Derived from the actual needs, and to contribute actively to the successful implementation of the project "Energy efficiency and conservation in the province of Hai Duong period 2009-2013", Hong Duong Co. has implemented many energy efficiency measures. According to the evaluation of the Center for Scientific Research and Technology (Department of Science and Technology) of Hai Duong, Hong Duong Co. is one of the most outstanding enterprises in Hai Duong province in implementing energy audit and energy saving solutions.

Production technology of the company includes many different stages and there are strict requirements on safety and other requirements of the manufacturing process. The company's main raw material is raw salt imported mainly from India, stored in warehouses of the company. At this place, salt is preliminarily ground; salt particles which are small enough are pumped up to the second cyclone and refined at the grinder level 2. Big salt particles are kept on the screen and continue to be ground to the desired size. Salt after the qualification of particle size is pushed into the water extractor. Centrifugal water extractor is responsible for removing a portion of water in the salt. Salt, after being squeezed, becomes refined salt, mixed with iodine in the standard rate (for iodized salt) and switches to the next stage of drying. Finished salt is packaged and stored in warehouses before being sold.

The audit process has shown that in drying areas which use coal as fuel, the operation of coal furnaces is relatively inefficient. Due to the mismatch between air flow and the amount of coal, the combustion is not optimal. Therefore, the efficiency of fuel combustion is very low. Besides, during the process of production, in the stage of drying salt, water in the salt is extracted and generates a lot of heat and steam, so this area is relatively hot and humid. This is also the area where the company pays attention to improve the production environment for workers.

Preliminary surveys in the drying system have shown that the rotary drying drum is old and consumes a lot of fuel; the operation of the drying system is mainly manual, resulting in lots of affection to the production environment. On the other hand, due to the production expansion of the Company, the drying system requires investments to increase capacity and consume less fuel, labor costs must be reduced and product quality must be increased.

The salt processing line uses 04 stirring motors with the capacity of 15 kWh. These motors have the rotation speed of 950 rpm; however, the stirring speed is only 300 rpm, operating time is 8 hours per day. From that fact, the company has replaced the old drying line by a new line with the capacity 2.5 times higher than the current capacity, and utilized a portion of thermal energy from the exhaust of the new line to dry agricultural products. The new line will be connected directly to the rear of the refined salt processing line. Along with that, the company has installed inverters to adjust the speed of stirring motors to reduce power consumption of these engines. After the new line is put into operation, the Centre for Application of Science and Technology, with the support from School of Heat Engineering and Refrigeration - Hanoi University of Technology, has conducted surveys and measurements to calculate the actual amount of saved energy. Results have shown that the installation of the new line has saved more than VND 758.64 million per year. In particular, with the new production line, quality of products has also increased, ensuring food safety and increasing competitiveness in domestic and foreign markets.

According to company’s representatives, solutions which the company has applied ​​have high efficiency and have saved 30.3% of costs. The installation of the new modern production line has also helped improving the work environment of workers, improving product quality, creating opportunities for the company to improve productivity, quality and meet the needs of domestic and foreign markets.

By Minh Duc