Rocket technologies adapted for China's cleaner coal use
Technologies gained from developing the "heart" of rockets are helping China, one of the world's major coal consumers, use coal more cleanly and efficiently.
"In China, a large proportion of the grain you eat every day is grown with chemical fertilizers made up of materials produced by coal gasification technology transformed from rocket technology," said Zhu Yuying, vice general manager of the Changzheng Engineering Co Ltd, a company affiliated to China Academy of Launch Vehicle Technology.
"Many of your clothes and a lot of nonmetallic components on your car, as well as lots of your daily necessities are products of the coal chemical industry," Zhu said.
China lacks petroleum and natural gases, but has relatively abundant coal resources. Clean and high-efficient utilization of coal is important to ensure its energy security and sustainable development.
Currently, China has three methods of coal utilization: burning directly, coking and gasification. Gasification is the cleanest, but most complicated use of coal. It can be used to produce chemical raw materials and clean fuels. Only 7 percent of coal resources are currently processed this way.
Zhu explained that gasification means transforming the carbon and hydrogen components in coal into carbon monoxide and hydrogen gases, which are raw materials in many chemical products.
Gasification occurs under high pressure at a temperature of over 1,400 degrees centigrade. The carbon monoxide and hydrogen gases are inflammable and explosive. It needs high-tech special facilities to ensure the process is safe, continuous and stable.
At the beginning of the 21st Century, China lagged in gasification technologies, which restricted the development of coal chemical industry. Chinese firms mainly depended on imported technologies, greatly increasing production costs.
The most difficult part of the technology is the making of the gasifier.
Researchers at a liquid-propellant rocket engine base under the CALVT found the technologies and facilities to produce a rocket engine can be adapted to make the coal gasifier.
Overcoming investment and technology hurdles, they successfully developed a gasifier in 2009 after almost five years of efforts.
"Because of our special technologies, the gas, liquid and solid emissions of the coal gasification can be properly treated and recycled, making the gasification process clean and environment-friendly," Zhu said.
The sulfur content in coal can be a major air pollutant - an issue they tackled.
"Our technology can transform the sulfur components into hydrogen sulfide, which can be recovered. We can recover more than 99.5 percent of the sulfur pollutants. The dust emissions can also be controlled," Zhu said.
So far, the company has produced 87 gasifiers, occupying more than half of China's pulverized coal gasification market. It has also been granted with more than 20 patents in the United States, Europe and other countries and regions.
Recently, it developed the first gasifier for lignite, a kind of fragile "young" coal with high water content. China has large reserves of lignite in northern Inner Mongolia Autonomous Region, and southwestern Yunnan and Guizhou provinces, making up 13 percent of the national total coal resources.
Exploiting and utilizing lignite efficiently has been a challenge.
Zhu said the CECO aims to promote the lignite gasification technology to regions with abundant lignite reserves, as well as such regions in countries like Indonesia and Australia.