According to his estimate, all extensive and complex overhaul works on the second unit of 620MW were well planned and realized on time thanks to a good organization and TENT B staff expertise and hired contractors.
The main job, which determined the length of the overhaul of unit B-2 (in duration of 120 days), was the reconstruction of electrostatic precipitators. With reconstructed ESPs the powder materials emission through flue gases will be reduced and will reach the values less than 50 mg per cubic meters which is defined by the National and European standards- states Stojanovic.
The reconstruction of electrostatic precipitators was very complex and hard work. It was mostly financed from EU donations, that is €5.5 million, and this part of the work was assigned to the Polish company “Rafako” with subcontractors “Goša” and “Izoprogres”. Part of the work financed by TENT was assigned to the same subcontractors and the value of that part of the job is about €4 million.
The extensive works were done on the boiler piping system. The companies “Termoelektro” and “Feromont” together with their subcontractors did the replacement of reheater 3 and superheater 1, says Director Stojanovic.
Under the contract with German company „Alstom“,the replacement of all rotor and stationary turbine blades of turbo-feed pump on turbogenerator plant was done.At the same time the replacement of all the pipes on the main turboaggregate condenser also was done by which the number of the so-called „partial outages“ will be considerably reduced- explains Stojanovic. In the long period before shutting down the unit B2 we were often forced to reduce the unit power and stop for inspection of damaged condenser pipes. In addition to reduced production, great number of overtime hours was accomplished, taking into consideration that such interventions had to be made and organized at night or on weekends. There are twenty-six thousand pipes replaced on the condenser and the job was done by the company „Kosovo“ – Obilic.
During the four-month overhaul of the unit 2 there was a major overhaul of post burning grate, device for slag removal and all the equipment on the ducts of flue gas and fresh air done. Some important interventions were made on the installation for pneumatic ash transport as well as certain changes of installations in order to increase plant reliability.
