System for safe, clean coal transport makes a difference

Transporting coal over long distances safely, and without leaving a trail of dangerous dust, can be tricky, but an energy research company in North China said it has come up with a viable solution.

CCTEG Shenyang Engineering Co, a subsidiary of China Coal Technology and Engineering Group, said it has recently developed and installed a new coal and fly ash transportation system with double-layer conveyor belt in Xiliin Gol League in North China's Inner Mongolia autonomous region.

The new system is environmentally friendly and a better alternative to open-top transportation cars, the company said.

The system is designed to prevent coal dust from escaping from uncovered vehicles and leakage of fly ash during transportation. It can also improve efficiency by transporting coal and its by-products of coal combustion at the same time, the company said.

Compared with traditional car-hauling, the new system is more energy-efficient and can achieve continuous transportation and automated control, the company said.

"Oftentimes, coal is hauled from mines to power plants on open-top cars or trains through cities, towns, and villages. During transportation, leakage of dust and fly ash could cause pollution to surrounding environments, threatening residents' health, and potentially causing several hazards like spontaneous fires," said Lin Boqiang, head of the China Institute for Studies in Energy Policy, which is part of Xiamen University in Fujian province.

Lin said that despite rapid development of clean energies, coal still plays an important role in ensuring energy supply in the short term, with coal-fired power generation taking up about 65 percent of the total energy mix.

"Proper handling of environmental pollution caused during the process of transportation is an important step in the coal industry's transition to greener and more sustainable development, which is meaningful to promote an environmentally friendly development of the country's energy sector," Lin said.

With the new system, the upper layer of the conveyor belt is used to transport coal from mines to Shenhua Shengli Power Generation Plant and Huaneng Shengli Power Generation Plant in Xiliin Gol League, and the lower layer transports fly ash－a by-product of burning pulverized coal－from power plants to waste piles of open-pit coal mines.

The company said the new system will transport 10 million metric tons of coal and 2 million tons of wet fly ash annually. The route length of the new transportation system is about 10.13 kilometers.

"In order to effectively prevent leakage of fly ash and coal dust, the company has set up research projects on technical innovation to better manage dust control during transportation, research on freezing and stickiness of coal fly ash particles at low temperature in winter, and research to optimize the structure of wind and rain-proof shelter," said Sun Xiao, deputy chief engineer of the company.

"We used DEM (discrete element method) analysis software to simulate how particles collide with each other and with the surface of the conveyor belt at the transfer points, designed curved chutes on the belt to make sure that the particles' falling speed is the same with their speed in contact with the belt to reduce collisions, so as to reduce dust generation," Sun said.

"We also conducted a replication study on the amount of water content in fly ash to prevent it from freezing or causing dust during transportation in winter," he said.

"Considering that Xiliin Gol League is a windy area, we also optimized the structure of the system's shelter to prevent fly ash from being blown away by wind."

In addition, Shenyang Engineering also cooperated with Shenhua Beidian Shengli Energy Co Ltd on multiple technology research and development projects.

The tie-up has effectively solved the problems of dust leakage, freezing, stickiness, blockage, and cleaning, and facilitated safe and stable transportation through conveyor belt in windy and cold area in Xiliin Gol League, where the temperatures can reach -42.4 C, the company said.

Apart from transporting coal and sending back by-products of coal combustion at power plants, the system can be used in industries like steel, cement and construction materials, Shenyang Engineering said.