HEATERS, DEAERATORS , PLATE TYPE EXCHANGERS , COOLERS ETC PART II _ ABC OF THERMAL POWER PLANT

Part I  i have discussed about the heaters ,coolers heat exchangers etc. In this blog I will discuss about the erection of  

DE AERATOR .

On erection point of view erection of  De aerator needs detail planning and equipment for erection .De aerator consist of  de aerator and FEED STORAGE TANK. De aerator is in one assembled unit and FST consist of three units pre fabricated but 

not assembled. Once assembled it becomes a very big round shaped

drum/ tank .There are other accessories also like platform around de aerator , saddle at the bottom of FST as such FST rests on it , stand pipes for level measurement ,misc pipe connection, misc structural items etc. Two dished ends are welded with respective pieces. This De aerator need to be lifted on 37M floor CD bay structure.

Approach to CD can be achieved from end only. If there is one unit then approach any one end will serve the purpose. If there is two unit then approach will be required from both the sides. If there is 03 units the approach from middle is required.

Minimum crane capacity required is 250 MT with adequate length of boom. You may have to remove a few member of roof structure

to accommodate the boom length and the angle. 

If you are having luxury 600MT/1200 MT cranes then you place your crane away from CD bay end but still you may have to remove some of the  roof structure for lifting FST and De aerator.

But having 600MT/1200MT will cost you more.

A 5T electric winch and 50 M pair of rail CR100 will be required to lay on the floor for dragging of FST. One end of the FST is lifted first and placed on the rail then dragged it to its position . Middle piece and de aerators are trial assembled at he bottom and then dismantled .This is done to avoid any mismatching during lifting at a height.2nd piece then lifted and locked temporarily on the floor . De aerator is then lifted and placed on the 2nd piece and bolted securely. Assembly was dragged into position by winch. Then third pieces were lifted.  

Different stages of FST erection shown in the above pictures.

HEATERS, DEAERATORS , PLATE TYPE EXCHANGERS , COOLERS ETC_ ABC OF THERMAL POWER PLANT

I have detailed major equipment of Turbine Package and their method of erection generally followed in India. There may be some differences during execution due project specifics but base is the same.

Already I have discussed main turbine , Generator and MDBFP and TDBFP.

In this article I will cover HP Heaters , LP Heaters , Deaerator , Plate type Heat exchangers ,coolers etc.

Erection Method of static equipment.

< All coolers are erected as soon as foundation is available.

   Normal foundation checking i.e level ,co ordinate w.r.t. turbine axis is checked before placement . Coolers are placed after checking the orientation. 30 mm to 50 mm packer plates are required for placement and subsequent secondary Grouting. Front piping opens after that as one end is fixed now. Same method is also followed for other heat exchangers. All the coolers are coming AB bay structures i.e Turbine hall.

HP heaters and LP Heaters

< In earlier days and upto 500MW plant all the heaters are erected vertically with the help of the TG hall EOT crane. An erection device is supplied with HP heaters for erection as clearance between EOT crane hook bottom and 10 M Turbine floor is minimal.Therefore erection device is necessary. 

Higher capacity unit like 660 MW and above heaters are placed Horizontally at BC bay of 17 M floor. Counter flanges for the connection of pipes to be checked .

Structural members for vertical heaters erection are to be checked , Specially welding between the members. It has been experienced that some of the members are not welded . Those are to checked and welded before erection. Also Level and co ordination are to be  checked and mark it in nearest column. This will help during piping erection for drawing reference. Vertical heaters are erected by EOT crane with a few packer plate in the bottom .As no grouting is involved therefore leveling and alignment is done through packer plate of different thickness.Once alignment is over then the heat is locked with temporary structure and release for piping.

Heaters require to be erected horizontally requires pre planning . All the heaters are erected one by one ,one after another side by side . Therefore pre planning is required to push heaters one by one . Heaters floor is concrete floor therefore guide rail is a must. Sequential erection is must otherwise there will not be enough space on the floor for overtaking . Location of heaters on 17 M floor such that approach is not available by EOT Crane. Heaters are unloaded on 17M floor at designated place.Dragging on rollers are carried out. Heaters are heavy weight items dragging to be done through particular place otherwise it can damage the concrete floor.

Picture shows horizontal heaters and Plate type heat exchanger . Erected and piping under progress from one end. 

continued to Part II

DISASTER AT KOLKATA / SHAME ON CONSTRUCTION INDUSTRY

Twenty six person lost their lives and around  one hundred are injured in this accident .Newspaper is full of stories , photographes ,weird theories about construction is going on endlessly. As a professional of construction industry a few statements need to be cleared in the mind of common man who does not understand construction industry

aa. Chief Minister is well within her rights for expediting its completion within March'16. One should  thankful to CM for taking interest on delayed project.I have seen and worked in different projects of national interest but never seen CM taking such interest for completion of the project. Ground rule is, series of meeting prior to CM meeting will be held for finalisation of dates and CM may take that or further squeeze the schedule and that becomes final for all the authorities.Therefore blaming CM for expediting is ridiculous.

bb. As reported in the newspaper span of this section is more than others . There will be engineering checks but experience says that there will be no problem in engineering as we are good in engineering and there may be three to four layers of check and such calculation is done through specialised software where in margin of error is minimum. The only area left is construction supervision ,methodlogy  and material etc. Civil construction does not require much items. Now all the major contracts contains a clause of cement procurement ( at five companies are mentioned with iS requirement). Therefore technically there will not be any problem in cement. Same procedure is follwed for TMT Bar and plates. These are modern procedures. Manufacturers are certified buy ultimate client , reputed consultant  etc. Major item left is HSFG bolts/HTC bolts which will be subject to scrutiny. \

cc. Therefore construction method is the kyt area to be looked into. KMDA is company which is more than fifty years old therefore their outlook is orthodox and may not fit for executing such time bound big project wherein the rquirement of decision and method /process is must . One need to look into DMRC execution as they follow most modern methods to carry out the project and KMDA may be found wanting . Old orthodox companies are averse to change their outlook. Therefore KMDA may not have a laid down procedure of quality management and safety management.. In spite of excellant management of DMRC they also faced the collapse of girder and number of cranes. All the root causes are construction supervison .

dd. IVRCL was awarded contract on 2009 that time company's performance was good . It is detoriated from 2013 onwards . Therefore awarding is wrong should not be a point to ponder.

Any company got a contract in a GOVT or PSU is very difficult to change in the midway whatever be the cause . It  may take more than a year to do so . Therefore official take softer root and compromise with quality and safety. This type of companies compromise with quality manpower ,try to bypass system etc. Therefore results into such happening.. If they had quality supervisor engineer at site during concreting then caution raised by workers should have been checked and accident can be avoided.

ee. Enquiry will be done for all aspect of labor supply the result will not come to the public. labor supply contractor cannot be blamed for this mishap as their role is limited to manpower supply and supervision of their manpower .

There will be number of state Govt agency will jump into this mishap to find out the cause but as it has been earlier only enquiry report will be bulky but the construction worker will not be benefited.

All arrest etc will not bring the dead man alive neither it will prevent recurrence of such incidents because we follow wrong procedure of vendor selection * based on finanacial value rather than qualitative value(*. we do not follow modern techniques of evolution of vendor..we do not follow basic labor laws and try offload the responsibility to incompetent people. This is a picture of construction industry. Only construction worker,supervisor and engineers are scapegoat.

There are many other aspect like insurance , compensation , minimum wages , PF , etc . All this aspect will come into play time to time. Whatever i saw in earlier cases this remain unsolved and political influence comes into play. Construction worker remain deprived of benenfit.

We request to CM to take immediate steps for improvement of process and monitoring the same otherwise this type accident will happen time and again.