Two steam units of the 60-year-old Loshan Power Plant in Rudbar County, Gilan Province, were fully renovated with the help of domestic engineers, the head of the provincial power company said.
“The renovation of the facility has doubled its efficiency from 25% to 50%,” Mehrdad Aligholami Shilsar was also quoted as saying by the Energy Ministry’s news service.
Operations to replace old steam units with new systems took three years, he added, noting that the power station’s massive water consumption has also halved as the renovation has stopped wastage.
The official said the steam units’ capacity was 240 megawatts in 1970 when Siemens Energy, Germany's largest engineering company, built the facility, which declined by 50% over the last six decades.
Giving a breakdown on the overhaul operation, he noted that close to 50 kilometers of pipeline in boilers were replaced.
Established in 1970 with two steam units, two gas units and a wet cooling tower, Loshan Power Plant has a nominal capacity of 360 megawatts.
Based on international standards, the average useful life of such plants is 25 years whereas the power plant is over 60 years old.
In addition to being outdated, another problem with Loshan was that it had an old wet cooling tower that is preferred in regions where water is plentiful, like the coastal regions.
In wet cooling towers, heat transfer is measured by a decline in processing temperature and a corresponding increase in both the moisture content and the wet bulb temperature of the air passing through the cooling tower.
When the facility opened over half a century ago, Iran was not struggling with chronic water scarcity. But conditions have changed and the population has jumped from 30 million then to over 80 million at present.
Electricity Projects
According to Bahman Darabzadeh, managing director of Gilan Regional Power Company, 10 electricity projects with an investment of $50 million are underway in the region.
Referring to the southern regions of the province as suitable sites for setting up solar farms, the official said two solar power stations will be constructed in Rudbar with an investment of $13 million, each with a capacity of 10 megawatts.
Darabzadeh noted that the equipment required for solar farms has been purchased and their construction will start soon.
Currently, there are 12 power stations in the northern province, two of which are combined-cycle (Paresar in Rezvanshahr County and Rasht in Gilan) and five are hydroelectric (Talesh, Bijar, Tarik, Sefidroud and Loshan).
In addition, three are small-scale power plants with distributed generation systems (Gil and Caspian) and a combined heat and power (CHP) plant in Bandar Anzali Free Trade Zone.
Manjil Wind Farm is the first and largest wind power plant in Iran and has a nominal capacity of 92.2 MW, he added.
Visiting a group of managers from Japan's Mitsubishi Corporation, Abdolmajid Dinarvand, the head of Hamedan's Shahid Mofatteh Thermal Power Plant, noted that all overhaul operations are conducted by local engineers, that’s why the station still has the same efficiency of 30 years ago.
The construction of the dry cooling tower of the second unit of the Hamedan plant has registered 70% progress.
The power station consumes about 12 million cubic meters of treated wastewater a year.
“Upon completion, it will help reduce water consumption by 85% in the unit and contribute to the stability of the production capacity of the 250-megawatt unit,” he said.
The water saved in the process will be supplied for agricultural and industrial operations.
“Previously, the project to change the cooling system of a power plant in Iran was carried out for the first time at the first unit of the power plant and it has saved 85% of water consumed in the unit,” he added.
Dry Cooling Systems
Dry cooling systems use air instead of water to cool the steam exiting a turbine. Such systems do not use water and can reduce total power plant water consumption by over 80%.
The main purpose of large, industrial cooling towers is to remove the heat absorbed in the circulating cooling water systems of power plants, petroleum refineries, petrochemical plants and gas processing plants.
While wet cooling towers are designed to evaporate water into the air that flows through the tower, dry cooling tower systems work differently in that they transfer heat from the power plant directly into the air.
Dry cooling towers conduct heat transfer through air-cooled heat exchangers that separate the working fluid from the cooling air. Because there is no direct contact between the working fluid and the ambient air, there is no water loss in such systems.
With a capacity of 1,000 megawatts, Shahid Mofatteh Power Plant is located 47 km northeast of the capital city of Hamedan.
The power station meets the total demand of over 1.8 million people in the province and also part of the needs of neighboring provinces.
