China's first LNG ship pump tower manufacturing progressing well

The first LNG ship pump tower built by Shanghai Dongding Steel Structure Co., Ltd. has progressed smoothly at present. After the main structure of the pump tower was approved by shipowners and the American Bureau of Shipping on March 30, May 18 , The pump tower base is also manufactured and passed one-time acceptance.

As a large structural component and functional part installed in the LNG cargo hold, the pump tower mainly undertakes the loading and unloading of liquid natural gas. Hudong-Zhonghua LNG carriers built four cargo tanks, a total of four dedicated pump tower.

Up to now, the first LNG ship pump tower being manufactured by Dong Ding Steel Structure Co., Ltd. submitted 100% pass rate and X-ray film pass rate each time. Its manufacturing level was affirmed by shipowners and classification societies. The company official said willing to invest, continued training of operators is the LNG ship pump tower manufacturing progress is the most important reason. At the same time, by controlling the accuracy of the parts themselves and overcome a series of technical problems such as welding shrinkage deformation, the LNG ship pump tower manufactured meets the high-precision requirements.

According to reports, since the first LNG ship pump tower started on January 18 this year, the company has always insisted on the production of all staff, Cengcengbaguan, quality first pursuit. In order to ensure the construction quality of the pump tower, the company posted the total production process flow table, welding process procedures, etc. at the construction site to facilitate operator inquiries at any time, strict implementation of various construction requirements. The company also strictly enforce the inspection system to strengthen on-site management, only the construction schedule tracking dozens of tables.

It is reported that at present the main structure of the first LNG ship pump tower has been formed, the base has also been completed, is expected to be completed by mid-August this year. The pump tower will be installed in No. 3 cabin of the first LNG carrier being built by Hudong Zhonghua Shipbuilding (Group) Co., Ltd. At present, Dongding Steel Structure Company has begun to manufacture the second LNG ship pump tower main structure.

Service Scope: Steam Turbine spare parts supply; steam turbine installation, inspection & overhaul, technological upgrading, turbine technology training, turbine low oil pressure renovation, turbine rotor shaft bend restoration, lower turbine`s vibration and noise, remove speed governing system abnormal volatility or load swing, solve turbine insufficient output, discontent load or other common/exceptional faults.


  Contract to overhaul and all kinds of turbine`s remould, turbine dynamic balance and so on, for satisfying practical operation requirements.


   Provide technical support and service for operation, inspection, maintenance, accident treatment and so on.


1. Steam Turbine Maintenance/Overhaul Service

 

   Steam turbine normal overhaul, failure treatment; main body components repair, heat exchange tubes of cooler replacement and so on.


2. Technical guidance


   Generating or Industrial driving turbine inspection, overhaul, upgrading and other items technical guidance.


3. Thermodynamic System Optimizing Services


   For operating or planning projects or equipment, according to end users` actual CHP(or heat-work cooling) requirements, make cycle efficiency analysis, provide system optimizing service.


4. Speed Governing System Remould

 

   Upgrade old hydraulic governing system to digital electro-hydraulic governing system, satisfy flexi-ble configuration all kinds of control strategy requirement.


5. Flow Passage Optimization and Modification


Total modification for steam turbine shall increase old turbine`s economic efficiency with advanced technology, service life also shall be extension.


6. Turbine Parameters Remold and Modification


Apply to processing or procedure transformation (or project site change) cause turbine operation parameters` change.


7. Uncontrolled extraction steam reconstruction


Consideration of turbine security and economic, open a hole for extraction steam normally in order to heat supply reformation.


8. Steam Turbine Engineering Service


Provide small & middle size Steam Turbine Generator or industrial steam turbine complete set engineering, project design and project installation service.


9. Vibration Analysis and Rotor Dynamic Balance

24Hours Service for emergency vibration analysis and wide range rotor dynamic balance service at project site or back to factory.


10. Condensing (extraction condensing) type remodel to back pressure type


Condensing (extraction condensing) steam turbine remodel to back pressure steam turbine


11. Steam Turbine Vacuum System Upgrade


Condenser three-dimension design and upgrade, reduce heat-transfer temperature difference, increase steam exhaust vacuum degree, improve turbine economic efficiency. Water cooling remodel to air cooling.


12. Steam Turbine Enlargement Capacity Reconstruction


Reconstruct the turbine`s capacity which are caused by system or equipment changing.


13. Motor Speed Governing Variable-frequency Remould

 

 Variable-frequency drive remould for pump systems of all kinds of industrial and mining enterprises.


14. Domestic Equipment Reconstruction


Domestic equipment reconstruction for imported turbine


15. Circulating Cooling Water System Optimization and Modification


Optimization and modification of operating circulating cooling water system, reduce operation energy consumption rate.


16. Waste Heat Steam Turbine Gland Seal System Upgrade


After upgrade, steam leakage ( effect gear box oil quality) shall be improved by the reason of waste heat parameters are not stable.


17. Spare Parts Marketing


Normal easily damaged parts warehouse, shorten delivery time.

Case 1


   A fertilizer company has 2 sets of steam turbine, model are: CB6-3.43/1.27/0.294 and CB6-3.43/1.17/0.294. Because end user`s power load and steam consumption are changed, the turbines must be reconstructed according to steam parameters, flow change and guarantee high efficiency.


   Remould Parameters: turbine max. inlet steam is 100t/h, when inlet steam is 97t/h and inlet pressure is 3.15MPa(g), its extraction steam is 62t/h extraction pressure is 1.51MPa(g), exhaust pressure is 0.21MPa(g), guarantee output is 5800KW (deviation±5% ).


   Main job of remould and overhaul:


   1. Casing was sent back to manufacture`s factory for rebuilding 2 valve seat hole, expand nozzle block steam passage.


   2. Change nozzle block, take out guide blade carrier.


   3. The original double row governing stage impeller and blade was changed to single row governing stage impeller and blade, add governing stage sheath, parts of rotor sleeve need to be changed and adjusted.


   4. LP stage 3rd diaphragm steam passage inspection optimization.


   5. Casing and rotor dismounting and assembling in factory with comprehensive inspection.


   6. Rotor low speed dynamic balance test.


   7. Governor static test in factory, overspeed test.


   8. Dismount & assembly, overhaul at project site.


   9. Clear incrustation for steam governing valve, nozzle and blade.


   10. Gland seal inspection and replacement, gland sealing clearance adjustment, change the seal block which was severe wear, spring leaf which are damaged should be changed.


   11. Every bearing repair and adjust.


   12. HP & LP governing steam valve grinding, stroke adjustment.


   13. Front bearing pedestal dismounting and inspection, patch oil leaking points.


   14. Inspection and patching steam leaking of HP steam governing valve link rod.


   15. Turbine mainbody troubleshooting.

   After remolding is complete, the 2 turbine sets are running very well.


Case 2

There is a paper mill which has a set of steam turbine: B6-3.43/0.981. Due to processing consumption in workshop and load were changed, the end user request reset new back pressure and achieve the best efficiency within the shortest time.


   Parameters reform to: when rated inlet flow: 55t/h, inlet pressure: 3.43±0.2MPa(a), exhaust pressure: 0.59MPa(a), steam rate guarantee value must be 11.65kg/(kw·h), output power must be 4700KW under rated working condition. The reconstruction project is a turnkey project, from preparing components to dismount heat material, equipment dismounting and installation, till to equipment commissioning successfully.


   For reducing the work amount, keep casing and pipelines still, main jobs are following:


   1. Change front & rear gland seal and diaphragm seal.


   2. Change main shaft assembling (keep mail oil pump and coupling still).


   3. Change HP nozzle block, HP guide blade carrier and original 2 stage diaphragm, add 3 stage diaphragm, 5 stage diaphragm adopts special design for satisfy the requirement.


   4. Change the original 3 stage impeller and add another 3 stage impeller.


   5. Steam governing valve link rod adjust inlet steam, check all butterfly valves matching conditions, improper ones should be changed.


   6. Original rotor`s coupling, MOP shall be mounted in new rotor.


   7. Rotor balance.


   8. Change sylphon of governing system.


   9. Change pressure transducer sleeve, adjust hydraulic servo-motor stroke.


   10. Governor static test in factory.


   11. Clear oil system.


  The reconstructed steam turbine is B4.7-3.43/0.59, end user evaluates steam rate, vibration, exhaust temperature very strictly, but the reconstructed steam turbine is running very well and fully meet the design performance.



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