Electricity producer change successfully from Shell & Tube to Plate & Shell

Sokolovská Uhelná is one of the largest producers of electricity from brown coal in the Czech Republic. It has a total annual capacity of around 3 500 GWh, which it transmits to the town of Karlovy Vary and other smaller towns in the region. Sokolovská Uhelná is also a coal mining company, producing thermal coal and chemical products derived from brown coal. The company mines about 6.5 million tons of brown coal each year.

Our relationship with Sokolovská Uhelná has been built through Vahterus distributor G-Mar Plus and its chemical specialist David Váňa, who has been working there since 2001. G-Mar Plus has been the official distributor for Vahterus Plate & Shell heat exchangers (PSHE) in the Czech Republic and Slovakia for over 10 years, and they have been in contact with Sokolovská Uhelná’s operations engineer Emil Holub throughout this time.

PSHE was first introduced to Sokolovská Uhelná at the International Engineering Fair in 2002 in Brno, Czech Republic. Even at first glance, it was clear that this was the product that Sokolovská Uhelná needed, combining the good points of traditional plate heat exchangers on the one hand, and shell and tube heat exchangers onthe other. “Right from the start, PSHE seemed to be a great solution,” says Holub

Before PSHE was installed, the client used shell and tube heat exchangers. The units were in poor condition and the high cost for maintenance and certification of the unit forced Sokolovská Uhelná to find alternatives. The compact size of the new equipment was one of the key advantages: the old shell and tube heat exchangers were four times bigger than PSHE. Another key factor was that PSHE can be used in high temperatures.

Holub has also noticed a further major advantage of PSHE: maintenance-free operation. There has been no need for maintenance or cleaning, and both units have been working non-stop since they were installed (in 2002 and 2004). Once every two years, the whole system is shut down for two weeks. Holub comments “When David asks about how well the PSHE are working, my answer is always the same – I’m happy to say that I don’t know anything about them because I have been able to forget them completely!”

The first unit was ordered soon after the Brno exhibition, at the end of 2002. The heat exchanger worked flawlessly and, during the following maintenance shut down in 2004, another identical unit was installed to replace a second old shell and tube heat exchanger.

The PSHE units use 2-bar steam to heat about 350,000 kg/h of demineralised water from 60–120°C. Both PSHE units are part of the system for supplying heat to Karlovy Vary and the surrounding towns and villages.

One of the key factors in the project was a successful relationship between the parties, which has continued even after these deliveries. “We are very satisfied with the 10 other PSHE that we have, mainly in steam and water applications,” declares Holub. Sokolovská Uhelná works with aggressive chemicals, and they were happy to hear that PSHE can be used for this kind of task as well. They have two heat exchangers in special applications with Has telloy (C276) plates. The 1200 kW heat exchanger is used in the pressure gasification of coal for cooling of a chemical mixture of ammonia water and organic compounds. The units have been working well and have been in continuous operation since 2003.