MSEB "cleaning" exchequer with waste

All the thermal power plants of the MSEB have a boiler system whereby steam is used to run the turbines to generate electricity. This steam later enters a condenser from where it is led to a cooling tower to recycle the water.

Around 5 to 10 per cent of the water is lost to evaporation which has to be made up by drawing water from a nearby river source. However, hard water from the rivers could lead to corrosion of the condenser tubes which in turn could affect the performing efficiency of the turbines.

In order to overcome this, MSEB had installed a `clarifier-softener’ system in all its power plants involving huge expenditure and at a cost of around Rs 24 crore at the Chandrapur power plants. This system involves a water treatment plant at the river source which ensures that only clarified and softened water enters the condenser. This, say sources, minimises to negligible chances of corrosion, or fouling and scaling of these tubes. The system, installed at a high capital and running cost, has been in use for many years now.

Now, the MSEB has come up with the idea of using a new system to clean the same condenser tubes in addition to the existing system. This new system is known as “on line condenser tube cleaning system.”

Curiously, this system is not, as it were, a newly developed technology. Almost all power plants in western countries are fitted with the on line tube cleaning system. The clarifier-softener system, on the other hand, is an unique feature of MSEB plants alone. This begs two questions: Given the on line tube cleaning technology, why were crores spent on the clarifier-softener system in the first place, and secondly, having opted for the latter in operation for several years now, what are the shortcomings that forced the MSEB to go in for the new system?

The `on line tube cleaning system’, involves the usage of large sponge rubber balls, bigger than the diameter of the condenser tubes which are let into the high pressured water stream to the condenser which then rub against the surface of the pipes and keep it clean. Among the new power plants in the country, the latest NTPC power plants and the power plants of the Tata Electric Companies (TEC) use this system.

Justifying the deployment of the new system in all its power plants, technical director of the MSEB (generation projects) M R Ambhore said that the MSEB had a successful run for the past five years with the on line tube cleaning system at Koradi unit no 5. But this is the only unit at Koradi which uses pond water and does not have an already-installed clarifier-softener system. Waxing eloquently on the need for the system, Ambhore said that a thermal power plant throws up a lot of coal and lead dust into the atmosphere, which enter the condenser and affects the vacuum of the tubes.

“The capacity of the condenser system then goes down. We have been having similar problems at Kaparkheda where condensers get choked up and vacuum reduction in the condenser tubes have been noticed,” he said. But technical sources pooh-pooh this explanation. They insist that the coal yard and boilers are so far from the condenser, which is itself a closed vessel, that there is no chance of any contamination from the coal yard.

MSEB first advertised for tenders on local competitive bidding for “on line condenser tube cleaning system’ in October last, and the tenders were opened in December 1996. The tenders were for the Chandrapur thermal power station units, 5, 6 and 7, all of which are 500 MW units. While Ambhore could not “off-hand” remember the total expenditure on the machinery, informed sources say the MSEB has spent Rs 9 crore in procuring the machinery for the Chandrapur units, even though it had earlier, spent Rs 24 crore in installing its existing machinery for softening water.

To top this, the machinery is yet to be installed in the Chandrapur units and its efficacy tested. Yet, a similar tender has been invited, this time for the Koradi power plant at Nagpur, where units 1, 2, 3 and 4 (all 120 MW) and units 6 and 7 (all 210 MW) are to be fitted with the tube cleaning system. The tender invited in March 1997, is to be opened tomorrow.

But this business of calling for local tenders is itself debatable given the condition that goes with it. The MSEB’s condition is that the bidding company must be in the business of supplying these systems for atleast three years.

According to Ambhore’s own admission there are only three companies in the country which can supply the machinery, and only one company which has been in the business for the last three years.

The three-year condition was deliberately laid down, allege sources, to favour a Madras-based company, GEA Energy Systems, since it is the only company to meet the condition, and not surprisingly, it won the earlier contract for Chandrapur. And since the situation has not materially changed, this same company is bound to win the contract for supply of the on line cleaning system when the tenders are opened tomorrow making the entire exercise a farce, sources allege, pointing out that had global tenders been floated the particular company might not have been so benefited. More so because all the units, 5, 6 and 7 ( the last is under construction) of the Chandrapur thermal power plant are World Bank-aided projects, it is more logical to call for global tenders. To this says Ambhore, “Global tenders require forex, and a proper approval by the CEA. A local tender on the other hand allows us to procure the machinery sooner”.

“We have taken a technical decision to install the system in all our power plants to improve the efficiency of the condensers. I don’t see why there should be a controversy over it,” Ambhore added.