Thai Nguyen province’s Luu Xa Cement Plant was built and became operational from August 1995 as part of a national program on producing three million tonnes of shaft-kiln cement and was a member of a building material company under the Vietnam Industrial Construction Corporation. The plant embraced on the cleaner production program which was presided by the Component in Cleaner Production in Industry (CPI) since 2007. With active support from consultants, the plant could save VND390 million in 2007 alone.

Employing a locally designed production process initially, the plant has continually applied latest science and technology achievements to innovate production technology. It has succeeded in raising its total designed capacity from 60,000 tonnes/year initially to more than 100,000 tonnes/year at present, creating stable work for over 300 laborers with incomes averaging VND2.3 million per month and bringing annual revenue of over VND60 billion.

From small measures

From the inception, the plant’s management got to know that shaft-kiln production lines were big energy consumers with most of the equipment designed and installed locally. Therefore, along with effectively tapping existing production lines and investing in specialized equipment for dust and smoke treatment the plant had launched a series of emulation movements in search of effective production solutions.

Its efforts to conserve energy were duly rewarded. Accordingly, energy consumption was reduced from 1,450-1,500Kcalo/kg of clinker in 1996 to 1,20Kcalo/kg of clinker in 2000, similarly power consumption was reduced from 125-130kW/tonne of cement products in 1996 to 105kW/tonne of steel products by 2000.

Significantly, since taking energy efficiency approach, the plant’s management adopted a number of solutions to help conserve energy in an efficient manner. Accordingly, production team leaders were encouraged to join courses on energy efficiency, efforts were made to survey, check and draw up careful analyses of production indexes, and enact energy consumption limits pertaining to some production stages.

In particular, the plant had replaced 14 screw conveyors frequently confronting breakdowns and bearing high overhaul and operating expenses with reasonably priced kinetic lines with stable performance. Estimates showed that the plant could save 3kW through replacing each conveyor screw and save VND8.5 million in overhaul expenses annually.

Besides, the solution to install large-capacity inverters to Road fan 215kW engines which were used to ventilate clinker furnaces helped the plant reduce 21.4 percent of power consumption for Rood fans.

The plant had also taken numerous other energy efficiency measures such  as raising transformer voltage level from 6kW to 22kW, renovating clinker furnaces and giving bonuses to best performers in energy conservation and production fields.

High efficiency

Initially the outcome resulted from energy efficiency efforts at the plant was modest due to the insider poor knowledge about the cause. As of 2007 the plant has invested intensively into innovating equipment and finding viable solutions to raise business efficiency.

The management said that the plant had taken a total of 19 energy efficiency solutions at a cost of more than VND1.5 billion by late 2007. Accordingly, efforts were made to replace broken washers, install inverters at suitable places and dispersion capacitors in areas nearby engines with more than 22kW in capacity or rationalize engine loading capacity. The plant could save VND390 million right in 2007, the first year it embraced the energy efficiency approach.

In 2008, the plant continued implementing energy efficiency solutions, focusing on innovating the material drying system to ameliorate drying quality and reduce level of dust and mud emitted to the environment. With a monthly investment of over VND1.5 billion, the solution helped the plant save 5,000cu.m of water, reduce the number of cleaners, utilize 150 tonnes of wet mud and save around 50 tonnes of soil and 25 tonnes of coal that were formerly discarded.

Also in 2008, the plant pumped capital into improving tempering technology and procuring a state-of-the art dust/haze filter system for clinker furnaces costing more than VND3.4 billion. Thereby, the plant had succeeded in lowering the dust/haze concentration at clinker furnaces from 305mg/cu.m to 42mg/cu.m and coal consumption from 0.241 to 0.233kg/kg of clinker. These solutions helped the plant save VND603.8 million through using less coal, electricity, clay and water and bettering laborers’ working environment.

In the period 2007-2008 the plant injected more than VND6.5 billion in energy efficiency and cleaner production efforts which helped it save over VND1 billion annually in the production cost, avoid emitting 178.5 tonnes of dust and 1,509 tonnes of dioxide carbon to the environment and recycle 825 tonnes of waste materials.

The plant is embarking on an in-depth investment project to heighten clinker production capacity and quality at a cost of around VND20 billion. Once completed, the project would reduce 15 percent of coal consumption in tempering clinker and raise clinker quality.

Not satisfying with these attainments, from 2009 the plant continued employing environmentally friendly techniques through cleaner production and energy efficiency approaches. Significantly, in the coming period the plant attempts to use low-quality coal for production to save cost, in the meantime further invest in cutting-edge equipment to achieve both production and energy expense targets, said the plant representative, Nguyen

Khac Duc.

By Tran Linh