An alternative to current carbon capture and storage (CCS) technology turns emissions into useable byproducts through a process called carbon mineralization.
According to the recent “International Energy Outlook 2011” report, only 15% of the energy produced globally is expected to come from renewable energy by 2035, including sources such as hydroelectric power, wind, and solar energy. This forecast echoes what the energy industry has known for some time – worldwide energy production will still rely heavily on fossil fuels.
Oil and gas are critical pieces of the world’s energy mix, and governments worldwide are putting increased pressure on companies within the sector to reduce the amount of emissions created during the production process.
In the U.S., for example, the Environmental Protection Agency is set to issue tighter emissions legislation over the course of the next year. The cost to comply with these new standards, in addition to other international emissions rules, is increasing the interest from oil and gas companies to explore new and effective clean technology processes that can viably reduce carbon emissions.
Carbon Capture Today
One meet-in-the-middle technique currently being researched and tested is carbon capture. Despite almost $3.4 billion in Department of Energy financial backing, the U.S. had the largest number of projects cancelled or put on hold in the last year, according to the Global CCS Institute.
Eight projects, including ones funded by companies such as Shell and BP, have been delayed or cancelled. The reasons vary from lack of funding and/or going over budget to lack of governmental policy and public support.
Despite this, there are promising projects currently in the works. Shell recently received funding from the government of Alberta, Canada, to begin construction on its Quest Project, a CCS plant near the Alberta oil sands.
Chevron’s Gorgon Project is the only project in Australia currently in the execution stage. These projects have the potential to reduce the negative impact on the environment and allow for facilities to comply with government emissions mandates.
Most of the current projects use a method of CCS known as injection, which is not without its challenges. Though this is the primary method of CCS, it is also the most controversial.
In an injection project, the captured carbon is injected into the ground for permanent storage, often into saline formations or coal seams that can’t be mined.
It also has been used for EOR in declining oil fields. Injection is an expensive process, usually costing between $0.50 and $8 per ton of carbon injected, plus additional costs for monitoring. Injecting the captured carbon also creates concerns about earthquakes, acidified waters, and CO2 leakage.
For these reasons, many doubt that injection will ever become a widespread solution without strong governmental policy in place supporting it.
Another method of carbon capture known as mineralization captures carbon as effectively as injection but without the high cost or potential side effects. After the CO2 and other harmful greenhouse gasses are captured, they are converted into mineral byproducts. These byproducts can be stored without the danger of CO2 leaks or sold to reduce the costs of implementing a carbon capture solution. This makes mineralization technology less costly to implement and easier to do in the current political environment.
Skyonic is the first company to secure a U.S. patent for a carbon-capture and mineralization process. The technology, called SkyMine, captures and mineralizes CO2 emitted from flue stacks into marketable byproducts, including sodium bicarbonate, hydrochloric acid, hydrogen chloride, chlorine, and hydrogen. Because it captures CO2 as solid carbonate compounds, there is no concern over earthquakes, groundwater contamination or leakage.
How Mineralization Works
The process is divided into three parts: gas handling, absorption, and electrochemical production. In the gas handling phase, the hot flue gas is cooled to room temperature, harvesting heat and water while heavy metals like mercury are removed. The harvested heat is used to undertake the cost of chemical production while the water is reused.
In absorption, the now-cooled flue gas is scrubbed to remove the CO2 and acid gases such as SOx and NOx. In a reaction with sodium hydroxide, the CO2 forms sodium bicarbonate, and the acid gases form sulfate and nitrate salts. The cleaned flue gas is then returned to the exhaust stack, now free of harmful chemicals and greenhouse gases.
In electrochemical production, a feed of salt, water, and electricity is used to create the sodium hydroxide that will be used in the absorption process as well as hydrogen and chlorine.
In contrast to many other forms of carbon capture, SkyMine captures CO2 as a stable solid, sodium bicarbonate, more commonly known as household baking soda. Because of the low concentration of acid gases, the bicarbonate is of unusually high purity, guaranteeing simple reuse or disposal. Other byproducts are easily sold to market.
Economics Of Mineralization
The process is the only carbon capture mineralization technology that profitably captures CO2 and converts it into marketable byproducts. There are a number of revenue streams available to plants using this technique, starting with the byproducts, which can be sold for a profit. Another option is to convert the chlorine produced to hydrochloric acid, which can be resold for use in applications such as enhanced oil recovery. There also are revenue opportunities available from SOx, NOx, and CO2 credits, upon certification.
|Skyonic’s lab facility in San Antonio, TX, tests the SkyMine process, removing carbon dioxide and other hazardous pollutants from the flue stack to be captured and converted into salable byproducts. (Images courtesy of Skyonic)|
In addition to the revenue streams, there are cost savings within the process itself. The primary costs associated with the process, which include salt, water, electricity and freight, are all affordable elements.
Salt appears abundantly in nature and is relatively inexpensive compared to the outputs produced. Most, if not all, of the water required for the process can be harvested from the flue gas. Chemical production can occur during off-peak periods when electricity is cheaper. There also is no need for an energy-intensive evaporation step, which helps reduce costs.
The SkyMine process also is relatively inexpensive to install. It can be easily retrofitted to existing structures, eliminating the need for costly remodeling. Instead, Skyonic builds the facility next door and pipes the flue gas emissions into it for scrubbing. This helps keep the initial costs for implementing carbon-capture technology low.
|The primary inputs of the SkyMine process are salt, water, and electricity, which can all be obtained relatively cheaply. The outputs can then be sold for a profit to offset costs.|
Skyonic has been testing its technology on a small scale for several years now. It will begin building the first commercial-scale carbon-capture mineralization plant in 2012. The plant, located at one of the largest cement plants in Texas, is designed to capture 75,000 metric tons per year of CO2 and is expected to reach this goal within two years.
|SkyMine profitably captures carbon dioxide and converts it into marketable byproducts.|
With greenhouse gas emissions on the rise, companies across the globe are trying to find an economic way to reduce their harmful emissions. This new solution process is a scalable, profitable, and effective solution for many industries to reduce CO2 and other harmful emissions.
Editor’s Note: This is the on-line, expanded version of the article “Carbon Mineralization Reduces Cost Of Emissions Compliance” that appeared in the January 2012 issue of Hart’s E&P magazine.