Archive for the ‘Carbon Capture & Sequestration’ category

Green Off-Patent Report (Powered by Cleantech PatentEdge)

April 20th, 2012

Our Green Off-Patent Report provides selected highlights of green patents which completed their 20-year term and expired within the last week or so (assuming the patentee paid all requisite maintenance fees; U.S. patents require payment of fees 3 1/2, 7 1/2, and 11 1/2 years after issuance to stay in force).

Many of the green technologies in use today are off-patent, i.e., the patents covering the technologies have run their 20-year term and expired.

Knowing which technologies are off-patent is important because those technologies are in the public domain and can be exploited by anyone.  It’s also interesting because it provides a window into what was cutting edge technology twenty years ago.

The green off-patent searching is performed by Cleantech PatentEdge™.

U.S. Patent No. 5,354,477 (Water Purification) entitled “Low Molecular Weight Amines and Amine Quaternaries for the Removal of Soluble Organics in Oil Field Produced Water.”  The patent describes a method for removing hydrocarbons from water by injecting low molecular weight amines and preferably amine quaternaries with strong acids into an oil and water mixture to remove oil based salts.  Filed April 7, 1992; issued October 11, 1994; expired April 7, 2012.

U.S. Patent No. 5,324,433 (Soil/Water Restoration) entitled “In-situ Restoration of Contaminated Soils and Groundwater.”  The patent describes a method for removing and stabilizing in-situ soluble heavy metal contaminants from soil and groundwater by injecting an aqueous solution of naturally occurring ions.  The solution solubilizes the heavy metals into solution where they can be removed.  Filed April 16, 1992; issued June 28, 1994; expired April 16, 2012.

U.S. Patent No. 5,261,970 (Photovoltaic Cells) entitled “Optoelectronic and Photovoltaic Devices with Low-Reflective Surfaces.”  The patent describes photovoltaic devices with low angle ‘V’ shaped grooves on the target surfaces.  The grooves increase the efficiency of the devices by promoting internal reflection of light from the target surface at the interface of the coverglass.”  Filed April 8, 1992; issued November 16, 1993; expired April 8, 2012.

U.S. Patent No. 5,260,588 (LEDs) entitled “Light Emitting Diode.”  The patent describes a light emitting diode formed as reverse mesas with mirrored sloping surfaces which reflect light in the direction of the light emitting diode surface, improving the efficiency of each diode.  Filed April 14, 1992; issued November 9, 1993; expired April 14, 2012.

U.S. Patent No. 5,317,979 (Greenhouse Gas Emissions Reduction) entitled “Method and Apparatus for the Complete, Dry Desulphurization of Combustion Waste Gases Comprising SO2 and Dust.”  The patent describes a method for removing SO2 from the combustion waste gases of coal dust.  The process includes heating the gas quickly to a temperature below the sintering temperature of the fly ash, then cooling the gas to a temperature where the distance between the temperature and the dew point is low and is below 25 degrees C.  This binds the SO2 gas to the ash, cleaning it from the combustion waste gas.  Filed April 16, 1992; issueed June 7, 1994; expired April 16, 2012.

David Gibbs is a contributor to Green Patent Blog.  David is currently in his third and final year at Thomas Jefferson School of Law in San Diego.  He received his undergraduate degree in Geology from the University of California, Berkeley.

DFC by FuelCell Energy: Is Clean Coal on the Horizon?

November 16th, 2011

FuelCell Energy is a Danbury, Connecticut, manufacturer of ultra-clean fuel cell power plants. Their Direct Fuel Cell (DFC) systems are currently producing electricity at more than 50 locations worldwide and have generated over 850 million KWh of power.

FuelCell was recently named by the Department of Energy as the recipient of a $2,994,108 award to utilize its DFC power plant to capture carbon emitted from a conventional coal fueled power plant.

The DFC utilizes FuelCell’s patented hybrid fuel cell system.

FuelCell owns U.S. Patent No. 6,356,290, entitled “High-Efficiency Fuel Cell System” (’290 Patent). The ’290 Patent describes a carbonate fuel cell system that produces electricity through a series of chemical reactions.

Heat produced from the reactions can be used to drive an unfired turbine generator. Figure 1 of the ’290 Patent depicts a heat engine (3), shown as a turbine generator, having a gas compressor (3A), and a gas decompression section (3B). By using the exhaust heat from the carbonate fuel cell reaction to drive a turbine, the plant is able to increase its overall energy output and efficiency.

Figure 1:


Fuel cell technology is efficient because it produces energy without going through the combustion process. Rather, fuel cells use an electro-chemical process to produce electricity and heat.

As a result, unlike conventional combustion based power plants, there are no harmful NOx’s or SOx’s produced. Learn more about fuel cells here and here.

The electro-chemical process used in the DFC fuel cell, based on the ’290 Patent, involves three chemical reactions depicted below:

Reaction One (Internal Reforming):  CH4 + 2H2O –> 4H2 + CO2

Reaction Two (Anode Reaction):  4H2 + 4CO3 –> 4H2O + 4CO2 + 8e-

Reaction Three (Cathode Reaction):  2O2 + 4CO2 + 8e- –> 4CO3

The first reaction takes a fuel source such as methane and combines it with steam to produce hydrogen gas and CO2. The hydrogen gas produced in the first reaction is combined with a carbonate in the anode reaction to produce water, CO2 and electrons (electricity).

The third reaction (cathode reaction) uses oxygen, CO2 and electrons to produce a carbonate and heat. The carbonate is then used in the anode reaction. The heat produced in this reaction is used to drive a turbine generator.

FuelCell’s DFC technology may be able to utilize flue gases from a fossil fuel power plant, such as a coal power plant, for use in the above process. Flue gases can be concentrated so that the CO2 can be separated from the remaining air and NOx gases.

The air and CO2 can be used in the cathode reaction. The CO2 from both the flue gases and the fuel cell reactions can be collected, stored and sold in either gas or liquid form.

According to a recent FuelCell Press Release:

FuelCell Energy’s carbonate fuel cell technology separates and concentrates CO2 as a side reaction during the power generation process. DFC carbon capture research conducted by FuelCell Energy has demonstrated the DFC is a viable technology for the efficient separation of CO2 from a variety of industrial facility flue gases such as cement plants and refineries. In addition to the carbon capture, the research also verified that DFC technology is capable of destroying some of the nitrogen oxide (NOx) emissions in flue gas streams, thus, reducing the cost of NOx removal equipment. This award from the DOE will advance DFC carbon capture technology further by funding research to assess the capability of DFC technology to seperate the CO2 within the flue gas emitted by existing coal fired power plants in a cost-effective manner.

A Department of Energy Press Release states the Department’s goal for FuelCell’s award is to achieve at least 90 percent CO2 capture from flue gas of an existing plant with no more than a 35 percent increase in the cost of electricity produced.

FuelCell states, “Technology currently in use to capture CO2 from the emissions of coal fired power plants are energy-intensive with high operating costs. DFC power plants potentially represent an efficient and cost-effective approach to separating CO2 while generating ultra-clean power rather than consuming power, as required by current CO2 capture technologies.”

If FuelCell is able to caputure CO2 from a coal plant while producing excess electricity, it will represent a dramatic departure from current carbon capture systems, which require large amounts of energy and are net energy consumers. FuelCell’s DFC may make the illusive goal of efficient clean coal a reality.

David Gibbs is a contributor to Green Patent Blog.  David is currently in his third and final year at Thomas Jefferson School of Law in San Diego.  He received his undergraduate degree in Geology from the University of California, Berkeley.

CO2 Effects Not So Nice? Use it Twice, Says Carbon Sciences

February 8th, 2010

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Carbon Sciences is a Santa Barbara, California company that has developed a proprietary process to recycle carbon dioxide emissions into gasoline and other liquid fuels.

The company breaks down CO2 and extracts the carbon atoms to make new hydrocarbon chains.  According to its web site, Carbon Sciences’ process requires less energy and is more scalable than previous known techniques, which used expensive inorganic catalysts.

The key to the process is a multi-step biocatalysis that uses organic biocatalysts.  The company’s biocatalytic method uses inexpensive, renewable biomolecules to catalyze certain chemical reactions required to transform CO2 and water into fuel molecules.

Through nano-engineering of the biocatalysts and efficient process design, Carbon Sciences can operate these catalysis steps on a large industrial scale.  In particular, the company’s smart particle technology provides improved encapsulation of the enzymes that prolongs their effective lives and allows them to perform many reaction cycles.

The major components of the process are a CO2 Flue Gas Processor, a a Biocatalyst Unit, a Biocatalytic Reactor Matrix, a Filtration system and a conversion and polishing unit.

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The Biocatalytic Reactor Matrix is the heart of the process.  It is here, in a matrix of liquid reaction chambers, that the large quantities of biocatalysts perform the multi-stage breakdown of CO2 and transformation to hydrocarbons.

The company’s CEO, Byron Elton, told me that Carbon Sciences has filed four as yet unpublished patent applications directed to its CO2 recycling process.  Elton expects the company to file 4-6 more new patent applications this year. 

Carbon Sciences owns U.S. Patent Application Publication No. 2008/0277319 (’319 Application), entitled “Fine particle carbon dioxide transformation and sequestration.”  According to Elton, the ’319 Application covers the company’s initial forays into carbon capture and sequestration.

The ’319 Application is directed to methods and systems for breaking down carbon dioxide into micron- or sub-micron-sized particles, classifying or separating out the particles of a desired size and reacting those particles to form mineral carbonates.

Carbon Sciences’ technology extends into several aspects of CO2 capture, sequestration and recycling, including advanced chemical processes that can use flue gas and brackish water to capture CO2 emissions and scrub it to yield pure CO2.

Because the market for gasoline and liquid fuels is likely to remain quite large for some time, Carbon Sciences’ recycling process provides an interim carbon mitigation option:  use the CO2 molecule twice.

C12 Energy (Continued): Harvard’s International Patent Application Provides More Clues About Stealth Startup

March 11th, 2009

In yesterday’s post, I wrote about C12 Energy (C12), a Cambridge, Massachusetts startup that is apparently working on processes for capturing carbon dioxide by increasing the alkalinity of the ocean, thereby enhancing its ability to absorb and store carbon dioxide.  

I noted that there was no publicly available U.S. patent or published application covering C12′s technology, though the company’s president and chief technology officer, Dr. Kurt Zenz House, published an article in the journal Environmental Science & Technology describing his carbon capture method.

An alert reader pointed out that Dr. House’s CV is available through his homepage, and the CV has a “Patents Filed” heading, under which it lists “Carbon Dioxide Capture and Related Processes” and states:

Primary inventor of a novel chemical process that removes CO2 from the atmosphere and stores it permanently-International patent filed by Harvard University

Indeed, after shifting my focus from U.S. patents and applications to an international search, I was able to locate House’s patent application.  International Application No. PCT/US2007/010032 (’032 application) was filed April 26, 2007 with the World Intellectual Property Organization (WIPO) and published on February 14, 2008 as WO 2008/018928

The ’032 application lists the owners as Harvard (where Dr. House got his Ph.D.) and the Penn State Research Foundation and claims priority to two U.S. provisional applications (provisional applications are essentially one-year placeholders which are not examined or published by the U.S. Patent & Trademark Office).

The ’032 application describes and claims the carbon capture methods discussed in House’s journal article.  Claim 1 broadly recites the invention:

1.  A process for capturing carbon dioxide comprising:

providing water;

processing the water to generate acidic solution and alkaline solution;

neutralizing the acidic solution; and

capturing the carbon dioxide from a source of carbon dioxide with the alkaline solution.

One intriguing aspect of the ’032 application is the synergy with fuel cell technology it claims.  Claim 33 recites an extension of the basic process wherein iron ions produced by neutralizing the acidic solution with reactive species provided from a rock and/or mineral source are oxidized in a fuel cell reaction to produce electricity.

Claim 15 recites another variation whereby the water processing step (to generate acidic solution and alkaline solution) of claim 1 is performed by electrolysis, and the electrolysis produces a halogen gas, a hydrogen gas, and sodium hydroxide.  The resulting halogen gas and hydrogen gas are then reacted in a fuel cell to form the acidic solution and produce electricity.

Another method, recited in claim 36, captures CO2 by reacting it with sodium hydroxide and generates chlorine gas and hydrogen gas.  The hydrogen gas may be oxidized with oxygen either in a hydrogen gas turbine (claim 43) or in a fuel cell (claim 44), in each case forming water and electricity.

The written description of the ’032 application states:

Another benefit of the process is that some of the steps (e.g., the formation of HCl in a fuel cell) produce useful energy that can be used in other aspects of the process.  The energy may be generated, for example, from hydrogen production during the dissolution of reduced minerals (e.g., minerals comprising iron), electricity production through a fuel cell (e.g., FeCl2-HCl-O2; FeCl2-O2), or heat generated during the dissolution of silicate rocks and minerals.  Because the energy cost is a large component of the total cost for most conventional CO2 capture and storage technologies, the low energy cost of the process represents a valuable technological advancement. 

Dr. House’s article together with publication of the ’032 application provides some interesting clues about C12′s technology and business model.  Whatever the company is planning, it wants to do it just about everywhere:  the ’032 application designates countries and regions for patent protection all over the world, including the U.S., Canada, Europe, Eurasia, Africa, China, Japan, Australia and many others.

Unpublished, Unpatented, but not Unimportant: C12 Energy May Use the Ocean to Capture CO2

March 10th, 2009

I’ve realized that limiting my posts to subjects for which there is publicly available intellectual property to discuss sometimes causes me to pass on reporting important technology. 

Thus, a new series – “Unpublished, Unpatented, but not Unimportant” – in which I will periodically report on clean technology developments for which I can’t locate a published patent application (in the U.S., patent applications are published 18 months after they are filed) or an issued patent. 

C12 Energy (C12) is a Cambridge, Massachusetts startup that recently secured a $4.5 million round of funding led by Sequoia Capital.  C12 has not made its plans public, but an article by the company’s president and chief scientist published in the journal Environmental Science & Technology is fueling speculation about a grand plan for carbon capture and sequestration.

Kurt Zenz House’s article, entitled “Electrochemical Acceleration of Chemical Weathering as an Energetically Feasible Approach to Mitigating Anthropogenic Climate Change,” describes a process of capturing carbon dioxide from the atmosphere by enhancing the solubility of carbon dioxide in the ocean.

House’s approach involves boosting the alkalinity of the ocean by electrochemically removing its hydrochloric acid and neutralizing the acid through reactions with silicate minerals.  The increase in alkalinity enhances the ocean’s ability to take up atmospheric CO2.  

Carbon dioxide will then dissolve into the ocean and be stored as bicarbonate ion “without further acidifying the ocean.”  According to the article, over time the carbon will be permanently stored in the ocean:

On timescales of hundreds of years or longer, some of the additional alkalinity will likely lead to precipitation or enhanced preservation of CaCO3, resulting in the permanent storage of the associated carbon, and the return of an equal amount of carbon to the atmosphere.

The article explains that the method is “equivalent to the electrochemical acceleration of the Earth’s natural chemical weathering process.” 

I spoke to Dr. House today and asked him if he has filed a patent application on the process.  He told me that C12 is in stealth mode and he couldn’t comment on the company’s IP strategy.  Given the article’s internet publication date of November 7, 2007, I wouldn’t be surprised to see a patent application publish some time between now and early May.

Dr. House has a Ph.D. in Geoscience from Harvard University (see his homepage here).

Vattenfall Builds Pioneering Clean Coal Plant

October 27th, 2008

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Matter Network recently reported that the first coal-fired power plant constructed to incorporate carbon capture and sequestration (CCS) technology went online last month in Germany.  Vattenfall, a Swedish power company, built the plant and will operate it as a pilot.

The system captures carbon dioxide from the plant’s flue gas, compresses it into a liquid and stores it underground.  According to Vattenfall’s web site, most of the carbon dioxide will dissolve in reservoir water and slowly mineralize (see the project description here).

Vattenfall owns over 50 international patents and published applications directed to power generation technology.  Much of the older technology relates to nuclear power, including cooling systems for nuclear power plants.

The company’s recent patents cover removal and separation of chemicals from water or flue gas, including WO 2004/112943 (Boron separation and recovery), WO 2004/026486 (Assembly for operating hydrocyclones, in particular for flue-gas desulphurisation plants), WO 2003/074430 (Nitrate removal), WO 2002/040406 (Process and apparatus for removal and destruction of dissolved nitrate), and WO 2001/027593 (A method and device for measuring, by photo-spectrometry, the concentration of harmful gases in the fumes through a heat-producing plant).

While the Vattenfall plant and CCS process produces almost zero carbon emissions, the Matter story points out that compressing and transporting carbon dioxide requires a lot of energy. 

CCS may be an important transition technology, particularly in countries that get most of their power from coal plants, but processes that chemically transform carbon into innocuous materials are probably better long-term solutions than systems that require compression and transport of CO2.

Chevron to Pay California Drivers $48M to Settle Unocal Patent Suit

September 1st, 2008

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Standards-setting organizations (SSOs) are industry or government groups that develop and publish uniform technology standards to ensure product quality and interoperability for new technologies.  Although rules vary among SSOs, generally private industry participants in the process have a duty to disclose patents or patent applications they own that relate to the industry standards under development. 

Failure to disclose relevant intellectual property can expose a company to legal liability (both through private lawsuits and by government agencies such as the Federal Trade Commission (FTC)) and render the company’s patents unenforceable. 

Companies that do disclose their patents early in the standards-setting process are more likely to see their patented technologies become the industry standards.  Often, companies in this situation are required by the SSO to agree to provide licenses to their technology under reasonable and non-discriminatory terms.

When the 1990 Clean Air Act mandated that gasoline be reformulated to reduce evaporation and cut ozone-forming and toxic air pollutants, the California Air Resources Board (CARB) worked with the oil and gas industry to develop reformulated gasoline (RFG) standards. 

After the RFG standards were issued, the U.S. Patent & Trademark Office (PTO) granted several RFG patents (which had been pending during the standards-setting process) to Union Oil Company of California (Unocal). 

In 2005, after Chevron Corp. (Chevron) bought Unocal, California consumers brought a class action against Unocal alleging that it had failed to disclose its pending patent applications during the standards setting process and had represented its technology as “non-proprietary” (the FTC also filed a complaint against Unocal in 2003). 

The class action complaint alleged that Unocal had manipulated and deceived the CARB and other industry groups into adopting RFG standards that overlapped with the undisclosed patent applications.

The patents at issue include U.S. Patent Nos. 5,288,393, 5,593,567 and 5,653,866, which relate to methods for producing gasoline having reduced nitrogen, carbon monoxide and other hydrocarbon emissions.  Unocal has since dedicated each of these patents to the public so they can no longer be enforced.

Last month, Judge Christina A. Snyder of the U.S. District Court in Los Angeles issued a preliminary approval of a settlement of the class action (settlementorder.pdf).  By the terms of the settlement, Chevron will pay $48 million to a class of consumers defined as all consumers who purchased CARB-compliant reformulated gasoline in California between January 1995 and August 11, 2005.

Obviously, it is important for patent owners participating in standards-setting activities to consult a patent attorney to review the disclosure obligations imposed by the SSO and analyze the company’s patent portfolio to determine whether patents and applications need to be disclosed to the SSO.

This issue is almost certain to come up again as new energy technologies emerge and mature.  Just last week, Matter Network reported that the Roundtable on Sustainable Biofuels is developing the first international standard for biofuel production.

Suzanne Badawi Explores the “Global Warming Insurance Claim”

July 25th, 2008

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Suzanne Badawi is a partner and insurance litigator at Luce, Forward, Hamilton & Scripps and the head of the firm’s Climate Change & Sustainable Technology practice.  Her article, “Global Warming: Are You Covered” appears in this month’s California Lawyer magazine.

The article explores whether claims made to defray the costs associated with carbon dioxide emissions will be covered by comprehensive general liability (CGL) insurance policies.  According to Badawi, the answer depends on the wording of the pollution exclusion in the policy and whether carbon dioxide is deemed a pollutant. 

Most CGL policies today have an “absolute pollution exclusion” (APE), which means they provide no coverage for the release of pollutants into the environment.  Not surprisingly, the scope of the exclusion often turns on the question of what constitutes a pollutant.  The article takes the reader through key cases that have ruled on the definition of “pollutant” and notes that the APE has not yet been addressed in the context of carbon dioxide emissions. 

Badawi speculates that the Supreme Court’s 2007 decision in Massachusetts v. EPA, which held that carbon dioxide is a pollutant subject to regulation by the EPA, provides an opening for insurers to argue that the greenhouse gas should be subject to the APE.

I’m always interested in how global warming impacts areas of the law outside of my field, and Badawi’s article is an interesting read.  With all the legal and regulatory efforts to curb greenhouse gas emissions, the article notes that emitters are looking for ways to defray related compliance and litigation costs:

And with that, the “global warming insurance claim” has arrived. 

Georgia Decision on Coal Plant Could Boost Carbon Capture Market

July 16th, 2008

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I depart from intellectual property issues today to report on a significant environmental law decision out of Georgia that could have major implications for the carbon capture and sequestration market. 

On June 30th, the Fulton County Superior Court overturned a decision of the Georgia Environmental Protection Division (EPD) issuing a permit to Longleaf Energy Associates, LLC (Longleaf), a shell company owned by LS Power, to build a 1200 megawatt coal-fired power plant in Early County, Georgia.  (see the Rethink Georgia press release here and the greentech media story here)

The key to Judge Thelma Wyatt Cummings Moore’s decision (longleaf-decision.pdf) was the Supreme Court’s ruling last year in Massachusetts v. EPA that carbon dioxide is an “air pollutant” subject to regulation under the federal Clean Air Act (Act).

Under the Act and the EPA’s regulations, certain areas of the country designated “attainment areas” must keep pollution levels within prescribed air quality limits (Early County is once such attainment area).  This includes the requirement that any new “major emitting facility” (a term that includes fossil fuel-fired electric plants such as the Longleaf facility) obtain a permit and abide by the emissions limitations outlined in the permit.

Major emitting facilities like the Longleaf facility must incorporate the “best available control technology” (BACT) to limit pollution.  This BACT analysis entails a determination by the permitting authority of the maximum reduction of each regulated pollutant for the particular project.  The emissions limitations in the facility’s permit must be set based on that “best available control technology.”

The Sierra Club and the Friends of the Chattahoochee (Petitioners) challenged the Georgia EPD’s decision to issue a permit for construction of the Longleaf plant.  After an EPD administrative law judge (ALJ) dismissed the challenge and upheld the permit, the Petitioners appealed to the Fulton County Superior Court alleging that the ALJ erred by making no findings on, among other things, carbon dioxide emissions, including failing to require that the EPD do a BACT analysis.

The court agreed with Petitioners and found the ALJ’s decision erroneous for deferring to the EPD’s inadequate permitting process.  In particular, the court found that, because carbon dioxide is an air pollutant under the Act, a BACT analysis should have been conducted by the EPD to set a carbon dioxide emissions target for the Longleaf project.

The immediate result is that the Georgia EPD will have to conduct a carbon dioxide emissions analysis, and Longleaf and its developers, LS Power and Dynegy Inc., will have to comply with the resulting emissions target to build the power plant. 

If other states follow the Georgia ruling, future coal-fired power plants will have to be designed to reduce carbon dioxide emissions if they are to gain regulatory approval.  One way to do that is to equip new plants with carbon capture and sequestration technology.  Thus, the decision could increase the demand for the technology and be a welcome boost to the carbon capture industry.

Capturing Carbon Dioxide from the Air

February 19th, 2008

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This discussion was supposed to be part of Green Patent Blog’s Best of 2007 post, a project that got lost amid holiday festivities.  So here it is now: 

While the important effort to reduce or eliminate greenhouse gas emissions continues, removing previously emitted greenhouse gases from the air may become necessary depending on how dire the climate change problem really is.  That’s what Columbia University physicist Klaus Lackner’s technology does.  Dr. Lackner is a named co-inventor on at least three patent applications and one issued patent relating to capturing and recovering carbon dioxide from the air. 

U.S. Application No. 2006/0051274 is directed to an apparatus for capturing CO2 called a laminar scrubber.  The laminar scrubber is a wind collector having a set of flat plates, or lamellae, arranged centimeters apart from each other.  Air is sucked through the plates by a natural pressure gradient, wind or convection.  A hydroxide based sorbent flows down the plates while a layered airflow passes through the thin spaces between the plates.  The contact between the air and the sorbent causes a chemical reaction which removes the carbon dioxide.  The patent application contemplates groups of laminar scrubber units combined in larger superstructures – what some of the press reports have called synthetic trees. (read articles here and here)

U.S. Application Pub. No. 2007/0187247 covers the next steps of the process, namely recovering the CO2-filled sorbent and separating the CO2 from the sorbent liquid.  The electrochemical methods of the application are more direct and energy efficient than prior art processes, which require transferring carbonate ions to calcium carbonate and then burning off the calcium.  Lackner’s process uses electrodialysis, in which the sorbent flows through cells having compartments separated by membranes.  At one end of the cell is a positively charged anode, at the other a negatively charged cathode.  The membranes also are charged to allow the passage of only positive ions or negative ions between compartments; a positively charged membrane traps positive ions while a negatively charged membrane traps negative ions.  Positive ions flow toward the cathode, negative ions flow toward the anode, and the ions are trapped in compartments along the way based on the type of membrane separating each compartment.  This structure separates the sorbent solution into hydroxide and CO2 by trapping and concentrating the negatively charged hydroxide ions in a compartment bounded by a negatively charged membrane.  The CO2 is released in a concentrated, pressurized stream, which can be sequestered or used for other purposes.