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What to Do with CO2 from Coal? How about Make Baking Soda

Skyonic lands funding to build a commercial-scale facility that takes flue gases and converts them into commodity chemicals.

Startup Skyonic said this week that is has raised $9 million from corporate investors to build a plant for converting carbon dioxide from a cement factory into ordinary chemicals, including sodium bicarbonate, or baking soda.

Working on the sky mine: Skyonic’s demo plant for converting flue gases from a cement factory into chemicals. Credit: Skyonic

The company plans to raise $35 million to build a commercial-scale plant for capturing carbon dioxide and other gases at a coal-powered cement factory in San Antonio, Texas by 2014. If the company meets its schedule, it will be able to use 83,000 short tons of carbon dioxide from the plant’s flue to make 157,000 short tons of baking soda. Its process also produces hydrochloric acid and other chemicals.

This type of carbon capture is an alternative to separating CO2 from flue gases and pumping it underground to avoid emitting it into the atmosphere. It’s also an attempt to convert what is a waste product–flue gases–into marketable products.

In addition to consuming CO2 from flue gases, the company figures that its Texas facility will offset 220,000 short tons of CO2 by avoiding the pollution from mining the raw materials that would have occurred from chemical production. Skyonic has a 20-year contract with cement maker Zachary at its Texas plant.

In the scheme of things, the reduction from this single plant is very minor: CO2 emissions from 2010 were estimated to be over 36 billion metric tons

But the Skyonic’s carbon capture technology, called SkyMine, could be used in places without suitable geological formations, such as underground caverns, to store compressed CO2. And while some question when and whether carbon capture and storage can be economical, Skyonic says its Texas operation will be profitable once it gets going.

“We’re very competitive with chemical production prices but chemicals are technically green chemicals, too,” a company spokesperson said. “There is definitely enough interest (among chemical buyers) to take up several plants’ production.”

Investors in this series C funding include ConocoPhilips, BP, and PVS Chemicals, which will be involved in the distribution of the baking soda, hydrochloric acid, and other chemicals Skyonic intends to make. The company also received $25 million from the Department of Energy for demonstration projects that convert CO2 into useful products. One planned customer for the baking soda is the cattle industry which uses it to aid the digestion of grain-fed cattle.

Part of the reason Skyonic says it can operate profitably is because the main inputs into the SkyMine process are salt, water, and electricity, which are readily available and relatively inexpensive.

Flue gases from burning coal or natural gas are cooled and then the CO2 and other gases are isolated. Mixing the CO2 with sodium hydroxide creates sodium bicarbonate, or baking soda. Another step combines salt, water, and electricity to create the sodium hydroxide as well as hydrogen and chlorine, according to an explanation at E&P Magazine

The company’s equipment can be retrofitted onto existing equipment and can work even when there is a relatively low concentration of CO2, according to a representative. That means it can work effectively with the flue gases from natural gas plants.

The technology can convert high concentrations of CO2 but the company expects that big polluters, such as utilities and cement factories, would only use the process, which consumes energy, to meet regulations. In the case of the Texas cement plant, the Skyonic equipment will capture less than half of the emissions. 

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