Serbia: Project of flue gas desulfurization in Thermal power plant “Kostolac B”, China CMEC European reference project, the report

Published on 24. December 2013., News Serbia Energy

Full attention is given to the current environment demands in the Subsidiary Company “Thermal Power Plants and Mines Kostolac”, with the main production activity, testified the project of flue gases desulfurization in Thermal power plant “Kostolac B” which is presented by mr Nebojsa Misic, coordinator of the first phase of the package projects in TPP “Kostolac B”.

He pointed out that this system objectives, which has being built in collaboration with a Chinese company “CMEC”, were to ensure reliable unit operation of 150,000 working hours, to achieve a nominal capacity of 348.5 MW unit with increased unit efficiency, then to ensure the availability on the level of modern world units, to short the planned overhaul, to increase energy efficiency, as well to coordinate the work with the environment protection.

Contractor in the plant construction is the Chinese company “China Machinery Engineering Corporation” (“CMEC”) from Beijing, the designer is “Northeast Electric Power Design Institute” from Changchun, and subcontractor “Beijing Boqi Electric Power Sci-Tech Co, Ltd “. Contract value is 130 MEUR, and deadline for its completion is end of 2014^th. The basic obligation of the “CMEC” company is to transmit plant, which would be fully operated and confidential in the work, and also to satisfy all project criteria. Goods and services transmit will be done in accordance with the proved engineering principles, where the modern technology and performance requirements, which have been defined by contract, will be taken into account, said mr Nebojsa Misic and added: – Plant for the flue gases desulphurization uses method with wet limestone- gypsum, and also uses absorber for one boiler.

The capability of flue gas processing in the FGD system is the gas flow when one boiler is at 100 percent loading. System for the lime sludge preparation, gypsum dewatering system and other systems are extra parts in FGD plant. Projected plant efficiency for flue gases desulphurization at nominal load is at least 97.5 percent of the projected coal use. Emissions of SO2 do not exceed 200 mg/Nm3 in the projected conditions. There is a bypass channel for flue gas within it with a load of 100% of the safe function of thermal power plant in each mode operation of the plant for flue gas desulfurization. Availability of the plant for the flue gas desulfurization is at least 95 percent, and work life is 15 years. – Project of flue gas desulfurization (FGD) is based on the process of limestone and gypsum.

FGD system consists of following subsystems: absorber system for flue gas, system for the lime sludge preparation, system for the gypsum collection and transport to the gypsum landfill, connection systems, the discharge and drainage systems. Subject of projected device for FGD includes the following: the absorbing process, electro energetics, hydraulic transport, fire protection, heating, ventilation and air conditioning (HVAC), communications, construction and architectonic solutions. The design phase includes the development of a designing project, main project and project of derived state. – Processing system includes the following: design and construction of the absorber, the flue gas flow system, the system of limestone preparation (including systems of warehousing, milling and transport of lime), gypsum dewatering system, a system of industrial and cooling water, discharge and drainage system and compressed air system for instrument. Absorption liquid (lime sludge) is inserted as jet into the spraying nozzle.

Then the liquid is divided into small droplets that cover the entire cross section of the absorber. The droplets come into contact with the flue gas in the return flow in the tower. Then start transmission and absorption reactions. The flue gas then absorbs SO2, SO3 and HCl, HF. The reactions of SO2oxidation and neutralization are carried out in an oxidation zone at the absorber bottom, and at the end, the gypsum is got here. In order to maintain a constant pH value, and reduce the limestone consumption, lime is introduced continuously into the absorber. At the same time, the sludge of absorption means in the absorber is mixed with mixers and oxygen, air and circulating absorber pump in order to accelerate equal distribution and dissolution of limestone in the slurry. Flue gas speed ​​ in the absorber is 3.8 m / s in the projected conditions. The absorber is the tower type with return electricity and spray.

The flue gas enters in the absorber from a side entrance. There are nozzles layers for sledge in the absorber. The flue gas comes into contact with the return electricity of atomized sludge in the awareness zone. The treated flue gas passes through the droplets eliminator above the spray layer. Then the flue gas exits through the flue gas way-out at the absorber top in the channel for a pure gas. The absorber is compact and has the internal spray layers. Droplets eliminators are located at the top, and the flue gas exit is at the top. – Among other systems it is necessary to mention another system for the lime sludge preparation, as well as systems of gypsum removal, drying and transport. Gypsum is taken out from gypsum storage by dotted loaders and transported to the area below the soil surface in underground funnel. The belt feeder is designed below underground hopper. Gypsum will be transported to one-way conveyor belt by ribbon feeder, which will transport gypsum to the disposal site of the open pit mine, said mr Nebojsa Misic in the presentation.

Plant for the flue gas treatment will be built in the Thermal power plant “Kostolac B” in accordance with the modern technology and will satisfy all requirements that are currently placed in relation to the environment protection. Solving the flue gases purification in relation to the sulfur oxides as well as reducing nitrogen oxides and dust emissions along with other measures of land and water protection, SC “TE –  KO Kostolac” will meet the deadline with all environmental requirements that are placed in front of a modern power plants.

Source; Serbia Energy