Cement industry is one of the industries that have been making a significant contribution to economic growth in Vietnam. However, in face of the soaring prices of fuels such as gasoline, oil and electricity, it is meeting with a lot of difficulties. Technological innovation, costs reduction, quality improvement and energy efficiency are what the Viet Nam Cement Corporation is endeavoring for.

Implementing of the "national goal of energy saving and efficiency" set up by the Ministry of Industry and Trade, in recent years Viet Nam Cement Corporation has intensively supplied concrete guidance in researching for management solutions and technologies aimed at reducing consumption of thermal and electrical energy in cement production lines. So far, with the efforts made by the staffs of companies throughout Viet Nam Cement Corporation, the cement industry has implemented many improvement projects that have been reducing energy consumption significantly, enhancing Vietnam's cement competitiveness in the market.

Making good use of emitted heat

Using two main energy sources which are electricity and coal in its production, the cement industry has been discharging large amounts of gas and dust with high temperatures (over 300 degrees Celsius) into the air, which causes environmental pollution, wastes energy, wastes natural resources and reduces production efficiency. To make good use of these emissions, turning them into sources of energy for production, a system utilizing thermal energy emissions has been installed as a solution.

In 2002, after four years of construction and a phase of test, a 2950 kWh power station utilizing the furnace exhaust heat was officially put into operation in Ha Tien Cement Factory 2. This Project was funded by NEDO of Japan, with the Kawasaki designing and supplying boilers, air turbine, generators, electrical equipment and water treatment equipment.

By 2009, the Thermal Emission Utilizing Power Station at Ha Tien Cement Plant 2 had generated 105 million kWh of electricity, bringing about tangible benefits in terms of socio-economic, energy saving, environmental protection, and significantly reducing the cement production cost. Only in the period from March, 2002 to October, 2006, this Power Station supplied a total of nearly 72 million kWh of electricity for production lines in The Ha Tien 2 Cement Company. Thus, besides saving electricity, The Ha Tien 2 Cement Company also saved 2.1 million liters of ADO oil from fuel drying. The Economic efficiency after 5 years of implementing the project is over 68 billion.

Mr. Do Cao Duong, Head of the Technical Section, Viet Nam Cement Corporation, said:  "Besides the main effect of utilizing the redundant heat from kilns to generate electricity thus reducing power consumption costs, the project also has other positive effects such as lowering the temperature of the input and output of the mills and the  electrical dust filters, helping the mills operate smoothly and indirectly increasing the mill capacity by about 10 - 15T / h, as well improving the dust filtration efficiency improved as well. As the generators utilize emitted gas and totally do not use oil as an energy source, they do not discharge exhausts into the environment. This is a clean and green system. "

With the results gained from the application of such technology in Ha Tien Cement Plant 2, the Viet Nam Cement Corporation is actively working on the investment project to build "Thermal-Emission-Utilizing Power Stations" at the Hoang Thach Cement Factory, Bim Son, Binh Phuoc, and Tam Diep.

Promoting creativity, removing obsolete technology

To achieve goals such as productivity, high quality, low cost, and enhanced competitiveness, VIET Viet Nam Cement Corporationhas long been encouraging member companies to actively participate in the movement of giving ideas, applying technical innovation and technical advances, and rationalizing production. Some energy-saving measures such as doing research and testing on additives to increase productivity of cement mills thus not only upgrading the cement but also reducing energy costs have been applied.

Responding to “The National Goals in Using Energy Economically and effectively”, Tam Diep Cement Company has successfully carried out a joint project of working out and installing frequency transformers in fan motors of clinker coolers. The application of such frequency transformers has improved the startup mode, speed control and power savings in production.

Since the installation of frequency transformers in 6 clinker coolers, each year the Tam Diep Cement Company has saved more than1 billion VND in power consumption as well as significant expenses in maintenance and replacement of valves regulating the flow of inputs, thus improving the heat radiating mode of the fan motor, which helps prolong the life of the fan.

At Luu Xa Cement Plant, since the launch of the energy saving movement, dozens of initiatives have been applied, thus producing significant economic benefits. Those initiatives ranged from simple solutions such as training, installing frequency transformers in fan motors of clinker coolers, and upgrading substations, to complex ones which required large investments such as replacing the under-load engines with appropriate-capacity ones, improving raw material drying systems, adjusting heating technology, investing in dust filtering system of clinkers kilns... Thanks to such solutions, the Plant has saved more than 1 billion VND from production costs, reduced 178.5 tons of dust emissions, 1500 tons of CO2, and recycled 825 tons of materials.

A common trend in the cement industry in the world today is the replacement of the obsolete cement production technologies, such as the wet process in vertical kilns and rotary kilns, with the modern ones such as the dry process cement production in rotary kilns with high level of mechanization and automation that produce high quality cement while consuming less raw materials and energy, and protecting the environment. To improve competitiveness, in 2002 with the guidance from Viet Nam Cement Corporation, Bim Son Cement Company implemented successfully a technology conversion project, replacing the wet process method with the dry one (which can produce 3,500 tons of clinker per day). Thus the plant can reduce more than 50% of energy consumption.

Currently, Bim Son Cement Company is working on a project of converting the wet process rotary kiln technology to dry process kiln technology in cement production lines No. 1. The project is expected to be completed and put into operation during the period from 2016 - 2025.

Under the plan, Viet Nam Cement Corporation will continue to direct the implementation of projects of replacing the two wet process production lines at Ha Tien Cement Company with dry process production lines to increase the capacity of 0.24 million tons per year to the one of 1.4 million tons per year. They are expected to be completed and put into operation during the period from 2016 to 2025. When the projects of converting these three wet process production lines completed, they will contribute significantly to Viet Nam Cement Corporation’s program of saving power as well as thermal energy, thus bringing high economic efficiency, helping reduce product costs, and improving living environment around the plants.

By Thu An