Utilization of full-fire filters and ball-cleaning at Zainsk condensation plant

System of ball cleaning (SBC) is designed for cleaning the inner surface of tubes of condenser of steam turbine from dirt, brought by circulation water or dirt occurs in its going through the tubes.

Intrusion and contamination of the tubes (from the water side) result in failure of part of the condenser tubes, aggravation of heat yield in condenser, increased hydraulic resistance and decreased vacuum, considerable increase of specific fuel consumption.

Other existing techniques of cleaning the condenser involve the whole or partial turning off the condenser with respective decrease of capacity or shutdown of the turbine generator, i.e. they can be done only from time to time and as a rule, are related to big expenses associated with manual labor. Unlike this the ball cleaning is a permanent, computerized, prevention cleaning, done during operation of condenser with pre-set frequency. There is no necessity to stop the energy block, nor to reduce its capacity.

For cleaning the condenser tubes we use the balls made of porous (foam) rubber of various hardness of diameter by 1-3 mm bigger than the inner diameter of the tubes. A hand of the balls is supplied to pressure water line, distributed by the flow along the tube board of condenser and water under pressure goes in the tubes cleaning their inner surface. Then the balls are caught by ball catching device, installed in exhaust water line, they are sucked from it by special pump and are again directed to pressure water line.

For collection and loading the balls into the line of circulation behind the pump special device is added, called loading chamber. In order to avoid contamination by outside big wastes of the tube board of condenser and ball catching device, the filter is installed in pressure water line, the filter catches these wastes and gets the wastes out of the circuit, cleaning the circulation water.

Filter of pre-cleaning (FPO) is a significant part of SSO and represents a housing with connected sizes, corresponding to diameter of pressure water line. Inside of the filter housing the filtering surface is installed.

In operation the filtering surface builds up the contamination, the hydraulic resistance of the filter grows, and after reaching the pre-set value, the cleaning is turned on. In each produced filter the principle of cleaning the filtering surface by return water flow is used.

Utilization of SSO results in reduction of specific fuel consumption, increase of capacity of TG, decrease of costs of repair. The environmental condition of water basin is improved, the consumption of cooling water is reduced.

In 2005 at Zainsk condensation plant were installed the SSO on 200 MW block #2 and on block #3. Vacuum after utilization of SSO on block #2 of Zainsk condensation plant increased compared to respective period of 2004 by average 1.85%.

By the end of 2006 the systems of ball cleaning of condensers were installed at five units of 200 МW of Zainsk Condensation Plant In 2006 the savings of fuel at Condensation Plant were 7.2 th. t.r.f. through vacuum improvemen.

In 2007 – 2009 will be mounted the ball cleaning systems at the three units, the system was mounted at of the units already.