Part.

2　The verticality deviation for the limestone（powder）silo shall not exceed 1/1000 of the height，and also it shall not exceed 15mm.The roundness deviation of the conical silo shall not exceed 20mm.The diagonal deviation for the square cone silo shall not exceed 10mm.

3　The pneumatic landslide in the lime powder silo shall meet the design requirements.

4　The erection of the wear-resistant devices in the limestone（powder）silo shall meet the design requirements.The connecting bolts or welds shall be equipped with effective protective devices.

8.2.2　The erection of the absorption tower and tanks shall meet the following requirements:

1　The prefabrication，assembling，welding，nondestructive testing and filling water test for the absorption tower and tanks shall meet the design requirements.If there is no design requirement，the related requirements of Article 6.4 of DL 5190.7 Technical Specification for Thermal Power Erection and Construction-Part 8：Processing & Prefabrication shall be met.

2　The welding control for the absorption tower and tank shall also meet the requirements of DL/T 869 Code of Welding for Thermal Power Plant.The welders shall take the welder technology examination and obtain the welder certificates according to the requirements of DL/T 679.The elders shall go in for the welding work according to the qualified examination items.Those welders who have passed the examination according to Examination Rules for Welders of Boiler and Pressure Vessel Welding and obtained the corresponding steel category/group/sample classification code certificates may also go in for the welding work of the corresponding locations in the absorption tower and tanks，and they shall not take the examination again.

3　The deviation of the hole position of absorption towers and tanks shall not exceed 6mm.For the connecting pipes which need internal corrosion protection on the spot，the forward reach of pipes shall consider the requirements of the internal surface treatment and corrosion protection construction.

4　The surfaces of the bottom plates in the absorption tower and corrosive medium tanks shall be flat，and the welds in the wall boards shall be in smooth transitions.

5　The welds of the internal accessories in the absorption tower and corrosive medium tanks and the internal reinforcement welds of the openings in the tank below the liquid level shall be full-length seal welds.At the same time，the penetrant inspection or magnetic partical testing shall be carried out，and the welds shall meet the related requirements of the defect grade elevation for the surface inspection in JB/T 4730.4-4730.5 Nondestructive Testing for Pressure Equipment.

8.2.3　The erection of the internal devices in the absorption tower shall meet the following requirements:

1　The elevation deviation for the internal support beam in the absorption tower shall not exceed±3mm.The deviation in the horizontal distance between two beams shall not exceed±5mm.The sealing and welding shall be carried out between the support beam and the wall.

2　The internal cleanness and the corrosion protection completeness of the inner and outer walls shall be inspected before assembling the spray tubes.There shall be no crack，contuse or other defects in spray tubes and nozzles.The angle and direction of the nozzle shall meet the design requirements.

3　The elevation deviation of the spray main pipe shall not exceed±3mm.There shall be the smooth transition at the joint of spray pipes.There shall be no obvious bending，and the connection shall be firm.

4　The distance between the spray branch pipe end and the column wall shall meet the design requirements，which shall be contacted well with the support and the soft liner shall be equipped，and there shall be no forced location.

5　After the erection of the spray pipes and nozzles，the nozzle spraying angle shall be inspected to verify whether there is any scouring to the surrounding components.If there is any scouring due to the design factors，the feedback shall be provided to the design company.

6　Before the erection of the demister，corrosion protection of the tower inwall shall be checked whether it is intact，the grilling of the demister shall be checked whether it is intact and clean.Moreover，the relative direction between the flue gas and the demister shall be confirmed.

7　There shall be the soft liner between the demister and the support beam.The fixing shall be reliable，and there shall be no flue gas short circuit channel.

8　The arrangement of the flushing nozzles shall ensure that all demisters shall be within the flushing scope.The trial spraying inspection and confirmation shall be carried out before the desulfurization equipment has been put into operation.

9　The erection of the filter-screen grilling of the absorption tower shall meet the design requirements.The lining rubber or corrosion resistant coating of the support frame shall be checked wether it is intact before installing.

10　The erection of the air atomizer shall meet the design requirements.

11　The erection of the pipes in the absorption tower shall meet the design requirements.The pipes and the supports shall be connected tightly with the correct erection direction and angle.

12　The locking measures shall be taken for all bolting connections in the tower.

8.2.4　The erection of heat exchangers shall meet the following requirements:

1　The erection of tubular heat exchangers shall meet the following requirements:

1）The erection of tubular heat exchangers shall comply with the requirements of Article 4.7.1 in this Part.

2）The box girder direction shall be noticed for the erection of the inner girder of the heat exchanger.The girder layer elevation deviation shall not exceed±3mm.And the allowable deviation of the spacing between different girders is 3mm.

3）The deviation for the center line of tube bundles in the heat exchanger shall not exceed 5mm.The corrosion resistant coatings shall be protected well when lifting the girders and tube bundles.

4）The corrosion protection treatment shall be carried out in time after the welding acceptance of welding joints.

2　The erection of rotary heat exchangers shall meet the following requirements:

1）The erection of rotary heat exchangers shall comply with the requirements of Article 4.7.2 in this Part.

2）Heat exchange elements of rotary heat exchangers shall be installed after sand blasting of the inner wall and corrosion resistant painting.Otherwise，heat exchange elements shall be isolated for protection.

3）The protective measures shall be taken to prevent any component from damage when lifting heat exchanging elements.

4）The installation and adjustment of seals shall be carried out after completing corrosion resistant painting.

8.2.5　The erection of the rotating machinery shall meet the following requirements:

1　The erection of the mixers in the tanks（pools）shall meet the design requirements.If there is no design requirement，the verticality deviation of the vertical shaft of the mixer shall not exceed 2/1000 of the length and shall not exceed 5mm.The torque of the impeller connecting bolts shall achieve the design value.

2　The erection of mills shall meet the related requirements of Article 10.4 in this Part，and the following requirements shall apply:

1）After the erection of the lining rubber tile in any wet mill，the grouting and sealing shall be carried out with the grouting material whose fluidity is relatively good.The grouting shall be carried out in stages according to the requirements of the manufacturer's technical documents.

2）After the erection of the lining rubber tile in any wet mill，it shall not be operated with the medium without water supply.

3　The erection of the belt vacuum dewaterer shall meet the related requirements of Article 11.2 in this Part，and the following requirements shall apply:

1）For the erection of the wind boxes，the height deviation for two boxes in the horizontal direction，the horizontal levelness and the vertical flatness deviation shall not exceed 2mm，0.5mm and 5mm，respectively.

2）The welds in the joints of the wind boxes shall be burnished smoothly.

3）There shall be enough lubricant for the lifting mechanism in the vacuum box，and the lifting operation shall be flexible.

4）The rubber belt center shall be consistent with the framework center through the adjustment.After passing the no-load trial operation，the drilling operation in the rubber belt shall be carried out.

5）After all welding and cutting operations within the dewaterer area have been completed，the filter cloth in the vacuum belt dewaterer can be installed.

4　The erection of the filter press equipment shall meet the requirements of equipment technical documents.During the installation of the complete machine，there shall be no sundries inside the filter press.The longitudinal and transverse axial line deviation and the base levelness deviation shall not exceed 10mm and 2/1000，respectively.

8.2.6　The erection of the pipes and accessories shall meet the following requirements:

1　The installation of flue gas/air ducts and material pipes shall comply with the related requirements of Chapter 7 in this Part.In addition，the following requirements shall apply:

1）When installing the fuel gas damper，it shall be ensured that the installation direction of the damper shall be consistent with the flow direction of the medium.The stainless steel surface shall face the clean flue gas side under the closed state.

2）The connection of internal stay tubes of the clean flue gas duct shall be concealed.The breathing holes shall be equipped outside the wall of flue gas duct opposite to internal stay tubes.

3）The load of the liquid collection connecting pipe for the expansion joint shall directly act on the supports and hangers.The expansion joint shall not bear the load of the connecting pipe.

2　In general，the installation of pipes for（sea）water，steam，gas，slurry and oil shall comply with the related requirements of DL 5190.5 Technical Specification for Thermal Power Erection and Construction-Part 5:Piping and System.And the following requirements shall also apply:

1）The installation of rubber lined pipes shall be implemented according to the corresponding requirements regarding lined pipes in DL 5190.6 Technical Specification for Thermal Power Erection and Construction-Part 6:Water Treatment and Hydrogen-producing Equipment and System.

2）The isolation valves shall be equipped in the connection between the rubber lined pipe or corrosion resistant material pipe and the ordinary carbon steel pipe.The diaphragm valve shall be equipped between the measuring instrument and the medium.

3）The connecting valves in the flushing water pipes and slurry pipes shall be close to the slurry pipes.The flushing water connecting ports in the slurry pipes shall be arranged above the slurry pipes.furthermore，the angle between the flow direction of the flushing water and that of the medium shall not exceed 90°.

4）Slurry pipes shall be sloped according to the design requirements without upward U-shape bends.

3　The erection of the hydrocyclone shall meet the following requirements:

1）The height deviation for the support leg foundation shall not exceed 3mm.The configuration and the secondary grouting of the pad iron group shall meet the related requirements of Article 10.2 in this Part.

2）Before the erection of swirl nozzles，the models shall be checked，and the connection shall be tight without leakage.

8.2.7　Corrosion protection shall meet the following requirements:

1　For the equipment such as absorption towers，the tanks with the corrosive medium，heat exchangers and so on which need corrosion protection to the lining，the welds shall meet the design requirements.Based on visual examination，there shall be no crack，slag inclusion，pore or undercut with the depth more than 0.5mm.And welds and spatters shall be grinded.Cutting temporary located ironblocks shall not damage the equipment，and then the corresponding positions shall be grinded with no trace.

2　Before conducting the lining corrosion protection of the absorption tower，the tanks with corrosive mediums，heat exchangers and so on，the welding of the supports for staircase and platforms，pipe supports，cable supports，insulation nails and so on outside the all doors，holes and shell plates shall be finished and pass the acceptance.

3　Corrosion protection of the absorption tower，the tanks with corrosive mediums，heat exchangers and so on shall meet the related requirements of Article 12.7 in this Part.