Carbon Capture: Turning Coal into Coke
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"Carbon Capture" may be a difficult technical term that only science professors will find terribly interesting. Fore a better understanding of the technology and what it can do in real life, our reporter Shen Le went to a coal power plant that has what it takes to capture carbon dioxide.
CCTV reporter Shen Le said, "I'm at one of Huaneng's power plant in suburban Beijing. Here, the engineers are adding fizz into their drinks, such as this can of coke. But how exactly are they doing it? Well, let's go and find out."
Coal burning at this power plant generates a lot of carbon dioxide, the magic substance to make coke fizz.
But the fumes coming out of the towers contain too many impurities to be used in beverage production.
Zhang Lin, the gas purification specialist at the carbon capture facility tells me the secret of turning coal into coke.
Zhang Lin, engineer of Huaneng Gaobeidian Power Plant, said, "An ammonia-based dissolvent absorbs the carbon dioxide in one tower under low-temperature conditions. And then the dissolvent is heated in another tower to release the carbon dioxide. The process is a reversible reaction so the dissolvent can be reused."
The purified carbon dioxide must be compressed and liquefied through a sophisticated refining system, making it easier to load into transport trucks.
CCTV reporter Shen Le said, "In order to turn carbon dioxide into liquid, you'll need extremely low temperatures, some minus 30 degrees Celsius. And that's why frost is forming on these pipes."
The liquefied gas is stored in this giant cannister and trucks from coke factories come once every few days for the pick up.
Du Chengjing, deputy GM of Huaneng Gaobeidian Power Plant, said, "The purity of the gas reaches nearly 99 percent and is in line with even the most rigorous food standards."
However, the high cost of this delicious technology is limiting its mass application.
Du Chengjing said, "We invested 23 million yuan to build the facility. And the capturing process consumes power, heat and the dissolvent is quite expensive. But we are optimizing the system and future facilities will be much more energy-efficient and less costly. "
Every year, this facility captures 3 thousand tons of carbon dioxide. Local coke producers buy the gas at an average price of 500 yuan per ton. This barely covers the daily operation cost, leaving very little for returning the initial investment.
For now, carbon capture remains an expensive business, but its mass application in the future may help bring down the cost.
(CCTV November 25, 2010)