One of the largest plants in the area of Chau Khe craft village, Dinh Bang commune, Bac Ninh province, the Xanh Ha Steel Plant sells about 3,500 tonnes of steel billets and 10,000 tonnes of finished steel products each year, consuming more than 4,000 MWh of electricity and about 900 tonnes of coal. The expenses on electricity and coal consumption account for more than 50 percent of the total production cost at the plant. The plant has undergone an energy audit to seek suitable solutions for energy conservation.
The
leadership of the plant said that except the expenditure on input materials, the
cost of energy consumption accounts for 50.4 percent of the total amount of all
the remaining expenses on steel billet production (the percentage is 68 percent
in the area of making finished steel products). Such a high expenditure on energy
consumption is unacceptable especially in circumstances when energy prices rise
continuously. Therefore, it is urgently necessary for the plant to improve management
and take appropriate technical solutions to save energy in order to enhance the
competitiveness of products and make a higher profit as well as prevent adverse
impacts on the environment.
The main types
of energy that are used by the Xanh Ha Steel Plant include electricity, coal
and fuel gas. The expenditure on electricity accounts for 43 percent of the
total cost of energy consumption, and coal 56 percent while the expenditure on
fuel gas accounts for just a small percentage. Each month, the plant has to
spend more than VND4 million to buy four gas tanks and 10 oxygen (O2) tanks.
Steel
production
Survey results
show that low-load operation and the low capacity coefficient of the engines of
most equipment items at the steel production workshop are the main reasons leading
to electricity losses. Apart from the two main stages of steel production, power
consumption in subordinate stages accounts for 21 percent of the total amount
of electricity that is consumed throughout the production process. Electrical
equipment items that are used to make finished products are of low capacity. During
the production process, only some types of equipment operate continuously while
other equipment items are kept at the no-load status wasting much electricity.
In the area
of crude steel production, an energy conservation solution proposed by the
auditors is to install the Powerboss power saving equipment, which can help the
plant save 18 percent of the total amount of power consumption, i.e. 10.26kWh each
day. This solution allows the plant to save 67,700kWh of electricity or more
than VND70 million.
In the area
of steel refining, the installation of inverters can help the plant save a large
amount of power or about VND106 million each year.
The installation
of water supply and treatment systems to cool the tempering furnaces also
allows the plant to save VND24 million each year.
Reducing heat
losses
Built in
2004, the tempering furnaces of the Xanh Ha Steel Plant cause big heat losses during
the operation process. The main reason is that the construction of these
tempering furnaces was incompliant with some technical standards. For this
reason, the furnaces consume too much coal to start the operation process.
There are
many solutions that can be taken to reduce heat losses, for example 1) choosing
a suitable coefficient of redundant air (this solution allows to save VND658
million each year), 2) reducing heat losses caused by unsuitable
heat-conducting materials to save VND227 million each year, and 3) reducing
heat losses when opening the door of furnaces to save VND354 million each year.
The
auditors said that the above solutions are feasible because they require low
investment and it takes not much time to recover the invested amount of capital.
Of the aforementioned three solutions, the second one requires investment of
VND52 million, and the remaining two solutions can be taken by organizing
training courses to improve workers’ consciousness of the need to save power.
Tightening
management
Currently,
many steel plants are actively saving power. The auditors said that though they
use the same kinds of input materials and similar production lines, the Xanh Ha
Steel Plant consumes much more energy than the Thai Nguyen Steel Joint Stock
Company. The reason is that the Thai Nguyen Steel Joint Stock Company keeps a
close watch on the situation of energy consumption and they have set norms for
energy consumption. Moreover, they use suitable kinds of input wasted materials
and have reduced the time needed to produce a batch of steel products.
Specifically,
the Thai Nguyen Steel Joint Stock Company consumes 760kWh of electricity to produce
each tonne of steel billets, 50.2kWh less compared with the Xanh Ha Steel
Plant. This means with the same production output, the Thai Nguyen Steel Joint
Stock Company can save 182MWh or about VND120 million each year.
Survey
results show that the average amount of no-load losses at the Xanh Ha Steel
Plant is 62,000kWh of electricity every year. A solution that is proposed to
the plant is to reorganize the production process to reduce no-load operation of
equipment by a maximum of 50 percent. This solution allows the plant to save
more than VND80 million annually.
In
addition, it is necessary to intensify training and propaganda in order to
improve the consciousness of workers and all staff members of the plant about
the need to save electricity. Maintaining equipment items periodically is also
necessary to improve their efficiency and reduce power losses during the
operation process.