A big energy consumer of Da Nang, in recent years, Hai Van Cement JSC has applied various solutions for energy efficiency and conservation. Hai Van cement is produced with fully automatic and synchronous technological line and equipment built by Krupp POLYSIUS of German.

Before the Instruction of the Prime Minister and documents of ministries, branches and localities on power saving were issued, leaders of the company implemented many energy saving measures in line with conditions of the business. “Saving electricity is an important solution to reduce manufacturing costs, lower production prices, increase revenues and profits for the company”, said Mr. Tran Van Khoi, Deputy Technical Director.

The company has set up plans for producing at off-peak hours, stopping production for maintenance during peak load tariffs, installing multiple price galvanometers to ensure economic benefits while not affecting general electricity consumption, investing in equipment replacement and technical innovations. Some electricity saving solutions that the company has implemented include:

Only one shared 6/0.4 kV transformer is used for all 0.4 kV loads in the two motor control centers (MCC1 and MCC2). As designed, these two transformers operate at the same time with the combined capacity greater than the current demand of loads. So they regularly work under load. Operating only one transformer and stopping the other does not affect the production line but save half of electricity consumption; running the cement cooling system when the temperature of cement output is higher than 80oC.

As designed, the cement cooling system runs continuously when the mill runs, while the cement temperature from the mill is usually smaller than 80oC (due to the large humidity of the additives, clinker is not heated so the clinker temperature in the mill is low). Most of the time, the mill can operate without running through the cooling unit thus saving electricity.

Only operating 55 kW large water pumps when the mill is running to cool equipment. When the mill is not running, but there is need to run packing cluster and air compressors, only use a small capacity water pump which is enough to cool the lubrication oil of air compressors. Installing a S6 water pump with the capacity of 5 kW, enough to supply cooling water to other points of the line.

Improving the cement pack navigating structure from electric motors to convenient, energy saving motors. Investing in new grinding engine with the capacity of 3,000 kW, operating current from 290 to 295 AP (previously used 3000 kW grinding engine, operating current from 315 to 320 AP). At the same time, maintaining old engines for necessary use. Use inert grinding matters to increase productivity and reduce power consumption, improve the lighting system of the entire plant, replace 300 W and 500 W incandescent bulbs with 50 W compact bulbs which are 6 - 10 times more energy saving. Propagate and mobilize all staff in the company to raise the awareness of saving electricity, apply programmed controllers for the lighting system throughout the company.

Previously, producing a ton of finished cement required 44 kWh of electricity, now, with applied energy saving solutions, power consumption has reduced to 39 kWh/ton. Production capacity of the company has reached 600,000 tons of cement per year, while the total volume of saved electricity is 3 million kWh which is equivalent to billions of dong.

Saving power not only brings real benefits for businesses but is beneficial for the country as a whole.

By Minh Duc