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18/08/2016

Why Stop At Carbon Capture Storage? Think CO2 Utilization.

Japan has come a long way since its self-inflicted environmental disasters of the 1960s when double-digit economic growth rates spawned garbage and pollution challenges of Mount Fuji-sized proportions. Steady progress came after the government finally got serious about dealing with the problems and promulgated new laws and strengthened rules for industry and municipalities to follow when disposing of trash and environmentally harmful by-products.

Consequently, Japan, once a Minor League player when it came to handling and treating garbage and pollutants compared to the Big Leaguers Europe and the U.S., is today competing with the best of them. What’s more, some of the technologies the country is employing in this field are now among the most advanced currently available, as I’ve written about previously.

The latest tech example is the world’s first commercial carbon capture and utilization system (CCU) integrated into a municipal waste incineration plant. The plant is located in Saga, the capital city of Saga Prefecture on the island of Kyushu. Toshiba, which has developed the carbon capture storage (CCS) technology to make utilization possible, says operation will begin on August 26.
Carbon capture is a means of separating and capturing CO2 (carbon dioxide, the gas that makes soda drinks fizzy) emissions from the flue gasses of power plants, for instance, to prevent it entering the atmosphere.
CO2 is widely blamed for the Greenhouse Effect. This happens when energy emitted from the Earth is reflected back in the form of heat by the increasing amount of CO2 blanketing the atmosphere—instead escaping into space. So CO2 carries the rap for global warming and climate change. But it needs to be pointed out that some of CO2’s loudest critics are the very people who produce more of it than anyone else through their private-jet globetrotting, fossil fueled lifestyles.

One much talked about method proposed to reduce the amount of CO2 we vent into the atmosphere is carbon capture storage, where CO2 is captured, turned into a solid or liquid for transportation, then stored deep underground, for example. Besides the high costs involved, an additional challenge facing this method, says Kensuke Suzuki, a senior manager in Toshiba’s Strategic Marketing & Business Development Dept., is finding suitable places to store the CO2.

This helps explain why Saga has decided not to treat carbon dioxide as a negative by-product to be hidden in the bowels of the earth. Rather, it views CO2 as an economic opportunity and hopes to exploit it by converting the stored CO2 into a saleable commodity. While capturing and processing CO2 will still be expensive, making a business out of the substance will help the city reduce such costs and eventually turn a profit if all goes as planned.
The Toshiba CCS system installed is capable of capturing 10 tons of carbon dioxide daily and works as follows. Flue gasses from the Saga incinerator are piped to a low-temperature absorbent tower where a chemical absorbent (an alkaline amine solution) captures the CO2. The solution is passed to a stripper tower and heated. This releases the CO2 in a pure gaseous form. The absorbent is circulated back for recycling, while the CO2 is stored as a pressurized gas.

With the help of specialist contractors, Saga city has constructed a pipeline connecting the stored CO2—which is also a high-grade fertilizer—to nearby farmlands to cultivate algae and other suitable crops.

While the Saga city council is not breaking down the economics of the venture, the entire project carries a price tag of 1.5 billion yen (US$15 million). Meanwhile, CO2 in liquid form is reportedly being sold for around 30,000 yen ($300) a ton today. Without the need to process the stored CO2 further, Saga city could price its CO2 gas competitively.

Toshiba’s Suzuki says the company originally developed its CCS technology to capture CO2 from thermal power plant emissions, and this remains a goal. “But the system has the potential to be applied to other kinds of industrial emissions, as the Saga project shows,” says Suzuki. “These include chemical plants, cement plants and the like.”

Because Toshiba is only in the business of capturing and storing CO2, the onus will be on these customers to follow Saga city’s approach and devise smart ways to utilize CO2, rather than merely seek to dump it underground.



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