VietNamNet Bridge - The Vietnam Thermal Technique Science Association has found a cost-effective solution which reduces the volume of consumed coal, reduces ashes and the greenhouse gas emissions, and improves the efficiency of the combustion chamber. 

 

 

The common characteristic of the coal power plants in Vietnam is that they use only one typeof coal for their lifespan.

According to Dr Truong Duy Nghia, the common characteristic of the coal power plants in Vietnam is that they use only one typeof coal for their lifespan. The types of coal to be used are identified when the plant is designed.

Most of the operating plants use anthracite, a type of low-quality coal which has a very high ignition temperature. It would be acceptable to mix anthracite with import coal of the same kind, but big technical problems would arise if different types of coal are mixed.

Meanwhile, the anthracite supply in the world is short due to small reserves of anthracite mines. Most of the coal power plants in other countries, therefore, use bituminous/sub-bituminous coal (steam coal).

This explains why there are not many research works on using the mixture of anthracite and bituminous/sub-bituminous coal for thermopower plants.

However, finding a way to mix the different types of coal will be a research work of significant importance for Vietnam due to its specific conditions. 

The research team of the Vietnam Thermal Technique Science Association could succeed with the first experiment of mixing sub-bituminous coal imported from Indonesia and Vietnam’s anthracite. The mixing reduces the high ash volume which helps improve combustion efficiency.

Thermal power plants which now use anthracite coal can shift to use mixed coal while there is no need to make big changes with the equipment.

A question was raised that the coal mixing needs to be carried out before or after the process of grinding coal.

Experiments were conducted at the Ninh Binh Thermopower Plant, which has been using anthracite coal only, and under the Northern Electricity Testing Center.

According to the plant’s general director Trinh Van Doan, the plant imported 580 tons of sub-bituminous coal from Indonesia, then mixed the imports with anthracite at different ratios of sub-bituminous coal on anthracite at 5/95, 10/90, 15/85, 20/80, 30/70, and at a different capacity of boiler.

Doan, while confirming that the combustion efficiency increased by 1-5 percent, said if the technology is utilized, the plant’s efficiency will considerably improve. 

The research team also worked to find out if the mixed coal would affect the equipment. They said that it would be necessary to adjust some operational parameters of the equipment, but the adjustments will be within control, which means the cost will be inconsiderable. 

They have come to the conclusion that thermal power plants which now use anthracite coal can shift to use mixed coal while there is no need to make big changes with the equipment.

Kham Pha